The battery on my Snapper lawn tractor is not holding a charge. I'm not sure if the battery has just gone bad or if the charging system is not working properly. Measuring DC voltage across the battery with tractor running, it will start a little above the idle battery's voltage then slowly rise 1/100 of a volt every couple seconds until it reaches 16V then it holds steady there. Is 16V normal or is that too high and I have a bad rectifier?
The strange this is that I measure 29 V AC at the battery with the tractor NOT running and about 36V AC with the tractor running. Normally I think this would mean a bad rectifier but with the 29V when not running, I'm not sure if I just have a flaky voltmeter or not. It's just a cheapo from Harbor Freight. Is it even possible to measure AC on an idle battery? I do get proper AC voltage readings if I plug into a wall outlet. I don't want to just buy a new battery then have the charging system ruin the battery and if it is the charging system I may just buy a new tractor as I think this one is about 18 years old.
The strange this is that I measure 29 V AC at the battery with the tractor NOT running and about 36V AC with the tractor running. Normally I think this would mean a bad rectifier but with the 29V when not running, I'm not sure if I just have a flaky voltmeter or not. It's just a cheapo from Harbor Freight. Is it even possible to measure AC on an idle battery? I do get proper AC voltage readings if I plug into a wall outlet. I don't want to just buy a new battery then have the charging system ruin the battery and if it is the charging system I may just buy a new tractor as I think this one is about 18 years old.