> doing a quick look on farnell I found a 10AH nimh D cells
> http://uk.farnell.com/jsp/Electrical/Batteries,+Chargers+&+Holders/ANSMAN=
N/5030641/displayProduct.jsp?sku=3D1173791&_requestid=3D100587
> but at =A37 each excluding vat they aren't cheap.
>

> oops wrong price, the actual price for the big nimh D cell =

> was =A38.73

At 1.2V nominal, that's GBP0.73/Wh.

A 12V 7Ah SLA would cost GBP61 at that rate.
here I can buy a reasonably OK 12V 7AH SLA for under GBP10 =

and an acceptable one for possibly half that.

If "green" issues are not the greatest factor then lead acid =

is still pretty attractive in this role.

If green issues ARE (or aren't) a key factor you can take =

suitable care with the recycling in due course. The highly =

enthused could even strip the cell when dead and meutralise =

the acid electrolyte prior to recycling the lead.

Here (NZ) people pay useful money for dead car batteries, =

suggesting that the lead is getting properly recycled. With =

NiCd batteries it's not at all certainthat they always =

actually reach Nirvana after having been 'properly" disposed =

of.



        Russell




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