Rechargeable batteries

[Big Jim]

This may sound odd to anyone who understands these things but bear with me please.
I need to replace a few aged and knackered c and d size rechargeable batteries. Good rechargeable are expensive but worth every penny, however I was looking at an adaptor that allows you to use aa size batteries in place of the bigger ones, they look like hollow batteries.
Has anyone used these?
Also will a 2500mh aa last as long as a 2500mh d size?
I know they have the same output, but is it only their size that is different.
Apologies if this is a really stupid question but electricity is all quite new down here in Wales

[tom_tom_go]

I bought some adapters once for a torch and they had poor contacts so might be worth just buying the actual battery size you need.

[James from Devon]

Hi JIm

I agree with Tom, I have had very mixed results with those adapters - particularly if they are bouncing around inside a loco. You can get some very reasonably priced batteries from Ebay, Amazon, CPC or Rapid Electronics.

If you really want to use AA size, the actual holders cost pence. If you are able, just change the battery holder.

Hope that's useful

Best

Jim

[Big Jim]

Thanks folks,
They need to be C or D size, all my locos have long been converted to AA power. It is for things like the Boy's toys and radios and things.
The only loco that they will be used in will be Big Big stuff that only gets run once in a blue moon.
I think I will bite the bullet and get some proper ones as the write ups I have seen don't seem to positive. I was just wondering that with batteries if they are the same amp output does it matter about the size?

[Chris Cairns]

The C size adaptors have no additional contacts, as C batteries are nearly (0.5mm shorter) the same length as an AA battery. So it is dependant on the length of your AA batteries and the C battery holder. I have some 7DayShop AA rechargeable batteries which are slightly shorter than their alkaline equivalent and can cause problems with some fixed AA battery holders. I have briefly run a Big Big 0-4-0 chassis holding AA batteries up in the holder.

I've recently had problems with the cheap Asian battery holders - had to throw away a 2 x AA + 2 x AA flat holder due to it twisting & breaking cell contact, and a 4 x AA battery holder due to a non-conductive terminal!

My understanding is that the same mAh capacity rechargeable will last as long no matter the battery size (their alkaline equivalents will have a different capacity).

Chris Cairns

[Big Jim]

Thanks Chris