Battery /cell Prices?, different manufacturer price comparisons

[treez]

Hello,

I am trying to decide on NiCd or NiMH cells for use in an emergency LED lighting system....however, i cannot find comparitive pricing websites for different manufacturers batteries/cells.....also, digikey hardly lists any such batteries/cells.

do you know of a website that i can use to compare different NiCd cell prices from different manufacturers.?

[MacFromOK]

Wouldn't NiMH be a better choice than NiCd for a rarely used system?

I'm referring to the NiCd tendency to form "whiskers" (dendrites) and short themselves without sufficient current flow.

[Geek]

NiCd is also banned in a lot of countries. Going NiCd will severely limit your markets.

[Colt45]

Care to explain a bit better?

Will this be mobile or not? Will it be on charge all the time? How much power will be drawn when the system is running? etc..?

NiMH is better than NiCd in most regards, but it has a fast self-discharge rate. Lead acid is pretty bad for this too... So either of those would have to be on trickle charge, or relatively frequent charging (once a month, say), or they'll be flat when you go to use them.

There are low self discharge NiMH, though, which doesn't have that problem.

If it's fixed, lead acid is going to be the cheapest. But it's big and heavy, so no good for mobile/small.

Lithium is the best of them all, in almost all areas... but is a little more complicated to deal with.