tag:blogger.com,1999:blog-953397841255562532.post6004327994147491533..comments2023-09-30T14:59:05.385+01:00Comments on G4ILO's Blog: The battery charger that wasn'tAnonymoushttp://www.blogger.com/profile/11984840704237681015noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-953397841255562532.post-50260803966749966142010-05-03T05:44:10.180+01:002010-05-03T05:44:10.180+01:00Hi Julian, Looks like the typical chargers I have ...Hi Julian, Looks like the typical chargers I have obtained with cheap chinese 2 meter handhelds. Its basically a resistor in series with the input voltage. The other components are probably just for running the led. The instructions normally read " Charge for 5 hours, any more and the battery will overcharge". If the NIMH are getting hot that means overcharging is happening, as the chemical reaction is complete, and heat is now being generated with the charging current. As NIMH cells don't have the pronounced voltage dip of NICADs towards the end of the charging cycle, a temperature sensor is normally used with NIMH chargers. When the temperature rise is somewhere around 1 or 2 degrees Celsius per minute , its time to stop or cut back the charging current. A constant current will do the job, but be careful, NIMH cells don't have the robustness of NICADs to overcharge.<br />There is probably a thermistor output built into the battery pack for this purpose.<br /><br />Good luck es 73sTheodorehttps://www.blogger.com/profile/07101835130508244184noreply@blogger.com