i am in the process of putting together a kit to install my aux fuel tank in the bed of my pickup. i am pumping the fuel into my main tank (not gravity feeding). i am looking for a simple timer of some sort to wire in with the switch for the 12v transfer pump to prevent overfill if i forget to turn it off. i have read other ways of dummy proofing the setup to prevent an over fill (such as plumbing the aux tank vent into the main tank). i do not want this. i want a 30 min or 60 minute timer of some sort. i have seen alot of fancy stuff online, but i dont understand any of it. is there something simple anyone has used that would fit my needs?

 

I installed some extra LED interior lights into the back of an ambulance and just used a regular bathroom fan timer. Might look kinda odd in your dash though.

 

i was going to put the fuel gauge and switch inside the center console.....so looks is not that important. all of the switches like that i see are for AC. can you run DC off of an AC witch like this?





this is another AC switch that would work PERFECT. but once again, can i use an AC switch in a DC in/DC out application?

 

This timer uses a spring (like a wind-up clock) and should work depending on the amps the pump pulls. Else you may have to use a relay/solenoid.

 

The first one would work fine as it is a mechanical timer. When you turn the dial it closes a set of contacts that winds a spring which then slowly unwinds and then opens the contacts. The contacts don't care if its ac or dc voltage and I doubt the pump would be more of a load than than the fan that the switch would normally run. You can always kick a relay with it. Control the ground side of the relay with the timer and then have the power to the relay come off ignition power and controlled by a switch so you and easily turn it off if it suddenly overfills and shuts off with the key off.

The second switch is unlikely to work as it looks like it probably has some circuitry in it that probably only works on AC.

 

thats exactly what i was thinking of doing if that mechanical, rotary style switch would work with DC. i like all the programable, electronic switching components you can find online. it seems good in theory, but 95% of it ships straight from china and only costs $15. in this case, i believe you get what you pay for.........and i dont want to be in the middle of know where with no fuel in my main tank and no way to transfer it from the aux tank because my $15 hong kong switch doesnt work.

 

I'm using the mechanical bathroom timer. It is mounted on the front of the stationary portion of the center console that is between the seats. I had to use a soldering iron to cut the plastic inside the storage compartment to allow room for the timer. Once mounted, the back of timer is flush with area of plastic that I had removed.
John

 

i just ordered one of those 60 minute mechanical switches with a black ****. thanks guys.