100% off topic!

[southpaw13]

But this board has the best answers!

If something thats electronic and takes AA alkaline batteries, can you use the new NiMH (nickel-metal hydride) instead?

Thanks,
Southpaw

[DaemonCollector]

As long as they are the same size and such yea. A camera that takes AA Alkline should take AA Ni-MH

[JB]

Yah.
But the battery indicator won't be accurate, as NiMH cells output a steady power level untill the end, where it plummets almost immediatly. Alkaline cells drop off far more gradually, from the start to end.

This makes NiMH cells better, BTW.

[cholin]

Makes me want to ask, what's the difference between NIMH and umm...the other kind (not alkaline - forget the name)

[Mooshoo111]

nicads? Nicads have a memory issue.

[cholin]

That would be the one, what do you mean memory issue?  Whats the difference if I order a Ni-Cad and a NimH one?  Is it a noticable differnece?

[Zero_Hour]

NiCads memory issue is this:

Say you charge the nicad up full and then use it for a bit, and run it to half of it's capacity. Then you recharge it to full.

Done enough times, the battery will "think" that the half of the capacity it's been running down and recharging is it's full capacity. Eventually over time, you will have difficulty getting any charge on them. NiMH is the way to go for sure.

[screaming]

I did a quick Google search and came up with this:

http://www.batterymart.com/battery_faq.php

[danny_galaga]

JB, battery indicator will still be working. it doesnt matter how the battery behaves, thats what the indicator shows. so if they go flat quickly (whether because of a different type of battery or because there is a high load, for instance a camera with flash set high and screen on all the time) then thats what the indicator is telling you. it doesnt care what type of battery it is. most 'battery level' indicators work either on voltage or current flow.

Mooshoo, they now think that nicads dont have a memory issue. it arose mostly from inaccurate recharging. so it used to be that you would completely discharge a nicad before you recharge it and then time it. now with intelligent rechargers you can charge them at any point all the way to full again.

[Mooshoo111]

Well I think there is some sort of memory issue. I can tell because I use them all the time, one of my hobbies is R/C. What do you mean by "intelligent chargers"? I have a $150 charger which doesn't solve the problem, although I just discharge the packs with the same charger/discharger before charging.

[danny_galaga]

im coming from an r/c angle too. i guess what i mean is that where they used to think there was a 'memory' now they think its mostly a matter of accurate charging. probably most of the problem occurs with overcharging- you know how hot those sub c's get!

but regardless, NiMh are heaps better for cameras etc anyway...

[Hoopz]

One of the best resources for items like this is Dan's Data.

[Mooshoo111]

Yeah those sub-Cs get pretty hot after a couple laps or after charging. Well, any battery gets that hot when youre sucking the power out of them that fast. Are you in the hobby?

[JB]

JB, battery indicator will still be working. it doesnt matter how the battery behaves, thats what the indicator shows. so if they go flat quickly (whether because of a different type of battery or because there is a high load, for instance a camera with flash set high and screen on all the time) then thats what the indicator is telling you. it doesnt care what type of battery it is. most 'battery level' indicators work either on voltage or current flow.

Right. And a NiMH maintains a steady voltage for a LOT longer time. End result is that they read the battery as about a third discharged untill the last... minute or 2 of life.

Hence, they aren't accurate indicators of battery status.

Mooshoo, they now think that nicads dont have a memory issue. it arose mostly from inaccurate recharging. so it used to be that you would completely discharge a nicad before you recharge it and then time it. now with intelligent rechargers you can charge them at any point all the way to full again.

Yah. It's a LOT more complex than common wisdom.
Also note: Fully discharging a set(as opposed to a single cell) WILL ruin your pack eventually, as they don't all discharge at the same rate, and one cell winds up with current being forced through it by the other cells, which is BAD.

Anyways, NiMH cells are less twitchy than NiCads, and if I recall, they have higher energy density too.

[danny_galaga]

Yeah those sub-Cs get pretty hot after a couple laps or after charging. Well, any battery gets that hot when youre sucking the power out of them that fast. Are you in the hobby?

yeah, cars and boats. not hard core though. never owned the latest and greatest of anything. like to scratch build my own boats...