Starter and fuel pump relays

[fiatslug87]

Does anyone know how many amps these two relays draw? Thanks

[Ωhm]

Fuel Pump Relay (Bosch cube) coil draw = ≈160mA

[Ωhm]

Measure Starter Relay coil in ohms and divide that number into Battery/Applied Voltage or I=V/R.

[Minuit]

I use 175 +/- 25 mA as a general rule of thumb for standard 30 amp Bosch style automotive relays. Larger relays with higher current ratings may vary, and likewise with smaller ones.

 

To calculate it for a given relay, measure resistance of the coil (in ohms) (usually pins 85 and 86 on an automotive relay), and divide 12 by that number, assuming it's a 12V relay. It is often possible to get a manufacturer datasheet for a relay (especially if it's an electronics or industrial relay) which has all sorts of useful info in it.

 

So, what Ohm said.

[fiatslug87]

Thanks guys. I was looking into this remote relay imobilizer https://www.mobilistics.com/nostart-remote-controlled-intelligent-relay-w-remote-starter-fuel-pump-immobilizer/ instead of adding a kill switch. Our trucks are not listed so I inquired saying the relays were standard Bosch type and their response was "its possible if the starter relay does not draw over 20 amps." Has anyone used these in any application? 

[Minuit]

You'd just use it in place of the fuel pump relay. Seems like a slick enough solution to me.