second auxiliary battery is not charging
 

1 have a 2004 e350 quigley 4x4 conversion and the battery on the pass. side frame rail is not charging and I also was wondering if anyone knows where the electric brake relay ford provides is supposed to be installed I found the plug where the brake controller goes is wired but the empty relay sockets are for the newer type smaller relays ???

Thread moved to Full-Size Van forum.

-Matt :-tap

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What's the voltage on the battery terminals with the engine running?
Is the water level on the battery correct? (only add distilled water here)

check the voltage drop from positive to positive and also to ground that should point you in the right direction.

aux batt not charging
 

I believe the relay that the aux batt uses is not being properly triggered. I have not trouble shot it yet though ( no blown fuse anywhere) I recently installed a 3000 watt AC power inverter and ran 2 4 gauge cable to aux batt instead of the main and after using 110AC several times the battery is not recovering does anyone know when the second batt is supposed to be charged? are both batterys used for cranking? are they isolated from each other? When you go to Key on should not the relay close and allow both batteries to charged? I left the radio on the job on once and drained the main battery (gel cell) down to nothing and had to use jumper cables from frame rail batt to under hood to "jump start myself". I have had the van for 9 months and I am now thinking the aux batt has never been charging since new. Thank you for any help Hal Moore Where does the relay ford provides for trailer braking get installed I found the plug in the driver kick that you use to install the controller but they give you a relay also and I do not know where it belongs....

Not sure if 03 and 04 are the same, but on my 03 the aux bat is connected to the main battery via a relay located under the main battery. To access it, you have to remove the main battery or reach way up from under. The relay should only close (connect the two batteries together) when the key is in the run or aux possition.
The aux bat does not assist in the start mode.
The circuit does not have a diode type "isolator".
The only factory loads connected to the aux bat are trailer loads.
In the key run mode, the main battery,aux battery, and the trailer plug bat (12V+) are all connected together, therefore providing a charge to all. This circuit is fused and seperate from the main bat, so as not to let dead or shorted aux bat or trailer current draw down the main start bat.
To check the function of the aux bat relay circuit, check the voltage at both the aux bat, and the trailer plug with the key off. Then check them again with the engine running.
Key off = 12.5 V or less, Engine running = 13.5V or more (+/-).
There is also an optional by-pass loop connector that, if installed, is located above the engin oil fill tube (on my 6.8L) that should be removed for operation as I described.
As for the trailer breaks and other trailer functions, the relays and fuses are under the hood in the main power distribution box. Consult your owners manual for location.
Let us know how things work out, or if you need further assistance. Rob

thanks for the dual batterry help
 

The aux batt. relay was right where you said it was, The switch line to activate the relay is of the primary batt. so if the primary goes dead the relay cannot energize thereby utilizing the second batt for emergency starting. I added a fused switch from the aux batt so in an emergency you could energize the relay and use the aux batt. for starting , While I was at it i Upgraded the charge line from the relay to the aux batt. to 4 gauge monster cable . The problem was the aux batt had a bad cell......Only 9 months old?? As far as I know I never completely discharged the OE lead acid but now I have 2 blue top optima deep cycle Gel Cells $$$$ Never Ends..