John Horsfield Posted January 18, 2009 Share Posted January 18, 2009 Straight forwards one this... Can I charge nimh batteries with a normal Sanwa RX/TX charger? It says nicd on it, but its a few years old, before nimh were in general use. Cheers John Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted January 19, 2009 Share Posted January 19, 2009 Yes if it is a slow charger (over night or longer) If you know the charge rate of the charger than you can divide this into the capacity of your new cells and get the charge time. Quote Link to comment Share on other sites More sharing options...
Hamish Posted January 19, 2009 Share Posted January 19, 2009 I purchased a NiMh glow start and found it got very warm using the NiCad charger. What should the charge voltage for a NiMh be? Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted January 19, 2009 Share Posted January 19, 2009 Charge voltage is the same as for Nickel Cadmium. Nmhi do get warm when they are full so you may have left it on charge for too long Quote Link to comment Share on other sites More sharing options...
Hamish Posted January 19, 2009 Share Posted January 19, 2009 Thanks Bruce I now use a stabalised (sorry if incorrect spelling, on wish list) PSU and charge at just over 13 volts. Again I was a bit concerned that the current draw was quite large at that voltage and did not come down as anticipated. Unit appears ok Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted January 19, 2009 Share Posted January 19, 2009 A glow start uses a single cell battery which is 1.2V nominal. I am not sure of the charge voltage but I would guess about 2V. If you are charging at 13V then You may well have ruined it.. What current draw are you seeing? Quote Link to comment Share on other sites More sharing options...
Hamish Posted January 19, 2009 Share Posted January 19, 2009 Sorry, missed the decimal point 1.3 volts. Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted January 19, 2009 Share Posted January 19, 2009 That sounds a bit low as fully charged a single Nmhi Cell is about 1.5V. The current should be 1C (C is the capacity of the battery) typically 2000mah so 2A charge or less. A 2A charge rate should charge in an hour or less. The problem is it is easy to over charge at this high rate if you do not have an auto sensing charger. I would suggest that a current C/10 or 0.2A for 10 hours would be the charge current you should be looking for. You could use the highr rate for a quick boost. Quote Link to comment Share on other sites More sharing options...
John Horsfield Posted January 19, 2009 Author Share Posted January 19, 2009 Hi Bruce, Thanks for your advice, the charger is an overnight slow charger and it does have the charge rate marked on it so Ill have a look and work out the chrge times. John Quote Link to comment Share on other sites More sharing options...
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