Charging Issues

[86loco]

I have been having problems recently with my three interior 8D deep cycle acid batteries. They charge 3 ways:

1.With the bus running with the 350 amp generator.

2. Running the 12.5kw gen-set.

3. Plugging into the house current.

With the bus running it charges at about 13.6 but with house or gen-set it only charges at 12.4 so it won't give it a full charge. I have a 75 amp charger. Any ideas for this problem? Thanks.

[TechTalk]

Either the 75 amp charger is defective, or it is being "pulled down" by one or more defective batteries, which may not be seen as a voltage drop when running on the alternator due to the much higher capacity of it compared to the charger.

I would park with engine off and inverter off and check the specific gravity of each cell with no loads. A bad cell will generally show up if you have one.

If nothing shows up purchase a 10 amp "fully automatic" battery charger with tapered charge reduction ($30. to $40.) and put the batteries on charge. Having been fully charged from the alternator, they should not take more than a few amps (with no loads on). If after several hours the batteries are taking little or no current, the problem is a defective 75 amp charger, which will eventually ruin the batteries -- if it hasn't already.

If the 10 amp charger pegs the needle and it stays there for several hours (with all loads disconnected), then you have one or more defective 8D OR a current leakage from a connector. Make sure connector and battery case are all very clean to eliminate leakage current to chassis ground.