# Goal Zero Solar Charging of Eneloops



## Bolster (Jun 4, 2012)

The Goal Zero “Guide 10 Plus Adventure Kit” is often recommended here at CPF for the solar charging of AAs and AAAs. This kit consists of the Guide 10 Plus* power pack which contains 4AAs, and the Nomad 7-watt solar panel. 

I’ve been curious if its charge rate is acceptable for standard Eneloops. GZ confirmed in an email that the maximum charge rate (using the 7-watt panel) is 1000 mA at 1.5-1.6v in full sun. The mA appears to be in the sweet spot of 1/2 C for Eneloops. 

Couple of questions: 

1) The voltage is 1.5-1.6, is that OK? It’s a bit higher than I see on my Maha charger. 

2) Wouldn’t this charge be too hot for AAAs? Yet GZ supplies an AAA adaptor. Seems that would be charging AAAs at 1-1/4 C, wouldn’t that be too much? 

3) GZ says that this kit recharges 4 cells in 3-4 hours. But wouldn’t empty Eneloops be charged in closer to 2 hours, given max sun? 

4) When the cells are full, a flashing LED goes to solid green. (I don’t know how that’s triggered.) Is my assumption correct: that IF four cells of equivalent discharge are inserted, and IF the user quickly removes the cells upon the charging LED indicating it’s done (showing solid green), that there should be no ill effects to charging AA Eneloops with this kit? Or can those of you with more knowledge and experience see problems here? 

*There’s an older “Guide 10” without the plus, that’s very similar except its USB output is .0.5A rather than the 1.0A of the “Guide 10 Plus.”


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## Bolster (Jun 5, 2012)

Bump, requesting info...any help?


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## Bolster (Jun 9, 2012)

This GoalZero kit just hit sub $100 on Amazon a couple days ago. 

Still looking for some input.


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## Beacon of Light (Jun 9, 2012)

Would like this mainly for the ability to charge from USB, but not for $100... Are all cells charged individually?


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## Bolster (Jun 9, 2012)

Hi, Beac. 

Yes, do-it-yourself electricity is expensive. Eneloop sells an inexpensive USB charger, maybe that would fit the bill?

No the cells are not charged individually in the GZ. 4 at a time. And as far as I can tell, no termination or any "fancy" stuff--hence my questions. If I need to use this during backpacking or emergency situations, I want to be certain I'm not killing cells!


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## reppans (Jun 9, 2012)

Hello Bolster, me again. I not up on all the technical details so this is just my opinion, but it doesn't seem like there are a lot of other GZ owners out there.

I've run Eneloops through mine and does charge in 3/4 hours... that's a reasonably long time given the MH C9000 can do it in about 2 so I wouldn't worry about overcharging. While the panel might be able to put out 1000 mah per cell in perfect sunlight, there's efficiency losses in the Guide 10 that's not present in the Maha, for example. Also to reach that level of efficiency, I think you would have to track the panel to the sun every few minutes to ensure perfect perpendicular alignment. If you're worried about overcharging AAAs, just cover up half the panel surface area. The Eneloops are a pretty tough cell, I think you are over-analyzing this.

Also, I personally wouldn't recommend the GZ for backpacking use as it is bulky and heavy. I like the Powerfilm 6xpanel, 4xAA charge when size and weight are concerned. If you hike/camp under any kind of tree canopy, as all of it is here on the East coast, solar is just not going to be practical, except as emergency backup... hence the ultralight/ultraportable Powerfilm recommendation. It's about half the efficiency but a third the size and weight.


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## Bolster (Jun 10, 2012)

Thanks Reppans, much appreciated. Here in So Cal the sun can be intense; I need to get an old set of Eneloops, discharge them, and see how long it takes to top them off. Encouraged that I won't be burning them up. But you do agree that one should pull the cells out as quickly as you get the "full" signal? And do you know by chance what signals "full" to the GZ Guide 10? Just curious. 

The Powerfilm is nice indeed. I understand its technology, while less efficient in bright sunlight, is _more_ efficient if there's cloud cover! Also the flexibility would be a big plus.


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## reppans (Jun 11, 2012)

Bolster, if I recall correctly, the green light will illuminate before the Eneloops are fully charged - I think around 70-80% of capacity as tested by the Maha discharge function. I don't know the charging program and how it terminates at full charge, but you could measure it with multimeter testing from when the green light starts and then at 1/2 hr intervals to seem how much more juice goes in after it turns green.

I don't have the same problem as you in on the East coast, I'm always waiting for it to finish and it's hard for me to get enough consistent light, in a normal day, to ever worry about over-charging. If I were in your shoes, and was worried about the Eneloops, and couldn't retrieve the cell in the allotted time, I'd simply know the E/W path of sun and position the solar panels for 3-4 hrs of reasonably perpendicular sunlight and so that at 4+ hrs the sun is hitting at a pretty step angle to the panels... these things quickly loose efficiency at less than perpendicular angles. 

Powerfilm has good "efficiency" chart on their website FAQ and it seemed pretty accurate with my testing.


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## Bolster (Jun 12, 2012)

reppans said:


> ...the green light will illuminate before the Eneloops are fully charged - I think around 70-80% of capacity as tested by the Maha discharge function. I don't know the charging program and how it terminates at full charge, but you could measure it with multimeter testing from when the green light starts and then at 1/2 hr intervals to seem how much more juice goes in after it turns green.



Good point; yes, I should test that. 

I was somewhat alarmed when I put 4 eneloops into the charger (unknown state of discharge, but thought they were well discharged) and I had the solid light in 60 minutes. (Bright clear day.) But yes, rather than relying on by-guess-by-gosh, I should just do an experiment. Thanks.


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## funkychateau (Jun 12, 2012)

Why not just buy a good charger, with reviews and known characteristics, that has a DC input jack, then buy a solar panel to go with it? You'd then have the advantage of a "regular" AC/DC charger when you don't want to go solar. 

At $100, you may be paying the middleman quite a premium to bundle these two items together for you.


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## Bolster (Jun 12, 2012)

funkychateau said:


> Why not just buy a good charger, with reviews and known characteristics, that has a DC input jack, then buy a solar panel to go with it? You'd then have the advantage of a "regular" AC/DC charger when you don't want to go solar. At $100, you may be paying the middleman quite a premium to bundle these two items together for you.



In part, because you can't use a charger as a power pack afterwards. Whereas the Guide10 acts as both "dumb" charger and as powerpack that can run or recharge other devices. Outputs 12v and also 5v USB, which is handy.

BUT: you bring up a very interesting point...could I run the Maha via 12v off the 7-watt solar panel??? Hmm...how does the Maha react to having its source interrupted? A dumb charger (like the GoalZero Guide10) shrugs off a shadow falling across the panels and just starts charging again when direct sunlight returns. Would the Maha do that, or shut down? Would I be sustaining damage to the Maha with an undependable power source--which defines solar? (A cloud drifts by and it shuts down.) 

...this is where I wish I were an electrical engineer!! Instinct tells me to run the Maha off something like a 12v deep cycle battery, where the lead acid battery absorbs the intermittent nature of solar but gives me an uninterrupted stream for charging AAs with the Maha.

It may be that a direct solar hookup is only appropriate for a dumb charger.


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## reppans (Jun 12, 2012)

Specs on the Nomad 7 say output is 13-15V, 0.2A... no way is that enough amperage to power the MH.


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## Bolster (Jun 12, 2012)

Didn't even think to look. Maha takes 2A at 12V. Answers that!


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## mousewizard (Jun 12, 2012)

Speaking from experience here: You need at least a 10-watt panel, like the Powerfilm F15-600 to properly drive a little 4-AA basic charger, and that's in full, direct sunlight. The problem is it's rare to have hours of full, direct sunlight. There are always clouds coming along, or a local storm, and they seem to know you're using a solar panel. So they all come and flock to you. If you read the fine print on those "backpackable" chargers, you'll see they're rated only for "full sunlight" and plenty of it. So in my mind the technology is not quite there, especially if you have to carry specialized radios and such.

IMHO, solar panels are best used for "base camp" situations. In that environment, I use 10-20 watts of solar panel to trickle charge a larger battery, like a 12AH SLA battery. Then I use the battery to run a little 4-cell charger. The setup I use has a low-end, 7-Amp solar charge controller in the mix, like the Sunforce 7 Amp controller. At $17 it pretty much automates keeping the battery up and protected. Then you connect your load, like the charger, to the controller and let it make sure you're not over-discharging your battery. You wind up with a miniature, set-it-and-forget-it solar system. Then you just get the adapters you need for the rest of your gear. For example, Motorola commercial-grade talkies have a special plug and require a special 12V "car charger" adapter to charge them. Same goes for Sat phones, etc. 

If you need to recharge just your cell phone and maybe a couple-few AA/AAAs, then the backpackable solar solutions are capable of doing it, but it's much cheaper and lighter to just get a battery pack that charges your iPhone and throw spare batteries in the bag.

If you need to drag a tablet, or laptop, or Ham rig along, then you're back to the base camp solar system.


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## mellowman (Jun 12, 2012)

........


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## Bolster (Jun 12, 2012)

mousewizard said:


> You wind up with a miniature, set-it-and-forget-it solar system.



Sounds ideal. Thanks for the post. I have no idea how to make certain that the solar panel, the charge controller, and the LA battery are of compatible sizes. There must be a formula somewhere that says "if your solar panel is X watts, get a Y amp controller and a battery with Z amp hours."


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## Wrend (Jun 13, 2012)

No real way to do it other than to figure out what your power needs are and what the different components take. If you're going with a deep discharge Pb, get one with at lest twice the capacity potential that you think you'll use per cycle.

I've looked into this pretty extensively myself, and something like this should work for the base camp scenario: Instapark 130W or to save some cash Instapark 50W, both mono-crystalline, and Sunforce 60031 10A digital charge controller, and SLI65AGMDPM 74Ah from BatteriesPlus. This is more of an inexpensive, but capable enough solution. You can of course spend a lot more for something like this if you want to.


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## mousewizard (Jun 13, 2012)

As per the previous poster, you have to work backwards from what you want to do to get the system you need.

OK, so the rules are:


Don't use more than 25% of the capacity of a SLA battery before recharging.
Charge the main battery at .1 to .2 C max. The most common calculation for this is C/8, where C is the Amp-Hour (AH) rating of the battery.
To calculate the panel wattage multiply Amps needed * 14 volts.

So let's say you want to charge up as many as 8-12 AA batteries using a MH-C9000 so you can light up your tent at night too. That puppy draws 2 amps, but only intermittently. It works on one battery, then the next. When I ran it on my bench it was varying between 200ma and 1.8A, so let's just call it an effective 1 Amp Hour (AH) load including resting, top-off, and fiddling with batteries. To charge up a couple sets of batteries could take as much as an hour, but let's say two hours because your friends found out you have a charger so now you have more batteries to deal with. So that's 2AH per day.

To stay within the 25% utilization rule you need to multiply 2AH by four and wind up with an 8AH 12V SLA battery.

Charge rate for that is C/8, so 8AH/8=1A over three solar hours, which is conservative for a solar day. Nets 3AH in to the battery on a 2AH draw, (batteries take in more than they give out) so we're fine there. All we need is a panel and controller that can do 1A.

The panel calculation is 1A * 14V = 14W panel. So you need a 10-20 watt panel. Best to go for 20W although there are 15W solid panels out there. If you use a folding panel everything will still fit in your backpack. Solid panel: Not so much.

You can't buy a solar charge controller below 5-7A, so go with whatever works for you on that point.

My personal kit is two 10W folding panels with a Y connector to hook them up in parallel to the SunForce 7A controller, and a 12AH SLA battery. I use a smaller Maha MH-C401FS 4-Cell AA charger since it draws less than 0.2A when charging four batteries, allowing me to conserve my main battery. This is because I also have to charge Sat Phone, Encrypted Talkie, Cell, Tablet, and batteries for Headlamp, HAM Transceiver, and GPS (can you tell I'm the comms guy?). Not all at once though. I kind of rotate through them as necessary. The whole power kit is about the size of those construction worker lunchboxes that hold the thermos in the top.

For the minimalist, you can make do with just a 10W folding panel, the smallest controller you can find, a 5-6AH SLA battery, and a small 4-Cell charger. You then load the batteries into your gear, or into one of those battery packs that you use to charge a phone or other USB device. The whole shebang will fit into a space of about two large soup cans. While this looks like a bits-and-pieces approach to the integrated backpackable products on the market, the problem is they use 4AAs as the "storage" piece, and that's less than 1AH of capacity so you wind up out of power fairly quickly.


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## Bolster (Jun 13, 2012)

mousewizard said:


> The whole power kit is about the size of those construction worker lunchboxes that hold the thermos in the top.



OUTstanding. Thanks so much for the info, Mouse. You don't happen to have a photo do you?

(PS: Like you, I have ham gear to charge too!)


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## mousewizard (Jun 13, 2012)

Bolster said:


> OUTstanding. Thanks so much for the info, Mouse. You don't happen to have a photo do you?
> 
> (PS: Like you, I have ham gear to charge too!)



Sure. The first one is the kit pulled out of the stuff sack, in travel mode. The paracord bundles shown are tie-downs for the solar panels. The green board is actually painted cardboard and is used to store the cables that go to the solar panels and also holds the charge controller. I found out long ago that cardboard, once painted, lasts an unexpectedly long time. The second is the kit unpacked and set up. The green cardboard folds up so the charge controller sits above the surface and has a chance of surviving spills and leaks and general wetness.

Not shown is the little 4 AA charger I use, a small analog multimeter, and a cheapo analog battery tester that rides along with this stuff.


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## Teobaldo (Jun 13, 2012)

What indicates mousewizard is the correct thing: panel, charge controller and a battery.

I made a review of another battery with solar panel here:

http://www.candlepowerforums.com/vb...r-Power-Battery-Charger&p=3868225#post3868225

Works fine for me and the last week I tested with a Nitecore IntelliCharger I4 with 2x16340 without problems. It weighs little and fits perfectly inside a backpack along with the foldable panel. Exist other alternatives of similar batteries and they seem me very adequate for somewhat portable.

Good luck.


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## Bolster (Jun 13, 2012)

So nice. Wish I owned that. May have to duplicate it. Pls check your PM.


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## mousewizard (Jun 14, 2012)

If you decide to duplicate it, use a better charge controller instead. It's better to have one that manages the load as well as the battery and provides automatic overcharge as well as cuts off the load from the battery if the battery gets too low. With my rig, I wind up using the multimeter to keep tabs on the battery voltage level so I don't draw it down too low. This Morningstar solar controller makes for a better "set it and forget it" rig. Significantly more expensive, but it turns out the cheaper ones are designed to manage car and other flooded batteries and can damage a SLA battery. I just ordered one. 

Guess I need to cut and paint a new piece of cardboard. I think I'll use thicker stock this time. Oh, and the pictures don't show the inline fuse and power plug spliced into the line between the battery and the controller. They were hiding behind the battery at the time the photo was taken. Always have a fuse in there somewhere.

Edit: Changed controller recommendation.


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## eh4 (Jun 20, 2012)

It would cost more up front but otherwise why not go with LiFePO4 battery chemistry instead?
Long life, tolerates deep discharges and high amp discharges, 1/4 the weight, and with enough hours of sunlight in the battery you could jump start a small car with two pounds of LiFePO4, not to mention charge lots of AAs.


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## mousewizard (Jun 21, 2012)

eh4 said:


> It would cost more up front but otherwise why not go with LiFePO4 battery chemistry instead?
> Long life, tolerates deep discharges and high amp discharges, 1/4 the weight, and with enough hours of sunlight in the battery you could jump start a small car with two pounds of LiFePO4, not to mention charge lots of AAs.



Because solar charge controllers aren't set up with the right charging algorithm. LiFePO4 has a different cell voltage than SLA, so that won't work out well.


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## Shadowww (Jun 21, 2012)

mousewizard said:


> Because solar charge controllers aren't set up with the right charging algorithm. LiFePO4 has a different cell voltage than SLA, so that won't work out well.



But there are LiFePO4 batteries which are sold as drop-in 12V battery replacements, they using internal charging PCB that makes sure internal LFP cells are well-maintained.


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## Wrend (Jun 21, 2012)

Pb batteries are pretty cost effective for capacity though. It just depends what your priorities are and how much you're willing to spend to get what you want up and running.


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## mousewizard (Jun 22, 2012)

Shadowww said:


> But there are LiFePO4 batteries which are sold as drop-in 12V battery replacements, they using internal charging PCB that makes sure internal LFP cells are well-maintained.


Got a link? I'd be interested in taking a look. If I can save pounds off my Bug-out kit, so much the better.


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## mousewizard (Jun 22, 2012)

Wrend said:


> Pb batteries are pretty cost effective for capacity though. It just depends what your priorities are and how much you're willing to spend to get what you want up and running.


Yeah, you can go nuts shaving weight. I know one guy that was replacing components on his bicycle to shave ounces. For example, titanium skewers replacing steel ones. He said he stopped when he was spending more than $100 to shave off a single ounce.


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## Shadowww (Jun 22, 2012)

mousewizard said:


> Got a link? I'd be interested in taking a look. If I can save pounds off my Bug-out kit, so much the better.



For example: http://www.a123systems.com/products-modules-lead-acid.htm


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## mousewizard (Jun 22, 2012)

Looks nice, but I can't find a US dealer.

K2 makes something similar, and at least it can be bought. 10AH instead of 7.


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## Kilted (Jun 23, 2012)

Shadowww said:


> For example: http://www.a123systems.com/products-modules-lead-acid.htm



http://voltiopowersolutions.com/alm-12-7-li-ion-lifeo4-lead-acid-replacement-battery
Price is; $125.00
These are actually only 4.6A in a 12v7 SLA form factor.
http://www.endrich.com.tw/html/ezcatfiles/i-web17/img/img/25755/A123_ALM.pdf

Solar charge controllers - Morningstar;
http://www.morningstarcorp.com/en/products

Update; 6/23/12

Do a search on Amazon Tenergy also produces a 12v7a LiFe drop in replacement. Watch out K2 produce two types one with BMS and one with out BMS.

=D~~ Kilted


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## mousewizard (Jun 23, 2012)

Thank you! I knew there had to be a dealer out there somewhere. From what I've read, the 4.6AH will last as long as a 7AH because of the flat discharge curve associated with LiFeO4 batteries. That's good enough for field work at least for me. I can always double up if necessary.

It _is _pricey, tho. Have to calculate the value per ounce I'll be saving and decide if it's worth it.


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## Kilted (Jun 23, 2012)

OK, got a $60 question (about the cost of a SunSaver SS-6). IF you use one of the LpFePo4 SLA replacement batteries WITH BMS is the Solar charge controller actually needed?

=D~~ Kilted


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## Kilted (Jun 23, 2012)

Kilted said:


> OK, got a $60 question (about the cost of a SunSaver SS-6). IF you use one of the LpFePo4 SLA replacement batteries WITH BMS is the Solar charge controller actually needed?
> 
> =D~~ Kilted



I answered my own question. I read the manual and the internal BMS is designed to operate off of what looks like standard AGM Pb SLA charge protocol.

=D~~ Kilted


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## Kilted (Aug 28, 2012)

Check out this LiFePO4 12v 12A battery;

Powerizer LiFePO4 Battery: 12V 12Ah (144Wh, 30A rate) with PCM - Replace SLA with 5 times longer life

http://www.batteryspace.com/Poweriz...V-12Ah-144Wh-30A-rate-with-Balancing-PCM.aspx

Dig around their site any they have LiFePO4 solar charge controllers also.

=D~~ Kilted


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## mousewizard (Oct 7, 2012)

Kilted said:


> Check out this LiFePO4 12v 12A battery;
> 
> Powerizer LiFePO4 Battery: 12V 12Ah (144Wh, 30A rate) with PCM - Replace SLA with 5 times longer life
> 
> ...




I finally got around to checking this out. That particular battery has a built-in PCM, which requires a CCCV charging input. Solar controllers for the most part don't do that. I believe a couple of high-end MPPT controllers will, but nothing small for backpacking. The solar controller on that site for LiFePO4 is designed to go onto a battery they have that does not have a PCM. So it's just dumping energy into the cell and there's no balancing or other protection happening. That means the very expensive battery is more likely to go bad, and sooner. They would need to put together a solar charge controller with balancing circuitry and a battery with a sensing connector to match. That would lead to a very complex system for a very tiny market.


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## RandomFlyer (Oct 14, 2012)

I have a Goal Zero Nomad 27W charger and came to a similar conclusion about using a battery to keep charged as the primary source to recharge other devices. Their lead acid power packs are not ideal for a lightweight kit.
I've been waiting to see their Sherpa replacement and it looks like they are starting with a 50 watt Li-Ion, supposedly November 1st 2012 (after a few delays). They are calling it a recharger instead of a power pack. It certainly has a few ways to connect. 
14 oz. weight and will cost $250. After reading some of the comments it looks like they are working on a 100 watt version as well. 
http://www.goalzero.com/sherpa50.html 
http://www.goalzero.com/blog/2012/01/10/goalzeronewproduct/


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## mousewizard (Oct 15, 2012)

Yeah, those look like either 50 teeny watt-hours or a 105 lb brick. Good luck packing that.

Still hunting. Still not finding.


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## RandomFlyer (Oct 16, 2012)

Still hunting here as well. The 100wh version will be more interesting. 

On a separate note, looks like some guy in Israel took your painted cardboard idea a step further and made a bicycle.
http://news.yahoo.com/cardboard-bicycle-change-world-says-israeli-inventor-090732689.html


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## mousewizard (Oct 17, 2012)

Yeah, cute bike. I guess. I prefer all-steel frame, no shocks. But that's just me.

As far as the backpackable power supply is concerned, I've been doing a bunch of noodling on the topic and I've come to the conclusion that it comes down to individual cell management. The discharge curve for a SLA looks like this:






While the discharge curve for NiMH looks like this:




The difference is dramatic, particularly at the 1C rate. With these curves it's now obvious that you can get more useful life out of a smaller NiMH pack than you can out of a larger SLA battery.

So build a pack composed of stacked 10-cell AA battery holders. Longer life, less weight.

The problem comes from charging. You probably can't just dump a charge into the pack overall. Individual cells go bad. This is both a bad thing and a good thing. With a pack you can disassemble, you can manage each cell individually in your charger. So you can swap out bad cells as they're starting to show up.

The expense of all those high-quality AA NiMH cells might be partially offset by the elimination of a solar charge controller. I've charged AA batteries directly off my 10-Watt solar panel using a Maha 4-cell charger that takes 12V. I checked the 12V cable that came with it, and there was no circuitry in the plug that goes to your car socket. This means to me that the charger can handle up to 15 volts and still function properly.

I've got another 4-cell charger on order (manages individual cells instead of pairs of cells) and will be running some bench and field tests to see how it manages without a charge controller. If it does OK, then it's possible to put together a simpler, more manageable, lighter weight unit with good capacity.

More after I get the testing done. Probably take a couple of weeks to get everything in, set up, and data collected.


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## TIP AND RING (Oct 17, 2012)

I've been following this thread. Thanks to everyone who has contributed. I'm looking forward to your findings Mousewizard. I have used a first generation, Maha Accumanager 20 with a 20 watt panel with decent results for charging AA Eneloops. The Maha is using 700ma max with 4 AA. The 20W panel at 1.2A does a o.k. job in full sun for topping off cells. The older Maha Accumanager 20 has a proper delta-v termination function, don't know about the latest versions. Regardless, it's far from a portable set-up, I know. 
Thanks for passing on the info on the Morningstar controller as well. Just placed my order.


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## RandomFlyer (Oct 19, 2012)

Here's another idea for a way to carry portable battery power. This battery pack was designed as a backup for a brick size bendix king radio and carries 9 AA's. The adaptor lets you run a 12v power port from it. You need a different charging source but it's a handy way to carry the batteries and use them if they are charged. I have one and run a USB 12 volt plug in it so I can plug in different electronics.
http://www.firecache.com/prodinfo.asp?number=900-65001
http://www.chiefsupply.com/5051-Pow...PH-LPA-LPH-LPX-Alkaline-Clamshell-Orange.aspx


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## asval (Oct 20, 2012)

RandomFlyer said:


> Here's another idea for a way to carry portable battery power. This battery pack was designed as a backup for a brick size bendix king radio and carries 9 AA's. The adaptor lets you run a 12v power port from it. You need a different charging source but it's a handy way to carry the batteries and use them if they are charged. I have one and run a USB 12 volt plug in it so I can plug in different electronics.
> http://www.firecache.com/prodinfo.asp?number=900-65001
> http://www.chiefsupply.com/5051-Pow...PH-LPA-LPH-LPX-Alkaline-Clamshell-Orange.aspx



Now that looks interesting. I've tried to find more info on it, but I've had no luck. Could you tell me if it accepts eneloops or any other info (like specs) from the manual?


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## RandomFlyer (Oct 21, 2012)

No manual, but it's fairly simple. The battery pack was created as a backup for the Bendix-King brick radios and is designed to hold 9 standard 1.5 volt AA batteries to provide acceptable voltage for those radios. Someone came up with the idea to create an adaptor, originally called the KomBatt, to accept 12v plug-ins. The adaptor works with Eneloops to charge phones, iPads, etc. However, you have me thinking now, since Eneloops are putting out less voltage, it may be worth modding to fit 10 batteries. Unfortunately, I'm traveling at the moment and won't be able to tinker with it for a couple weeks. I actually have two of the battery holders and one adaptor. 
It doesn't solve how to charge Eneloops but it does make them useful while being carried.


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## RandomFlyer (Oct 25, 2012)

Just saw this 60 watt hour option from Voltaic. 
http://www.voltaicsystems.com/v60.shtml


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## mousewizard (Oct 26, 2012)

RandomFlyer said:


> No manual, but it's fairly simple. The battery pack was created as a backup for the Bendix-King brick radios and is designed to hold 9 standard 1.5 volt AA batteries to provide acceptable voltage for those radios. Someone came up with the idea to create an adaptor, originally called the KomBatt, to accept 12v plug-ins. The adaptor works with Eneloops to charge phones, iPads, etc. However, you have me thinking now, since Eneloops are putting out less voltage, it may be worth modding to fit 10 batteries. Unfortunately, I'm traveling at the moment and won't be able to tinker with it for a couple weeks. I actually have two of the battery holders and one adaptor.
> It doesn't solve how to charge Eneloops but it does make them useful while being carried.



9 rechargeable batteries won't add up to 12V, so most things that depend on 12V to run, like USB car charger adapters, won't work properly.


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## HighlanderNorth (Oct 26, 2012)

If this charger is made for charging AA and AAA type batteries, and most of the modern AA/AAA batteries are 1.3v when fully charged, then why would the charger continue to charge them past 1.3v to 1.5 v? That makes no sense to me. Alkaline AA and AAA, C and D batteries are 1.5v, but they arent rechargeable, but the rechargeble versions of these batteries arent 1.5v. Even my cheap $25 I4 charger is able to stop charging at around 1.3 volts, so why wouldnt a $100 charger kit contain the basic, inexpensive circuitry to shut off the charging process at 1.3v?


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## RandomFlyer (Oct 27, 2012)

Even more reason to try modding this to take 10 cells.


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## blgentry (Oct 28, 2012)

HighlanderNorth said:


> If this charger is made for charging AA and AAA type batteries, and most of the modern AA/AAA batteries are 1.3v when fully charged, then why would the charger continue to charge them past 1.3v to 1.5 v? That makes no sense to me.



I think you're mistaken on the Voltage. AFAIK NiMH batteries are supposed to be charged to approximately 1.48 to 1.5X until they dip slightly in Voltage and are then fully charged. *After* this point, the Voltage will naturally sag to 1.36 or so and rest there (in an LSD cell) for quite some time. Under load they will drop to about 1.2V, but when the load is removed will return to a higher Voltage. The key point here is that charging is supposed to end in the neighborhood of 1.5V.



> Even my cheap $25 I4 charger is able to stop charging at around 1.3 volts, so why wouldnt a $100 charger kit contain the basic, inexpensive circuitry to shut off the charging process at 1.3v?



Again, I think you're mistaken. I have the same charger and it terminates the charge around 1.48 or so if memory serves. I'm putting a couple of eneloops in it now to test...

After charging for a few minutes they finished (they had been sitting around for a few weeks, but not used) and I checked Voltage. Hot off the charger they were at 1.46X and started dropping almost immediately. So definitely terminating the charge at nearly 1.5 V as expected.

Brian.


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## mousewizard (Nov 2, 2012)

OK. The results are in.

Bottom line: There are three options. Ultralight, In-Between, and Go Big.

*Ultralight option:*






The ultralight option is simple. A 10 Watt folding solar panel (I used a PowerFilm F15-600) and a Maha MH-C401FS charger. The panel puts out 20V. When I put 4 AA batteries in the charger that were about 60% full and set it on Fast Charge mode, the system loaded down to 19.52V and drew 150 to 170 ma while it tested the batteries. About 30 seconds later it started drawing 560 to 700 ma while it charged the batteries About 20 mins in it was sitting at 670 to 700 ma. Toward the end it was drawing 700 ma.

Total weight: 1 lb.

Conclusion: Doable, so long as you stay within the limitations of the panel. No solar charge controller is required. If you put the charger on slow charge it doesn't draw all that much less, but it takes a heckuva long time to complete, so I recommend using fast charge mode only.

What you can do with this: You can charge up to 3 (count 'em - 3) AA batteries but four is pushing it. This kit will allow you to spread your panel across the top of your pack and charge up to three batteries while you're moving. This is the kit to use when you're constantly on the move and sitting in a base camp for a couple of days per week is not an option. It's useful when the only things you're charging are small things like a uv water treatment unit, a headlamp, and other small devices that use individual cells. If you need 12V to hook up a car adapter to your cell phone or tablet then you'll need...

*The In-Between option:*

Add to the ultralight option a 10-cell AA battery holder. This gives you, depending on the battery, an average of 2.5 AH of capacity. Use the charger to charge the AA batteries, and cycle them through the 10-cell pack to keep it fresh. Basically, you're operating as a manual Battery Management System but you have the ability to power small 12V loads that come with adapters.

Total weight: 1 lb 15 oz.

I chose to wrap the 10-cell pack in leather and incorporate an Anderson PowerPole connector. I've standardized on these and have replaced all my cigarette lighter plugs and sockets, saving quite a bit of weight and bulk in the process. My son named them "skincells."











*Go Big option:
*
20 Watts of solar panel tied to a Morningstar charge controller which is then hooked to an ALM 12V7 (12V, 7AH) LiFeO4 battery. Be sure to get the one that has the built-in BMS that allows it to act like a conventional SLA battery.






This is the kit to use when you are sure you'll have time at base camp to recharge the main battery. This puppy can deliver enough power to charge multiple devices at once, as shown above. But you won't be charging on the move. This is your basic "set it and forget it" system. I've added a voltage adapter that takes 12V and produces 3V, 5V (USB), and 9V for various uses and a miniature PowerPole distribution box, both built by me.

Total weight: 6 lbs, 8 oz., not including the voltage adapter and the charger for the 2 meter talkie.

Before changing to the LiFeO4 battery I was using a Werker 12V 12AH battery. Switching to the lighter battery shaved 5 lbs 7 oz off the kit, nearly cutting the weight in half. It also essentially doubled the useful power I could get from the battery due to the difference in discharge curves between the two chemistries. The whole thing packs into a stuff sack about this size:






I also included a long cord to run between the solar panels and the controller. This is a 14AWG cable and it's a little over 20 ft long:






The reason for this is that solar gain and shelter location seldom coincide. For example, I like my tent to sit in the afternoon shade when possible. So I need a long cord to allow this to happen. It's a larger gauge to minimize voltage drop across that run. If it was shorter I'd be using 20 AWG wire, but shorter isn't worth the little bit of weight saved with this kit.

Great pics, but,
Your images are too large and have been replaced with links Please resize and repost.
See Rule #3 If you post an image in your post, please downsize the image to no larger than 800 x 800 pixels. - Thanks Norm

OK. I think they're fixed now. --mw


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## "J" man (Nov 6, 2012)

That's a very nice breakdown mousewizard. Ironically, I also have 2-10W Powerfilm F15-600 panels. I found the combined cost of the 2-10W panels and daisy chain cheaper than buying 1-20W Powerfilm panel. That, and the redundancy of having 2 is a better deal IMO. I also have a Maha MH-C401FS and MH-C9000 with CLAs with a whack of Eneloop batteries.

My goal is to have a hybrid system that can be broken down into a smaller portable system when on the move, and then easily convert it back to the base camp type when needed. So, to sum it all up, I'm looking for a very modular setup that can adapt to my needs (powering small electronics such as flashlights/UV sterilizer based on AA/AAA, and 2-2000mAH HT radios). 

For this, I'm planning to upgrade and buy the newer Gen. 3 Morningstar Sunsaver SS-6L-12 with low-voltage disconnect and battery status indicator LEDs. This newer Gen. 3 has float charge capability. I was about to go with a http://www.power-sonic.com/images/p...s/ps_psg_series/12volt/PS-12140_11_Feb_21.pdf. 

Questions:

1. The _*much higher life cycle*_, better low-temp performance, and lighter weight of the LiFeO4 battery compared to the SLAs is making me rethink my battery purchase. Tech specs of SS-6L-12 show that float charge voltage is 13.7v, what effect would a float charge have on a LiFeO4 battery with built-in BMS? Is LiFeO4 battery chemistry compatible with a float charge? 

2. How easy is it to change out the connections to Anderson Pole? How waterproof are they? 

3. I live in Canada, so there's less light up here than in NM. Would I be able to get away with hooking up 2-10W panels in parallel to my Maha MH-C401FS charger for a total of 20W to compensate for less sunlight, or would that end up frying the charger? I'm hoping that it would just burn out the in-line fuse found in the CLA adapter before any damage would occur to the charger if it was too much. 

Thanks.


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## mousewizard (Nov 7, 2012)

The BMS in the LiFeO4 should handle the float charge situation. It's designed to emulate a SLA battery. So there should be no problem there. I'd be careful to make sure the Sunsaver controller has a setting for "Sealed" vs. "Flooded" batteries. You'll need to use the Sealed setting.

Anderson powerpoles require a special crimping tool and so this kind of thing is typically reserved for multi-project people like Hams that use 12VDC extensively. It's become pretty much a standard in the EMS and Ham world. These connectors are NOT waterproof. In fact, I removed the powerpoles I had set up at the panels for this reason. Now the wiring goes straight to the waterproof connector on the panel. Powerpoles are intended to be used indoors, in a vehicle, or at least in a tent or other shelter. My preferred supplier is http://www.powerwerx.com/anderson-powerpoles/.

Two 10W panels in parallel is how I tested the 4-cell Maha charger. Worked fine for me in strong sunlight. Remember, a device _draws _power (amperage). A panel doesn't push power. Not how electricity works. The trick is having enough supply of power for the device that's doing the drawing. Hence my advice not to charge more than two or three batteries (depending on available sunlight) on a single 10W panel. Put four batteries in and the panel may not be able to provide enough current for the charger to work properly.


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## funkychateau (Nov 7, 2012)

The ultralight matches what I was suggesting in my original post back on June 12. No reason this couldn't work, as long as you can have uninterrupted sun and a panel output sufficient to drive the charger without too much sag.



mousewizard said:


> OK. The results are in.
> 
> Bottom line: There are three options. Ultralight, In-Between, and Go Big.
> 
> ...


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## Jpwhit79 (Jan 6, 2013)

Mouse wizard. Seeing your projects really piqued my interest in trying to make something similar to this. I will be picking your brain for help. I am totally out of my league, but am trying to learn.


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## Simple_One (Apr 24, 2013)

As per above, most of this is over my head at this stage, but a great thread nonetheless!


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## IonicBond (May 4, 2013)

Nice setups!

I've been through three replacements of the Goal-Zero battery chargers and finally threw in the towel on those. Note that you MUST use 4 cells when charging otherwise, you will burn up the charger. Ask me how I know.  New versions have a little addendum sheet. There have been two or three production modifications to those chargers and even the improved version burned up on me. Typical failure is just behind the power switch. While I've been through three, others have had no problems so maybe it boils down to QC. One alternative to using the 6.5v fast charge input is to stick to the regular usb input, but then your charge times will be longer.

I suspect that the included LSD cells from Goal-Zero are re-badged LSD Rayovacs - but can't prove it. At any rate, Eneloops are proven performers.

My preference is for the PowerFilm 4AA version since the charge algorithm seems to take into account clouds/shadows. It seems to charge up to about 80% initially when the led's go solid (about 1.35 volts hot off the charger), and do a slow charge thereafter. If you want full capacity, let them charge for an additional two hours. Now when you measure hot off the charger, they will read about 1.42v. Seems like if they are already full, clouds / shadow won't re-initiate the fast-charge and they stay in slow-charge. Watch out if you are charging in direct sunlight under very hot conditions, or even if shaded but the ambient temp is above about 85 degrees. I won't let them top off if that is the case.


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## t_bone22 (Jun 19, 2013)

Sorry for the necro but,
Mouse did you make all new connectors for your plugs, I.E. the radio charger usb ect? also do you have a list or a thread to build you battery option I am looking into getting this done but would like to keep it simple with either a regular 12v plug option and a cigarette plug option what would you recommend? Also I see you guys use the f15-600 but I was looking at the r14 rolling panel. Is the extra 4w and waterproof worth the extra 20 bucks and the size? because it won't be foldable but just be able to roll? Where did you end up getting your battery? I was looking at this one on amazon and not sure if it is the correct one or not? I am looking for something I can take with me backpacking and set up at a base camp but be able to charge AA or AAA for GPS, flashLights, ect... I want to be able to power my kindle fire HD 8.9 for use to read on and what not lots of information on there.
A123 battery
http://www.amazon.com/dp/B008VVO6LE/?tag=cpf0b6-20
r14 solar panel
http://www.amazon.com/dp/B001QKWTLG/?tag=cpf0b6-20


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## mousewizard (Jun 23, 2013)

Yes, I replaced all my connectors using Anderson PowerPole connectors. I did this both to standardize and to minimize weight, but that was before the day when USB became a major player in the accessory power market. For most people, I'd recommend sticking with the standard 12V connector and using one of the USB power connectors intended to plug into that. Lot's easier than building your own power supply or converting one from the auto connector format to the PowerPole format. Using PowerPole allows one to make a little distribution box like the one shown at the right edge of the picture of all the gear above. Of course, you don't need one if you're going to be just charging one thing at a time. For that matter, you can get a 12V three-female connector at Auto Zone. What I'm saying is you really have to work out in your mind how you'll be using the system, then run a few prototypes through their paces before you settle on a final setup.

The battery is the right one and you can pick your choose of solar panels. Doesn't matter where you get it, although I don't like to shop Amazon because of the labor conditions at their fulfillment centers, so I'd look around for a small, independent shop that stocks and ships from their own site.

I'd check the weight between the rollable and foldable panels before I bought. Backpacking and all requires counting ounces, even for base camp gear. BTW, the foldable panels are also waterproof, although not marine grade.

The whole thing isn't cheap, but based on the comments re the Goal Zero products appears to be the best way to go.


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## t_bone22 (Sep 3, 2013)

Mouse what is your morningstar mounted onto?


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## ChrisGarrett (Sep 3, 2013)

t_bone22 said:


> Mouse what is your morningstar mounted onto?



He states on page 1, that's it's just painted cardboard, the paint making the cardboard a bit stiffer.

I went to SirSpeedy and asked for a junker piece of plastic corrugated sign stock and made this for free:












Chris


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## t_bone22 (Sep 8, 2013)

yeah I had seen that post I was talking about his second design, might be the same thing not sure.


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## mousewizard (Sep 9, 2013)

It's cardboard as well. I just used it to practice my digital camo painting technique prior to doing my MTB.


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## slbear (Jan 31, 2014)

Great thread. Even if it started "awhile" ago, it is definitely timely for me, as I was shopping for a scalable system instead of the Goal Zero options. A recent trip to Joshua Tree had me 10 miles from an AC outlet, but with tons of sun. My camping friend used his van engine to recharge his phone. I had a Solio pinwheel charger a few years ago, but it doesn't really work with my recent smart phones. I have a few battery packs (Motorola just for my phone, a new Sony 10aH brick, and a starter set of Eneloops. I also have a DieHard jumpstarter with AC, 12V and USB ports that I typically take when I'm going to the desert (or otherwise remote). Now I want a way to charge them without the grid. Budget is always an issue, so upgrades need to be planned and targeted

In any case, I had a few questions/comments.

1. No one mentioned Instapark, but they seem to have better priced high-end mono-crystalline foldable panels. I've talked myself up to a 27W for basecamp usage (http://www.amazon.com/dp/B00EVFEBKU/?tag=cpf0b6-20). Maybe overkill for a backpack, but good for basecamp or even minimal emergency preparedness. With my So-Cal sun, should I still consider the PowerFilm option at a higher cost per W?

2. Instapark also has a battery pack, (http://www.instapark.com/external-b...60-27-000-mah-dual-external-battery-pack.html), Curious on anyone's experience or feedback on that product. Seems like this takes care of battery charging with multiple output options (similar to a Goal-Zero larger unit but without the inverter), but it isn't cheap and still doesn't handle my AA and AAA needs (and isn't downscalable for backpacking). Is it worth it just for the basecamp capacity?

3. If not something modular like the Instapark pack, do you think I could introduce the jumpstarter for capacity in the basecamp-type setup Mousewizard or ChrisGarrett described? Ideally my setup will directly charge any battery, from AAA, to my rechargeable lantern, to the Sony 10aHr module and the DieHard jumpstarter. Each comes with it's own unique AC power supply, which I'd rather bypass. Is it asking too much? Maybe the solar chargers take care of this? 

4. No one mentioned inverters. Despite my focus on charging batteries, every now and then AC is needed. I doubt the inverter in the jumpstarter is very efficient. I can see the digital readout drop quickly. Any recommendations for a value priced quality inverter is greatly appreciated.

Thanks in advance if the knowledgeable folks here can re-engage on this thread. Surprising there isn't more meaningful discussions compared to the reviews of the packaged chargers. Maybe they are out there, but just hard to find (I found one that talked about a home backup power system based on a salvaged UPS). Semi-home-made is the way to go with the help of some good folks, so thanks again for the information.

-SLBear


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## slbear (Feb 5, 2014)

Bump in case anyone's still listening. So close to buying a Goal Zero Yeti 150 and Nomad 13 or 20 panel, but I re-read though each message again on this thread, and still think semi-home-made basecamp setup would be better. After noodling on this more I tried to distill down what I want to recharge, which is: (1) AA/AAA cells, (2) Black Diamond lantern with rechargeable 3.6V pack (3) USB battery packs and devices up to 2.1A, and (4) top off my jumpstarter. 

The Yeti 150 is appealing because it has 12V 14Hh capacity and a USB, 12V car, another 12V port and an 80W inverter, although it's older battery technology (12 lbs), and still $200. The Nomad 13 or 20W panel is appealing, because it has the right connectors, but is probably underpowered if I become THE Basecamp charging station for my camping buddies, i.e. it won't recharge the Yeti in a day, and it cost upwards of $200. Even with these I need to get a AA/AAA charger.

Recreating the same functionality as the GZ combo above, with the info provided here, I would probably lean towards:

* An Instapark 27W foldable panel for $110 (cheaper and more powerful than GZ or powerfilm) - Anyone have experience with that?

* A morningstar controller - curious why both Mouse and Chris got the 10A instead of a cheaper 6A?

* LiFePO4 battery with BMS

* And possibly an inverter - any recommendations? 

I still need an AA/AAA charger (with either system), but after reading reviews would go for the MH-C401FS or BT-C2000. USB could come with the inverter most likely, or 12V to USB converter. 

I was thinking the jumpstarter could be topped off straight from 12V out of the battery or from the Sunsaver directly. This is something I could still use some help with. The jumpstarter has a wall-wort that puts out 17V (up to 1A), and drops to trickle charging when it gets close to full. The instructions say you can also charge it from one of the 12V car ports, but you need to be careful to unplug it when it gets to 100%. That worries me because I want a set-and-forget system either charging from the sun or LiFePO4 battery. I know I could create a voltage converter to put out the 17V, or go to AC and back through the inveter, but do you think the SunSaver will take care of the charging since it is essentially a standard 12V LA battery, or do I still need to worry about overcharging while I'm not around?

I was also thinking how to charge the lantern, which uses a 6V wall-wort. Looks more and more like I rely on the inverter or make a custom voltage converter. I used to know how to do that theoretically. Let me know if anyone has come across a good one for sale.

Again, thanks for the great info in the thread and thanks in advance for any additional advice,

-SLBear


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## mousewizard (Feb 24, 2014)

I went with PowerFilm for the weight and packability. Same reason ultralight folk cut their titanium sporks in half.

The controller decision was based on load capacity. Their load capacity is the same as their charge capacity, and I wanted the ability to handle more than 6A draw.

I recommend against an inverter. All inverters are intended to put out 'way more power than a little backpackable battery is prepared to provide. You can almost see the sides collapsing on the poor battery from the huge suckage going on.

Not familiar with the "jumpstarter," so can't comment.

It's easy and cheap to get a cigarette lighter thingy that has a pair of usb charging ports on the other end. Found this out after I built a custom one.

In general, if it can't be easily done with 12V, and also has minimal power draw, then I'd think hard about deploying it when it has to be supported by a backpackable solar system.


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## slbear (Feb 24, 2014)

Thank you mousewizard. 

I also got some good ideas from some radio guys on another forum, and additional online research. I just today stumbled on the 12V USB mountable ports and also picked up a BT-C2000 AA/AAA charger from Amazon that I'm quite happy with. 

Still need to pull the trigger on the PV panel, charge controller and batteries, and just trying to decide on capacity (i.e. how much I'm willing to spend and potentially schlep around). I found a nice portable (but not packable) system using LiFePO4 technology here: http://www.aspectsolar.com/products_Power_Package_Pro.aspx. For me this is over-priced and probably over-powered, but it gives me a reference point to see if a homebrew system can be cheaper. I'm guessing you are about $200 for battery and charger, and jumping up to a 20Ah prismatic batteries is not that much more. 

One more question if you don't mind - It looks like you are running all your chargers and devices off the load port. Are you doing this for the Low Voltage Disconnect protection? It wasn't clear to me if the SunWaver would provide sufficient protection. After reading the A123 documentation, I'm confused. On one hand they say to avoid letting the battery enters a UVP state (at 2V per cell or 8V for your battery pack). The SunSaver turns off the load port at 11.5V, which would average out to 2.875V. That sounds like a fine place to stop discharging (other batteries suggest 10V or 2.5V per cell is the lowest limit). But the A123 docs go on to say "The battery also enters the UVP state if any cell in the battery drops and remains below 3.2V for longer than 24 hours. 3.2V per cell x 4 = 12.8V, the nominal voltage of the pack, which suggests to me you need know when the voltage is below 12.8 and act quickly (within 24 hours) to save the battery. I'm convinced the LiFePO4 battery packs are the way to go, but just want to make sure my investment and backup system is protected in a set-it-and-forget-it way. Any additional feedback you have on this is greatly appreciated. 

Thanks again for your help and advice,

SLBear


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## avrilcory (Feb 26, 2014)

Solar system model out of many types of materials. The purpose of this lesson is for students to acquire information about objects in the solar system while collecting solar system trading cards through interactive computer use. The calculation assumes that all the strain that results in thrust faulting resulted from contraction of the planet as it cooled.


Thanks 
Luminousrenewable


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## slbear (Feb 26, 2014)

avrilcory said:


> Solar system model out of many types of materials. The purpose of this lesson is for students to acquire information about objects in the solar system while collecting solar system trading cards through interactive computer use. The calculation assumes that all the strain that results in thrust faulting resulted from contraction of the planet as it cooled.
> 
> 
> Thanks
> Luminousrenewable




That went way-way over my head, but it sounds very professorial.


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## mousewizard (Mar 6, 2014)

Well, when the device has a load port I tend to put loads there instead of directly on the battery. The SunSaver can wind up with three different voltage levels happening during charge cycles. One from the solar panel of up to 18v, one at the battery typically 14v or so, and one at the load of 13.8. Basically I just tend to go with what the paid engineers have come up with.

Not sure about the A123 battery UVP state. Might be a mistake in documentation. As I understand it these batteries will self-protect but can be recovered by just charging them. I've got four of them for different things and have never had a problem yet.


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