Um, I got a 1 hr charger from eBay (2 or 4 at a time AA or AAA) for like $20. Monitors temperature and the other variables. Not much point in DIY unless you are going to make a high end battery conditioner.
I fly r/c model aircraft powered by electric motors. There is an awful lot of information on batteries available at the www.ezonemag.com discussion forum that may be of interest - try:
http://www.rcgroups.com/forums/forumdisplay.php?f=129
There are tremendous variations in the abilities of different cells to provide current, and model planes ( & to an extent cars) are at the cutting edge of battery technology where power/gram is all. Look at the cells model flyers use where current draws of 40+ amps are the norm and you will be looking at the sort of cells you might want. Ni-Cads are still (imho) the best for their ability to provide high discharge rates but things like memory effect require good management. Panasonics NiMH like their GP3300 (3.3Ah) are about as good as you can get at the moment in a sub C package - I don't know what size we're talking here.
Please, please, please though DO NOT EVER EVER EVER (have I said this loud enough) short one of these beauties because, unlike those described earlier, you will have an exploding/burning metal event and associated damage, not least to your underware!
Modern Lithium Polymer cells like for example Kokam have a much greater energy density and can in the right cell deliver high discharge rates (10C+) but if you don't need light weight then they're expensive and require very careful charging/discharge controls for reasons of safety.
In terms of charging/discharging a model plane charger/discharger will satisfy your every need. I use a german Orbit which interfaces to my pc but the cheaper models from Hitec and Supernova (try http://www.rcbatteryclinic.com/nova.htm) would, I think, meet any hi-fi needs.
Model flyers tend to use 10 - 30 cells so I may be going ott on the spec. The toy car merchants use much lower cell counts so the car market may be a cheaper source. For our cousins across the Atlantic FMA-Direct are a good source, in the UK try www.overlander.co.uk
http://www.rcgroups.com/forums/forumdisplay.php?f=129
There are tremendous variations in the abilities of different cells to provide current, and model planes ( & to an extent cars) are at the cutting edge of battery technology where power/gram is all. Look at the cells model flyers use where current draws of 40+ amps are the norm and you will be looking at the sort of cells you might want. Ni-Cads are still (imho) the best for their ability to provide high discharge rates but things like memory effect require good management. Panasonics NiMH like their GP3300 (3.3Ah) are about as good as you can get at the moment in a sub C package - I don't know what size we're talking here.
Please, please, please though DO NOT EVER EVER EVER (have I said this loud enough) short one of these beauties because, unlike those described earlier, you will have an exploding/burning metal event and associated damage, not least to your underware!
Modern Lithium Polymer cells like for example Kokam have a much greater energy density and can in the right cell deliver high discharge rates (10C+) but if you don't need light weight then they're expensive and require very careful charging/discharge controls for reasons of safety.
In terms of charging/discharging a model plane charger/discharger will satisfy your every need. I use a german Orbit which interfaces to my pc but the cheaper models from Hitec and Supernova (try http://www.rcbatteryclinic.com/nova.htm) would, I think, meet any hi-fi needs.
Model flyers tend to use 10 - 30 cells so I may be going ott on the spec. The toy car merchants use much lower cell counts so the car market may be a cheaper source. For our cousins across the Atlantic FMA-Direct are a good source, in the UK try www.overlander.co.uk
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