LD 18 wont charge batteries

[cold comfort farm]

Does anyone have any Idea why my lister SOM is discharging the batteries shown on the amp meter as -ve. I just cant get it to charge the 24v bank.  If i cant get it to work then i will have to disconnect it an use the 230v to charge the batteries via a standard charger, just seems a waste though.



Stephen

[ronmar]

I don't think you have given us enough information to help you.  What exactly is a LD 18, some sort of alternator? How exactly is it wired?  If it is an alternator, what is it's rated RPM?  what is it's max rated output?  How are you driving it off the lister?  How large is the battery bank?  we need more info to help you pinpoint the specific problem.  Diagrams or pics would be nice.

In general, what voltage is it outputting?  What is the static battery voltage and what is the battery voltage when you are attempting to charge? 

I don't know your background, but I like the water analogy.  If you hook up a 15 PSI water line to your 25 PSI pressure tank(battery), water is going to flow out of the tank in an attempt to equalize things.  In order to put something into the tank, you need to apply a greater pressure(voltage) than what is already in the tank.  In the case of a 24V bank, I would think you need something in the area of 28-29V at the battery terminals to overcome resistances and put current into the battery.  Need a comparison, hook up the 240V charger and see what voltages it outputs to the battery.  If the LD-18 is some form of auto/truck alternator, you might be slightly more efficient charging with the 240V charger...

Ron

[cold comfort farm]

Sorry for not getting back.  The LD18 is a lister generator.
The batteries are 2 x 12v making 24v. I dont know much more other than its very similar to an Lister SOM.  If I cant get the batteris to charge then I will disconnect it and just use a 24v charger.

Stephen

[ronmar]

stephen
  What is the voltage across your 24V bank while you are trying to charge it?  What is the LD-18 output voltage to the batteries with the batteries disconnected(unloaded LD18 output)?