Nimh Batteries — Poor Results

[+Bob Blaylock]

  A few months ago, my wife and I bought a set that included a bunch of Energizer brand NiMH cells in AA and AAA sizes, along with a charger for them.

 

  I have found that if I charge them all up, put a set in each of our GPSes, store the rest of them in a drawer, that by the time the ones in the GPSes are going weak, the ones in the drawer are even lower.  It seems that they lose their charge faster sitting unused in a drawer, than getting occasional use in our GPSes or other devices.

 

  What gives?  Am I the only one having this experience?

[+NWMOhunter]

Did you get the batteries from Sams? If so I think I got the same pack and I have the same problems. I figured I could charge up a set and have them standing by for when the others run out, but it seems that you have to plan ahead and pull the fresh set out of the charger right as the others run down.

 

I have tried cycling them through a few times to see if you just need to build them up, but this doesn't really seem to help.

 

Check out this thread...Fyi - Energizer Battery Charger

Edited May 24, 2006 by NWMOhunter@HC

[+drbugs]

I know NiMHs lose charge as time passes. I read somewhere it can be as much as .5 to 1.5% a day, though I don't know where I read that.

[+Bob Blaylock]

I know NiMHs lose charge as time passes. I read somewhere it can be as much as .5 to 1.5% a day, though I don't know where I read that.

 

  Any batteries will lose charge over time.  With alkalines, a set of batteries after several years will still have most of their charge.  It seems that in just a few weeks, a set of NiMH cells go mostly dead.  The weird thing is that the ones sitting unused in a drawer seem to lose their charge faster than the ones actually in a device being used.

[kb9nvh]

I've noticed this too with energisers. The powerEX ones I buy dont do it.

Try powerEX and I think you will have a different experience

 

 

I know NiMHs lose charge as time passes. I read somewhere it can be as much as .5 to 1.5% a day, though I don't know where I read that.

 

  Any batteries will lose charge over time.  With alkalines, a set of batteries after several years will still have most of their charge.  It seems that in just a few weeks, a set of NiMH cells go mostly dead.  The weird thing is that the ones sitting unused in a drawer seem to lose their charge faster than the ones actually in a device being used.

[+clubbuild]

I've noticed this too with energisers. The powerEX ones I buy dont do it.

Try powerEX and I think you will have a different experience

 

i too use nimh batteries. they are new and fully charged but do not last as long as non rechargagle batteries. if i recharge 2 sets and use one set first the second set looses some charge in the drawer. when i do use them they last fewer hours. it is still cheaper to use rechargables and i am happy to recycle.

[ImpalaBob]

NiMH batteries need to be conditioned ..... meaning they get better after a few discharge / recharge cycles. I have also had the best results with PowerEx batteries. The MAHA charger I have has 2 charging cycles....One that just recharges and another that fully discharges and then recharges. The discharge-recharge cycle should be used a few times each year. I put a note as to the charging date in each 4 pack battery container. Any packs older than 30 days should be considered to have lost some of their charge. Cycling a group of 12 batteries works best for our 2 GPS units. We keep a spare 4 pack of Duracells in the backpack for GPS emergencies and to use in our flashlight. ImpalaBob

[mbeckwith]

NiMH batteries discharge over time while sitting around.

New technology has been recently developed and manufactured to dramatically reduce this self-discharge.

 

SANYO ENELOOP batteries claim a 15% self-discharge over a 1 year period. This is a huge difference from the norm. Currently they are hard to find and you MAY need a good charger in order to charge them.

 

I'm on a flashlight forum and found them there:

http://www.candlepowerforums.com/vb/showth...ghlight=eneloop

 

If you're just looking for the best performance (w/o self-discharge concerns) or if you'd like more battery info, look here:

http://www.candlepowerforums.com/vb/showth...ghlight=eneloop

 

Marco

[planewood]

I have some Energizer AA Nimh batteries in my camera that I have used for 5 or 6 years. I haven't recharged that set of batteries for 2 months and when I looked while ago they still were showing to be full charged in the camera.

 

I have 8 of those batteries that I cycle through my 60cx and never any problem with them. Got them at Sam's too.

 

You do have to cycle them a few time to get then up to snuff, so to speak. It's always possible for there to be a bad apple in the barrel.

[toddm]

Yep, I've noticed that most of my nimh batteries (energizer, duracell, etc) if they are not used within a couple weeks of being charged they are pretty low in charge.

 

As someone else said nimh loose around 1.5% of their charge a day, however this does not mean that in ~66 days they are empty, it's 1.5% of what's left per day, so 98.5% after day one, 1.5% of 98.5% the next day etc. However it still means that after 14 days best case you have about 80% of the total charge. That's assuming a perfect world it's probably closer to 70% in real life, about 50% after a month, about 30% after two months.

 

Lion batteries are even worse, I've read anywhere from 3-5% a day, nimh and lion have better capacity, and lighter weight, and the ability to supply higher current, but nicad batteries were more tolerent of charging abuse, cold weather, and they held their charge longer. However they used toxic cadmium and just don't offer the run time we want. Certainly some cells and chargers are better than others, as others have said I've always seen good things about the powerEX cells

 

On the plus side with 15 minute chargers out now for nimh cells it's no big deal to charge them up before needed them if they have sat around for more than a couple weeks. Using a 15 min rapid charger to top off batteries with say 95% of their charge left might be bad, I'm not sure how well the charger can pick up on the voltage drop, or more of a flattening with nihm, if the charge is already that high, probably depends on the charger. A lot of times if I know I'm going to need some AA's and they have been sitting around for a couple weeks instead of slapping them in the 15min charger I'll put them in a 8 hour charger for a couple hours to top them off.

 

That said even with discharged cells I've seen those 15min chargers make nimh cells so hot you can't touch them, and this one even had a fan on it to keep them cool, and supposidly had thermal shut off if the battery got too hot, I'd hate to see what their idea of too hot was

[sudamar]

I keep all my rechargables in the frig. I think they hold their charge longer in the frig. rather then at room temp. I have read where the normal chargers will make the life of the battery longer than it you use the 15-minute quick chargers.

[+embra]

Lion batteries are even worse, I've read anywhere from 3-5% a day, nimh and lion have better capacity, and lighter weight, and the ability to supply higher current, but nicad batteries were more tolerent of charging abuse, cold weather, and they held their charge longer. However they used toxic cadmium and just don't offer the run time we want. Certainly some cells and chargers are better than others, as others have said I've always seen good things about the powerEX cells

Does anyone corroborate the LiIon discharge rate? I was under an impression that they held their charges much better than NiMHs...although maybe I'm thinking about non-rechargeable Lithium batts. I'm not too lazy to ask, just to lazy to search out an answer.

[+comphelp]

Does anyone corroborate the LiIon discharge rate? I was under an impression that they held their charges much better than NiMHs...although maybe I'm thinking about non-rechargeable Lithium batts. I'm not too lazy to ask, just to lazy to search out an answer.

That was my understanding too (That LiIons were better). I wouldn't know where to look for evidence though. Edited May 25, 2006 by comphelp

[stevesisti]

Does anyone corroborate the LiIon discharge rate? I was under an impression that they held their charges much better than NiMHs...although maybe I'm thinking about non-rechargeable Lithium batts. I'm not too lazy to ask, just to lazy to search out an answer.

That was my understanding too (That LiIons were better). I wouldn't know where to look for evidence though.

 

Numerous sources quote the self-discharge of lions as 3-5% per month.

[+embra]

Numerous sources quote the self-discharge of lions as 3-5% per month.

At first taking this for confirmation of the original statement (I overlooked that the first assertion was "3-5% per day") I martialed enough resolve to look it up in Wikipedia. It gives a nice comparitive statement:

Li-ion batteries do not suffer from the memory effect. They also have a low self-discharge rate of approximately 5% per month, compared with over 30% per month and 20% per month in nickel metal hydride batteries and nickel cadmium batteries, respectively.

So, while Li-Ions are better than NiMHs on the self-discharge rate, I still had an overvalued sense of how well they held a charge. I'm glad for the clarification.

Edited May 26, 2006 by embra

[+Runaround]

Something to consider on all NiMH batteries. There are only a few manufacturers of these batteries and chargers. Often you will see testimonials that brand x is great while brand y and z are junk. In many cases, they are all the same cell made by company z with a different label. The same applies for the chargers. The molded plastic and labeling may look different but if you take them apart you'll find identical circuitry.

[+dumketu]

Check out this link on nimh batteries -

 

http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

 

Brian

Edited May 26, 2006 by dumketu

[CO-Zman]

Some more NiMH info that I have posted before:

 

1) NiMH 20-30% more capacity than NiCd

2) NiMH have a 3-4% self-discharge rate / day. NiCd 1% / day.

3) NiMH are much less tolerant to poor charging techniques (read=damage easily w/ overheating)

4) If you want to quick charge them (peak charge), the charger needs to specifically support NiMH. NiCd only peak chargers will most likely cook the batteries if not burn down the surrondings . This is due to NiMH having a much smaller peak voltage drop (5mV/cell) than NiCd (10 mV/cell). The charger just won't sense it.

 

For those inclined, the R-C community (aircraft, cars, etc) really has tons of info on batteries.

 

The short of it, plan on topping off the NiMH's during breakfast, and don't forget a spare set of alkalines and your rain-gear.

 

Z

[+BAMBOOZLE]

I have done a lot of experimenting withe these batteries and I think the most important thing is the charger....you can't beat MAHA chargers or MAHA PowerX batteries.

Try WWW.thomasdistributing.com and check out the MAHA charger/battery sets.......I have a lot of batteries and two chargers and have had no problems. I had 4 Powerx 2500 in my camera flash for almost a year and just used the flash several times.

[+Thrak]

I have the Energizer 15 minute charger. I'm unsure as to what other batteries can be charged on it. Are the batteries that come with that charger any different than any other rechargable batteries?

[aranjit]

I have the Energizer 15 minute charger. I'm unsure as to what other batteries can be charged on it. Are the batteries that come with that charger any different than any other rechargable batteries?

 

Yes, those batteries have circuitry which controls how fast they charge as opposed to the charger controlling this. This way they can charge faster without damaging the battery. If you put in regular NiMH batteries the charger will charge them at a normal speed.

 

In terms of chargers, the best I have seen is the

Lacrosse BC-900. It has discharge/charge cycles, battery conditioning (cycle 20 times), variable charging rate, charging circuitry for each battery and LCD's to test how much charge is in a battery.

Edited May 31, 2006 by aranjit

[+Thrak]

I have the Energizer 15 minute charger. I'm unsure as to what other batteries can be charged on it. Are the batteries that come with that charger any different than any other rechargable batteries?

 

Yes, those batteries have circuitry which controls how fast they charge as opposed to the charger controlling this. This way they can charge faster without damaging the battery. If you put in regular NiMH batteries the charger will charge them at a normal speed.

 

In terms of chargers, the best I have seen is the

Lacrosse BC-900. It has discharge/charge cycles, battery conditioning (cycle 20 times), variable charging rate, charging circuitry for each battery and LCD's to test how much charge is in a battery.

 

Hmmmm....... so are there any other batteries that will work with the charger for the 15 minute charge or do I need to stick exclusively with Energizer?

[aranjit]

Ignore my last post, apparently I haven't been keeping up on NiMH chargers. Apparently your charger will work with any rechargeable. From Amazon:

 

"Whether capturing Baby's first steps on film, or taking your portable CD player for a run, it's easy to be prepared when you own this 15-minute charger by Energizer. Ideal for digital cameras, portable audio devices, handheld games and other high-drain devices, this unit charges any 4 AA or 4 AAA NiMH batteries in only 15-minutes. Includes 4 AA batteries. Imported."