I need a 12 volt rechargeable battery pack for something I'm building for work. Something using AA cells would be a decent size/capacity compromise. The pack will be external to allow quick changing and will have a flying lead connector. I'll need three to cover requirements and a charger which can recharge in say four hours but have an automatic cutout if left on for longer.
Obviously I can source them from RS etc, but wondered if there was perhaps a model pack that would be better value?
See my reply in the Black&Decker 12v drill thread. What I had there was originally for a similar application for home-made NIMh batteries. Today, I use a holder for individual AA cells and charge them separately using a rapid delta-V charger, as this allows replacement of one cell at a time in the event of failures. This isn't often so perhaps I should go back to the convenience of charging 10 at once in the battery...
Since its external, and does it have to be AA cells? how about laptop batterys? you can pick these up cheap on ebay in all different sizes. As to the charger I'll leave that to you. ;-)
-- Sir Benjamin Middlethwaite
Have you thought of a sealed lead acid battery?. Maplins do various sizes and also the chargers. Trevor Smith
That's a thought. But presumably they need to dock in a housing to make contact?
It's likely to be the easy part.
Bit too heavy for this application.
quick charging might rule them out
Nope a make shift connector... car spade bits
-- Sir Benjamin Middlethwaite
Hi,
How about a couple of 6v packs?
Or maybe a DC-DC converter with 7.2v or 9.6v pack.
cheers, Pete.
Suitable NiMh delta V charger:
cheers, Pete.
That's certainly a possibility - the cost of that might be smaller than the cost of the battery packs over the projected life - if 'model' packs were indeed better value. But so far I'm not sure they are.
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