Question? I leave my bus on shore power in storage. 1. I have a four part 12V "Battery Tender" on each of the 4 pairs of 6V golf cart batteries for the house. That system takes care of itself.

2. I put a 24v " Battery Tender " on the 24V part of the chassis batteries, that's working fine. My thinking was the 12v portion of these 4 batteries would receive charging from the 24V charger. In checking the 12V output last night it was at 11V. Do I need to put a 12V "Battery Tender'" on the 12V section of the chassis batteries? When engine is running, there are two alternators supplying these batteries. One 24V ALT & One 12v Alt. It makes sense two chargers are required. If you can understand what I'm getting at please answer the question.

I fought chassis batteries going down too low to re-start the engine to and from POG2. I put a meter on the + outlet of the 24V alternator and no reading.
After removing the alternator and taking it to our local motor shop, they checked it out and it worked fine. [B]THE REASON I GOT NO READING WHEN I CHECKED IT, I PUT THE PRODE ON THE BOLT HOLDING THE CABLE TO THE + CONNECTION POST, AS YOU WOULD DO ON A BATTERY. WRONG! THE BOLT IS ISOLATED IN THAT CONNECTION AND IF YOU LOOK VERY CLOSE AT THE TINY PRINT ON THE HEAD OF THE BOLT IT TELLS YOU THAT. /B]

$75 Lewbucks later I re-installed the alternator and it was charging fine.

The Mystery is still not solved as to why the batteries went down while on the road. The problem may still be with me. There is a regulator built in to the alternator. It may be intermittingly stopping the charging cycle when the batteries reach the their peak and not coming back on when they are discharged below 24V. I guess time will tell. I'm open to any other explanations offered. Meantime I think I'll order a regulator to carry with me.
I survived the problem on the trip by starting the generator every so often and letting the battery charger keep the engine batteries up. Owning a Prevost is so much fun ??
Harry
1989 XL Royale