# Solar powered battery chargers???



## CaptainpPicardX (Apr 28, 2013)

Hey guys, I'm still new here, but anyway, I was looking around on the net, trying to find a good solar charger for my batteries. I have pretty much left behind buying alkaline batteries for good. At the same time I like to prepared for emergencies, which often times include power outage. I have a few thing for ER's that run on batteries. I really hate trying to find batteries during/after a disaster, people hoarding, not to mention trying to find a store thats open, so a solar charger would be a lot of help,... But, anyway,...


Are there any good Solar batter chargers out there, especially ones that can charge AA,AAA, and even 18650's? I know 18650's is a long shot, but how bout just AA,AAA and/or C,D cell?

Thanks, Denis.


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## TEEJ (Apr 28, 2013)

Cottonpickers is what you want. Go to cpfm and find his thread.


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## ChrisGarrett (Apr 28, 2013)

At 60w, it'll even run your laptop while you're surfing CPF. That's an Xtar WP2 II charging a couple of Soshine 16340s, IIRC.

http://www.candlepowerforums.com/vb/showthread.php?342073-Portable-solar-charging-setup-I-just-built

Brunton, Global Solar/Sunique, CottonPickers, PowerFilm and Goal Zero all make foldable/rollable panels in the 5w-62w range. For batteries, phones and smaller things, 20w and a controller will get you started. 26w-27w, would be better, as you loose watts via inefficiencies. US Armed Forces are using the PowerFilm 30w and 62w panels, so they're milspec.

Chris


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## rpm00 (Apr 28, 2013)

Take a look at Goal Zero products as well. Very high quality. I have the 7W panel and Plus pack and love them.


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## CaptainpPicardX (Apr 28, 2013)

WOW, what a giant pain in the ***, not that its too complicated I like fooling with wires, but still... Over $200 waiting for different parts, etc... I cannot believe no company put this whole thing into a single small portable product?! So basically from the Very quick research I have just done, you cannot directly power up the charger with panels? you have to charge the golf cart? battery first? so you are actually powering the battery charger (btw I got that same chrager two weeks ago myself) With the GC battery, and just using the panel to keep the GC battery charged in the first place?? Still cant believe there aint no easier way... Oh, well, I might have to come up with one..


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## hiuintahs (Apr 28, 2013)

I've got a setup similar to ChrisGarrett. with solar, You really need a storage battery and then from there you can run a USB or 12v input charger. That way you can pick any 18650 charger or AA/AAA charger that has a low voltage (USB or 12v) input. My setup is just getting built right now and haven't had a chance to try it out other than I did measure the voltage and short-circuit current one day out in the sun. I've got two 80 watt foldable panels, an Xantrex C35 charge controller and a 52 amp-hour deep cycle AGM battery.

The problem with the small solar setups is that I'm not sure how some chargers react to intermittent power input unless they are desiged specifically for solar and can re-start in case a cloud floats over and causes the voltage to drop out that was running the charger.

I'm currently working on the design of a 18650 charger that will be able to handle such a situation. I have a 12v to 3v dc adapter that I power my Lacross BC-700 with when working with the 12v power (solar or auto).


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## ML2013 (Apr 29, 2013)

I have a Goal Zero Nomad 7, it's total crap, i've looked into solar chargers since my bad experience with goal0, it weighs about 13oz and measure about 2.5 watts at a 5 volt output which equals .5 Amps of output current.. which is nowhere near enough to solar charge a cell phone at a decent rate, it'll take more than a freakin day to fully charge a smartphone! So i then got my hands on Suntactics sCharger-5, weighs 8.3oz and it pulls 1.0 Amps at 5 volts, plenty for cell phones and rechargeable batteries. I use it to charge my iphone, which fully charges it in 2 hours with no problem. You can look around online to find USB rechargeable AA/AAA batteries, i've seen some on ebay that could charge 4 batteries that has a USB connection.


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## Aperture (Apr 29, 2013)

Double the Watt rating of what you need and you're pretty safe. The problem is that the specified Watts are measured without a load and when you actually start charging something the actual produced Watts are 25% lower plus you'll have a 25% loss for the battery charging process itself. Going bigger than twice the needed power rating assures better performance in less than optimal conditions.

As an example my 4W USB panel measures 0.8A @ 5V with the multimeter on the open connectors which is the advertised 4 Watts but when it charges something it drops to 0.58A @ 5V which is only 2.9W.

Knowing the charging specs of your charger (or devices with a built in charger) is key to get the right panel as this is the limiting factor of how much power can actually be used. The iPhone 4 can only handle a 0.72A @ 5V which is a mere 3.6W, a 27W panel will not fry it but is a bit overdone, 7W should be the minimum and a 10 to 12W panel is perfect to be on the safe side.

It's also advisable to use a regulating batterypack between the panel and the charger to ensure a constant charge on the charger in case a cloud obscures the sun, etc. Be sure to use a pack that supports pass-thru or load balancing, with this feature the power that gets in goes out the other side without charging the internal battery which would result in a 25% loss. When more power comes in than is needed it will store the excess power and when the panel can't deliver enough power it will supplement it for a constant output.

Personally I prefer all my chargers and sources to be compatible with the USB format as it's the smallest most universally used power socket and you can use other sources besides solar like the BioLite stove and PowerPot cooking pot.

This is my off the grid charging solution sance the sources:





The Voltaic V11 pack transforms the 8.4V input from the Nikon EN-EL15 DSLR battery to a 0.9A @ 5V to charge the 18650 3400mAh in a ML-102 USB charger (max 5W) which charges another EN-EL15 battery in a Pixo C-USB (max 4.5W) multi charger (3.7 & 8.4 Li-Ion, AA, AAA). The 18650's are used in my Surefire lights or Spark headlight, they also serve as my backup power (I'll bring 2 to 10 spares depending on the length of the trip).

My big solarpanel is a Voltaic 16.8W panel btw, when using a dual USB car adapter in the 12V socket I can charge two USB chargers at once with ample reserves for less than optimal light conditions.

That said I prefer to bring enough batteries with me to last me the whole trip as the sun doesn't shine that much during hiking season in Northern Europe, with the setup posted above I can use whatever charge I have in my 18650's or DSLR batteries to charge anything else if needed.


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## reppans (Apr 29, 2013)

ML2013 said:


> I have a Goal Zero Nomad 7, it's total crap, i've looked into solar chargers since my bad experience with goal0, it weighs about 13oz and measure about 2.5 watts at a 5 volt output which equals .5 Amps of output current.. which is nowhere near enough to solar charge a cell phone at a decent rate, it'll take more than a freakin day to fully charge a smartphone! So i then got my hands on Suntactics sCharger-5, weighs 8.3oz and it pulls 1.0 Amps at 5 volts, plenty for cell phones and rechargeable batteries. I use it to charge my iphone, which fully charges it in 2 hours with no problem. You can look around online to find USB rechargeable AA/AAA batteries, i've seen some on ebay that could charge 4 batteries that has a USB connection.



In all fairness, GZ specifically states it maxes out at 2.5w through its USB port. It is designed for optimal integration (6+ watt) with its Guide 10 4xAA battery pack. If the OP uses that Suntactics 5w panel with a third party USB 4xAA charger, my guess is that you'll end up with longer charge times. The Suntactics certainly seems the better choice for direct charging to USB devices though.


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## ChrisGarrett (Apr 29, 2013)

CaptainpPicardX said:


> WOW, what a giant pain in the ***, not that its too complicated I like fooling with wires, but still... Over $200 waiting for different parts, etc... I cannot believe no company put this whole thing into a single small portable product?! So basically from the Very quick research I have just done, you cannot directly power up the charger with panels? you have to charge the golf cart? battery first? so you are actually powering the battery charger (btw I got that same chrager two weeks ago myself) With the GC battery, and just using the panel to keep the GC battery charged in the first place?? Still cant believe there aint no easier way... Oh, well, I might have to come up with one..



You can simplify things by buying the 62w PowerFilm foldable unit. They run about $800+, but they're a lot more portable than my setup. I guess you could daisy chain two 30w panels together for about $840, or three 20w panel, for $900, lol.

I'm in hurricane alley here in Miami and I wanted something that could charge things up when the power goes down. I don't want to be waiting around for hours on end, like one would be when using smaller panels. I don't need this to fit into a backpack, just be light enough (22# total w/chargers) to carry downstairs, or pack into the truck if I need to haul a$$ out of town.

My little system does that and with another 'mother' battery, or two, I don't even have to run down everyday and set the thing up.

Chris


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## Spork (May 2, 2013)

Another informative post

http://www.candlepowerforums.com/vb...-of-Eneloops&p=4055819&viewfull=1#post4055819

I picked up the ccrane solar charger but have doubts about its reliability. I've considered putting something together with a 20 - 30 watt panel for charging eneloops or phones. The powerfilm panels are ridiculously priced though and if your go with a nice LiFeO4 battery to save all that energy its going to cost some money. Also for me it would mostly be a backup for extended power outages and would rarely be used. 

It would probably be much more practical to use a car charger for me anyway and put that extra money toward more eneloops. If we had to some of these flashlights can last for over 20 hours on a single aa. My wife has several portable usb chargers as well.


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## ChrisGarrett (May 2, 2013)

Spork said:


> Another informative post
> 
> http://www.candlepowerforums.com/vb...-of-Eneloops&p=4055819&viewfull=1#post4055819
> 
> ...



Yeah, I don't know about the Crane solar dohickey. If you want cheap, but not really portable, go with a rigid panel, as the warranties are generally 10 yrs @ 90% rated output and 25 yrs @ 80% rated output. Foldable/Rollables come with either 2 yrs (Brunton Solaris) and 3 yrs (GZ, PF and Global Solar/Sunique), so we're not talking about a lot.

Rigids are also much cheaper and and more efficient, depending on what 'type' you get, than the flexi-panels. 

Also, you can save some cash by getting basic SLA/AGM batteries in the 12Ah-18Ah range for 'mother battery' duties, for not a lot of cash and they'll be fine for charging smaller stuff and you'll get 3-5 years out of them. The boutique stuff is nice on paper, but for charging batteries, smart phones, GPS, iPad type things, you can save some money, by buying standard stuff, IMO.

Chris


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## Sub_Umbra (May 3, 2013)

I'd recommend a 12v AGM battery and a solar panel with as good a charge controller as you can afford. The Morningstar Sunsaver 10L is a great controller used by industry in remote sites and harsh marine environments all over the world (over 1 million units in the field) and it's in the ~$50-60 price range. With the above setup you may use any charger that has a 12vdc input for *mobile* charging. I like the Accumanager 2020 for charging with AGMs.

I also like small AGM scooter batteries in ammo cans. Very handy for charging phones and running small LCD TVs when the power is out. I just ordered an 18AH scooter battery from Amazon for $21.99 with free shipping. It'll charge a phone quite a few times.

Our serious hurricane season where I live doesn't really start 'til August. I bought a big ammo can that I'm going to fit out with a 35AH AGM scooter battery. I may make more if I like the way it comes out. After Hurricane Isaac last year I began working on smaller systems that may just be carried outside when the power goes out.
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Almost forgot. I had one of the CCrane chargers when Katrina rolled through. The one with the Fresnel lens. It was $15-$17 IIRC when I got mine. Because I bought it partly for the potential entertainment value involved in figuring out how to make it work if I ever needed it I never even took it out of the box when it came.

In the following six weeks that our power was out I used it to charge AA NiMH cells so we could listen to Audiobooks. It works. Mine is still in the storm kit even though I have a much bigger panel now. It's a 'dumb charger' so you'll have to do some math and time it's use. A multimeter is handy.

Multiple units would be much better than just one.


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## IonicBond (May 4, 2013)

I'm also into the backyard 12v nominal panel / controller / battery setup, but I find the most convenient just for AA's is the small foldable PowerFilm four-AA charger.

What I like about it so much is that it seems to take into account solar conditions that involve passing clouds / shadows without repetetive harsh EOC termination triggers. Under normal use, it will fully charge up to about 80% SOC quickly, and then do a slow charge. If it is already at 80% SOC and a cloud / shadow is encountered it seems to just go back to a slow charge. Thus, kind of like the Maha C9000, for the most capacity, count on charging for at least 2 more hours when the red led charge indicators are solid and not blinking.

There is also a combo 2AA / USB powerfilm charger, but I find that the USB function is just too little of any real use with only 2 AA's, and have had the usb port burn out. The 4AA only charger is my favorite for portability AND seeming to take care of AA's well.

There is still the matter of having cells out in the sun or indirect heat if you shade the top portion, so take that into account - on 90-degree plus days, I pull them when the indicators are solid and forego the 2 hour top-off.


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## Spork (May 4, 2013)

How long can the agm batteries sit unused? This is something I probably won't use very often. 

So far the setup I'm planning is

LiteFuze 30w panel , Morningstar Sunsaver 10L , for the battery I was considering a UPG 85980/D5722 Sealed Lead Acid Battery (12V; 35 AH; UB12350) It doesn't say if its agm. There is also a similar 7ah battery and wonder if that would be big enough. For the charger a MH-C401FS. 

Also what kind of fuse do I need and where does it go? This will be my first experimental setup. Maybe I should go with something smaller? The instaspark panels have some complaints in reviews and the 10 watt powerfilm is expensive. The litefuze seems to be in the middle for price.


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## Sub_Umbra (May 4, 2013)

Spork said:


> How long can the agm batteries sit unused? This is something I probably won't use very often...


AGMs are very LSD. 



Spork said:


> ...So far the setup I'm planning is
> 
> LiteFuze 30w panel , Morningstar Sunsaver 10L , for the battery I was considering a UPG 85980/D5722 Sealed Lead Acid Battery (12V; 35 AH; UB12350) It doesn't say if its agm. There is also a similar 7ah battery and wonder if that would be big enough. For the charger a MH-C401FS...


The next battery I order will be the UB12350. It is an AGM. I'm going to install it into an 800 crtg 5.56 m27 link surplus ammo can I just picked up. If I like it I'd like one or two more... 

Below is a link to the UB12350 spec sheet:

http://preview.tinyurl.com/cbmbplp

7AH is pretty small. While many online write about drawing down AGMs to 40 to 50% (which may certainly be done at the cost of some service life) I try to design my stuff so I don't have to go below the 80% sweet spot where I may get many more charge/discharge cycles.



Spork said:


> ...Also what kind of fuse do I need and where does it go? This will be my first experimental setup. Maybe I should go with something smaller? The instaspark panels have some complaints in reviews and the 10 watt powerfilm is expensive. The litefuze seems to be in the middle for price.



Everyone's needs will be different but after letting the 'magic smoke' out of a wiring harness I tend to put fuses everywhere. In general you have at least two things to protect: fuses to protect each device and fuses to protect your wiring harness. If your fuse is too big to protect your wiring, *your wiring becomes the fuse.* 

For my uses automotive blade fuses have been working well for me, but as always, if I was smarter I might use something else. /scratches head

I've had AGMs over the years but I've really just started experimenting with the smaller ones in the last six months. Wheelchairs and scooters have made them cheaper to play with.

One last note: Keep the wires from the Morningstar to the battery to two feet or less. You not only want the temp sensor on the Morningstar in proximity to the battery, you also very important to minimize any wire induced voltage drop between the controller and the battery. Your run from the panel(s) to the controller may be longer but for the health of your battery the run between the controller and the battery needs to be short and the largest gauge wire that will fit on the controllers terminals.


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## Rexlion (May 5, 2013)

I have a couple of chargers that came with 12v 'cigarette lighter' style plugs. My travel trailer has such a receptacle built into it, overtop the kitchen counter. I recently went to Solar Blvd and bought a W Solar 75w panel for under $100, and a Morningstar controller for about $25. Wired it up so it plugs into the trailer's pigtail (that plugs into my car normally, but now it's attached to the solar) and it is not only maintaining my trailer battery, I can charge 4 NiMH cells anytime.

See, all you guys need is a travel trailer...... :devil:


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## SemiMan (May 5, 2013)

Spork said:


> How long can the agm batteries sit unused? This is something I probably won't use very often.
> 
> So far the setup I'm planning is
> 
> ...




6-12 months of standby if the battery is kept cool, 3 months if the battery is kept warm. It also depends on the quality of the battery.

The UPG is an average quality battery. 99% certain this one is just private labelled for them, so hard to say exactly what quality. Their data sheets are limited in details.

In terms of panels, so many of the panel names I hear thrown around, LiteFuze, W Power, etc. are just meaningless rebrands. Most of these companies (based in China) will out of business well before the panel warranty expires, but fortunately, panels are pretty simple so short of dropping them, you are likely to get at least 10 years, but then again, initial power may not be to spec. In the U.S. I generally suggest people buy from Sunelec as at least you have some initial purchase recourse. They have been in business a long time and I think they plan to keep it that way. There are others out there that are reputable as well.

Can't emphasize enough to buy ONLY a name brand charge controller. It is plain stupid to pay $100 for a battery and hook it up to a $20 controller. The controller is the only thing keeping your battery alive and many do a poor job of charging a battery.

Always keep in mind with any lead-acid battery is that they like to be 100% charged all the time (or close to it), so charge them fully as soon after use as you can. Sulfation in the top 75% of the charge tends to be low, but increases beyond that. They also like to be cooler. Heat (>35c) quickly kills lead acid batteries. Of course cold temps and a poorly compensated charger is also a death knell to batteries.

If getting larger panels (100w ish), consider an MPPT charge controller as you usually gain another 25% out of the panel. Unfortunately good ones are still pricey.



Semiman


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## hiuintahs (May 5, 2013)

My AGM battery sits around for months on end without being used and I just put a top off charge on it about once every couple of months. Like SemiMan says, best to keep lead-acid batteries mostly charged up. I use a Xantrex Truecharge 10 for that when AC is available. Solar is for if/when the power goes out for any length of time.

Semiman had some good comments and I'll throw in some more about MPPT vs PWM vs cheap charge controllers. MPPT will cost twice that of a good PWM charge controller. Though an MPPT does take advantage of maximizing the power output of a solar panel, the only difference between that and a good PWM controller as far as getting the job done is time. If the solar panel is needed to be working all the time, then it makes sense to have an MPPT type. But if just pulling the panel out occasionally to charge up the battery, then it really doesn't make economic sense to have a more expensive MPPT type controller. MPPT type controllers really only are worth getting on a solar system that is in constant operation which usually is only on bigger (non-portable) systems.


A PWM charge controller that is made by a good reputable company and that adheres to 3 or 4 stage battery charging.......bulk / absorption / float / Equalization, would be very adequate. Now the cheap charge controllers...........I wouldn't trust a good AGM battery to them.

This isn't a plug for Morningstar or Xantrex but I like both and both are very popular and very reputable and I have researched them. The Morningstar 15A MPPT charge controller is just above $200. The Morningstar Sunsaver 10L PWM is $70.00. The Xantrex C35 MPP is around $100.00. I think it depends on how big your system is. I'd size the charge controller to handle at least double the rated solar panel current just to be on the safe side of reliability.


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## IonicBond (May 6, 2013)

Note about the Morningstar Sunsavers and AGM absorb voltages.

The default jumper select is between sealed and flooded. Since nearly all of my AGM's in cyclic mode want to see a 14.7 volt absorb voltage, I actually run with the jumper removed because per the manual and measurements, that actually provides a 14.7v absorb. Even though it seems frightening to run an agm in the "flooded" setting, I say take a look at the actual voltage spec of the jumpers and see if interpreting the actual voltage, and not the silkscreen is more appropriate.

For me, "sealed" is more like 14.1 volts, and is more applicable to gel, or when running mostly in float mode. Cyclical semi-daily use, and with limited solar-insolation hours, I run with the 14.7v absorb by removing the jumper for my AGM's - the UB12350, PowerSonics and many others.


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## Spork (May 6, 2013)

I ended up with the litefuze 20 watt panel and the 1270 upg battery (7.2 ah). As I mentioned before all I want it to do is power a battery and phone charger. If this one poops out and I'm still into the solar thing maybe I will pickup a lithium battery. I am also curious about running a small fan. Are there any that work well with direct drive from the panel? Maybe a large pc fan might work with a regular setup. 

I also ordered a mc4 connector , blade fuses, and a female cigarette adapter but other than that I'm not sure what size wiring to use. Where do you find the nice premade cables with the rings? Also unsure of what I should use for the battery connectors. Maybe my questions are quite basic but I just want to make sure its done right.


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## hiuintahs (May 6, 2013)

Be sure to bite the bullet and get a decent charge controller...........like the Morningstar 10L................and all will be well provided you wired it up good :devil:. With a good charge controller (which is the brains of the operation), you can rest assured that all is going well and your battery will never get over charged and so you can just leave it and not worry about it.

Let's see a 20w panel is around 1 amp max. You could get by with 20 guage but I'd use 16 gauge wire. If your wire length is long, use 14 or 12 gauge.

Look into some type of container, contraption or small wooden platform to mount everything on so that it's fixed and not moving around. Once you know your physical or mechanical position, then you can neatly route your wires. I'd use connectors between solar panel and the charge controller so that your solar panel can be disconnected easily and also so that the panel can be placed according to sun while the rest of it is under cover in case of rain. The rest of it just hard wired together without connectors. If the battery has screw terminals then I'd get some crimp style ring terminals from Lowes or HD.

Once you get it built and working, you may then see ways to improve things..........like mounting a 12v receptacle instead of having it dangle off of the leads of the battery. Also may want to have blade fuse in series with this 12v receptacle.

Fun stuff!


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## Spork (May 6, 2013)

thanks everyone for the help! It was around $150 for the 20 watt panel, 10L , and 7ah battery. I also added a C401FS and a 2.1 amp car plug charger for android / apple phones and ipads. I can't wait to put it all together. 

I don't own any gas tools. I use a electric mower too. So a generator is not something I want to mess with. I'm in the midwest and we've had storms knock out power for 1-2 weeks although its rare. I won't be able to run the fridge so I guess I would leave the door closed or start up the grill and use what I could.


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## ChrisGarrett (May 7, 2013)

Spork said:


> thanks everyone for the help! It was around $150 for the 20 watt panel, 10L , and 7ah battery. I also added a C401FS and a 2.1 amp car plug charger for android / apple phones and ipads. I can't wait to put it all together.
> 
> I don't own any gas tools. I use a electric mower too. So a generator is not something I want to mess with. I'm in the midwest and we've had storms knock out power for 1-2 weeks although its rare. I won't be able to run the fridge so I guess I would leave the door closed or start up the grill and use what I could.



The good thing about solar panels is, is that you can daisy chain them together with the right connectors, so having 20w now, doesn't mean that you're stuck with 20w tomorrow and the Morningstar 10L can handle up to 10A of current, so you've got plenty of room to grow with that controller.

You can even upgrade mother batteries, or buy additional ones. I'm looking at 2 PowerSonic 18Ah scooter batteries for $75 shipped, that would be plenty, even a single 18Ah coupled to my 12Ah would give me ample daily capacity for my particular needs.

Chris


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## independent (May 7, 2013)

Had big solar panel setups in the past with fridge freezers, made all my charge controllers... I live off my micro solar setup here is a rundown on what I've found.. 

 90% of store bought solar chargers are glorified external batteries with a token amount of solar thrown in. 
 The Powerfilm AA chargers are good little panels but the wires at the folding parts do break. Unless you are checking to see the current output of the panels they will appear to work even though the output is seriously hampered. I've ruggedised mine. It is a USB AA modified with a six panel - um - panel and the hinge wires have around 5x more tiny copper flex for durability. 
 The Nokero Single AA charger is very usable, cheap and reliable. Gang them up for multiple cell batteries (2, 3 & 4). 
 I have the Nokero Raycell arriving soon by mail and looking forward to seeing how that works out direct charging cell batteries (camera batteries might work in it as well) 
 Voltaic series of chargers and panels are really well thought out. Their service is excellent. Cool people. 
 Using solar to charge a battery --to charge a battery is redundent. A friend and I have a (15-20w max) MPPT regulator design (with adjustable power point) to look like a regulated output. It works in real -world terms about 80+% efficient. Ie out of a 5w 12v CIGS panel I can achieve an 800mA charge into 5v USB (measured). When finished testing we will upload the EagleCad file so anyone can build it (CC licensing).


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## SemiMan (May 7, 2013)

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## SemiMan (May 7, 2013)

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## SemiMan (May 7, 2013)

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## ChrisGarrett (May 7, 2013)

SemiMan said:


> Good advice here. In solar battery charging, battery failure is mostly due to battery undercharging, not over charging. Bumping up the absorption voltage is a good way to alleviate sulfation.
> 
> Semiman



I use the Morningstar 10L and a PowerSonic 12Ah SLA/AGM battery, but I've kept the jumper on, as that's what I thought I should do.

Should I remove the jumper when topping off my seldom used battery? Won't hurt it?

Chris


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## Slazmo (May 8, 2013)

Hmm - wonder what I would need on top of my 10 Watt PV panel to charge up Sanyo Eneloops AA's the 'environmental' way... Anyone got some simple instructions on what you would need on top of a Kemo solar charger regulator plumbed into a 10 Watt PV panel as to charge AA & AAA batteries.


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## mousewizard (May 8, 2013)

Slazmo said:


> Hmm - wonder what I would need on top of my 10 Watt PV panel to charge up Sanyo Eneloops AA's the 'environmental' way... Anyone got some simple instructions on what you would need on top of a Kemo solar charger regulator plumbed into a 10 Watt PV panel as to charge AA & AAA batteries.



Make sure you have a battery plugged into the Kemo. That way the Kemo is constantly charging the battery. At 10W, you don't have a lot of solar panel there, so you need to constantly charge a battery at a low level and then charge your AA and AAA batteries by hooking up a 4-AAA battery charger to it.

If you haven't already committed to the Kemo, then I recommend you switch to the Morningstar. The Kemo doesn't have a "load" connection so you wind up with your charger in parallel with the battery. There exists the possibility of damaging your battery through overuse that way. The Morningstar will disconnect the load when the battery drops its voltage, thus preventing damage.


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## IonicBond (May 8, 2013)

ChrisGarrett said:


> I use the Morningstar 10L and a PowerSonic 12Ah SLA/AGM battery, but I've kept the jumper on, as that's what I thought I should do...Should I remove the jumper when topping off my seldom used battery? Won't hurt it?



Not at all provided that if you run your gear while charging the SLA, it can handle 14.7v. Most of my nominal 13.8v gear has no problem with 14.7 since that fits between the typical +/- 10% of 13.8 v rating.

In the jumpered position, the default to "sealed" is a protection mechanism for users that don't know their battery chemistry and will protect sealed gels. If you KNOW you are running an agm, removing the jumper - even though the silkscreen indicates flooded - the actual proper voltage of 14.7 volts will be applied for absorption for agm's. If you ask Morningstar about it, they will tell you to follow the right voltage, and not necessarily the silkscreen label.

The smaller Morningstar Sunguard 4.5a and also the PowerFilm RA9 (rebadged Sunguard) default to the lower 14.1v which is not ideal for agm either. It will work, but for those using them, they may want to consider upgrading to the Morningstar 6L series that provides the jumper.

Reaching the absorb voltage of 14.7 volts is crucial for agm's. You could play it safe and use the sealed setting, but it just means you'll be buying batteries more often as the agm's are never getting a *full* charge. By never getting a full charge, the capacity is "walked down" by sulfation bit by bit. And just merely reaching 14.7v is just the *start* of the absorb cycle. Now that the maximum voltage is limited, the battery finally gets fully charged and is indicated by a natural reduction of current as dictated by the battery itself.

Put it this way: when an agm leaves the factory, it has been charged to 14.7v first.


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## IonicBond (May 8, 2013)

WARNING - forgot to mention that these voltages are at a 68F temperature. Fortunately the morningstars are temperature-compensated. Just wanted to mention this so nobody goes into their 100F garage and starts charging an agm at 14.7v with a lab supply. See your battery's spec-sheet for temp comp.

The end of the absorb cycle is usually when the battery current is .03 * C. That would be about 210ma for a 7ah agm.

State Of Charge SOC voltage:
While the following test will tell you nothing about your agm battery's health or capacity, you can get an idea of how well your solar setup is doing. With NO CHARGE and NO LOAD, let the battery rest for 4 hours and take an open-circuit voltage measurement:

100% = 12.9 to 13.3v
75% = 12.6v (good cycle life)
50% = 12.2v (ok, but limits cycle life)
25% = 12.1v (try not to go here except in emergencies)
Dead = 11.9v (damage / dead)

The actual manufacturer's spec may differ a little bit, but this is a very close ballpark.


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## hiuintahs (May 8, 2013)

IonicBond said:


> The actual manufacturer's spec may differ a little bit, but this is a very close ballpark.



The specs on my Dekka AGM battery with no load:
100% = 12.80v or higher
75% = 12.60v
50% = 12.30v
25% = 12.00v
0% = 11.80v and below

Note they say to take the measurement after the battery has been sitting with no load for 24 hours.


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## independent (May 8, 2013)

@semiman. Yes 5w panel. It's difficult to explain here the answers to the rest of your question here. But the purpose of (was "an" but corrected to "our") our MPP regulator is to provide a voltage regulated output. Essentially a solar panels is a current regulated output which makes them great battery chargers. However a solar panel will not maintain provide a proper output for variable loads (remember a battery presents itself as a dead short for most it's charge depending on the chemistry). However we are only charging batteries through a circuit we are not supplying 5v regulated to a circuit which depends on it, to do this you would need to up the source (solar) massively guessing 5-10x basic requirements. Anyway, the circuit I am trying to describe "fails" honorably. It holds 5v as well as it can and current supply drops as the energy input lessens. You want it to maintain 5v well. The main question is how does the load (phone/tablet) respond to the ability of a source to provide the current. The phone I tested staggers it's current and will not go beyond what the source will supply. Yes you need light to use this charger!


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## independent (May 8, 2013)

@slazmo I would highy recommend building yourself a "ghurd" controller for your AA NiMH battery. I have built two of them and other than having a great deal of respect for the man I have no other connection. Its a kit 15-17$US shipped anywhere in the world. LSD NiMH make the absolute best micro solar batteries. Adjustable voltage cut off the can be built as LVDs, simple slam-bang controllers or proper diversion controllers. I've built them as the last two types. Really good, reliable controllers with decent componentry. Regarding battery chemistry types, the eneloop stress tests to 1000+ recharges would kill any SLA in a dozen or two cycles using the same procedures. Deep cycles flooded probably wouldn't handle much more (SLAs, VRLASs, and deep cycles should not be used beyond %50 DoD at any rate). LiFePo4 act like normal lithium and charge resistance doesn't rise appreciably as SoC rises. They need complex controllers with cell management even in single series batteries (yes tried it). LSD NiMH for simple long lived micro- and nano- solar setups.


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## IonicBond (May 9, 2013)

hiuintahs said:


> Note they say to take the measurement after the battery has been sitting with no load for 24 hours.



That long of a wait will be very accurate! I'll bet that if you check after 4 and then check again after 24 hours, you might opt for 4 hours as close enough. 

Dekka is a good brand of AGM. Good docs too - usually an indicator of quality manufacturing.


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## hiuintahs (May 9, 2013)

Ya, you're right 4 hours is probably good enough. Dekka was handy as there is an East Penn distributor in town and so no shipping costs. When my truck battery finally bit the dust, I replaced it with Dekka's Intimidator (rather than go the Optima route). The Intimidator is a combo starting battery / AGM. It wasn't cheap though!

On my portable battery, to keep the voltage from dropping too low and damaging it, I have an adjustable trip point that opens up and disconnects the battery from the output port connections.


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## independent (May 9, 2013)

@slazmo again. I misread your post sounds like you are looking at charging AAs and AAAs independently for use in other devices. I wrongly assumed you were making a 10xAA (ie 12v) battery. 10w is a good sized panel for AAs (half an amp of solar) and a ghurd controller. So IMO Your only realistic option is either a 12v battery (like an SLA or 10xAA NiMH) battery option an a simple maha type independent cell charger like the venerable 401fs charger. OR something like a MPP solar direct Linear Current Booster (LCB) like the one I mentioned several posts back running batteryless and the LCB as a kind-of psuedo-battery..


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## SemiMan (May 9, 2013)

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## SemiMan (May 9, 2013)

IonicBond said:


> WARNING - forgot to mention that these voltages are at a 68F temperature. Fortunately the morningstars are temperature-compensated. Just wanted to mention this so nobody goes into their 100F garage and starts charging an agm at 14.7v with a lab supply. See your battery's spec-sheet for temp comp.
> 
> The end of the absorb cycle is usually when the battery current is .03 * C. That would be about 210ma for a 7ah agm.
> 
> ...




With a good quality battery, you can discharge to 25% SOC hundreds of times. The issue is making sure you charge the battery soon after as it is leaving it in this state that really does the damage.


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## SemiMan (May 9, 2013)

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## independent (May 9, 2013)

@semiman. from the above statement and your earlier questions it seems you don't fully understand how, what I am describing, works. I am talking about a specific MPP (strictly without the tracking) designed as an LCB. This is not the same as chucking on a USB charging device to a solar panel. Our MPP (without the tracking) LCB is designed with the best components money can buy with big low ESR input and output caps--nice. Solar battery-less USB charging easy ;-) I have tested them with 2x diff expensive N-series microUSB smart phones as well as other devices without problems. Each charging device works differently--but after watching (ie taking note of current flow over different charging scenarios) them react to lesser available current you can see it working well. Also, on our CC licensed circuitboard there are reverse engineered (thanks Lady Ada et al) voltage dividers for 500mA limiting charging currents and a non or higher limited current output. That is 2 different USB outlets with separate voltage dividers on both sets of data pins for the different outputs. Also some of this is academic because much (smaller) cellphone charging is done after the charging regime is into constant voltage mode and the current is tapering down. However, with tablets and big battery cellphones that is another story as they require far higher current capable power supplies.


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## IonicBond (May 10, 2013)

SemiMan said:


> With a good quality battery, you can discharge to 25% SOC hundreds of times. The issue is making sure you charge the battery soon after as it is leaving it in this state that really does the damage.



I couldn't agree more! At that low of an SOC, one has to get it recharged nearly immediately. I regularly reach 50% SOC even though ideally one doesn't want to go lower than 75% for the most cycles. However, one can go overboard if they only draw down to say 75% SOC but only do so a few times a year - the battery will die of old age (4-5 years or so depending) before dying of too many cycles.  It's all about the power budget.

Re MPPT controllers - they are great, but if your system is about 200 watts or lower, it may be cheaper and easier to just pick up another panel as long as the PWM controller and battery can handle the additional input.

I have a lot of fun with Odyssey / Hawkers. However the *minimum* charge current is .3C and it's a blast to fast-charge them via solar in an hour if you have enough panel/controller. If one has a panel big enough, the Hawker Monoblocks may be an ideal replacement for small setups when there is very limited solar insolation since you can charge them so fast. I only take the Monoblocks up to 1C, but the big Odysseys can handle a lot more.


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## independent (May 10, 2013)

@semiman and others. Apologies. I've been trying to describe a project a friend and I have been working on in our spare time as well as at the same time contribute to this conversation. It's come out a bit muddled (by me) and generally just added confusion to the topic being discussed. My friend and I have built and tested a solid Maximum Power Point (MPP) Linear Current Booster (LCB) circuit. The circuit has been pretty well tested and once the printed PCBs are looking as good we will release the Eaglecad files under some kind of Creative Commons license. Google LM2596 LCB and there is a thread on fieldlines should show some of the preliminary work done..


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## hiuintahs (May 10, 2013)

Not to be antaganostic independent, but I haven't quite understood what you've been talking about all along until I Googled "LM2598 LCB" and saw the thread at Fieldlines.

OK so you guys are having a little fun with a circuit and TI's LM2596 simple switcher buck regulator. Of course any buck regulator would work in this case but you also use a terminology that I've never heard of......(LCB). When I first saw the circuit and only a buck regulator, I knew it couldn't be an MPPT charge controller because there is a lot more to them than just the buck drop down circuit.........such as the smarts that go along with providing the proper 3 or 4 stage charging algorithym. So what is linear current boost?

edit: so reading back on some posts, it sounds like it's a battery-less type of charging that you are doing..........How does it work to keep the charge currents regulated or the charge voltages proper to the device being charged? And how does it know to terminate charge when the device is all charged up?


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## independent (May 10, 2013)

@huintahs If you look at the circuit as it is designed on the fieldlines thread there are actually 2x regulators (with big caps on the input and output). For my version there is an LM723 on the front end which is adjustable according to where you decide the MPP of the solar panel to be (from memory operahouse uses zenar diodes for the same function, simpler but lesser granularity). The LM2596 is used for regulation but also in pure LCB mode where voltage is left floating ie the output voltage is not regulated. The capacitors store the energy just long enough so it can be efficiently regulated into a lower voltage. I can't explain here better than what is already in the the thread at fieldlines. But I'll give it a go anyway 

If you can get your head around a MPP regulator with a floating regulated output you are more than halfway there. 

Consider a solar panel. The voltage when faced with a load, collapses. It is a pure current source output. Great battery chargers but not much good for doing any work. 
Now consider an LCB. When connected to a motor current demand goes up with voltage more or less linearly. More power = more voltage + more current in more-or-less equal amounts. An LCB will attempt to provide for this demand much like a battery would. The circuit we are using will do this when configured with a floating output. 

And that is what this circuit does simply and efficiently. The circuit is adapted from a circuit designed by Chris Graecen of homepower magazine fame.


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## SemiMan (May 12, 2013)

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## SemiMan (May 12, 2013)

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## SemiMan (May 12, 2013)

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## Spork (May 20, 2013)

I just wanted to say thanks to everyone again for the informative information. I charged my first set of eneloops on solar. I bought a ammo can to keep everything in. I used deans instead of the mc4 connector and I also ordered a solar breaker switch so I can easily disconnect the battery when not in use. Fuses on the positive side of the battery and the load output from the controller. I was able to find the 3/16 f1 connectors at radio shack for the battery terminals. I pulled the jumper on the 10L so hopefully that is ok for my battery (ub1270). The instructions for the c401fs say it will run from 9-15 volts. I hope that will work ok for the phone charger too. 

The only other thing that I'm looking at is fans right now. There is well reviewed 12 v fan called the endless breeze but it eats up 15 watts even on low. I might scavenge some 120 mm pc fans and put a hangar on them or something. It was a very fun project and I picked up all kinds of goodies like a digital volt meter and automatic wire strippers.


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## IonicBond (May 20, 2013)

Nice! Just remember to switch on the battery first, and the panel last. Smart controllers need a battery reference voltage first before applying the solar input, otherwise they assume that you have a totally discharged 0V battery, and can prevent charge, or sometimes default to a float trying to protect what it thinks is a dead battery.  It is also the reason that trying to check a controller for proper operation without a battery attached first makes some think the controller is bad when it isn't. 

What might be interesting is after starting from your fully charged 7ah agm, is to charge the eneloops, and then let the agm rest for 4 hours and take an open-circuit voltage reading and compare it to the values listed earlier to get an idea of how much it has taken out in one charge cycle.

If the endless breeze draws 15 watts on low, then lets see .... 15w / 12v = 1.25a. Yikes - that would mean about 3 hours of operation before reaching the 50% SOC point on the 7ah agm. Keep an eye on that thing!


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## Sub_Umbra (May 20, 2013)

(Spork) Glad you are able to move along.



Spork said:


> ...The only other thing that I'm looking at is fans right now. There is well reviewed 12 v fan called the endless breeze but it eats up 15 watts even on low. I might scavenge some 120 mm pc fans and put a hangar on them or something. It was a very fun project and I picked up all kinds of goodies like a digital volt meter and automatic wire strippers.


Many in the teardrop tiny trailers forum have discussed the fan issues you are looking at. Many of them like 12v computer fans.

I have found the teardrop tiny trailers *electrical forum* to be very informative from my prepper's point of view. Though they are recreational, they are also dealing with the nuts and bolts of *tiny systems,* which is right where many preppers are at.

Please let us know what you learn about fans.


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## jamesperner (Dec 19, 2013)

You can use solar power to charge your standard rechargeable battery power. This is not only a green practice it can reduce the amount of power you use. Building a solar-powered battery charger needs a screen, a preventing diode and a battery holder.


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## Sub_Umbra (Dec 19, 2013)

jamesperner said:


> You can use solar power to charge your standard rechargeable battery power. *This is not only a green practice* it can reduce the amount of power you use. Building a solar-powered battery charger needs a screen, a preventing diode and a battery holder.


Emphasis mine.

There is *nothing* inherently *GREEN* about power derived from photo-voltaic cells or panels. The *entire* service life of ANY PV panel _will not produce more power than the petroleum required to manufacture it._ Thats not to say PV power doesn't have its place...*its just not green.*



If you want to prove that PV panels are *"GREEN"* go ahead and lay out a breakdown of just how much energy it takes *to create one* compared to the energy produced by the panel in question _throughout its service life._ Without such a breakdown such claims are totally meaningless.

Some facts:

PV panels do not occur spontaneously in our universe. 

There are no solar powered earth movers to dig the ore. 

There are no solar powered trains to bring the ore to the refiners. 

There are no solar powered refineries to process the ore. 

There are no solar powered factories to turn the refined materials into PV panels. 

There are no solar powered trucks to deliver them to your house.

*All* of these operations rely on *more* energy from either *petrochemicals or coal* and to not figure that into the mix is dissembling at best.

On the other hand, I agree with what you said about the diode.


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## ChrisGarrett (Dec 19, 2013)

Spork said:


> The only other thing that I'm looking at is fans right now. There is well reviewed 12 v fan called the endless breeze but it eats up 15 watts even on low. I might scavenge some 120 mm pc fans and put a hangar on them or something. It was a very fun project and I picked up all kinds of goodies like a digital volt meter and automatic wire strippers.



I went to Walmart and bought an Ozark Trails branded '02 Cool' 10" 12v fan that has a 12v DC input and which runs on 8D batteries.

I used it a lot over the summer, on my patio here in Miami, to beat the heat and humidity while smoking my cigars. You can find them on Amazon for over $20, but I think I paid like $9.99.

I don't expect it to last a lifetime, but the fan blade design is nice and it's got two speeds. Runs on 12v/500mA input, so not a huge drain.

Chris


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## SemiMan (Dec 19, 2013)

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## Sub_Umbra (Dec 19, 2013)

Sub_Umbra said:


> snip...If you want to prove that PV panels are *"GREEN"* go ahead and lay out a breakdown of just how much energy it takes *to create one* compared to the energy produced by the panel in question _throughout its service life._ Without such a breakdown such claims are totally meaningless....snip



Lay it out.


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## Norm (Dec 19, 2013)

Sub_Umbra said:


> Yeah, so what part of that is beyond *your grasp*? I'm not interested in *you writing* about how easy it is to it out. Lay it out.



Sub_Umbra discuss and respond to the post if you wish, there's no need to make this discussion personal - Norm


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## Sub_Umbra (Dec 19, 2013)

Aforementioned post edited


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## SemiMan (Dec 19, 2013)

No worries Norm. If Sub would like to change feet that's okay but a little bit of Google goes a long way. There was a ton of research on this 4-5 years argue then it stopped being discussed because its a non issue as anyone who has done the research knows. As I am not the one trying to refute the common knowledge on this I dont really feel a need to defend my position since its not really a position its fact.

Semiman


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## harrycolez (Dec 20, 2013)

*Solar power for charger*

Hey sorry if this is the wrong place,
So I have this charger:
http://www.amazon.com/gp/product/B004AWE2L2/?tag=cpf0b6-20
and I noticed it has a power input of 12v 1a which is 12w correct? 
Since im looking for a portable solar charger would I need one that has an output of 12w?
Also are there any or is it ok to under-power the charger?
Thank you for your time.


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## ChrisGarrett (Dec 20, 2013)

*Re: Solar power for charger*



harrycolez said:


> Hey sorry if this is the wrong place,
> So I have this charger:
> http://www.amazon.com/gp/product/B004AWE2L2/?tag=cpf0b6-20
> and I noticed it has a power input of 12v 1a which is 12w correct?
> ...



That looks like my Xtar WP2 II charger that I use with a solar charging system.

The problem that you'll have is, is that by going straight from a solar panel to that charger, you'll have erratic voltage swings. Assume that you have a 20w 12v panel. That panel can have an open voltage of ~15v-22v with no load and that might wreak havoc on your Xtar charger, possibly burning it out.

Some here fell that unless you want to be there for a month, charging at 300mA, you'll want a starting point of 20w. The 10w foldable panels output about 600mA on a laboratory test bench, so less in the real world.

What you really want to do is get something in the 20w range for panels, either two 10w panels daisy chained together, or a single 20w panel. You'll then want to get a digital solar controller, that acts as a buffer between your panels and your load, modulating/regulating the panel(')s voltage. Most of us run a 12v SLA/AGM mother battery in between and then charge off of that, back at home base. 

The panels will send amperage into the controller, which will then charge the battery AND power the load.

Here's my setup from August of '12. That is the Xtar WP2 II on the bricks and you can see the small 12Ah mother battery there as well. The black thing on the white signboard is a Morningstar SS 10-L controller and that allows the 12v cigarette socket to get power from the battery, which is being topped off by the PV panels (2x30w.)







You can go smaller on the battery, if you want.

Here's the link:

http://www.candlepowerforums.com/vb/showthread.php?342073-Portable-solar-charging-setup-I-just-built


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## hiuintahs (Dec 21, 2013)

*Re: Solar power for charger*

 


harrycolez said:


> ........ I noticed it has a power input of 12v 1a which is 12w correct?
> Since im looking for a portable solar charger would I need one that has an output of 12w?
> Also are there any or is it ok to under-power the charger?.....


  
 You can power that charger with less power as long you're not charging at the max rate. It's a function of
  
 Total power input = power output + power lost by the charger's electronics.
  
 As an example, suppose you are charging only one battery at 500mA and the battery currently is at 4.0v in the charge cycle........well that is 2 watts. That is the output power.
  
 Assuming that the charger is utilizing switching power supply technique (not linear) for best efficiency, then let's assume a 75% efficiency. That means it will be drawing 2w / 0.75 = 2.67 watt requirement for input power. So the 12v supply needs to source at least 0.222 amps with this example. (12v x 0.222a = 2.67w)
  
 The issue is that its not a good practice to go straight from solar panel to charger because the solar output can swing all over the place based on clouds and sun movement.
  
 There is 3 areas of caution when going straight from solar to lithium ion charger:
  
 1) Can the charger handle input voltages up to 22v which would be worst case high voltage from solar panel?
  
 2) Be prepared for numerous resets if voltage drops too low on your solar system due to clouds, night time, changing sun angle.
  
 3) Solar panel needs to be sized such that its rated maximum output is say 3 times greater than the maximum load you intend to draw from it. This accounts for the variance as described in #2 above.


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## harrycolez (Dec 21, 2013)

*Re: Solar power for charger*

So if the input for the charger is 12v and the output to the battery is 4.2v at a peak of .5a but it was unable to provide the current it would just scale down? So long as it was able to provide the voltage needed?


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