Need some help with primary 12 Volt layout

[heinz wittenbecher]

I'm about to replace my relay with a combiner (used instead of the diode) to
connect aft and forward batteries.

While doing that I'm going to check for voltage drops, etc and am trying to
figure out what goes where

I have it pretty well under control except for one wire.

The one in question connects to what I assume is a self resetting circuit
breaker that is installed just below the aux battery relay.

It has a lead from the POS side of the aux battery connected to the same
terminal that has the wire in question connected to it. The other terminal
on that round/oval shaped device is about a #8 red wire that connects to the
street side terminal on the aux relay.

The wire in question, i.e. the one connected to the same terminal of the
?circuit breaker? as the POS aux battery dissapears down and then seems to
cross over to the right hand side of the coach.

Is that device I refer to as a circuit breaker really a circuit breaker?

Any insight wher that wire goes to on the right side... or is it actually
going there?

TIA - Heinz
'76 Transmode

 

[jim bounds1]

Heinz,
Yes, that is a circuit breaker. It is there to protect from shorts in the
8ga. wire running from the back to the front, it is usually an 80amp.
rating. It is resetable but, if you know how a resetting circuit breaker
works, usually destroys itself at the high current ratings.

You may see a voltage drop through the unit, if soo get another one! Under
no circumstances bypass the unit, it is there for your protection and I
have seen situations that, if it were taken out of the circuit, the coach
would have had some major problems.

BTW, I think your idea of using a contactor instead of the isolator is a
good one, the isolator seems to be up there on suspect electrical
components. I would run the contactor trigger from the alternator output,
the same as input to the hi blow relay. That way the relay would only do
its thing when the alt. is putting out.

Hope this helps,

Jim Bounds
- ------------------------

>I'm about to replace my relay with a combiner (used instead of the diode) to
>connect aft and forward batteries.
>
>While doing that I'm going to check for voltage drops, etc and am trying to
>figure out what goes where
>
>I have it pretty well under control except for one wire.
>
>The one in question connects to what I assume is a self resetting circuit
>breaker that is installed just below the aux battery relay.
>
>It has a lead from the POS side of the aux battery connected to the same
>terminal that has the wire in question connected to it. The other terminal
>on that round/oval shaped device is about a #8 red wire that connects to the
>street side terminal on the aux relay.
>
>The wire in question, i.e. the one connected to the same terminal of the
>?circuit breaker? as the POS aux battery dissapears down and then seems to
>cross over to the right hand side of the coach.
>
>Is that device I refer to as a circuit breaker really a circuit breaker?
>
>Any insight wher that wire goes to on the right side... or is it actually
>going there?
>
>TIA - Heinz
>'76 Transmode
>
>
>
Jim Bounds/Co-op Motor Works Orlando www.gmccoop.com

 

[heinz wittenbecher]

Thanks for the input Jim.

I have been using a relay/solenoid (triggered by ignition on) instead of the
diode for many years, ever since the diode failed on the road one time
(after several prior failures/replacements).

Thanks to Gene Fisher I got on the trail of the Combiner from West Marine,
which is a smart relay. It allows one to get the primary battery (the
primary one being the one that is receiving charge current).

Now, back to my setup...
Best I can figure is that:
Aux Pos goes to one end of the CB
connected to same terminal of CB a wire goes to the genset, genset start.
A #8-ish red goes from the other, i.e. protected, terminal up to the street
side of AUX/BOOST relay.
on that same terminal I have a #4-ish or better welding cable going to the
rear battery.

In my setup the rear is the house battery.

This would mean that when Aux/Boost is closed it puts the rear battery as
well as the front aux battery on line. The rear via the #4 welding cable and
the boost via the #8-ish red.

I'm going to assume (there's that dangerous word and action again ;-) that
the #4 welding cable from rear batt to aux-solenoid and and then to diode is
not exactely 'standard'?

When "boosting" it would seem that it's just that #8 wire that puts the
batteries in parallel? Seems kinda small? No?

Guess I'll take a few more things apart to check voltages.

Heinz

> Heinz,
> Yes, that is a circuit breaker. It is there to protect from shorts in the
> 8ga. wire running from the back to the front, it is usually an 80amp.
> rating. It is resetable but, if you know how a resetting circuit breaker
> works, usually destroys itself at the high current ratings.
>
> You may see a voltage drop through the unit, if soo get another one!
Under
> no circumstances bypass the unit, it is there for your protection and I
> have seen situations that, if it were taken out of the circuit, the coach
> would have had some major problems.
>
> BTW, I think your idea of using a contactor instead of the isolator is a
> good one, the isolator seems to be up there on suspect electrical
> components. I would run the contactor trigger from the alternator output,
> the same as input to the hi blow relay. That way the relay would only do
> its thing when the alt. is putting out.
>
> Hope this helps,
>
> Jim Bounds
> ------------------------

> >I'm about to replace my relay with a combiner (used instead of the diode)
to
> >connect aft and forward batteries.
> >
> >While doing that I'm going to check for voltage drops, etc and am trying
to
> >figure out what goes where
> >
> >I have it pretty well under control except for one wire.
> >
> >The one in question connects to what I assume is a self resetting circuit
> >breaker that is installed just below the aux battery relay.
> >
> >It has a lead from the POS side of the aux battery connected to the same
> >terminal that has the wire in question connected to it. The other
terminal
> >on that round/oval shaped device is about a #8 red wire that connects to
the
> >street side terminal on the aux relay.
> >
> >The wire in question, i.e. the one connected to the same terminal of the
> >?circuit breaker? as the POS aux battery dissapears down and then seems
to
> >cross over to the right hand side of the coach.
> >
> >Is that device I refer to as a circuit breaker really a circuit breaker?
> >
> >Any insight wher that wire goes to on the right side... or is it actually
> >going there?
> >
> >TIA - Heinz
> >'76 Transmode
> >
> >
> >
> Jim Bounds/Co-op Motor Works Orlando www.gmccoop.com
>
>