Bob, I just bought 2 NiMH batteries for my MT1000's... Same packs (and probably the same charger) as yours. Once you've completed the engineering, could I impose upon you for a copy?
No sense in both of us chasing the same rabbit. <wink/grin> Thanks! Mark - N9WYS -----Original Message----- From: [email protected] On Behalf Of Bob M. I have a schematic of another unit that seems to match mine. I'll check out the end-of-charge signal. Maybe I can increase the gain of the circuit so it detects the smaller signal better. I guess I was hoping someone else had "been there, done that" and found a cure. Maybe I'm the first? Thanks. Bob M. ====== --- "John J. Maurer" <[EMAIL PROTECTED]> wrote: > Bob > > The rapid charge rate is probably fine - the problem > normally is that the charger does not stop the > rapid-charge cycle properly. As you probably know, > the negative slope dv/dt is significantly less for > NiMH chemistry than for NiCd chemistry. You > probably have the schematic - can you see how the > end-of-charge signal is generated? Another > possibility would be to adjust the overtemp cutoff > downward - although I've never liked that method it > would protect your packs. > > The GP300 rapid charger also suffers the same > problem. A buddy of mine got a new pair of NiMH > GP300 battery packs last year, after the battery > vendor assured him the stock charger would work > fine. His packs also got warm during the rapid > charge cycle. They lasted about 9 months before > they were toast. He ended up going back to NiCd > packs. > > 73, > John Maurer WØDP > Ames, Iowa > > > ----- Original Message ----- > From: Bob M. > To: [email protected] > Sent: Wednesday, March 28, 2007 8:48 AM > Subject: [Repeater-Builder] OT- Motorola NTN4633B > Charger for NiMH batteries > > > I've got a pair of UHF HT600s that now have NiMH > battery packs. The NTN4633B charger was made for NiCd > packs and while it does seem to charge the NiMH packs, > the charger and the packs get alarmingly hot. > > Is there a modification to this unit, or maybe I need > a completely different unit, to rapid-charge these > NiMH packs properly? I think some of the MT-series > radios use the same battery (10V, 1100mAh NiCd, 10V, > 1700mAh NiMH). > > Thanks. > > Bob M.
