Well, system up and running. I went over to Radio Shack and picked up a project box (remember them?). I did some major surgery on the box to cover the isolator terminals and most of the relay. I installed a dash indicator light when isolator is activated. I also have a pillar installed volt meter that reads everything off the ignition switch (ignore the warning, there is a red light that comes on below 11.5 volts)
Having this two battery system is great. Starting voltage has not been below 12.3 volts, normally 12.6 - 12.8 starting volts now, and I have been doing short trips last couple of weeks. Before I would drop to as low as 11.5 volts (no start) with short trips.
I made a modification to make it easier to test and charge the frame battery from under the hood by adding a metal strip at the isolator connection. Then I added a removable cover to the end of project box
I am going over the entire two battery system I installed, just to be sure everything is ok. It is working great except I may have been experiencing a power surge on the LED dash indicator light that shows that the Isolator is activated. Two new lights burned out about three weeks apart. I must admit it was not fused at the time. It is fused now, and I would like to list the fuses that I am using and get an opinion as to if I am in range of where I should be.
100 AMP MEGA FUSE - BETWEEN FRAME BATTERY CABLE AND ISOLATOR LARGE TERMINAL
20 AMP MINI FUSE - BETWEEN LARGE ISOLATOR TERMINAL (same isolator terminal as above) AND #30 PIN ON RELAY
10 AMP MINI FUSE - BETWEEN SOLDERED CONECTION TO FUSED SIDE OF 20 AMP FUEL INJECTOR FACTORY FUSE AND #86 PIN ON RELAY (as a true ignition power source)
10 AMP MINI FUSE - BETWEEN RIGHT HAND ISOLATOR SMALL TERMNAL AND LED DASH INDICATOR LIGHT (mentioned above)
With my general knowledge of automotive wiring I think I am safe with the above, but if I am wrong please share with me.
About the LED surge part, I looked at this post right away, and have pondered it since. Haven't had the first suggestion till now, and it's only a stray thought. So here goes...
The old Points and Coil Ignition works off of a COLLAPSING Magnetic Field in the Primary (12-Volt) side of the Coil. To put it another way, a Field is created when the Points first Close. When the Points OPEN, the Primary Field collapses with a BANG. Faster than it had Charged. Works good for Ignition but anywhere else, it's a Voltage Spike. So, I wonder if there's a Spike when the Isolator (even the Bosch Relay) shuts OFF. LED's are electronics and electronics often don't tolerate spikes. That's why we find Diodes in strange little places. For example, the connector to your A/C compressor clutch probably has a Diode in or close to it. How and Why it works, I Dunno. I just know it's there to control the spike caused by the clutch disengaging.
Thanks jd for the input. I was wondering about a possible power surge. I did a couple things. First I went over all my connections especially splice connectors. I replaced some of the splice connectors and put shrink tubing over them. I also bought a red indicator light for the dash. The last two that burnt out were green indicator lights (just on the chance the red lights are not as sensitive...I know they may both have the same lamp)
Anyway it has been a few weeks and it has not blown a lamp or fuse.
Hi guys, and I am sure there are some mechanic ladies out there. First let me Thank You all for your great advise during the year. It is worth it's weight in gold.
Also, I know it has been a year but I finally finished the dual battery system in my e350 Super Duty. I put in a disconnect switch and updated some of the wiring.
To those that helped (big time) me install this from scratch, Thanks
System works like a charm. Accessories draw 0ff single battery when parked, runs on dual battery system to start van and while running. If one battery is run down the other one makes up the difference.