16 Slot NiMH AA Chargers - Recommendations Needed

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muzzleblast
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16 Slot NiMH AA Chargers - Recommendations Needed

The rural Tennesse community where I live has an ever increasing problem with coyotes. Lately, between 9:00 PM and 2:00 PM the packs (and there are several) will begin their calling. I recently received one of the Maxtoch BLF group buy version M24 Sniper flashlights. So, after the howls began one night, I lit the pack up in an adjacent pasture from a few hundred yards away. There were over 10 pairs of eyes in the group. Basically, the situation has gotten to the point that neighbors family pets have been taken.

So, I decided to purchase two Primos Alpha Dogg electronic predator calls with the remote “Strat Cat” decoy. In all, 15 AA batteries are required to operate each unit. I have ordered 32 Panasonic Eneloops to feed these predator callers. Now, I need to be able to charge them.

I have done some googling for 16 slot NiMH chargers and it seems the Tenergy TN438 and Knox 16 Rapid charger have mixed reviews. The SunLabz 16 slot Smart charger seems to have somewhat better review. The Titanium MD-1600L has more favorable reviews.

The Maha PowerEx MH-C808M Ultimate Professional Charger seems to have the highest reviews, but only charges 8 at a time, and costs about twice compared to the Titanium MD-1600L.

It would be appreciated if any members have experience or recommendations to share about charging Eneloops in bulk.

Thanks

onetrickpony
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I don’t have the other models you mentioned but fwiw I have the Powerex MH-C808M and it has been abolutely flawless in several years of ownership. It gets used every day, and often has to charge 8 batteries at a time two or three times in a row. No problems at all, I’d highly recommend it.

I like that it came with a massive power supply that is halfway down the power cord as well, no cheapo wall wart taking up extra spots on a power strip.

Good luck with the coyotes Smile

muzzleblast
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Thank you onetrickpony for the valuable feedback. Can you tell me approximately how long it takes to charge 8?

onetrickpony
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muzzleblast wrote:
Thank you onetrickpony for the valuable feedback. Can you tell me approximately how long it takes to charge 8?

It depends on the capacity of the batteries and I haven’t actually timed it, but I’d say about an hour for my best/newest cells. I use Imedions and some Duracell, all lsd type.

It also has a slow charge feature, which I have literally never used Silly

wight
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Have you considered charging these cells as a pack? Good NiMH pack chargers are much larger supply than good high-cell-count individual NiMH chargers. The stock wiring and battery holder look to be on the thin/weak side (which is fine for the intended use!), so some caution might be needed. Personally here’s what I think I’d do:

  1. Make a little adapter to go from a standard high-current pack connector (such as Deans Ultra or XT60) to the connector used by the Alpha Dogg. (Is it a 9v battery connector?)
  2. Solder up my Eneloops into a pack with my chosen high-current connector.
  3. Done. Now I can charge the pack properly but I haven’t modified the pricey Alpha Dogg in any way. There should be plenty of space for all of this in the battery compartment.

Charging Eneloops at 2C+ should be fine IIRC so 1/2hr charges should be easily achievable. IIRC they’ll handle much more, I think that I previously charged Eneloops at around 5C? An inexpensive RC-oriented pack charger such as the ultra-cheap-crap $30 B6AC clones on eBay can charge at around 2C. HobbyKing might be the best place to purchase one or more of those since HK provides them with an XT60 ready to go (and HK is slightly more reputable than random eBay dealers). If you have a DC power supply to use then higher quality clone chargers are available for <$20.

EDIT: I forgot about the stray cat decoy. I haven’t seen it, so I don’t know whether there’s enough space for a pack with a charging connector or not. The hobby chargers I mentioned should happily charge whatever voltage NiMH pack you attach to them, so having both 4-cell and 8-cell packs wouldn’t be a problem.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

Halo...
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Fast charging can reduce the life of batteries. How much that matters depends on how often / fast you use the batteries and need to recharge them.

For example If you recharge once a week that is only 52 cycles a year. If the batteries have a useful life of 1000 cycles then they will last 19 years. If you recharge once a day it’s 2.7 years. Maybe fast charging will cut that in half due to the wear it causes. But if I recharge once a week, I really don’t care. The newest eneloops are rated at 2100 cycles but I’m assuming the capacity toward the end of 2100 is not great (just a guess) and instead using 1000 recharges for it “useful life”.

ggf31416
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Another option would be purchasing 4 panasonic aa charger packs”:http://www.amazon.com/Panasonic-Advanced-Individual-Rechargeable-Batteri... (4xaa each one), available for $16.21 each plus a power strip.

The disadvantages are that you already purchased the eneloops and that the CC-17 charger is slooow (7 hours for a full charge).

wight
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Halo… wrote:
An hour for a full charge from empty? That’s really fast. Fast charging can reduce the life of batteries. How much that matters depends on how often / fast you use the batteries and need to recharge them.

For example If you recharge once a week that is only 52 cycles a year. If the batteries have a useful life of 1000 cycles then they will last 19 years. If you recharge once a day it’s 2.7 years. Maybe fast charger will cut that in half due to the wear it cause. If I recharge once a week, I really don’t care. The newest eneloops are rated at 2100 cycles but I’m assuming the capacity toward the end of 2100 is poor (just a guess) and instead using the 1000 recharges for it “useful life”.

Meh. While it’s true that charging at these rates can reduce cell lifespan – who do we know of who’s worn out an Eneloop? I suppose there’s this: http://www.candlepowerforums.com/vb/showthread.php?392229-Japanese-Vs-Ch...

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)

muzzleblast
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Guys, thanks for all of the feedback.

It looks like the NiMH batteries charge pretty fast. That’s good.

Wight, yes, the Alpha Dogg uses an 8 AA battery carrier that snaps in/out using a standard 9v connector. The remote (3 AA) and Stray Cat (4 AA) have fixed compartments. I thought about contacting Primos to get some spare carriers for the Alpha Doggs just to make field swaps easier. Great suggestion about rigging up to charge a carrier full of batteries. But, I am a sub-novice here. About the only soldering I have done in years is on copper plumbing. But, the pack you describe may be a project for me in the future. It would be nice if the Alpha Dogg was compatible with some of the high capacity USB powerbanks. But, I’d bet from a marketing perspective, the typical “consumer” for the product is good to go with the ubiquitous AAs.

I had already ordered the Eneloops from a US dealer. After I read the linked CPF thread, I had an “oh no” moment. I reread the product listing and “made in Japan” was not stated. So, I probably have some of the “made in PRC” lower grade batteries in route. Oh, well, we’ll see. If so, at least the price was OK.

I’ll probably go with the Maha Powerex MH-C808M since it seems to be a quality unit and I should be able to rely on it for a long time.

Thanks again, everyone.

wight
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Gotcha. A complete lack of experience does make my suggestion a bit daunting, but it’s definitely not a big deal with the right equipment. To simplify my suggestion (if you are interested) you may skip all of the soldering. Here is what should be a compatible battery holder (they are common). Here is the connector (again, common). From there to interface with a charger it’s a simple matter of attaching the 9v clip-on wires to some of the wires included with the charger – this may be done with crimps if you can’t solder at all. Once that’s done you’re ready to go – the caveat here is that the cheap plastic holders will melt at high amperages. I can’t say exactly what current it’ll melt at, but you can easily determine that yourself at <$2/ea. 1C charge rates (~2A) might be OK, but I’m confident that 2C (~4A) will melt the holder.

As far as the Eneloops, I don’t want to get your hopes up but AFAIK the US market still gets the Japanese ones. As you said, worst case is that you’ll receive “acceptable” batteries from the Chinese factory(ies). Best case is that you get the Japanese / FDK manufactured ones which will last nearly forever and survive immeasurable abuse.

Still fine, still on a break. One day I’ll catch up with you folks! previous wight catchup Wink
list of my drivers & variants (A17DD, FET+1 stuff, WIP stuff, etc)