In message <001c01c60829$f85725a0$9d42acce@personalrvuq8e> "microsoftwarecontrol" wrote: > But it seems too expensive if reach > the specification of yours. discharge > 5A? Charge 5A is easier than > discharge 5A. So, simplifying you > plan seems unavoidable. The 5A discharge pulse only has to be sustained for 5ms. I've got an MJE2955T that should be able to handle that. I might make the charge/discharge system symmetrical - i.e. 5A charge or 5A discharge. The charge system would only ever run at a maximum of 2.5A though. Reflex charging supposedly works by using a negative pulse to "knock" the hydrogen bubbles off the cell plates - the "metal hydride" portion of the cell then recombines these into the cell electrolyte. Because you're not getting as many H2 bubbles sticking to the plates, you can push more power into the cell. That's the theory, anyway. As long as I can charge a 1600mAh Kodak AA NiMH in three hours, I'll be happy. Like I said, the whole point of the experiment is to make a charger that I can use not only to charge my NiMHs, but also to play with charge algorithms. It's also an excuse to play around with high current switchmode converters and power transistors :) > Those big > ic manufacture's charger ic, none > of them really work! most funny thing > is those 15min/one hour charger, > they are just battery killers or 1/3-charger. The MAX712/713 isn't too bad, but it's not the best charger in the world either. OTOH, at least its charge termination circuit is reliable, unlike most of the Chinese elcheapo chargers I've used... Later. -- Phil. | Acorn RiscPC600 SA220 64MB+6GB 100baseT philpem@philpem.me.uk | Athlon64 3200+ A8VDeluxe R2 512MB+100GB http://www.philpem.me.uk/ | Panasonic CF-25 Mk.2 Toughbook ... Law of Insurance and Taxes - Whatever goes up, stays up. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist