"Separator" relay - connect/disconnect house battery

I like the BLUE SEA SI-ACR Isolater idea for what I am doing here.. This is available from AMAZON...

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When engaged this smart relay monitors the CHARGE STATUS of the Start Battery and only switches in the HOUSE BATTERY when the truck alternator is putting out 12.75VDC or so... This prevents the HOUSE Battery from ever discharging the START Battery...


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Other brands doing the same thing are availabke also...

Roy Ken

1. Forget switch

2. Forget switch

3. Forget swtich


Connect the ground terminal to chassis negative. Chassis battery to one post, house batteries to other post.

It's all automatic and correct. No wires to dash, no stupid switches. It connects and disconnects batteries correctly. On time, never forgets and never makes a mistake.




http://www.ebay.com/itm/Sure-Power-1315-200-Battery-Separator-12-Volt-200-amp-Bi-Directional-/331883637941?hash=item4d45ce6cb5:g:aq8AAOSw-4BXYzNU&vxp=mtr

What year and model do you have. It may be as simple as a blown fuse that supplies the same thing as the switch you mentioned. It would be powered when the ignition is on.

One common arrangement is to have the emergency start switch be a SPDT switch. The common contact goes to the relay control line. The normally closed contact (i.e. when the switch is not pushed in) goes to some ignition switched power source in the chassis. The normally open contact goes to a house 12V circuit. The same relay is used both for emergency starting and as the battery isolator. Obviously in this case that relay needs to be rated for continuous duty and also capable of handling a short duration high current.

Sometimes the two systems are completely separate, too, and another relay or solid state power diode used to permit charging the house battery from the engine alternator.

Mount a Ford starter solenoid above the battery charge divider. They are built to withstand 800 amperes for 15 seconds. wire the relay base to chassis negative. Run a wire to s dash switch then to chassis battery positive. A shorted field coil will almost instantly fry a charge divider solenoid. How about having a ten dollar Ford solenoid laugh at an armature or field short while the charge divider solenoid stands back and watches the show? This is an extremely easy modification and it works like a charm. Fuse the Ford relay/solenoid for a 15 amp draw (inrush).

YC 1 wrote:
What year and model do you have. It may be as simple as a blown fuse that supplies the same thing as the switch you mentioned. It would be powered when the ignition is on.

1995 Fleetwood Tioga Montara 29ft Ford 350 Econoline Chassis 460 7.5 liter.

vtraudt wrote:
I need to properly wire up the separator relay that connect the house battery to the drive battery.

I have a switch on the dash that runs 12V from the house battery to the relay, closing the contact and connecting the house battery to the car battery in case the car battery is drained.

But with the engine running, the house battery should also be connected to the drive battery so it gets charged.

How is that done?

Note: that switch did NOT work. I ran a separate wire from house battery to the switch to the separator solenoid. So now I can connect car and house battery manually.

But reading up on IRD and BIRD, and remembering 'funny' readings when checking the switch (at some point I THOUGHT I saw 12V at the switch, shorted the switch but could NOT measure 12V at the separator relay), I am not concerned that I do have a mystery device (IRD or BIRD). And by running a separate wire for the Emergency switch, I eliminated that device and now the house battery is only connected to car battery when E button is pushed; hence would not get charged during driving.

Anyone know where the IRD, or BIRD (or Ford/Fleetwood may call it BCC battery control center is located on the 1995 Tioga Montara 29ft Ford?

MEXICOWANDERER wrote:
Mount a Ford starter solenoid above the battery charge divider.

The separator solenoid itself works. Applying 12V to the coil clicks and closes the (normally open) relay.

What would an additional starter solenoid do?
Or are you saying:
a) use existing separator relay for manual switch to connect both batteries (drained car battery)
b) use 2nd Ford starter solenoid, run "key on" power to it. This will ensure that house and car battery are connected when engine is running (and both get charged).

Before doing any modifications, I would like to FIX what is there (or at least determine what is broken). Here: do I have a IRD or BIRD or BCC that is not working properly? Where is it located? Is that IRD or BIRD fused (maybe bad fuse)?

A solenoid/relay can click like a telegraph operator on steroids and the relay can be complete junk. It's the electrical contact points inside the relay, the ones that carry the current that fail, seldom the magnetics.

INTERMITTENT duty relays have much more power handling capability because their contact size is much larger, but even more importantly the magnetic force that slaps the contacts together is many many times stronger. A lot more amperage. A lot more heat build-up. When engaged too long the solenoid magnetic coil winding overheats then burns out.

I've seen too many shorted 10-MT Delco starters consume 500 amps + from a large chassis battery. This indeed and absolutely will burn the contact points of a constant duty solenoid. Older style big block Ford 460 starters can short and earlier DIESEL 6.9 failed starters taxed their solenoid. Power the solenoid coil and switch from the HOUSE battery not the chassis battery.

Mounted 6" apart, the paralleling wires can be of 6 AWG and they will work fine to jumper. I've done with 20MT Delco Diesel starter rigs and it works fine.

The bonus comes with much longer life for the constant duty solenoid that allows the chassis bank to charge the house bank. 800 amps is a lot of armor.

The BIRD is a delay module that connects to your isolator/separator solenoid. It delays connecting your coach batteries to your engine battery. In the event that your coach batteries are dead, it gives you enough time to start your engine before connecting the coach batteries.

Here's a diagram: