selecting a timed 12volt swtich setup

this is a little off the beaten path of normal conversation around here......but i hope one of you guru's can lend your advice. i am installing an auxiliary fuel tank in the bed of my truck. i am using a 12v transfer pump to pump fuel from the aux tank to the main tank. i want to install some sort of switched timer on transfer pump so i dont accidentally forget the pump on and overfill my main tank.


it doesnt have to be anything fancy. my only reqirements are:

1. simple to use
2. time range of at least 30 minutes, but does not have to be more than 60 min.
3. under $50

Don't laugh, but years ago I wired up one of the mechanical bathroom fan timers to a rear cargo light to where you would twist the knob to the desired time to have the dome light on and then after it timed out, the dome light went off ready for the next time to be used. I mounted it in a single gang electrical box but some come apart to where you could do something custom.
Just watch the amperage ratings and your requirements. If the pump draws less power than the switch,your good, but if it draws more you may have to add a relay.

https://www.amazon.com/Woods-59717-Decora-60-Minute-Mechanical/dp/B001XCWLX8

Jim

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1968 Chevy II Nova Garage Find 2012
1973 Nova Custom
1974 Spirit of America Nova
1973 Nova Pro-Street

I would use a pac tr7 timer module and program it to whatever time you like. It seems to me tho that if it was left running and was set for a time and you forget it depending on the tank it could still over fill. If it were me I would tank level sensors which are cheap and wire them to a relay so when the tank reads full it cuts power to the pump. That means no timer and 100% no chance over over filling or forgetting. Or even a washer fluid style level sensor like this one.

https://www.carparts.com/details/APA-fs-URO_Parts/Washer_Level_Indicator/W0133-1632206.html?TID=80000000CP&origin=pla&CP=1&CP_SRC=PPC&003=27372932&010=cpW0133-1632206WaLeInAPPa&gclid=CjwKEAjwsOKpBRCDtfOnzaDg3HsSJAAJ2oji7z6BCXzj_wdeaeZByuwAzn-DPuBzs-_mqxu3KnoAPRoC7_fw_wcB&c_aid=45534008133&c2cid=6bbc3ea5-1a32-4b46-94a9-81cbcf6577d1

$6

And a $1 spdt relay from Napa.



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Gary Sather

Or a fluid level switch wired to a relay like this switch.

https://www.onlinecomponents.com/honeywell-lle102000.html?p=11935504&utm_content=hwEQc92v&utm_medium=cpc&utm_source=google&utm_campaign=Shopping+4&utm_term=&cshift_ck=7C6E44E4-1EA1-4C6B-94CC-7149D36B0927cshwEQc92v

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Gary Sather

This still does not Guarantee that the tank will not be over filled.
a float would be a nice add-on to this circuit.

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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !

my pump will only do 20 gal/hour. my main tank is 34 gallons. if i use my head, it wont overflow even if i forget to turn the pump off.

Custom_Jim wrote:

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Don't laugh, but years ago I wired up one of the mechanical bathroom fan timers to a rear cargo light to where you would twist the knob to the desired time to have the dome light on and then after it timed out, the dome light went off ready for the next time to be used. I mounted it in a single gang electrical box but some come apart to where you could do something custom.
Just watch the amperage ratings and your requirements. If the pump draws less power than the switch,your good, but if it draws more you may have to add a relay.

https://www.amazon.com/Woods-59717-Decora-60-Minute-Mechanical/dp/B001XCWLX8

Jim

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Great Idea Genius
Home Depot $19.97 Defiant Model # 49823 Internet # 204209953 Store SKU # 1000015594

20 Amp 60-Minute In-Wall Spring wound Timer with White and Almond Wall Platehttps://www.homedepot.com/p/Defiant-20-Amp-60-Minute-In-Wall-Spring-wound-Timer-with-White-and-Almond-Wall-Plate-49823/204209953?N=5yc1vZc334



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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !