Isolating stator/alternator on 470

[Oshawapilot]

Working on my brother in laws boat, installed a new set of batteries for them last weekend and had intended to isolate the new house batteries (2x6v golf cart) from the main single 12v engine start battery. Unfortunately I ran into some confusion with isolating the charge circuit from the voltage regulator.

Yes, I know this engine uses a stator vs alternator, and yes, I know it has the funky water cooled regulator. The issue is that there appears to be two outgoing (live charge) feeds from the regulator - one goes to the power lug on the starters, so logic dictages that this is a charge circuit, but it appears that there's another wire (off the top lug of the regulator) that goes into a wiring loom and appears to go to the main harness/plug, beyond which it's unclear where it goes to me.

I want to isolate the charge circuit from the stator and feed it directly to a battery isolator, and then run the charge circuits from there to the battery banks. However, without a clear plan of attack on properly isolating the stator I'm concerned that I'll THINK we have things isolated, but something actually ends up connecting the two banks after the fact, and the first time they anchor somewhere overnight and deplete the house batteries they end up depleting the start battery as well accidentally.

Can anyone offer any insight?

 

[Bt Doctur]

Given the nature of the 470 charging system I don't recommend adding more amps to a already anemic system but if you must:

 

[Oshawapilot]

THANK YOU! Exactly what I was looking for.

Yes, I know the charging system on the 470 is craptastic, so I'm going to wait a few weeks before putting this in place to see how the house batteries fare given the "typical" cruising they do - the boat rarely spends a night outside the marina (mostly day cruising) so the two golf cart batteries are MORE than enough to power everything for the day, and honestly, I'm pretty sure it could go multiple days for that matter, at which point they could be replenished by the onboard charger when the boat sees shore power next versus having to rely on the stator.

Is the water cooled regulator more prone to failure if the stator is running at 100% output? I know it's a failure prone part at the best of times, but it's a bit of a weird system and I'm still wrapping my head around it - basically, does the regulator generate more heat (which is presumably a lot of what contributes to it's failure?) when it's handing 100% of the stators output versus when it's handling only a small portion of it once the start battery has been replenished?

 

[Bt Doctur]

If you examine the so called "water cooled regulator" you will see that the copper tube is just clamped to the back of the reg body. No real water cooling effect .
people have had their reg fail because they had a dead battery and instead of fully charging it they jump started the motor . A alt might be able to pump 60 Amp into a dead battery but not a stator system. Some have also experimented with Harley Davidson regulators off the bigger bikes.

 

[Oshawapilot]

Bump. Bt, would you still have that image available by chance? I know this is a thread from last year, but I never got around to tackling this project but have plans to finally do so next week...but the wiring diagram you posted at that time is now a broken link.

Thanks!

 

[Bt Doctur]