out board charging system
 

what do you do when someone wants 2000 watts of power in a 37' intrepid with tripple 250 outboards. how do you supply enough current with stock charging? help.

d.

Average 250 horse OB has a 35amp alternator. This means that ech alternator can put out (35a x 13v) 450watts. 3 motors makes (450w x 3) 1,350 watts.

Using a 3-input isolator will allow you to combine the outputs.

You're going to need 170 amps of alternator output to get what you're after.

NOW, are you sure you need 2000watts CONTINUOUS? If not, then your 3 35a alternators should keep your batts charged.

Each group 27 battery gives around 90 amp-hours of juice. If you are running 2000 watts off the battery, and you have all 3 motors running 3500 rpm or so, then you are losing around 850 watts to the load. At that pace, you could be discharging to the tune of 70 amps. This means that you can run like that for a little over an hour before you get into undervoltage...

1 grp 27 - 1.25 hours
2 grp 27s - 2.6 hours

you get the idea...

tell us what the intended use is - might be interesting...

It is unlikely that the 2000 watt stereo will run at more than 200-300 watts at any time and certainly not for more that one or two songs before everyone's ears start to bleed:eek: I have played parties for 200-300 people and never used more than 150 watts per channel on the meters. I think that with a stereo system of that nature a couple of dedicated gel cell deep cycles might be nice, but worrying about a constant 2000 watt load is probably not necessary.

oh, is this a stereo we are trying to power here?