Is there a good way to text funtionality of a dual battery switch?

[jumpjets]

I've got a perko dual battery switch, and two charged batteries. I don't think that the dual battery switch is hooked up correctly though. Is there a foolproof way to check the funtionality of the switch and see if it is indeed hooked up correctly?

 

[Silvertip]

Re: Is there a good way to text funtionality of a dual battery switch?

First, the switch is normally connected as shown below. Next, set the switch to OFF and measure the voltage between the COM terminal and system ground. It should read 0 (zero). Next set the switch to BAT #1 and measure again. Voltage should be +12 volts. If not, there is a problem. Set the switch to BAT #2 and measure again. Voltage should b3 +12 volts. Set the switch to BOTH and again, voltage should be +12 volts. Next, disconnect the POS battery cable at either battery. Set the switch to BOTH and measure voltage. If it is 0 (the battery that remains connected is not properly connected to the switch or is dead. You can repeat this test for the other battery and again, in the BOTH setting, disconnecting one battery or the other should still produce +12 volts at the switch. With two fully charged batteries, and reading of zero or significantly less than 12.6 volts says there is a wiring issue.

 

[jumpjets]

Re: Is there a good way to text funtionality of a dual battery switch?

Thanks. I'll run that exact test soon. I hope it's correct, but I have a feeling it's not based on it's current behavior. All and bat 1 both register on the dashboard voltmeter, but bat 2 doesn't register.

 

[Silvertip]

Re: Is there a good way to text funtionality of a dual battery switch?

That's because there is an obvious break in the path between the COM terminal and BAT 2. The reason you read voltage in BOTH is because that voltage is actually coming only from BAT 1. Remember, BOTH parallels the batteries so just because you see 12 volts on a meter at the COM terminal does not mean both batteries are supplying power. That's why my test has you disconnecting the batteries to make sure the SWITCH is actually working.

 

[jumpjets]

Re: Is there a good way to text funtionality of a dual battery switch?

That's because there is an obvious break in the path between the COM terminal and BAT 2. The reason you read voltage in BOTH is because that voltage is actually coming only from BAT 1. Remember, BOTH parallels the batteries so just because you see 12 volts on a meter at the COM terminal does not mean both batteries are supplying power. That's why my test has you disconnecting the batteries to make sure the SWITCH is actually working.

Silvertip-

that test worked perfectly. I discovered that my bat 1 had a bad cable. On your test, I got 8 volts on the COM, but the battery itself it had 12 volts. I installed a new cable and i've got 12+ volts from each battery. Now the system will work as advertised.

 

[Fireman431]

Re: Is there a good way to text funtionality of a dual battery switch?

Thanks. I'll run that exact test soon. I hope it's correct, but I have a feeling it's not based on it's current behavior. All and bat 1 both register on the dashboard voltmeter, but bat 2 doesn't register.

Glad it worked out for you. But you didn't consider that the voltmeter could have been wired to only one position on the batt switch or directly to Batt 1.

 

[jumpjets]

Re: Is there a good way to text funtionality of a dual battery switch?

Glad it worked out for you. But you didn't consider that the voltmeter could have been wired to only one position on the batt switch or directly to Batt 1.

There was no voltmeter wire coming off the battery switch. The voltmeter wires come directly off the engine, so whatever the COM is getting, thats what the voltmeter gets.