I Havew a decent sound syste in my boat, and am in need of advise. I have (4) pioneer 50 watt RMS speakers in my tower. They are power by a Sony the is putting out 150 X 2 RMS ( i have the gain turned down) I have a Profile Pushing 60 X 4 front channels are pushing my four boat speakers( 35 watts RMS) parellel. and rear is bridged pushing a bazzoka 10" woofer. Any way, I have added a Blue top battery to run the radio, and amps.I have an isolator in the system. so the the primary battery is not affected. <BR>My question is this. I am going to up grade my alternator. I dont plan on adding any more sterio. will a 100 amp alternator be enough?

I'm not a stereo guru, but I would say no to upgrading the alternator. Grant is hooking me up with a bigger system than that and we're leaving the alternator stock. Hope that helps.

I've done some research and your alternator should should be 25% of your total battery amp hours. Add up all your batteries ....

Tim: The reason I am up[grading is I found out the one in the boat is not Marine. PLus I dont know how many amps it is putting out, and also, When I am idleing, my gauge drops down. It is not an accurate reading, but it drops a few volts from where it normally is. <BR>I plan on putting a volt meter to it this weekend. Is there a way to tell how many amps the alternator is pushing wihtout taking it out of the boat? <BR>ANother question is if I get the 100 amp alterantor will I have to change my wiring from the alternator? I have a 93 mastercraft prostar 205. <BR>

Kaboom !! don't use car parts on a boat unless you want your car alternator to potentially blow up your boat from the gas fumes in your bilge. I would not operate the boat until you get a marine unit. <BR>do a google search and you'll find sites like: <a href="http://www.daviscoltd.com/Public/Engineering/documents/ignpro.htm" target="_blank">http://www.daviscoltd.com/Public/Engineering/documents/ignpro.htm</a>

You definately need to change out that alternator, regardless of working order. This thread should help you out: <BR> <BR><a href="http://www.wakeworld.com/MB/Discus/messages/3183/212570.html" target="_blank">http://www.wakeworld.com/MB/Discus/messages/3183/212570.html</a>

I just replaced my stock alt out of my 96 PS 190. I would definatley suggest replacing your stock alt....My guess is it only puts out 40 amps or so max. check the MC owners website for the specs. Even the 105 amp alt will only put out 20-25 amps at idle. Switch to the one wire alt and the install is easy. you should be able to find a good 105 amp alt for under/around $150. Make sure it marined (screen on the back and no holes in the housing)

How about the wiring. Will i need to replace the original wire with one that is larger. <BR>I had one guy tell me that it needed to be 4 gauge ot bigger. <BR>