PD4106 Chassis Battery Disconnect Question

[richard5933]

I've got two brand-new 8D chassis batteries. I was doing a bit of testing this weekend on some wiring and discovered that even when the disconnect switch is set to disconnect the chassis batteries there is still about 2v showing on the volt meter.

Don't think this is normal, but I really have no clear idea. Possibly something is bleeding from the house circuit? Possibly there is no isolation circuitry?

But, right now my question is a bit more specific. The disconnect switch appears to be original. If not original, pretty ancient. Does anyone know if these are serviceable? I'm thinking that there might be enough schmutz built up inside the switch to conduct a phantom 2 volts. I'm tempted to take it off and give it a go, but since that involves quite a bit of maneuvering some stubbornly large cables I thought I'd ask first.

If they are not serviceable, does anyone know a good option for replacements?

Thanks. This 'bus thing' is a blast, but I'm learning more each day how much I don't know.

[HB of CJ]

Can you get a amp/milliamp drain reading?  Lots of time even cooling coaches will set up a voltage differential/electron flow.  Or are there some phantom load circuits not yet discovered?

[richard5933]

Not sure if there is a drain going on - what I did was to turn the disconnect switch to the off position. Then I measured voltage from now-disconnected terminal on the switch to the other terminal on the battery. With the switch in the open position there should have been no voltage. The fact that there was a residual voltage reading led me to believe that the switch was not going totally into the open position.

[Brassman]

Take the battery cable off the battery and measure the resistance across the switch in the open (& closed) position. Best to take the leads off the switch too. I'm with HB of CJ, sometimes I think modern voltmeters read the capacitance in the circuit. An ammeter would show if you got current flow.   

[Melbo]

Hard to explain in a post but what you are seeing is feedback.  something is still connected and the voltage you are seeing is coming BACK from the place it is connected.  This is just my opinion from working on electrical systems for years.

I agree with disconnecting the battery post and checking again.

HTH

Melbo

[Hi yo silver]

My experience has been that this type of troubleshooting is best accomplished using my old Simpson 260 analog multimeter. Fewer wild goose chases and ghost currents.
Dennis

[robertglines1]

Ck for extra wire hooked up to battery. Do you have a inverter somewhere in your system fed by shore power? Like others said disconnect cables and use your ohm meter to read if there is still contact within the cut off.