Rechargeable AA NimH and Quick Chargers

[david lloyd]

I bought some Energizer Rechargeable AA batteries today with an Energizer Compact Charger. To charge

my batteries with this charger takes 8.5 hours. I know about one hour chargers, but I remember reading

somewhere to avoid them. Is this correct? (I can't find the source of that info anymore.)

 

Surely with a one hour charger something has to give. Can anyone throw some light on this for me?

[tom_bunnell]

I bought my RayoVac one hour battery charger five years ago along with three sets of batteries. I got batteries coming out my ears and when I misplace some my charger charges the dead ones in about an hour, they feel hot when there first charged but they go forever I think and this charger is great. Best thing that ever happened, I download with batteries all the time too. I got endless juice.

[wigwam jones]

I am not an expert on this subject. I have read that the 'fast' rechargers do not get the final 5% or 8% of juice in the battery - kind of like filling your gas tank up on full speed versus sneaking it in slowly. As well, some say that the heat is detrimental to the battery's lifespan on the fast chargers.

 

The 'smartest' AA NiMH rechargers are supposed to be those with small electronic brains that sense the true state of the battery and apply charge accordingly. I am have been pleased with the ones I found recommended on Steve's Digicams (www.steves-digicams.com) at Thomas Distributing (http://www.thomasdistributing.com/index.htm).

 

However, having said that, I can also say that I have grown tired of AA batteries that don't last long enough. I switched to rechargeable CR-V3 Li-Ion batteries in place of AA's in whatever devices I have that can physically hold them. I've ignored warnings about overpowering the devices with greater than 3 v (so this is my caveat: warning, warning, warning), but have not suffered any ill effects, and my battery life is way way better and I'm a happy guy.

[john schroeder]

The issue with fast chargers is heat. Heat kills batteries! The faster the charge the hotter the battery gets. At work we use 90 min. Sunpak charges and a variety of batteries. We do everything that your not supposed to do. We mix battery ratings and brands while charging. We run batteries while still warm from the charger. We over-charge and over-discharge our batteries. Genneraly we abuse the hell out of them. Nimh batteries are tough little suckers. Over four years we have had ten out of fifty batteries fail. The most durable have been Promaster branded 1300 Mah. The least have been Sunpak 1800 Mah.

[terry_rory]

My daughter uses a Duracell quick charger and Duracell 2100 mah AAs for her Canon A620.

 

No problems. The batteries get warm but not hot.

[User_1172872]

I don't think you're supposed to charge any old NIMH in the fast chargers - only the ones designed for the fast charge. Doesn't the battery itself have some kind of protection circuit?

[david lloyd]

Thank you for the responses... So the issue is heat, and therefore the ultimate life of the

battery.

 

I suppose I'll keep my Slow Charger and use that as a primary one, and maybe get a Quick

Chargerone for when I need it most like when I'm away? I don't know, maybe I'll think about it

first:)

[jcuknz]

Check out here http://www.batteryuniversity.com/

[chuck_c_charlottenc_]

David,

 

About 3+ years ago I bought from Thomas Distributing. I bought the Maha MH-C204F Smart Charger and 8 of the PowerEx AA 1800 mah NiMH batteries. I am still very pleased with the charger. But I have not been happy with the PowerEx batteries. One of the eight failed in less than 6 months and I only have four left that I can trust.

 

I also bought the Energizer AA 2300 mah NiMH batteries at Sam's Club almost two years ago and have been vary pleased with the Energizer performance.

 

I think the Smart Charger is the way to go, but aside from it I'd stick with a trickle charger. I don't think the quick charge chargers are good for the battery's life.

 

I hope this helps.

 

//Chuck

[robert lee]

The LaCrosse BC-900 is the nicest charger I've used (if you've a geeky bend.) I also have a Maha C801D which is simpler to use, and will charge 8 AA's at once.

 

Both of these are amongst the best you'll find. In general, you'll want chargers that will charge each cell individually, and can automatically discharge before charging.

 

Also, I've found tremendously variability in battery quality. Sanyo has been the only brand that has consistently delivered rated capacity and higher.

[glenn_holden]

Folks:

 

To some extent you get what you pay for. Yes, the better chargers completely discharge the cell first before re-charging.

 

Ideally you want a "fast" charger that uses a peak detect circuit for each cell, rather than two or four parallel cells. The way this works, is it "hits" the cell with a slug of current, then nothing for a few seconds to allow the cell to cool then "hits" it again. The duration of the charge pulse varies as the cell starts to charge. The amplitude of the pulse also varies on the better chargers to suit the cell capacity (the higher the MA-Hr rating, the higher the amplitude of the pulse to it). On some of the less expensive chargers this is just a switch between AAA and AA charge rates.

 

You have to really look at the literature to see what you are getting as most peak detect chargers only work on a parallel combination of 2 cells.

 

However, for conventional "photo" use you could go through seveal sets of batteries and chargers for the price of just the peak detect charger.

 

Apparently the peak detect charger works to charge the cells faster than a steady charge rate. A trickle charger charges at typically 1/10 of the cell capacity.

 

My 2c anyway.

 

LGH