Automatic power shut off to fuse block via relay and powerwerx module

[acruxksa]

Any comments on this plan from the electrical guru's on the forum?

Powerwerx automatic shutoff.
Automatic Power Off Switch

Fuse block - RigRunner4005
RIGrunner 4005

I've got the rigrunner installed in the center console of the FJ and power is via 10gauge wire to the battery. It is not switched with the key so power is provided constantly. This is the way I want it, but I have an idea to add the automatic shutoff via a 40amp relay to shutoff power if the battery gets too low. It would be simpler to just wire the auto shutoff to the rigrunner directly, but it can only switch 20amps and I'm planning to use 30 amps on the rigrunner distribution panel (probably a lot less, but it pays to think ahead just in case). Does anyone see any problems with hooking the automatic power off module to the relay where the ignition sense wire would normally go? Would this work like I think it would? IE, the automatic power off module would sense a low voltage and shut down power to the sense side of the relay which would then kill power to the rigrunner distribution panel and all accessories attached to it.

If it works as planned I shouldn't have to worry about draining the battery, while still having power to several accessories with the key off. The accessories are a Yaesu FT-8800R radio, 2 cigarette lighter outlets and a usb power outlet. 30amps should be enough of a margin considering the radio is supposed to draw less than 10amps at full Tx power. This will also work nicely when my future plan to add an additional battery becomes a reality.

[doublejfj]

acruxksa previously said:

Any comments on this plan from the electrical guru's on the forum?

Powerwerx automatic shutoff.
Automatic Power Off Switch

Fuse block - RigRunner4005
RIGrunner 4005

I've got the rigrunner installed in the center console of the FJ and power is via 10gauge wire to the battery. It is not switched with the key so power is provided constantly. This is the way I want it, but I have an idea to add the automatic shutoff via a 40amp relay to shutoff power if the battery gets too low. It would be simpler to just wire the auto shutoff to the rigrunner directly, but it can only switch 20amps and I'm planning to use 30 amps on the rigrunner distribution panel (probably a lot less, but it pays to think ahead just in case). Does anyone see any problems with hooking the automatic power off module to the relay where the ignition sense wire would normally go? Would this work like I think it would? IE, the automatic power off module would sense a low voltage and shut down power to the sense side of the relay which would then kill power to the rigrunner distribution panel and all accessories attached to it.

If it works as planned I shouldn't have to worry about draining the battery, while still having power to several accessories with the key off. The accessories are a Yaesu FT-8800R radio, 2 cigarette lighter outlets and a usb power outlet. 30amps should be enough of a margin considering the radio is supposed to draw less than 10amps at full Tx power. This will also work nicely when my future plan to add an additional battery becomes a reality.

I believe what you've described here will work just fine.

I agree with your reasoning on the 30 amp margin, I'd definitely keep that.

One note: since you're looking at keeping this continually on, you may want to look into a solid-state relay for the main one. The quiescent current draw would likely be much lower than the say, 100mA or so of the 40A standard automotive-style relay. The other benefit is that since the standard relay would be energized continuously, the overall lifetime may be slightly shortened, whereas the solid-state would likely outperform it due to the lack of moving parts.

[acruxksa]

doublejfj previously said:

I believe what you've described here will work just fine.

I agree with your reasoning on the 30 amp margin, I'd definitely keep that.

One note: since you're looking at keeping this continually on, you may want to look into a solid-state relay for the main one. The quiescent current draw would likely be much lower than the say, 100mA or so of the 40A standard automotive-style relay. The other benefit is that since the standard relay would be energized continuously, the overall lifetime may be slightly shortened, whereas the solid-state would likely outperform it due to the lack of moving parts.

Thanks for the tip about the solid state relay. It really didn't occur to me that a standard relay would leak that much voltage. Thanks again.

[doublejfj]

Anytime!

I'd go with something like the D06D series from Crydom, here. Quiescent draw is about 0.1mA. Don't forget the snubber diode to take care of any transients, since SSR's are very susceptible to inductive spikes. If you have anymore questions, I'll subscribe to your thread and keep an eye out.