802A alternator issue

Recently bought an 802A with 30 hours on it. Alternator would not charge the batteries and I got battery voltage at the battery terminals when running. Took off alternator and had a shop fix it supposedly. They charged 100 bucks and i put it back on and same deal on voltage at battery. Took it back and they put a voltage regulator on it. Still not fixed. I cut my losses or tried to and bought a new one off ebay. Now with battery voltage at 25 volts when not running it is 24.7 when running. I wired the new alternator per the prestolite information I got of the internet. Can anyone else suggest trying anything. I can run it for 7 or 8 hours but then I have to charge batteries to get it to start. I don't want to take life out of batteries and need the genny to keep working on off grid cabin/barn. Any suggestions would be appreciated.

Did you check the fuse behind the gauges?? Right below the 7.5amp breaker.

If the FU1 fuse is good, don't just look, test, then see if you have proper voltage at wire number 112B, on the back side of FU1. If no voltage is present, then mesure at MT4, pin one, (it's the other end of wire 112b) and see if you have proper voltage.

Will try this weekend when I can get over the river and through the woods to the generator. Thanks for the information. Should have been able to figure this myself but the schematics are hard to follow on this little computer screen. I see it now that you pointed me to MT4 and FU1. Thanks again and will let you know what I find.

One of my MEP-802A alternator went bad last year. I did not fix the alternator. I went with solar panel and charger controller instead. Even you have a good alternator, you still need to keep the batteries as their top every month. However, the solar panel does just that. I left the MEP-802A for 6 months and it started right up. I checked the batteries from time to time. Just another alternative.

I have dual trailer mounted MEP-802A. It has one set of batteries. I can start another one with NATO slave cable.

You really need to check for proper voltage before you go throwing parts at it. Just because its not charging the batterys dosnt mean its the alternator.

Did you check the voltage at the back of the alternator?
In a pinch you can plug a 24v battery charger into the convience outlet.