Charging car battery, how high v is too high?

pianotuna wrote:
Hi,

When a battery exhibits that kind of behavior it is pretty much done.

15.7 is definitely too high for an RV (fridge board is 15.4), but I know not about a car.

It depends on the model of refrigerator. This is from Dometic

DIAGNOSTIC SERVICE MANUAL
AMERICANA & AMERICANA PLUS
RM 2351, RM 2354, RM 2451, RM 2454
RM 2551, RM 2554, RM 2652, RM 2662
RM 2663, RM2852, RM2862 & NDR1062

dc
Voltage
The operational range
of the unit is a minimum of 9.6V DC to a maximum of
22V DC. The unit will automatically shut down until volt
-
age has decreased to 18V DC.

The charger is working correctly.

The voltage you were reading was what the charger was putting into the battery to bring it back up to capacity. Once the battery gets near to 100% the charger will then switch to a trickle charge mode. I have a "smart" charger that starts out at about 13.2 volts & cycles in small increments up to 16.0 volts over the charging period, once the battery reaches capacity, the charger senses this & backs down voltage.

Hi,

When a battery exhibits that kind of behavior it is pretty much done.

15.7 is definitely too high for an RV (fridge board is 15.4), but I know not about a car.