Rechargable Battaries? Alkaline or NiMH

[r3cc0s]

Rechargable Battaries? Alkaline or NiMH?
I've been using pure energies for a while
and I noticed that their voltage is quite accurate to a standard battery (cuz i guess they're alkaline) but they have a so/so battery life.

As well they can only be recharged like 50-100 times, as per pureenergy.com

Are NiMh worth getting into?
I heard their voltage is less, but they have more mah
which would have more capaticy

meh?

 

[Hirsch]

I'll cast a strong vote for NiMH. The voltage is close enough for most purposes. However, the voltage loss as the charge goes down is much lower for NiMH rechargeables than for alkalines. So, the voltage advantage for alkalines doesn't last long. That steadier voltage output is a big advantage of NiMH. NiMH can be recharged up to 500-1000 times, although you need to be careful not to damage them by overcharging them too much. Different brands have different mah, so you'd have to look to see what charge each particular battery could hold. IMO the only reason to use alkalines any more is in a piece of equipment that sits for a long time between uses. NiMH loses its charge slowly, used or not, but alkalines can retain their charge for much longer when not in use.

 

[fiddler]

Another rec for NiMH. They can't be beaten capacity-wise I think, at least in the AA form factor. I think AA's go insanely high now, like over 2000 mAh.

 

[Watchdog]

If you're using a high drain device i.e. digital camera, or portable music device go Nimh

If you're using a low drain device i.e. the remote for your TV, then go alkaline

 

[r3cc0s]

that's cool to hear

so i guess for something like my pda i would use the alkalines like the pure energy
but for like a cdp that I use alot the nimh would be good

 

[Audio Redneck]

Quote:

Originally posted by r3cc0s that's cool to hear so i guess for something like my pda i would use the alkalines like the pure energy but for like a cdp that I use alot the nimh would be good

Which ever type you use, check with the manufacturer about when to recharge them. With the alkilines you don't want them to ever drain all the way down or it will kill them quickly. (It doesn't hurt them to "top them off" when they've only been used a little.)

 

[Hirsch]

Quote:

Originally posted by Audio Redneck Which ever type you use, check with the manufacturer about when to recharge them. With the alkilines you don't want them to ever drain all the way down or it will kill them quickly. (It doesn't hurt them to "top them off" when they've only been used a little.)

I hope you meant lead-acid here. Those really won't survive full discharge. When alkalines are gone, they're gone (non-rechargeable)... and AFAIK an NiMH can survive full discharge (a full discharge cycle or two might actually revive a failing one, although it shouldn't be necessary during the normal life of the battery). A NiCad requires full discharge periodically (ideally every charge cycle) to maintain maximum performance.

 

[LamerDeluxe (tm)]

I'm not sure if you should let rechargable Alkalines run completely dry. I do know you have to recharge them as soon as you can after they run empty.

With NiMH's indeed you musn't let them run dry, though devices like Dismans will shut down before that happens. NiMH's will deplete relatively quickly when not in use, so top them off before using.

I very strongly recommend getting a smart charger, they are a bit more expensive, but your batteries will live longer and they will really be charged fully. Cheaper timer based chargers will either under or overcharge your batteries, neither situation is good.

I have a GP Smart Powerbank 60, it will charge four 1600mAh AA batteries in an hour (more powerful ones in a slightly longer time). Each of those four batteries is charged independantly and monitored for when it's full, so the charging will stop. Great for topping them off before use.

 

[Hirsch]

Quote:

Originally posted by LamerDeluxe (tm) I'm not sure if you should let rechargable Alkalines run completely dry. I do know you have to recharge them as soon as you can after they run empty.

My error. I haven't run into the rechargeable alkalines.

 

[recephasan]

I've always preferred the Sanyo AA NiCds. They are 1100mAh and retain their charge for a long time and have long life. NiMHs drain too fast for my taste of applications.

 

[LamerDeluxe (tm)]

Though NiCads suffer from the memory effect, you have to drain them completely before recharging. You can charge NiMHs anytime you want and with a one-hour charger you can top them off in minutes.

NiMH AA batteries are currently at 2000mAh and I think there's still enough headroom to keep increasing that value.

 

[Audio Redneck]

Quote:

Originally posted by Hirsch My error. I haven't run into the rechargeable alkalines.

WELL DON'T LET IT HAPPEN AGAIN! (

)

I like the rechargeable alkalines for seldom used devices (flash lights, portable radios) because they store so well.

 

[LamerDeluxe (tm)]

IMPORTANT WARNING!!!

I just got two AA battery holders, one for 8 and one for 6 batteries.

(NiMH)
8 x 1.2 volts= 9.6 volts (Sony)
5 x 1.2 volts = 6 volts (Denon/Optimus)

Turned out the plug they gave me for the Denon was the wrong one

Tried the 9.6 volts pack on a D-25s, nothing. Measured the output... WHOA! almost 11 volts!!!

I thought I had fried my D-25s, luckily I found out this plug was also the wrong one, so this time I was lucky.

Measured the NiMH batteries and they all were around 1.4 volts!!!

(six batteries totalled 8.2 volts, enough to power the D-25s)

Now I don't know if that is caused by the voltage my charger uses or something, but just don't take the 1.2 volts written on the batteries literally, you could fry your PCDP.

My Gamegear batterypack delivers almost exactly 9 volts.

Someone mentioned using a camcorder battery, I've seen ones of 6 volts as well. I don't know how to connect those though.

 

[stan23]

are we even close to getting Lithium Ion rechargables in AA format?

 

[Lisa]

Quote:

Originally posted by stan23 are we even close to getting Lithium Ion rechargables in AA format?

No, we're not

From what i've heard Li-ion batteries can only be rectangular shaped and AA's are round.

Some facts about NiMH batteries (if anyone is interrested)

They discharge slowly when you don't use them.
The first 24 hrs the discharge is 5-10% followed by 1% a day.
They discharge faster with higher temperatures.
When stored in the fridge the discharge will be less. You can store them in the fridge when you don't have a trickle charger. But put them in a sealed plastic bag and when taken out of the fridge let them warm up to room temperature before getting them out of the bag. This way they won't get wet.

When you don't know how long you need to charge batteries you can use this (maths thingy - don't know the English word, is it equasion?)

- slow, normal charger: (capacity in mAh /charge current in mA) x 1.4 = charge time in hours
- fast charger : (capacity in mAh / charge current in mA) x 1.5 = charge time in hours