How to wire for Emergency start from Aux Battery?

[jimtmcdaniels]

Ok Greg, well this is come of my confusion, first:
I'm under the assumption that this is how it is factory wired:
Terminal 30 is connected to the starter battery 12v.
87(normally open until relay is energized) is connected to the solenoid energize terminal.
87a (normally closed until relay energized open) is not used.
85 (positive to energize the relay) is connected to the ignition run position.

Upon ignition in run position, starter battery energized relay with 12v, closing the relay main circuit and so energizing the onward solenoid which connects the Aux to the Starter battery.

[Scalf77]

My diagram is an additional SPDT relay, the existing solenoid is not shown just the 12 volt control line. The solenoid would be SPST relay, there would not be a normally connected throw.

[jimtmcdaniels]

Ok Greg, so you are suggesting adding both a momentary switch and a relay, I see it now!
Ok well simplifying it even more, it seems I could instead, add an on-on 15a switch to do it all couldn't I?..:
Wiring it so that when the switch is in ON 1 position, that the factory solenoid energize power circuit just passes through the switch unaffected.
Then when the switch is moved to ON 2 position, the factory energize power circuit is switched to a a manual feed.
Seems I could even use an ON-OFF-ON switch if I desired the third option of OFF, disconnecting the Aux batteries from charging although I don't know why that would be desired.

I do like the idea of the switch not being a momentary because the switch would probably be under the hood and also I've read if the starter battery is really dead, the switch may need to be on for 5 minutes to give it enough juice to come back.

Although I like the momentary switch to make sure the switch is not left on after it is needed. I see some ON-ON switches can have illumination in one of the ON positions and this would help remind to turn the switch off when done.

In the factory set up, I wonder if the Solenoid energizing is provided by the Aux battery 12v. Because I think it's been said that the system-solenoid "knows" if there is an Aux battery present or it won't energize.. This could be accomplished simply by using the Aux battery 12v to energize. So if it's been removed and the positive cable is just dangling and couching metal body grounding, it wouldn't power a connection.
Although if it is the Aux battery power that energizes the Solenoid, then if the Aux battery was dead, then it wouldn't power the solenoid to start recharging back up..

[Vanzila]

use Cables. I have the OEM Aux Battery system FORD put in the Ambulance's.. it works great to Jump start myself. Its isolated already . if My Main Bat is Dead i just use cables to jump myself

Also "I'm also wondering if the system would already connect the two batteries if the key is just moved into the run position without starting the engine"




No.. They are only connected by Out put from the Alternator. So it Charges both Batts at the same time with Diode to keep them from feeding back on each other.. If you just turn the Key on to the Aux position the Aux Battery will not help you..

PS I also have the 1996

[Darkstar]

The Blue Sea ACR attaches both batteries and gives you the ability to have them forcibly connected, or passively connected where they cycle on and off but won't allow one to drain the other past a point. The third setting is disconnect both which allows each to operate solo.
From the first two settings your alternator or a trickle charger can provide recharging to both batteries.

[86Scotty]

Originally Posted by Darkstar

The Blue Sea ACR attaches both batteries and gives you the ability to have them forcibly connected, or passively connected where they cycle on and off but won't allow one to drain the other past a point. The third setting is disconnect both which allows each to operate solo.
From the first two settings your alternator or a trickle charger can provide recharging to both batteries.

This ^^^^ However, you can never go wrong with Scalf's solutions either.

[palsing]

Well, I just use the auxiliary batteries and the inverter to power my regular battery charger and I charge up the starter battery until it will start the van! Easy-peasy! Fortunately, this only happened once, but it worked like a charm! Of course, you need to have a "regular" battery charger with you!

[Gooseberry]

Just use another ford starter solenoid to bring in the house battery and wire to a switch.