Maha MH C808M Charger

[Sub_Umbra]

Hello Cam,

Welcome to CPF.

It is not quite as difficult as Sub Umbra makes it out to be. He, myself, and others are just put off by the inadequate instructions that came with this charger. It would have been nice to have this "undocumented" procedure "documented."...

SilverFox,

As usual, you sum things up pretty well. I use the AP 2020 and the C808M and for my needs those two chargers work together very well. Contrary to my ravings I like the C808M well enough that I would buy the exact same charger again, even if it was accurately discribed in the ads. It does what it does for me so well that I have no qualms about it's functionality. It is only Maha's advertizing distortions and the lack of a comprehensive owners manual that really leave a bad taste in my mouth.

This page contains a copy of the AP 2020's manual which seems pretty complete and lacks (many of) the distortions and omissions of the one page instruction sheet that comes with the Maha C808M. AccuPower thoughtfuly provides a manual that attempts to make all of the features of their product accessable to the buyer even though the ticket price is less than 60% of the Maha. If I run across the instruction sheet that came with my Maha I'll scan it and put up a link to it.

While the feature sets of the two chargers are like apples and oranges, at least Accupower makes an effort to explain its product's capabilities to the purchaser. IMO Maha does a disservice to it's product and it's customer base by making generalized claims for this high quality product that are not accurately supported in the documentation it ships with.

I would love to be able to do a search for all of my posts about the C808M instruction sheet and edit each of them to reflect that this issue has been resolved.

 

[Ares]

The operators manual also states that you should not leave an empty slot when putting your cells in for charging. Maha does not know why that statement is in there… Anticipating some problems, I did a number of tests starting from right to left, filling the middle slots, and skipping every other slot. The C808M took it all in stride and performed flawlessly. It truly is an independent 8 channel charger – with no restrictions.

Here's what I found from the review linked on Maha's product page for the C808M:

Maha states in the MH-C808M manual sheet the largest capacity battery needs to be placed in the left-most side of a charger slot, followed by the next lowest capacity battery, and so on. Also, there should be no empty slots in between batteries in the charger. The reason for this advisory is because of the nature of larger capacity batteries and smaller capacity batteries being attached to the same electrical connection. If a smaller battery is placed first in line, then followed by a larger capacity battery, the larger capacity battery has the potential to draw more power from the smaller capacity battery, resulting in a false reading.

Based on this review, it seems SilverFox's tests should have worked fine, but some of the batteries may not be charged completely (or possibly overcharged?). SilverFox, can you try again and test the battery, in light of this new information? It might explain this post:

My feeling on this charger is that it doesn't seem to charge to as high a capacity as my MH-C204W, but it comes off cooler. I think I'm going to spend some time in the next few weeks to do a controlled experiment to see which of my chargers produces what charge results on my batteries.

A thing I find a little concerning is that it seems slot 3 and 4 seem to charge to a higher capacity than slot 1 and 2. I can only say this is true when charging 4 batteries at once as that is my only test scenario right now. I thought it was the batteries at first, but I swapped the positions and it happened again, so then I mixed the batteries up, and it still came out the same way. Slots 3 and 4 came out with higher capacity than slot 1 and 2. They were about 50mah apart. I have to do more testing to verify, and try out the other slots as well.

Tom, when you tested to make sure all the slots in your unit charged evenly, was that charging with all of them at the same time, or did you use one slot at a time and test the capacity after each charge? I've seen a couple of slots go from charging to complete at the exact same time which seems odd. I notice this with a few other independent cell chargers too. I wonder if the signal from one battery completing causes the other ones to trigger finished even if they're not. This needs some more investigation.

So, bcwang, try putting the batteries in left to right order by mAh capacity. So throw your 2500 mAh's in first, followed by 2,300 mAh's, 2000 mAh's and so on. See if that solves your problem.

Side story:
I've been the proud owner of the MH-C401FS for about a year. Unfortunately the darn thing got hit by lighting yesterday, evidently. It was plugged up but the LED's were off. I unplugged and plugged it back in, same thing. I also noticed that when plugging it back up, tiny sparks would fly out of the jack.

Crazy part is, I woke up this morning and tried it again.. and it works again! Although the sparks (just about 2mm long) zip out as I plug it in. Is this normal or not? I never really paid close attention before it started acting up. I know sometimes when you plug a power cord in, it can spark a little teeny bit. I'm not sure if mine is busted or not, and I'm afraid to leave it plugged up while I'm not at my house.

Basically, that's why I'm looking into this charger now. I was looking for reviews when low and behold I stumbled upon this review on CPF. Must say I love this forum! :twothumbs

Also, does anybody know of a Eneloop / Rayovac Hybrid type C or D battery? I was looking to use 8D's in my Maglite, but I don't want the batteries to leak all their energy before I get around to using the flashlight!

 

[SangYuP]

I heard the Maha C800s is exactly the same except the charge time is double. Does this mean that the 800s does trickle charge automatically after the charge is complete? So it goes into trickle once the display says "DONE"? Or does trickle charge only work when conditioning?

 

[SilverFox]

Hello Ares,

Welcome to CPF.

I missed your post when you posted it, so sorry for the delayed reply.

The reason to put high capacity cells toward the left of the charger has to do with the heat from the discharge circuit. If you discharge C and D cells you will notice that the right side of the charger warms up. This is where the discharge circuit is located. By keeping the higher capacity cells away from the heat, the whole charger runs cooler. Each slot is independent, so there is no advantage in charging regarding placement of the cells.

Since each slot is independent you can also skip slots, or load from right to left, or any other combination you care to use. Just keep in mind that the right side of the charger gets warm.

Lightning tends to over voltage things... I would toss your old charger and get a new one. The 808 would be an excellent choice.

The low self discharge battery manufacturers will start producing C and D cells with the new chemistry when there are as many C and D cells sold as there are AA and AAA cells. In other words, don't hold your breath...

Tom

 

[SilverFox]

Hello SangYuP,

Welcome to CPF.

The 8xx series of chargers all go into a very small trickle charge after charging. This happens regardless of the charge rate. The trickle charge is really a maintenance charge. While it is not recommended to leave batteries on a charger after the charge is complete, this charger would be easier on cells left in it than most other chargers.

Tom

 

[SangYuP]

Silverfox,

Thank you for the information! That really helps out since I am expecting mine to arrive tomorrow. So the 800s is exactly the same as the 801D except for the slower charge rate, right? Thanks again!

 

[john2551]

Tom,

The funny thing is in the promo pic it show the big cells on the right: http://www.thomas-distributing.com/maha-mh-c808m-pic-win.htm

Someone at MAHA should have read the instructions before taking the pic!

John

 

[GarageBoy]

Also, fan is on the left

 

[SilverFox]

Hello GarageBoy,

I wasn't aware that any of the Maha 8xx chargers had fans...

Tom

 

[LEDAdd1ct]

Now that low self-discharge C and D cells have finally arrived, has anyone had the chance to play with either this

http://thomasdistributing.com/shop/...P_id=&osCsid=0269a6cf0ecbadac7ad49e29ed2e9968

or this

http://thomasdistributing.com/shop/...P_id=&osCsid=83b8bb2b81510fff13789f59dd2b604d

in the C808M?

I am thinking of picking up a bunch of the LSD D size and a pair of the C to use, and was wondering how they do/how they do in this charger.


LEDAdd1ct

 

[Anders]

Hello LEDAdd1ct.

A good choise, they should perform as good as C808M perform on AA and AAA LSD cells, flawless

Anders

 

[ChuckD]

What a great discussion! This is my first post here and I'm not sure this is the correct place for this question so I'll start a new thread if desired. My question is about the C808M tho.

I have around 30 of those solar lights you stick in the ground to illuminate walkways, etc. I did some research on them and found the Westinghouse Europas to be the best, and they are great. Each has two LEDS and two rechargeable AA NiCds. The batteries are labeled IDC brand 900 mAh.

I've been using Powerex NiMHs for my digital camera needs for several years now, 2000 and 2100, and I decided to try them in the solar lights as I retired them from photo use. They work fine.

My question is as follows. Now I have a boatload of rechargeable AA's of various ages and capacities. I'm finding my solar lights are showing uneven charging and suspect many of these well used batteries are failing.
But since the lights each take two batteries, I can't be sure which is the weak one. So, can this charger be used as an indicator of battery health? Obviously if a battery won't charge, that's a clue right there. But is there something about how the charger reacts to a given battery that I can use to weed out the depleted ones?

Also, given that these batteries are charged on a solar charger during the day (possibly not to capacity) and depleted overnight, what's the best strategy for prolonging their life? Would they benefit from periodic conditioning?

Thanks all for your participation, it's been very 'enlightening' (sorry!).

ChuckD

 

[Sub_Umbra]

Now that low self-discharge C and D cells have finally arrived, has anyone had the chance to play with either this

http://thomasdistributing.com/shop/...P_id=&osCsid=0269a6cf0ecbadac7ad49e29ed2e9968

or this

http://thomasdistributing.com/shop/...P_id=&osCsid=83b8bb2b81510fff13789f59dd2b604d

in the C808M?

Thanks much for the links. I've been out of touch for a couple months and I've been hoping someone would come out with lsd Cs and Ds for some time now. This is great news to me.

Thanks again for the links.

I love this place.

 

[Canuke]

Ditto here. Somebody had said in passing elsewhere that C and D LSD's were out, and I was just about to post asking where they were.

Thanks LEDAdd1ct for the links!

Now I just need to figure out what application I need these for, instead of AA Eneloops in adapters...

 

[SilverFox]

Hello ChuckD,

Welcome to CPF.

While the 808M is a great charger, it lacks analytical capabilities.

If you are in the market for another charger... check out the C-9000. It has the analytical capabilities you are looking for.

You may be able to check voltages and weed out some of your cells. Also, you can measure the voltage of the cell under a load. You can use a resistor as a load and sort your batteries by voltage under load after they are fully charged.

The next step is to check the cells for matching capacity. Your lights use 2 cells in series. If one cell has less capacity than the other, the light will prematurely dim. If you get up early in the morning, you can pull cells from the lights and immediately measure their voltages. If one cell in a set is a lot lower in voltage, or has gone to negative voltage, it was the one that had lower capacity. It takes some time to go through your batteries this way, but it usually works. You can mark the low voltage cells and begin using them together in sets. Or you can set aside the low voltage cells and use the stronger cells.

You can also do this testing with a flashlight.

Tom

 

[ChuckD]

Thanks for that SF, wasn't aware of this analyzer. I was hoping there would be something about a battery's behavior in the C808 that would be a give-away to it's health.

Thanks again.

C.

 

[Ares]

Hello Ares,

Welcome to CPF.

I missed your post when you posted it, so sorry for the delayed reply.

The reason to put high capacity cells toward the left of the charger has to do with the heat from the discharge circuit. If you discharge C and D cells you will notice that the right side of the charger warms up. This is where the discharge circuit is located. By keeping the higher capacity cells away from the heat, the whole charger runs cooler. Each slot is independent, so there is no advantage in charging regarding placement of the cells.

Since each slot is independent you can also skip slots, or load from right to left, or any other combination you care to use. Just keep in mind that the right side of the charger gets warm.

Lightning tends to over voltage things... I would toss your old charger and get a new one. The 808 would be an excellent choice.

The low self discharge battery manufacturers will start producing C and D cells with the new chemistry when there are as many C and D cells sold as there are AA and AAA cells. In other words, don't hold your breath...

Tom

Thanks for the welcome! It seems I missed your post as well, though. I had subscribed to this thread but never received any notification - although other threads notify just fine. But anyway...

Thanks for the info about the heat and battery placement. That makes a lot more sense. The way other sites / people had been explaining it, it sounded like it didn't have independent slots. I've read several places that you should not skip slots, etc. Slightly confusing. I emailed Maha about this, and my charger that was acting screwy. The guy from Maha frankly told me he had no idea why their website stated to do that, and to disregard it haha. I'd post the email, but it's been so long that I've deleted it.

Seems I didn't have to hold my breath for too long for those low self-discharge D batteries, eh? Haha. Thing is, I still have my old charger actually. The Maha guy said that short little "spark" when I first plug it in, is normal. And that if you plug the charger in with the batteries already inside, sometimes it will not do anything at all (e.g. appear to be broken due to a lightning strike, I suppose). So my charger is just fine. Was just a fluke, evidently. I'm still considering this other charger though - but I'm thinking some AA to D battery converters would be just as good, and way less expensive. Those Powerex D batteries are expensive! Thing is, I can't figure out where to buy any 3 or 4 AA to 1 D converters (I'd want them as parallel, not in a series). I found where Warren was selling a few on here, but he doesn't seem to be around anymore...

Any clue where to get those? Perhaps you could PM me, as to not get this thread too horribly off-topic

Thanks!

 

[SilverFox]

Hello Ares,

You will have to do some searching on CPF. I believe there are some AA to D adapters available, or in the process of being made.

It would be interesting to see how well AA cells stay in balance if they are paralleled in a D holder and charged in the 808...

Tom

 

[john2551]

Ares,

Eastgear & aventrade used to sell 4AA to D parallel adapters.

 

[Ares]

Yeah, they are both sold out. Believe me, I did my homework. I scoured this site like crazy before posting, but I can't find any available.

http://www.eastgear.com/shop/index.php?cPath=29_50
http://www.aventrade.com/baad.html

I see where SilverFox mentioned someone might be in the process of making them here - but after looking, I have no idea whom. Except that Warren guy that hasn't posted in a month.