magstang1
Active Member
I have twin 4.3 Mercs and a 4kw Kohler generator. 3 batteries total. One starting battery on the starboard motor isolated from all other loads, and two batteries in parallel on the port motor for house loads as well as starting the generator.
All three batteries were replaced at the same time in the summer of 2011. They are Walmart marine batteries (previous owner bought them). The charger is an original Charles Charger.
We overnighted on the hook last night. Motors turned off around 7pm Tuesday night. The radio played most of the night at low volume. The fridge was on dc power. The anchor light was on all night. My son watched a movie on a 19" dc powered TV.
Morning came and I turned on the GPS to see my voltage. 11.8v. I fired up the genny and batt charger for about 30 minutes and made a pot of coffee.
A few more hours of radio throughout the morning and I decide to fire the engines. Port just goes click. Generator cranks very slowly and won't fire. GPS says 11.7 volts. I fire the starboard no problem and hold down the emergency start for about 2-3 minutes. Try to start the starboard and it trips the circuit breaker on the starboard and kills everything.
Reset breakers. Restart starboard motor and tach it up to 1200rpm. Hold down the emergency start for about 5 minutes and try to fire the port engine. Trips the breaker and kills everything. Reset, restart and try the genny after holding the emergency start. It cranks slowly and won't fire. Maybe a little faster than before but not enough to fire it.
I disconnect the batteries and check voltage with a meter. Starboard was 12.5. One of the ports was 11.7 and the other was a little lower. I switch the two with the higher voltage and leave the low one disconnected. Fire the starboard motor on the battery that just wouldn't start the port (but the second paralleled battery is disconnected). Fire the genny and the starboard engine and turn on the battery charger, then I reconnected the third battery.
The genny and charger ran for about 1-2 hours and everything was good again.
I don't understand why the emergency start didn't work. The batteries were low, but nothing was under 11 volts. Why did the breaker keep popping? Does it seem like the batteries ran flat too fast? The port motor didn't even try to turn over. My 280ss could keep the fridge running and radio playing all night and still turn over a 350 with no sweat.
I hope the answer to this isn't three new batteries and a triple bank charger.
All three batteries were replaced at the same time in the summer of 2011. They are Walmart marine batteries (previous owner bought them). The charger is an original Charles Charger.
We overnighted on the hook last night. Motors turned off around 7pm Tuesday night. The radio played most of the night at low volume. The fridge was on dc power. The anchor light was on all night. My son watched a movie on a 19" dc powered TV.
Morning came and I turned on the GPS to see my voltage. 11.8v. I fired up the genny and batt charger for about 30 minutes and made a pot of coffee.
A few more hours of radio throughout the morning and I decide to fire the engines. Port just goes click. Generator cranks very slowly and won't fire. GPS says 11.7 volts. I fire the starboard no problem and hold down the emergency start for about 2-3 minutes. Try to start the starboard and it trips the circuit breaker on the starboard and kills everything.
Reset breakers. Restart starboard motor and tach it up to 1200rpm. Hold down the emergency start for about 5 minutes and try to fire the port engine. Trips the breaker and kills everything. Reset, restart and try the genny after holding the emergency start. It cranks slowly and won't fire. Maybe a little faster than before but not enough to fire it.
I disconnect the batteries and check voltage with a meter. Starboard was 12.5. One of the ports was 11.7 and the other was a little lower. I switch the two with the higher voltage and leave the low one disconnected. Fire the starboard motor on the battery that just wouldn't start the port (but the second paralleled battery is disconnected). Fire the genny and the starboard engine and turn on the battery charger, then I reconnected the third battery.
The genny and charger ran for about 1-2 hours and everything was good again.
I don't understand why the emergency start didn't work. The batteries were low, but nothing was under 11 volts. Why did the breaker keep popping? Does it seem like the batteries ran flat too fast? The port motor didn't even try to turn over. My 280ss could keep the fridge running and radio playing all night and still turn over a 350 with no sweat.
I hope the answer to this isn't three new batteries and a triple bank charger.