Using the boost switch as battery isolator

[Robert K]

I want to get rid of the 2oo amp Noco Isolator. I don't know if it is easier / better to use the current boost solenoid or install a seperate continuouse duty solenoid. I attached a sketch of how my current set up works when boost switch is pressed
thanks for the help

[TDJohn]

I want to get rid of the 2oo amp Noco Isolator. I don't know if it is easier / better to use the current boost solenoid or install a separate continuous duty solenoid. I attached a sketch of how my current set up works when boost switch is pressed
thanks for the help

Robert,

Check the label on your boost solenoid. It is likely that your boost solenoid is a constant duty solenoid. I know mine is and many others I have seen were constant duty. If your boost switch is rated for constant duty, you should have no issues converting your boost switch for the dual purpose of solenoid based isolator and boost solenoid.

Be aware that the boost switch brakes the ground not the positive, when the switch is disengaged.
Jim Exler had some drawings on the old group. I might have a copy of it on one of my hard drives, but I will need time to look for it. Let me know if your interested. Also, if your are interested, send me a private message, I have some thoughts on how this could be done very simply, with minimal changes and fuss.

[stuplich@ymail.com]

Jim Exler had some drawings on the old group.
I might have a copy of it on one of my hard drives, but I will need time to look for it.

Robert & JD
Here's a link to Jim Exler's "Safari Motorhome Electrical" page:
http://jexler.s3.amazonaws.com/safari/s ... rical.html

[TDJohn]

Mel,

Thank you! You saved me some digging.

[Robert K]

Thanks John , Mel,
I have removed my boost solenoid and there are no numbers on it no name on it. I will put a relay on under the dash and have it fire when ignition is on to combine on boost solenoid.
l also think I will replace the boost s. as my alternator was rebuilt to 200 amps.
I like that idea of the oil pressure switch to fire the relay and will look into that also

[TDJohn]

Thanks John , Mel,
I have removed my boost solenoid and there are no numbers on it no name on it. I will put a relay on under the dash and have it fire when ignition is on to combine on boost solenoid.
l also think I will replace the boost s. as my alternator was rebuilt to 200 amps.
I like that idea of the oil pressure switch to fire the relay and will look into that also

Bob,

Why complicate things, there is really no need to fire the isolator/boost solenoid off of the oil switch. Wiring it up to ignition power produces the same result and is much simpler and easier to wire. I would also suggest to have a manual on off switch tied with the ignition supplied relay. This will allow you to keep the batteries isolated until you start driving (higher rpm). If the batteries are deeply discharged and you load the alternator at idle, it will build up a lot of heat and get stressed. Having the switch will allow you to delay the charging until you get rolling.\
Also, if you can, post a picture of your boost solenoid. Most OEM boost switches were rated at 200 to 250 amps and were constant duty, so there is really no need to replace it, (just something to consider).

[Safaritoonces]

Did you see the project under "Boost Solenoid - Isolator replacement addendum" the drawings and explanation are there? This seems to be what you are trying to do.

This was under Coach Upgrades.
viewtopic.php?f=6&t=39891

[Robert K]

Yes I saw it , and left a comment. Yes it seems that will be the simple way to go.
My brain must have been stuck thinking it had to be done in the engine compartment.

[Robert K]

As I was getting parts to put the relay in I thought why not just change momentary boost switch to a latching on off switch,
Still thinking.

[Robert K]

So I took the momentary switch out and hooked up a toggle switch to try it. Ithe worked fine for switching and I could see the voltage change when I started the engine.
I have the coach hooked up to 30 amp outlet so I let it charge.
I left it on for an hour or so, the solenoid was warm but I think that is probably normal.
I need to find a rocker switch to replace the boost switch on the switch panel .