How To Make Ni-Cd AA's Ready For Duty?

pobox1475

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I just ordered three 900mAh AA cells from China. My LED solar lights specify Ni-Cd only. The last have died after about five months use and were listed as 1200mAh cells. They tested out at only 600 on MAHA C9000. Hope these have at least that capacity to start.

Using the C9000 should I run a "Break-In" or "Refresh & Analyze" on them prior to use?

I'm not as familiar with Ni-Cd's as my trusty Eneloops.
 

Mr Happy

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Wow. If you ordered them from China they may only have 300 mAh given the rampant label inflation over there. But you should run a refresh and analyze to get a handle on the true capacity and then maybe run a break in using that actual capacity and see what happens. You should not have to go to China though--I have seen many NiCd solar lighting cells in places like Home Depot or Big Lots in 4-packs at $6-$7 or so.
 

pobox1475

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Money is really in short supply and I had a whopping $1.68 in eBay bucks to blow. So basically three cells cost <$2. Do know the source (China) is a crap shoot :~(

In all honesty mostly looking to satisfy the lady. I am not a fan of anything that calls for Ni-Cd cells and needs replacements a few times a year.

Thanks for the reply. Knowing from past experience (with your experience) I am good to go now ;~)
 

Zyban

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If things don't work out, or you replace them again, check out the Made in Japan Sanyo Cadnica 700 mAh AA batteries. The N-700AAC is the regular battery and there is a 1 mm shorter verison N-700AACL. Some solar lights are made for the shorter battery with shallow button on top whereas others using a conventional sized AA. I have two sets of lights in which each set uses one of the designs. I had excellent results using the N-700AACL as a replacement and found them to be underrated and just bought some N-700AAC replacements for the newer solar light set today. They run about $2-3 each.

I ran refresh cycles on my LaCrosse and it only took 2 cycles to maximize them.
 

Napalm

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Anyone knows why solar LED lights require NiCd? What happens if we stick a NiMh instead?

Nap.
 

Mr Happy

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Anyone knows why solar LED lights require NiCd? What happens if we stick a NiMh instead?
My guess is they don't especially require NiCd. I think they use NiCd mainly because they are cheaper.

In theory, NiCd cells are more resistant to the uncontrolled trickle charging found in a solar light, but in reality if you work out the numbers there is not enough charge available in a day of sunlight to fully charge an NiMH cell, so the danger of overcharging is minimal. Obviously if the solar cell was bigger this would be less true, but solar lights typically have very small solar cells.
 

45/70

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Anyone knows why solar LED lights require NiCd? What happens if we stick a NiMh instead?

Considering the conditions under which cells in solar lights are used, I think NiCd cells are an obvious choice. When compared to NiMh cells, they are more resistant to heat, are not damaged from over discharging (it's actually good for them), are considerably more tolerant of "reverse charging" in series applications, handle extended trickle charging well, as Mr H mentioned, and on top of that generally are capable of many more cycles than NiMh cells.

The biggest problem nowadays is finding good quality NiCd cells. Sanyo's Cadnicas seem to be the only ones still around. Most of the Chinese cells reportedly under perform and/or deliver a low cycle count.

Dave
 
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