07-20-2008, 12:38 AM
hey guys I have a 89 p/s I just recently added a audio system in it with a battery switch and auxiliarly battery. i know my boat only comes with a 35 amp alternator. on the normal boat batt with the boat running it will only read on my meter @ 13.8 volts sorry guys do not have a vat 40 machine. and then with both of the batt on with the amps on still running the boat it will drop down to 13.1 ? is the 13.8 normal ? with only the normal boat circuit load ? and does anybody know of a after market marine upgrade alternator ?
Looking at voltage as pressure, if you try to supply a fire truck with your garden hose, what happens to your water pressure when their pump starts?
Don't bother trying to run everything on a 35A alternator. It's not made for that load and it won't last long, possibly stranding you at a bad time.
Go to a local distributor/starter rebuild shop and ask for the same type, but much higher output. If you have the large alternator body, it may be capable of more than 150A, but you should be able to use about 95A and have some reserve, in case you add more amps later. If you increase the capacity by more than about 30%, you'll need to increase the gauge of the charging lead. Don't try to avoid doing this- it's not worth having a fire.