I'm not that into the ins and outs of battery charging but surely this project: Http://www.instructables.com/id/LED-Resin-Cube-V2/ Reeks of burning battery in the near future? He is using 4 x AAA Eveready rechargeables - which will be NimH. Uncontrolled charging will cook them quite quickly. There are ways he could manage them. Easiest is to clamp voltage well below maximum. This reduces capacity but that is not an issue here really. NimH charged at say C/5 or less need about 1.45 V/cell. So say 1,3 V/cell would be below full capacity - maybe too muh so. I'd suggest trying clamping the battery at 4 x 1.3 =3D 5.2V to start and se= e how it went. This could be done without potting to see what sort of capacity you get. 1 x LiIon or 1 x LiFePO4 is more controllable. LiIon will work OK with any LEDs and LiFePO4 with some white & blue (with low Vfon ) and most other LEDs. Sheer dissipation may be an issue. Better than a clamp is a charger that open circuits battery at full charge (low dissipation) but that adds complexity. Russell On 5 August 2013 09:26, Robin Bussell wrote: > Hi Folks, > I'm not that into the ins and outs of battery charging but > surely this project: > Http://www.instructables.com/id/LED-Resin-Cube-V2/ > Reeks of burning battery in the near future? > Looks like he's charging four cells (chemistry not specified but probably > NiMh these days) from a wireless power system that delivers 9V at 600mA > with batteries encased in acrylic resin. > I've left a "Danger Will Robinson" comment as "Zedsquared" ... Am I being > too alarmist and spoiling everyone's fun? > > Cheers, > Robin. > -- > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .