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compmc
09-15-2019, 10:50 AM
1995 sun voyager, my coach batteries got up to 17.2 volts on shore power when running the converter charger. Either my batteries have an internal short, or the on board charger is not switching into float charge. Is my diagnosis correct?
Update; After further investigation, the batteries are 12.6 with charger off and 13.2 when charger was on, so all good. The high voltage I encountered may have been due to a new LED motion porch light fixture I had recently installed. There must be a capacitor on the pcb that had stored a higher voltage when the charger is on. After turning off the charger, the high voltage drains back to battery voltage.
Thanks for your comments.
"Still Learning"

DolceFarNiente
09-15-2019, 11:06 AM
You can try this (I have a hard time believing your batteries are still good if they've had over 17 volts consistantly pushed into them). Where are you reading this, BTW? For my money, you've got a failed converter charger.

Check water levels.

First try an ordinary battery load tester; you may be able to rent one from your local O'Reilly's.

Second, you can unhook the connections to the converter, discharge the batteries and when they are fairly flat, hook up an ordinary auto battery charger with a digital readout, like this one;
https://www.amazon.com/STANLEY-BC25BS-Automatic-Maintainer-Alternator/dp/B01BM51QD6/ref=sr_1_9?gclid=CjwKCAjwwvfrBRBIEiwA2nFiPaxgZ2HoQ 8V15w5GB3MVtk1URW_XwFmCm2CJRib7PDXxn4z2-ZhGDRoCfGMQAvD_BwE&hvadid=153640185110&hvdev=c&hvlocphy=9033559&hvnetw=g&hvpos=1t2&hvqmt=e&hvrand=12029367412997843202&hvtargid=aud-676677759484%3Akwd-313678866947&hydadcr=6616_9165515&keywords=50%2Bamp%2Bbattery%2Bcharger&qid=1568563169&sr=8-9&th=1
(https://www.amazon.com/STANLEY-BC25BS-Automatic-Maintainer-Alternator/dp/B01BM51QD6/ref=sr_1_9?gclid=CjwKCAjwwvfrBRBIEiwA2nFiPaxgZ2HoQ 8V15w5GB3MVtk1URW_XwFmCm2CJRib7PDXxn4z2-ZhGDRoCfGMQAvD_BwE&hvadid=153640185110&hvdev=c&hvlocphy=9033559&hvnetw=g&hvpos=1t2&hvqmt=e&hvrand=12029367412997843202&hvtargid=aud-676677759484%3Akwd-313678866947&hydadcr=6616_9165515&keywords=50%2Bamp%2Bbattery%2Bcharger&qid=1568563169&sr=8-9&th=1)
This will let you determine if the batteries accept a charge normally, what their peak voltage is and how quickly they self discharge.