batteryguy89
Newly Enlightened
- Joined
- Jul 23, 2019
- Messages
- 1
hey is 2000mah good for charging NIMH/NICD or is it to high seems to high
2000 mah charging for NiMH ?
- Thread starter batteryguy89
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archimedes
Flashaholic
Hello and welcome to CPF
Your post has been approved, but thread title was edited to be more informative
The thread was also moved out of the Administrative area, to the proper forum instead
Your post has been approved, but thread title was edited to be more informative
The thread was also moved out of the Administrative area, to the proper forum instead
Mishanchik
Newly Enlightened
Capacity - mAh
Current - mA
In your question it is clear that the difference between these two quantities is not understood for you.
Current - mA
In your question it is clear that the difference between these two quantities is not understood for you.
ChrisGarrett
Flashlight Enthusiast
Panasonic has a fast charge protocol for 2A, but unless you need to snap that million dollar money shot within the next hour, you're better off at 1A, or .5C. It's enough to trigger the Delta Klingon Temperature termination point and it's a rather benign current rate for that battery.
I think I once charged a quad up at two amps, on my Maha Wizard One, but that was the only time in seven and a half years that I've had the charger and Eneloops.
Chris
I think I once charged a quad up at two amps, on my Maha Wizard One, but that was the only time in seven and a half years that I've had the charger and Eneloops.
Chris
And if you're talking about AAAs, even that's too high - .5C for just about every AAA works out to less than half an amp.
ChrisGarrett
Flashlight Enthusiast
Yeah, I was pinpointing the AA, since the OP mentioned 2000mAh. I charge my AAAs up at either 400mA, or 500mA, which is at .5C, or slightly higher.
Chris
Yup, figured that was why you went with that -- the "if you're talking about..." was meant to the OP, which was unclear from how I replied to that; apologies there. Figured he was mentioning 2000mAh because that was 1C for him, but on the chances that perhaps it was instead because that's what his charger maxed out at or something I didn't want him wildly overcharging some AAAs. 
IonicBond
Enlightened
Technically, 1C charging is actually better per Eneloop and some other high quality manufacturers.
BUT, that is only if you dig into their specs, which the average consumer is unlikely to find. Lesser quality nimh may not like 1C. Yes, they get warm during charge, but that is expected of an exothermic chemistry.
But it really comes down to a charger quality issue. The AA-only 8 bay Maha Powerex charge at 2000mah unless you purposely tell it to hold back the reigns at 1A. Maha/Powerex has (had?) a good relationship with Eneloop so they know what they are doing.
But yeah, if your cell quality isn't top-tier, and charger not really top-end either, then .5 - .7C is what I'd recommend to catch some sort of cell EOC signalling.
BUT, that is only if you dig into their specs, which the average consumer is unlikely to find. Lesser quality nimh may not like 1C. Yes, they get warm during charge, but that is expected of an exothermic chemistry.
But it really comes down to a charger quality issue. The AA-only 8 bay Maha Powerex charge at 2000mah unless you purposely tell it to hold back the reigns at 1A. Maha/Powerex has (had?) a good relationship with Eneloop so they know what they are doing.
But yeah, if your cell quality isn't top-tier, and charger not really top-end either, then .5 - .7C is what I'd recommend to catch some sort of cell EOC signalling.
WalkIntoTheLight
Flashlight Enthusiast
Yes, that's fine.
Agreed. 2000 mA (as in the OP) would be way over 1C for Eneloop AAAs, as I was saying (which are 800mAh, iirc). But 500mA gives a good margin of error.
That's the other thing about charging to 1C -- 1C of what? It has to be of the battery being charged, not the capacity of a new battery. Even if your Eneloops have seen a few cycles, 500mA should still be <1C since there's a healthy margin of error there. A lot of folks will "okay" certain charge rates because they're "1C," without even questioning the state of the specific battery being charged. And while 1C is fine for good quality batteries, battery degradation can speed up pretty quickly even just a bit higher than that. It's in no way unthinkable that a perfectly usable battery will have 2/3 of original rated capacity, at which point a "1C" charge from new spec is actually 1.5C... unless you have built-in heat throttling in your charger, that quickly becomes a pretty bad idea if you want to get long life out of your batteries.
That's the other thing about charging to 1C -- 1C of what? It has to be of the battery being charged, not the capacity of a new battery. Even if your Eneloops have seen a few cycles, 500mA should still be <1C since there's a healthy margin of error there. A lot of folks will "okay" certain charge rates because they're "1C," without even questioning the state of the specific battery being charged. And while 1C is fine for good quality batteries, battery degradation can speed up pretty quickly even just a bit higher than that. It's in no way unthinkable that a perfectly usable battery will have 2/3 of original rated capacity, at which point a "1C" charge from new spec is actually 1.5C... unless you have built-in heat throttling in your charger, that quickly becomes a pretty bad idea if you want to get long life out of your batteries.
IonicBond
Enlightened
Good point! Other than eneloops which you can trust right out of the box (unless counterfeit), to being near stated capacity - other, not so much.
So do a normal charge / discharge capacity test, and base your C charging rates from that.
The general idea is to charge with enough current, so that the EOC dv signal drop is easily recognized by the charger, and fnishes the cycle.
That rate has gone up over time from maha - initially 0.3C, (too low), and later the reference was at least 0.5c. So that's where I hang out - between 0.5C to 1C depending on the quality of the cell.
So do a normal charge / discharge capacity test, and base your C charging rates from that.
The general idea is to charge with enough current, so that the EOC dv signal drop is easily recognized by the charger, and fnishes the cycle.
That rate has gone up over time from maha - initially 0.3C, (too low), and later the reference was at least 0.5c. So that's where I hang out - between 0.5C to 1C depending on the quality of the cell.
