Which rechargeables do best in a cold environment?

[Luca]

Hi all,

Which rechargeables do best in cold circumstances Nicad, NiMH? I'm looking for the best option to put a light in my garage, outside the block where I live. So basicly the light will be 'outside' all the time. This means exposed to cold temperatures in winter and to heat in summer. Does anyone have experience in this matter?

Thanks!

Luca

 

[Empath]

Neither should be recharged while they're under extreme temperatures. If one was better, I'd suspect NiMH, but that's only a gut feeling. I'm curious as to how you're planning to charge them. Solar? Direct line to them? Are going to charge them inside, and then install them outside?

There's a good website that can give you a lot of battery information at: http://michaelbluejay.com/batteries.html

 

[recercare]

I think NiCd is obvious here. NiMH is much more sensitive to temperature, less robust. That's why NASA usually uses NiCD.

 

[Luca]

Empath, recercare

Thanks a lot for your help. Some additional info: I plan to charge them inside and then install them in a flashlight left in the garage all the time for my missus to use. She wants a big light to prowl around in the dark garage as she's afraid of spiders. ;D Better hope she doesn't catch me letting you guys in to this secret ;D

I think I'll go with Nicd first and see what they do. Now all I need to find is a decent cheap light.

Luca

 

[Empath]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Luca:
Thanks a lot for your help. Some additional info: I plan to charge them inside and then install them in a flashlight left in the garage all the time for my missus to use. She wants a big light to prowl around in the dark garage as she's afraid of spiders. ;D Better hope she doesn't catch me letting you guys in to this secret ;D

I think I'll go with Nicd first and see what they do. Now all I need to find is a decent cheap light.

<HR></BLOCKQUOTE>

Might I make a suggestion? If you're going to charge them inside, and then take them outside, why not use two sets of rechargeables and just swap them out. That ?way you could let their temperatures reach room temperature before hitting them with the juice. There would be one less temperature concern to consider.

 

[Luca]

Thanks empath,

That's what I had in mind. I was planning on charging them inside. The thing that I am concerned about is the amount of juice they'll lose whan lying out there in the cold, and whether they'll give off enough when we need it.

Luca

 

[recercare]

Well, NiMHs do have a higher self discharge rate than NiCds.

Average self discharge in percent during a period of 1 month:
NiMH = 30%
NiCd = 20%
Li-Ions = 10%
SLA = 5%

However, extreme temperatures can change the results above. In cold winter the SLA's self discharge rate would increase more than NiCd's