My battery charger is 42 years old and since we have had several batteries die recently I did a test on it. The battery voltage is raised to 12.8 on the low setting and to 16.1 on the high setting. The battery doesn't boil or stink during the normal high rate charge time of 30 minutes. Could the high charge rate for that amount of time kill battery life? I know that rate would be bad for one held there for days at a time but don't know about a short interval. Anyone else ever put a volt meter on a battery during charging and if so what was the reading?
To answer your actual question:
If your charger is the type that controls the rate and shuts down automatically, then you are OK. "The battery voltage is raised"...I assume means that during charging, the battery reads 12.8V and 16.1V. This is normal but, charging at 16.1 for long periods is bad. 30 minutes is not long. That's why you need a charger that tapers down automatically as it senses amperage. A fully charged battery is 12.4-12.6 Volts. It sounds like your charger is operating normally. 16V is peak charging rate for most chargers and will "equalize" and stir up/knock off sulphation. But 16V for long periods is no good as you said. You did not say what the battery reads after charging with charger disconnected. 12.4-13.4 ?
