Picky 15-minute energizer charger.

slvoid

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Does anyone have an energizer 15 minute AA charger?

I bought one a while ago along with 2 packs of four energizer brand 2500 mah AA's and 2 packs of four 2300mah AA's. The 2500mah's are fine but fresh out of the pack, the damn charger gives me an error on 1 of the batteries out of the 4 from each pack of the 2300mah's.

What gives?!
 

wptski

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New cells may have high internal resistance which cause the E-15 to reject them. Older cells develope high IR too. There are other threads about problems with Energizer/Sanyo 2500mAh cells also.

It's best to charge new cells at .1C for 16 hrs. if possible to form them.
 

JackJ

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Slvoid!

Welcome to CPF! I enjoy your posts and humor at bikeforums. Yeah, the Engergizer 15 min. is picky, but that's probably a good thing considing the current it pumps out. As wptski suggested, try cycling the cell(s), using your slowest charger. The cheap timed model that comes with 4 Engergizer 2500's is probably ok, though I believe it's a little more current than 250 mAh. Once the cells are "formed", you might have better luck.

Jack
 

slvoid

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Crap, I threw away three AAA cells cause I thought those were “bad.” Son of a… Energizer, you just made the “list.”

I believe the energizer charger rams it in at 7-8 amps. Thankfully I have a cheezy wall wart charger that provides a gentle nudge at 165mah.
 

wptski

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slvoid said:
Crap, I threw away three AAA cells cause I thought those were “bad.” Son of a… Energizer, you just made the “list.”

I believe the energizer charger rams it in at 7-8 amps. Thankfully I have a cheezy wall wart charger that provides a gentle nudge at 165mah.
Not on AAA cells, it's PWM or Duty Cycled to about half what a AA gets.
 

slvoid

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Ok, I ran the two "bad" AA's down and recharged it again, the energizer AA works in the rapid charger now but the other one is still kaput. The saga continues..
 

wptski

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What doesn't charge in a E-15 "may" charge in other chargers like a MAHA C808M or others.
 

SilverFox

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Hello Slvoid,

I might also throw in that the cells that won't charge in the Energizer 15 minute charger may not give you good performance.

Yes, they have "some" life left in them. Yes, you can get them to charge on another charger. However, they will probably run at a lower voltage under load, have less capacity, they will heat up more, and may exhibit a higher self discharge rate.

Perhaps they should be labeled as substandard and reserved for low current draw applications that are not critical.

Tom
 

wptski

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Tom:

As mentioned before elsewhere. I have two Sanyo 2.7Ah cells that a E-15 rejects "only" when connected externally. These high capacity cells and others I've checked using a Duratrax ICE internal resistance parameter generally check higher than a 2Ah cell.

I'd guess that the added resistance of my external connection causes the rejection. I have a gadget called a TesLoad which is made for automotive circuit diagnostics. You just plug it into a regular DMM I've been using it with a 7.2V Ni-MH pack for power. What it does is put a load on your source battery. If it's perfect, the noload and loaded voltage will remain the same. By experimenting I've found that if you have a drop of in tenths of volt, you've got a problem. In checking my connection through my clamp, wires, et. I get a drop of .013V. It doesn't seem like very much but if the cell's IR is already high, it must be enough to push the E-15 to reject it. I have to look at the TesLoad paperwork as there's a way to figure the resistance.
 

slvoid

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SilverFox said:
Hello Slvoid,

I might also throw in that the cells that won't charge in the Energizer 15 minute charger may not give you good performance.

Yes, they have "some" life left in them. Yes, you can get them to charge on another charger. However, they will probably run at a lower voltage under load, have less capacity, they will heat up more, and may exhibit a higher self discharge rate.

Perhaps they should be labeled as substandard and reserved for low current draw applications that are not critical.

Tom

I'm not sure about what you mean by "have some life left in them." They're all brand new...
 

SilverFox

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Hello Slvoid,

Well... New cells probably do "have some life left in them..." :)

My point is that someone that is using a 15 minute charger, probably wants good performance from their cells. If some cells have higher internal resistance and are rejected by the quick charger, they may not give the best performance.

Tom
 

slvoid

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Well to be honest... these AA's are for a battery powered closet light hooked up with a motion detector, current regulator and 1 watt luxeon emitter, not really a high performance product. :)
 

MrAl

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Hi there,

I hope i dont start having trouble charging my NiMHs after they age a little bit.
I guess i better keep the backup slow charger around for a while yet.
Too bad Energizer didnt forsee this problem...now i need to have two chargers.
Well, one of these days i'll sit down and design my own fast charger and at least
have the sense to make it do slower charges too.
Seems a waste to have all that power current available in the E15 charger and
yet cant charge some cells. I had my 'Digital' brand cells rejected too, and they
are not that old...hardly cycled 20 times max in slow charger.
 

Curious_character

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Just about every charger I've had has trouble charging new NiMH cells. What will happen is that they'll shut down early, thinking the cell is fully charged way before it really is. This can be a real bummer, since you don't ever know if the cells are really charged or not, unless you check on them once in a while during charging to make sure the charge time is reasonable. This is a good reason to avoid the multi-cell chargers with a single light, since they won't tell you if one of the cells has finished early. If you're using the cells in a multiple-cell device with no low voltage shutdown, you can even end up ruining the low-charged cell due to reverse charging by the others.

It takes about 6 - 10 full charge-discharge cycles for new cells to settle down, and even then it happens once in a while. I'd love to find a charger that never does this with new cells, but haven't found one yet.

c_c
 
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