Dual batteries in e350

#63
JackC, I've been knocked on my butt by 12 volt spark, arc, and just not too smart.

Anyway, I have learned (ok, so I had sparks flying off the wire cutter on a 110 volt job a few weeks ago)

So, my point. I checked this circuit with the key out of the ignition, and in the lock position, every way possible for a hot reading.

Cold and safe....but good point!
 
#64
JackC, I've been knocked on my butt by 12 volt spark, arc, and just not too smart.

Anyway, I have learned (ok, so I had sparks flying off the wire cutter on a 110 volt job a few weeks ago)

So, my point. I checked this circuit with the key out of the ignition, and in the lock position, every way possible for a hot reading.

Cold and safe....but good point!
And now eat humble pie. The fuel pump circuit is HOT all the time. I did one more good test today and 12.6 volts pops up on the screen.
So looks like the injector 20 Amp circuit (position 16) is the only cold circuit engine off
 
#65
I was using a poor body ground under the hood for my initial testing. As my last post states the fuse circuit I am going to use is the 20 Amp injector, piggy backed with the 10 Amp fuse for the "Bosch Relay". I also installed a 100 Amp inline fuse between the isolator and the frame battery cable connector to the isolator ( Tried to find a 80 Amp but connections were too small)
 
#66
I did a test run of the under hood circuits this morning. I hooked up the line running from the 20 Amp Fuel injector fuse, to the 10 Amp in line fuse, to the "Bosch Relay".
I then used the under hood battery as a power source to the Bosch Relay. (The frame battery has been removed while putting this all together).
I then hooked up a 1.5 volt circuit test light to the isolator .
All ground circuits are connected
When key is off, test light is off
Key is in the on position, start position, and run position, light is on.
 
#69
You can always count on Mobile Dan, as with many of the great BAT people like nickb2, JackC, jd, and many more.
I will check in as soon as I get the frame battery installed. Frame box is installed and wires are all run. I'd call in sick today, but I'm the boss, crap!
 
#70
You can always count on Mobile Dan, as with many of the great BAT people like nickb2, JackC, jd, and many more.
I will check in as soon as I get the frame battery installed. Frame box is installed and wires are all run. I'd call in sick today, but I'm the boss, crap!
System up and running! I don't have a dash indicator light installed, but I did run a test light. Van pulls off under hood battery only when key off/lock. Pulls off both batteries during on, start, run
 

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#73
A question did arise in manually charging the two batteries. I assume the under hood battery can be charged the normal way, just hook up the charger, small 6 amp. Can the frame battery be charged by using the connection at the 100 amp fuse before the Isolator and a good frame ground. And just an idea: could the negative connection on the under hood battery be used to ground the frame battery while charging . I have added a second ground cable to the under hood battery
 

jd

Hero Member
#74
Yes. You can connect the (+) cable of your charger to the large terminal of the Isolator Relay that does NOT go hot till the engine's running. For the (-) cable, connect to the best ground closest to the (-) of the frame battery.

Remember, the Frame Battery is Isolated from the Chassis Battery unless the Engine is running. If you remember to turn the LED lights off, the Frame Battery won't run down till you use the lights again. BUT!!! If you connect something "parasitic" (meaning it uses power even when OFF), it will drain the Frame Battery. RV's are like this. They have LP Gas Leak Detectors that are ON full time and they'll drain the "House" battery, the one you call "Frame" so there's a Battery Disconnect to remove all loads when the RV will be parked awhile without a power source. You shouldn't need that as long as you have only lights. Say you want a second Car Stereo running off the Frame Battery. If it's Display doesn't turn off when the Sound is turned off, say to display Time, it'll run the battery down. The Time and Station Memory doesn't draw enough to worry about.