Dumb electrical question???

[K. Lane]

I know its probably a really dumb question but if you dont know, you just dont know i guess....

Recently picked up a new to me rv, and sold my pop up camper. When the pop up left. I kept the brand new deep cycle battery with intentions of putting it in the new rv because it does not have one and did not have one when i bought it.
I certainly dont want to hook it up backwards and cause all those issues that can arise but i am not 100% certain which battery cable is the positive one and which one is the negative

Question is; is there an easy way for an electrical moron such as myself to determine which is which by using my handy dandy multimeter

[stoic]

The negative will typically go to the engine block on a car/tractor/etc. I would look to see if a lead goes to the trailer frame. That should be the negative.

[WTucker]

Like said above maybe the negative is grounded to the frame. If not, can you plug the trailer in and maybe it will produce dc voltage to charge the battery? If so, check the battery cable then to verify polarity.

[Wes Chaney]

Red is positive, Black is negative [emoji16]
Maybe set your multimeter to continuity and check it, one lead on a battery cable the other on the frame if you have continuity that would be the ground if not check the other cable


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[Robertt]

Here is something I found on the web. Learned it the hard way on my lease camper.

In the trailer world BLACK is POSITIVE (+) and WHITE is NEGATIVE (-)

You might want to trace out the WHITE CABLE and make sure it comes from the trailer FRAME GROUND to be sure.

Sometimes the AUTOMOTIVE WORLD gets mixed in with the RV TRAILER World where the RED cable is POSITIVE (+) and BLACK is ground (-).

If you hook them up backwards (REVERSE POLARITY) it will blow some fuses...


Good luck. I blew some fuses hooking black to negative on mine.

[K. Lane]

Red is positive, Black is negative [emoji16]
Maybe set your multimeter to continuity and check it, one lead on a battery cable the other on the frame if you have continuity that would be the ground if not check the other cable


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This is along the lines of what i was thinking but was/am a bit unsure if my thinking was correct

[Pedernal]

This is along the lines of what i was thinking but was/am a bit unsure if my thinking was correct

Just be aware that if a light switch is on and the bulb is good you will have continuity to ground via the positive terminal. Safest bet is to trace the lines as one will be tide to the frame somewhere.

[wise1]

Here is something I found on the web. Learned it the hard way on my lease camper.

In the trailer world BLACK is POSITIVE (+) and WHITE is NEGATIVE (-)

You might want to trace out the WHITE CABLE and make sure it comes from the trailer FRAME GROUND to be sure.

Sometimes the AUTOMOTIVE WORLD gets mixed in with the RV TRAILER World where the RED cable is POSITIVE (+) and BLACK is ground (-).

If you hook them up backwards (REVERSE POLARITY) it will blow some fuses...


Good luck. I blew some fuses hooking black to negative on mine.

Yep. Found out the hard way also after son crossed them.