Cable size for battery Isolator.

[wschneid]

I have a 2000 FR Sunseeker 23.5. I have the isolator switch on the drivers seat, but It doesn't work, nor does the house battery charge while I am driving. I cannot fine the isolator solenoid after looking all over for it. I decided to do a seperate smart battery isolator (off brand) the installation seems simple, but I am not sure what size wire to use to go from the start battery to the isolator and from the isolator to the house aux. battery. any suggestions?

Bill Schneider

 

[bikendan]

Moved thread from the Tech and Repair section to the Motorhome section's Coachmen sub-forum for better help from other Coachmen owners and possible factory support.

 

[BarabooBob]

I had to replace the wire on my old class c from the isolator to the coach battery. I used the same size wire that supplied power from the alt to the isolator, which was a 2 gauge wire. The original was a 4 ga from the isolator to the coach battery but due to the 10 ft run, I went with the 2 ga.

 

[Aussieguy]

a good guess would be that if the switch won't work ... battery cant be charged from alternator

an Isolator switch's purpose is to help connect/disconnect different batteries so they can be charged together from the alternator
you can test it by using a multimeter set to read OHMs
put the probes of the meter on the switch terminals and check for continuity

The wires from the switch will probably go to some sore of solenoid/relay that does the actual connecting of the high amp cables between batteries... much like your car's ignition switch activates the starter solenoid

a) test switch
b) find solenoid ... make sure it is getting voltage from switch
c) use multimeter OHMS to confirm solenoid is working
d) check all cables are connected and clean

solenoid.... may be called Bird, Bim , Relay find what is installed on .... YOUR RV

Refer to any manuals and / or watch some youtube videos

common solenoid/isolators ---->Google Search

 

[Aussieguy]

others can answer this.... is the switch on the seat momentary and only work while it is held down?
emergency connect house battery to chassis

 

[Bill and Gail]

others can answer this.... is the switch on the seat momentary and only work while it is held down?
emergency connect house battery to chassis

That's what it does in my 2016 Sunseeker. It's to help you start the engine if the battery is weak. You hold it and try to start.

 

[Twinboat]

Wire gauge depends on isolator rating. If its a 100 amp isolator use wire that can handle 125 amps.

You should already have cables, from each battery to an isolator solenoid, usually battery cable size. They are on both sides of the isolator solenoid you can't find. Find the lost one, there may be 3 to look at. The one your looking for will have battery volts on one side and house volts on the other side. Hook your new device to each side of it.

 

[Aussieguy]

the switch wire ... is often low amps it just sends a small signal current /volts ......to the isolator / solenoid / relay
The isolator/solenoid / relay ...... has the HIGH load cables needed to parallel batteries together

simply look at the back of the switch to tell if it is a small wire or a much bigger battery cable

 

[RamblerGuy]

I have a 2000 FR Sunseeker 23.5. I have the isolator switch on the drivers seat, but It doesn't work, nor does the house battery charge while I am driving. I cannot fine the isolator solenoid after looking all over for it. I decided to do a seperate smart battery isolator (off brand) the installation seems simple, but I am not sure what size wire to use to go from the start battery to the isolator and from the isolator to the house aux. battery. any suggestions?

Bill Schneider

The battery isolator solenoid on our 2011 Sunseeker is behind a panel on the left side of the coach steps. Mine went bad, too. It would engage (I could hear it click) but it did not carry current.

It would be simpler to replace the isolator than change the isolator. You can easily test yours with a voltmeter. With the shore line unplugged and the engine not running, check the voltage between the two large terminals, and check the voltage between each large terminal and ground. Start the engine, wait a few seconds, and if you hear a click, check the voltage between the terminals again. It should be much less, and the voltage from BOTH terminal and ground should be over 13.5 volts, indicating the engine's alternator is charging the coach batteries. In my case, it didn't change after it clicked, so I knew the solenoid contacts were not working. You can use a jumper to put 12 volts to small terminal to make the solenoid engage. If it doesn't, it's bad. If you use a jumper to engage the solenoid and the engine begins charging the coach batteries, the problem is not the solenoid. It may be the Battery Isolator Controller. Mine is the small black box that has the solenoid harness plugged into it. It's marked Bi-directional Isolator Relay Delay.

If you buy a new solenoid, be sure you get one rated for 200 amps CONTINOUS duty. The solenoid looks identical to those used on some older cars (Fords and AMC's), but they are rated for 200 amps intermittent. I replaced mine during a trip, and could only find one for trailers, which was rated for 30 amps continuous. That was fine when the engine was charging the coach batteries, but I could not use it to start the engine with the coach batteries. No problem, I didn't need to, and had jumper cables anyway. I replaced it with the correct one when I got home.

 

[RamblerGuy]

others can answer this.... is the switch on the seat momentary and only work while it is held down?
emergency connect house battery to chassis

The switch is momentary. Hold it down to connect the coach batteries to the chassis (engine) battery and turn the ignition switch to start the engine.

Oops. I didn't notice this was already answered.