DC system and Battery Jump Starter

[earudick]

A question for the electricity gurus. Assuming I am camping and running soley off of my battery, can I connect a battery jump starter to the cigarette adapter of my Jayco 28BHS and extend my rv battery, or run off the jump starter if my rv battery dies? Just want enough juice to run the furnace overnight and did not want to buy another battery if I didn't have to.

Thanks!!

[Flapper]

Probably not - the wiring for the adaptor is small, and cannot handle the load well from the jump. Your fan may not even run, while you may blow fuses. Better is to connect the jump directly to the main battery itself, then it would use the intended wiring and everything would continue to work.
But not for long. The battery jump starter is nothing but a small battery, so it won't have much capacity and would likely give up relatively soon after you plugged it in. You should figure out the amp hours of your current battery, the jump battery, and how much you need each hour to run the furnace, to see if the total capacities meet your needs. Don't forget, it is generally bad to use more than 1/2 of the total amps a battery is capable of.....

[eldermike]

Paralleling two batteries with totally different capacities is not a good idea.

[Mustang65]

Originally Posted by eldermike

Paralleling two batteries with totally different capacities is not a good idea.

Eldermike is correct. That jumpstart will not last long and as soon as you would have plugged it into your 12VDC accessory outlet the discharged batteries would have brought the jumpstart to a voltage that would not be of any use. Pulling the fuse from the main batteries will not help either.

The 12VDC accessory outlet is not wired for that type of drain, and it could heat the wire up and cause a fire.

What concerns me is that you are or would be discharging your TT batteries lower than the 50% level of 12VDC. That will shorten the life of your TT battery(s).

If you are thinking about or doing any dry-camping a 2nd battery is a must, no two ways about that.

Just my thoughts,

Don

[Bassdogs]

Plug in your tow vehicle and start your engine for a while.

[earudick]

Thanks all! I decided to go with a second battery.