Generator charging issue???

I need some help. When off the power grid, my generator does not seem to be charging my batteries very well. I have an 8 golf cart bank for my house with a xantrex inverter, 12.5kw Westerbeke generator and a battery charger. When on my battery bank, I have 920 Amp hours and go through about 20 per hour. But, when I run my generator to recharge for a few hours a day, it seems to put about 110 a/h into the system for about 10 minutes according to my inverter monitor, but then drops to 10-12. So, over the course of a few days my batteries slowly die. When I plug into shore power my inverter reads 110 a/h until the batteries get back to full charge. So, my question is do I have a problem? If so, what is the likely culprit....charger, inverter, batteries,generator? When running, my generator powers my boat with no problems.

Any comments welcomed.

Without being there and seeing for myself exactly what's going on,I can only guess.



How are your connections?Have you cleaned them lately?It sounds like to me that the batteries are unable to take a charge and the charging source,IE genny or battery charger,is throttling back to prevent damage.Low electrolyte levels or a layer of sulfates may have accumulated on the lead plates inside.Does your charger have the option of desulfating the batteries?I prefer to do this on each battery and not the entire bank.It seems to work better for me.

baldpaul said:

I need some help. When off the power grid, my generator does not seem to be charging my batteries very well. I have an 8 golf cart bank for my house with a xantrex inverter, 12.5kw Westerbeke generator and a battery charger. When on my battery bank, I have 920 Amp hours and go through about 20 per hour. But, when I run my generator to recharge for a few hours a day, it seems to put about 110 a/h into the system for about 10 minutes according to my inverter monitor, but then drops to 10-12. So, over the course of a few days my batteries slowly die. When I plug into shore power my inverter reads 110 a/h until the batteries get back to full charge. So, my question is do I have a problem? If so, what is the likely culprit....charger, inverter, batteries,generator? When running, my generator powers my boat with no problems.

Any comments welcomed.

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Did this just start? How old is your generator?

I had something similar happen a long time ago, where my battery charger did not like the A/C output of my generator.

I have a 36 year old Onan 7.5 kw and the governor was not holding the generator at a constant speed. The generator was running too slow when under load, which caused the A/C to be much less than the 60 cycles it should have been putting out and the voltage was also low. The trouble began when I installed a new smart battery charger. It would run for a while on generator, then it would sense the low cycle rate in the A/C and go into a standby mode. Once the load came off the generator and it sped up a little or you plugged into dock power the battery charger would come back on line. The governer on the generator was replaced, speed adjusted and haven't had a problem since.

Some of the smart chargers are a little more touchy about the A\C line power you feed them than the old ones used to be. It may not be what's causing your problem, but just something else to look at.

Larry B

Sometimes boats were OM with "converters" instead of battery chargers.

These were great at staying dockside and nor overcharging and requiring water to be added too often. Check what you have installed.

The converters would hold the voltage at 13.3 or so which does charge , but very slowly.

FF

All of my equipment is 2005 vintage. I am unsure of the battery age, as I bought the boat a year ago, but am presuming they are not original. As mentioned, they seem to accept charge from shore power, but not as well from my generator.

You could put a Kill-a-watt meter on it to monitor the generator output frequency. It might tell you something for as little as $20.

12.5kw Westerbeke

Usually a 10KW or larger noisemaker will have the power (area in the sine wave output) to operate a larger battery charger to rated output..

Check the dock voltage it could be 10V above the noisemaker.

IF really rapid DC charging is important a 135A truck alt and 3 stage regulator belted on the set would be best bet.

FF

baldpaul said:

All of my equipment is 2005 vintage. I am unsure of the battery age, as I bought the boat a year ago, but am presuming they are not original. As mentioned, they seem to accept charge from shore power, but not as well from my generator.

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P.S. Is this by chance a Xantrex battery charger, I know you mentioned your inverter was Xantrex? I was reading the manual for my Xantrex charger and it talks about older generators producing poor sine wave being a problem, but it also mentions that the start battery for the generator needs to either be charged by the generator or by the Xantrex charger, but not both. If you have it setup to charge from both sources, the smart charger will sense the generators alternator charge and switch to standby/ready. I have the generator charge circuit disabled on mine.

Just another thought of something to look at. It's usually the dumbest things that cause these little problems.

Larry B

So.....I figured out my problem, after dishing out a few dollars to my boat professional. After a couple hours of troubleshooting, he asks me when I put my power switch to GEN. I had to think, but I said I thought I usually switched over before I started the generator. He said that is probably my issue, as most Inverters will kick the power source out if it does not like it. So he said to start the generator and let it run for about 30 seconds, then switch to GEN. It WORKED My generator was putting a good load back into my battery bank.

I feel dumb of course, but I am sharing my stupidity in case others search for such a thread in the future

I feel dumb of course, but I am sharing my stupidity in case others search for such a thread in the future

Everybody learns from others missteps.

Thanks, BP! I'm sure that will help others with similar issues. Good to hear it's solved.