Read some posts about voltage draw on cold starts but I need help with a problem. Mine pulls down to about 10 volts on the guage when manifold heaters are on, is this normal? This is on an 99 2500 with only 70,000 miles on it and I have gone through Five sets of batteries since new.. at $250 a crack it is getting tough to do.. every two years I have to replace batteries.. Any help on what the problem could be would be appreciated. Alternator appears to be charging alright and cables look good, what could be burning up these batteries so fast??

 

make sure your voltage isn't more than 14.5 volts after truck is running and batterys are charged. i'd rather see about 13.5 volts, but the charging system seems to be a bit overzealous on these trucks. higher voltage will cause electrolysis and 'boil' the water away. if more than about 14.5 volts, the cause could be the temperature sensor located underneath the drivers side battery tray, or the voltage regulator (part of the ecm, unfortunately). 10 volts with the grid heaters on isn't abnormal.

 

I agree with checking the charging voltage. It does sound like you are experiencing overcharging issues. It could be anything from a poor connection to a battery temperature sensor (under the left battery) to the ECM. It may take a while to figure it out so just take your time to avoid throwing parts at it. If worst comes to worst search for a thread that shows how to install an external voltage regulator (I can't remember but I think it is by Haulin in Dixie).
BTW, has anybody heard from him lately?
Tom

 

Are you doing a lot of short trips? You may not be getting your batteries charged fully. I am guessing this because of a 99 with 70,000 miles only. If it is a case where the truck sits a lot, you may just want to have an automatic charger hooked up or something.