01-07-2020, 08:53 PM
Bill
The correct charging voltage for wet cell batteries is between 13.7 and 14.7 volts. Most automotive systems produce 14.2 volts which is considered standard.
My alternator is producing 14.2 volts but I am losing .8 volts at the isolator so voltage going to the battery is 13.4 volts.
Due to inherent charging losses you need a minimum of 13.7 charging volts to obtain a full charge.
I know 1/2 a volt doesn’t seem like much but it actually is.
The batteries are brand new,
I replaced them because the old batteries were old and seemed weak.
Most likely the old batteries were actually still ok, just undercharged.
When the new batteries wouldn’t start the coach I started looking at the charging system.
That’s when I found the problem!
I’ve learned a lot about battery charging in the last couple of months.
The correct charging voltage for wet cell batteries is between 13.7 and 14.7 volts. Most automotive systems produce 14.2 volts which is considered standard.
My alternator is producing 14.2 volts but I am losing .8 volts at the isolator so voltage going to the battery is 13.4 volts.
Due to inherent charging losses you need a minimum of 13.7 charging volts to obtain a full charge.
I know 1/2 a volt doesn’t seem like much but it actually is.
The batteries are brand new,
I replaced them because the old batteries were old and seemed weak.
Most likely the old batteries were actually still ok, just undercharged.
When the new batteries wouldn’t start the coach I started looking at the charging system.
That’s when I found the problem!
I’ve learned a lot about battery charging in the last couple of months.
Coach 1267, 2009 front entry