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. __________________________________________________________ Food fight? Enjoy some healthy debate in the Yahoo! Answers Food & Drink Q&A. http://answers.yahoo.com/dir/?link=list&sid=396545367 ------------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.446 / Virus Database: 268.18.18/734 - Release Date: 3/26/2007 2:31 PM
