JokerOne

I would like to be able to charge my 12v deep cycle marine battery from the rear 12V DC power outlet while driving.

Question, is the distance from the engine battery too great, or the gauge of the wiring too small to do this safely?

I am putting a RigRunner powerpole system in for my Ham Radio(s), and can set something else up, but didn't want to if I didn't need to.

thanks in advance.

jedg

Perhaps. A few things to consider. First, what rate do you want to charge at? If 2-3amps it might be possible. Would need to consider the distance versus the gauge of wire for that power outlet. I use the attached chart for my guidance. If you're charging at 3 amps, 18 gauge wire should be okay.

JokerOne

very cool. thanks for responding.

Do you know if 18 gauge what is used on a 2018 JK unlimited for the rear power outlet?

I have used the battery at home as a test for my CPAP. It lasted 5 nights on a full charge before choking me on the 6th night at 3am..

I'm assuming a 7 day trip. Long drive the first night, then maybe 1 or 2 hour drives during the rest of the trip before heading home.
My main concern was safety. Didn't want to overload the wire drawing too many amps.

thanks.

JokerOne

very cool. thanks for responding.

Do you know if 18 gauge what is used on a 2018 JK unlimited for the rear power outlet?

I have used the battery at home as a test for my CPAP. It lasted 5 nights on a full charge before choking me on the 6th night at 3am..

I'm assuming a 7 day trip. Long drive the first night, then maybe 1 or 2 hour drives during the rest of the trip before heading home.
My main concern was safety. Didn't want to overload the wire drawing too many amps.

thanks.

jedg

It's at least 18 gauge. That said, I'd be sure to get a good quality trickle charger (not to exceed 3amps). If you want to be extra safe, you could pop the power outlet out of the body molding and feel the wires to see if they are getting hot after an extended charge time.

JokerOne

thanks. I have a good charger but its at home hooked to my sump pump backup system. It only works for AC to DC.

I'll see what I can come up with.

thanks for the help!

ronjenx

If you connect a battery to the power outlet in the rear, it is very likely the fuse will blow. Uncontrolled amperage will flow from the battery with the higher charge to the battery with the lower charge.
If you connect a low battery to the outlet while the engine is running, the fuse will very likely blow because the 140 amp alternator, (or whatever you have in your JK), will see it as a load and try to supply what the low battery will draw.

JokerOne

that was what I was worried about. I thought this might be the case.

So RVs and such must have some sort of power handling system to prevent this correct?

thanks!

ronjenx

RVs are equipped to do this. I'm not sure how they do it.

I just googled 12v-12v battery chargers and got some good links. Give that a try.

Otherwise, an inverter to run a regular "smart" charger may be the easiest solution. I would go with a pure sine wave inverter. Some chargers don't like modified sine waves.
It would give you the advantage of being able to run lots of other AC devices, too.

JokerOne

I would like to keep my wife from dragging her blow dryer along leaving me without my CPAP all night..
If she doesn't see a 110AC outlet then she won't think of it..

I'll google the 12v to 12v and get back to you on what I found. thanks for the help.