A battery separator is used to both electrically tie together and separate the van's starting battery and house batteries. It contains a solenoid that opens and closes to join the two systems. During camping the van's electrical systems should only be fed from the house batteries so the separator opens to prevent the draining of the starting battery. When the engine is running the separator closes so the alternator can charge both sets of batteries. Now that Hal has solar panels installed the battery separator will also tie together the systems when the solar controller is outputting enough electricity.
I'd posted back in December about running a wire from the starting battery under the hood to the inside of the van. That wire ends up at the house electrical system under the sofa-bed. There it's wired to this Sure Power model 1315 Battery Separator.
The wire from the starting battery comes in from the right.
The wire on the left runs to here on the main breaker.
Looking at the above picture of the separator label there are connections for "Start Lamp", "Start Signal" and "Ground". The install instructions call for a 10 amp fuse in the ground connection. I used an in-line fuseholder for this connection from the separator ground connector to the grounding terminal strip on the back of my main fuse panel.
For the Start Lamp and Start Signal connections I'll need to run a couple of wires from here to the instrument panel.
The two wires will connected to a led indicator and a momentary push button switch.
The switch will provide the "Start Signal" to the separator. The separator's normal operation is to not close until either the house battery or starting battery is at 13.2 volts. In the situation where the starting battery doesn't have enough power to start the engine then pushing this switch will close the separator solenoid joining the two systems. The install instructions have one pole of the push bottom switch going to the Start Signal connector and the other pole going to a "power on start" source. I'll be doing it a little different.
Run the two wires from the separator to the underside of the instrument panel. Decide where to put the push button and led indicator. It needs to be on the left side of steering wheel since in starting operation my right hand is cranking the engine. To do this I'll have to first remove part of the instrument panel. Start with the headlight switch. Reach in under the dash and feel around on top of the light switch for a small button. Push down on the button and you can remove the knob with it's metal post.
Next unscrew this collar from the front of the cover piece. I've already remove the cover piece in this photo.
Take out the two screws at the top and the cover pops out.
Decide where there's room for the push button.
Drill holes for the push button and led indicator and install.
After soldering wires to the push button the back popped off the first time I pressing it.
Rats! I've already drilled the hole. Where am I going to get a push button switch the exact same size? I know!
Wire up the led and replacement push button to a male plug.
The positive power for the led indicator comes from the Start Lamp wire that goes to the separator. To complete the circuit I need a ground. Add a second wire to a ground connection on the left side of the instrument panel.
For the Start Signal it needs 12 volts. Instead of "power on start" I'm going to use a "hot all time" source. There might be times when I want to tie the two electrical systems other than just during engine start. Under the dash is this white wire that powers the radio from the house batteries. Use that as my source. Instead of cutting the wire use a tap. The tap slips over the source wire. Insert the new wire into the tap then squeeze the metal tab with pliers.
After the tab is squeezed all the down close the plastic latch. Done.
Add a female plug to these wires.
Plug in the new push button and led indicator. Give it a test before putting the cover back in place.
Light comes on and I can hear the solenoid in the battery separator kick in.
Not done yet. The separator has exposed connectors. I could easily drop a wrench and create short against the house battery frame.
Fix this by making a protective cap from scrap acrylic pieces. The Weld-On 3 cement I use works very quick so as long as a newly made joint isn't stressed just give it a couple minutes and keep building.
The solenoid on the separator gets warm so I left a lot of open space for air to circulate. Add a foot so it can be screwed down.
That's the end of the Battery Separator post.
One more thing. The replacement red capped push button. Removed it from something I'd built several years ago.
It's the Reset Button for a computer built into a Stanley toolbox.