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In standard wiring configuration, relay stays on even after ignition as shut off, therefore NOT isolating, if either starting or auxiliary battery is above 13.2V.
The following educated guesses are not documented on NVX literature/website:
Copper tab is for sensing starting battery.
Red wire senses auxiliary voltage and should only be connected IF using solar/external charging for the auxiliary battery.
I emailed NVX about how to wire so it will ACTUALLY ISOLATE when ignition is turned off but got no response. So I tried alternate wiring based on my guesses above and it worked.
Relay energizes a few seconds after copper tab senses 13.2V or greater. Turns off (isolates) when voltage to copper tab is disconnected or goes low (<12.7V). Same with red wire.
Red wire only needed if solar/external charging is used. STANDARD WIRING FROM NVX MANUAL - Relay stays energized and keeps batteries connected even after ignition is turned off if either battery is fully-charged.
THIS WIRING WILL ISOLATE WHEN IGNITION IS TURNED OFF
Good write-up and research. I have to say, when you started describing the wiring, I was scratching my head but now its really making sense and looking fairly straightforward.
The isolator looks like a good product. Let us know if it performs or not.
...The isolator looks like a good product. Let us know if it performs or not.
Yes it worked during our 5-day trip to Mammoth Hot Springs. Except, this alternate wiring will make it work better (isolate as soon as I turn ignition off). I'm just waiting for hardware to help me mount and isolate that copper tab isolated from the stud terminal.
Good write-up and research. I have to say, when you started describing the wiring, I was scratching my head but now its really making sense and looking fairly straightforward.
The isolator looks like a good product. Let us know if it performs or not.
Finally finished the alternate wiring of control circuit. Works exactly as shown in youtube video above.
AS INSTALLED
The system is functional now, and I'm planning a trip next week so will work auxiliary lighter, USB and Anderson outlet later
Takeaways from this project:
The NVX system or similar where the control sense can be isolated from the starter battery terminal is needed if desired to isolate batteries immediately after alternator shuts off.
There is approx 5-second delay after 13.2V is sensed before the relay closes (connecting the batteries), so this system prevents the auxiliary battery from sending current through the 50-amp wiring/fuse to starter.
Cool alternate system would be to use the same voltage sensitive module but with a relay and wiring rated for cranking current so the "bypass" button cold be used to connect batteries, OR the two stud terminal could simple be jumped to readily use auxiliary battery as jump starter.
Last edited by RAD4Runner; 01-18-2021 at 10:23 PM.
I installed Anderson Powerpole outlets on my house battery, and converted compressor and inverters to same.
The system is safer, more convenient and more reliable than cigarette lighter plug. it allows quick connection and disconnection and allows using full capacity of my 300-Watt pure sine wave inverter. One outlet to match compressor and another to match Inverter. When I get the chance, I'll make both 30-Amp capable.
I did not mount to truck body, so system is completely portable; i.e., taking battery to nearest rock wall where we can project "Wrong Turn" or "Deliverance".
I also made adapters to allow connection to cigarette lighter and/or battery with clips when used with vehicles without Anderson Powerpoles...
Last edited by RAD4Runner; 03-12-2022 at 09:45 PM.
01-01-2021, 01:52 PM
