NiMH Battery Tests...One Year Later

[arcas]

About a year ago I bought a set of 10 2000mAh Powerizer NiMH batteries that were listed in the Hot Deals forum. I performed some discharge measurements and threw together a web page detailing the results. Basically the batteries had somewhat lower measured capacities but that's probably to be expected given the test setup I used.

A few weeks ago I noticed that my Nikon camera started indicating 'low battery' even though the batteries were fresh out of the charger. Clearly either the charger was failing (not likely) or the batteries have deteriorated over 12 months. I figured it'd be interesting to retest the batteries and compare with results from a year ago.

Here it is

Some deterioration over time is expected but one wonders how other brands of NiMH batteries would compare using the same tests.

 

[Spikesoldier]

one of my energizer NiMH batteries i think also bit the dust.

its too bad because i only have 4, and i dont have any replacements.

ETBF was around a year also.

 

[JulesMaximus]

I bought a Canon 300D a couple weeks ago and only charged it once when I first opened the packaging. I've probably shot 70 or so images with it, at 3.5MB each, maybe half of them with the on camera flash and I used the camera to download the images onto my computer. It is still reading fully charged.

I'm pretty impressed with it so far.

 

[RossMAN]

Originally posted by: Spikesoldier
one of my energizer NiMH batteries i think also bit the dust.

What size battery?

 

[dman]

I also purchased some Powerizer cells. I noticed recently that the camera seems to be draining faster than normal and took out the voltmeter.

My problem is that most often the charger used charges the batteries in pairs, and, it seems to me that they don't always discharge the same amount (in pairs) thus I suspect that over time they are not getting equally charged.

I try and account for that by individually charging them (Have a 8cell charger that will do 4 individuals) but I broke out the voltmeter and started testing. Turns out one was completely bad, read 0.05v even after letting it try and charge a few times.

The others were all at various voltages between 0.95 and 1.38 or so. I paired them off so that the closest values were charged together and so far things seem to be working pretty well again. I can say that the 2000Mah cells last longer than some 1400 and 1600 cells I've used. I imagine if the same tests were perfomed that all the manuf tend to lie a bit. There was one internet company that advertised that their cells were minimum rated at the mah rating, and would be guaranteed. Unfortunately I'm too lazy to perform those tests. I thought they used 1ohm load for tests... so using 2.6/2.7 may change the curves.

Anyway, good info. I wonder how well they'd do not constantly being trickle charged. I have more battereies than charger spots, so, I rotate them out every once in a while, the batteries I've been using go into storage and others come out. I know on LiON batteries they last longer at 50% charge than they do constantly full charged, etc, that may make a difference too.

I'm about ready to order some new batts, the old ones do well in our daughters toys and the new ones get used for digicam duty.

I'm also tempted to build a 10Cell / 12-14v portable power pack for use with my laptop on long trips. Been too lazy thus far, and also concerned about getting it through security... but would be a lot cheaper than a replacement cell for my laptop and should give me an hour or two runtime longer than what I have now.

 

[sciencewhiz]

approximately how many times was each one charged?

 

[FrustratedUser]

Good post.

My powerizer batteries still works great. They are only 1850mAh but they still last longer than a couple of Energizer 2100mAh.

 

[dartworth]

Originally posted by: JulesMaximus
I bought a Canon 300D a couple weeks ago and only charged it once when I first opened the packaging. I've probably shot 70 or so images with it, at 3.5MB each, maybe half of them with the on camera flash and I used the camera to download the images onto my computer. It is still reading fully charged.

I'm pretty impressed with it so far.

umm...the DR takes a lithium-ion battery

 

[arcas]

sciencewhiz, aside from those associated with the measurements, each cell probably went through a dozen or fewer charge cycles over the year. I have a total of 14 NiMH AAs (10 2000mah Powerizer and 4 older 1300mah Rayovac) and a 10-slot charger. Since my only AA device is the camera (4 AAs), I rotated batteries and any batteries not in the camera were in the charger on trickle charge.

dman, I wondered the same thing about whether constant trickle charging causes damage. I don't think it was a case of overcharging since the rate was only 25ma (== C/80 for these cells) but the constant potential could have affected the chemistry perhaps? I was tempted to rebuild my cordless drill's battery pack using some of these cells but perhaps not.

 

[edro]

Originally posted by: JulesMaximus
I bought a Canon 300D a couple weeks ago and only charged it once when I first opened the packaging. I've probably shot 70 or so images with it, at 3.5MB each, maybe half of them with the on camera flash and I used the camera to download the images onto my computer. It is still reading fully charged.
I'm pretty impressed with it so far.

Yeah, I got 2 spare batteries for my 300D, when I bought it, but I haven't used them yet.

 

[JulesMaximus]

Originally posted by: dartworth

Originally posted by: JulesMaximus
I bought a Canon 300D a couple weeks ago and only charged it once when I first opened the packaging. I've probably shot 70 or so images with it, at 3.5MB each, maybe half of them with the on camera flash and I used the camera to download the images onto my computer. It is still reading fully charged.

I'm pretty impressed with it so far.

umm...the DR takes a lithium-ion battery

Umm, yes. So, I guess my point would be that I would recommend buying a camera that takes this type of battery.

 

[dartworth]

Originally posted by: JulesMaximus

Originally posted by: dartworth

Originally posted by: JulesMaximus
I bought a Canon 300D a couple weeks ago and only charged it once when I first opened the packaging. I've probably shot 70 or so images with it, at 3.5MB each, maybe half of them with the on camera flash and I used the camera to download the images onto my computer. It is still reading fully charged.

I'm pretty impressed with it so far.

umm...the DR takes a lithium-ion battery

Umm, yes. So, I guess my point would be that I would recommend buying a camera that takes this type of battery.

Umm...it's not what this thread is about...