Marine battery voltage reading?????

[peanutbay1]

Hi everyone;
I have a battery related question. I put a season old battery in a boat I just got. It turned over the engine 2 times at 5 seconds and after that the starter cellenoid just will click and the voltage on my dash guage drops off the scale. I took the battery out and it read 12.3 volts. I put it on my 1 amp charger and it registered a 5 and 0 is full charge. I left it on overnight and checked this morning the charger reads 0 and when I check the volts accross the terminals now I read 15.5 volts. Is this normal and if so is that why my starter would not turn over the engine and the dash guage would drop off scale?????

 

[Silvertip]

Re: Marine battery voltage reading?????

A battery that measures 12 volts (12.6 actually) may indeed register zero or anything less than 12.6 volts when a load is placed on it. The starter draws a great deal of current when it is cranking the engine. The battery was not fully charged or it has begun to fail. It was simply not capable of spinning the starter. A 1.5 amp charger would take forever to fully charge a deeply discharged battery. With the charger ON the battery, it may very well measure at 15 volts. That means it is charging. It does not mean the battery is good or fully charged.