adding a switch to a gauge

[JGrammatico]

My old boss used to have an autometer volt meter connected to a small toggle switch so that he could monitor two separate batteries. I was think about doing this not only with a volt meter too. Does anyone know how to wire it?



Thanks

 

[CKelley1]

ok but first tell me about the batteries, where are they. you can not individually monitor the truck batters and the voltage drop to a trailer battery will not read accurately. given that if the grounds of the batters are connected together then a single pole double throw switch is used. connect the meter negative lead to ground. center pole of switch to meter positive and each battery positive lead to each side of switch. if the negative side of batteries are not connected together then you need a double pole double throw switch and wire the negative of each battery to the switch the same as you did for the positive

 

[rbattelle]

The batteries are wired in parallel, so I don't believe you can measure the voltage of only one of them at a time unless you physically disconnect them.

You could measure the current from each battery, then convert it to voltage with a known resistance. But I suspect that's quite a bit more advanced than you're thinking.

Ryan

 

[JGrammatico]

he had the switch mounted in an RV. he used the toggle switch to monitor the house batteries and the rv batteries... . which were not connected. I wanted to see if i could do the same with the differential temp gauge... . be able to use on gauge to montior front and back.

 

[CKelley1]

ok i do that all the time the gauge is available at any auto parts place along with the sensors. get as many sensors or probes as you want. example one for rear end one for trans fer case one for transmission one for engine and one for front differental. the probe, sensor transducer or what ever you want to call it uses the pipe threads for ground the probe has one wire connection in the middle of it. run a wire from each probe to where you mount the gauge you can use a rotoary switch or individual toggle switches i use single pole double throw with center position off switches if you have two probes connect a probe to each side of switch and the center contact to the probe side of gauge the hot side of gauge to a switched truck power source if more than two probes just mount another switch and connect the two centers together