House battery charging options

[etrippe]

We are 4 months into our new travel trailer and having never owned one before I have some questions about battery charging. I was wondering if while camped, would plugging back into my running tow vehicle charge the battery? We don’t plan on any extended boondocking but for one or two times a year for maybe 5 days maximum. No ac, tv or microwave required. However our refrigerator is 12 volt and we have a max air fan that would be running all night possibly. Just looking at our options. Generator, solar or just run the car. Trailer has 1 12v. battery, and most likely low quality.

[toedtoes]

naturist wrote:
They put the cheapest 75-80 AH battery possible on new trailers, so, yeah, first step IMHO is putting on a real battery.

I agree with everything, but would say first thing to do is do a trail run with just your current battery power. You can do it at a full hookup campground, just don't plug in. Determine how long your current battery lasts. Then you can figure out the best size battery for your needs. Then you can add appropriate solar for recharging the new battery.

[naturist]

Agreed, leaving the tow vehicle running and connected to the trailer is a horrible idea. Besides being a VERY slow charge, it will burn up too much fuel doing it (ie, it is highly inefficient).

Some RV fridges use 12 volts only for the control board, but some do actually use 12 volts to cool. You need to determine which it is.

Generators are noisy, and will be a pain overnight as well as most unwelcome amongst any neighbors at 2 am. Solar is a much better choice, but it sounds to me like you are going to need a battery upgrade. They put the cheapest 75-80 AH battery possible on new trailers, so, yeah, first step IMHO is putting on a real battery.

[theoldwizard1]

DrewE wrote:
Plugging into your running tow vehicle will generally not charge very quickly; by the time the current gets through all the (fairly small) wires and connectors between the alternator and the trailer battery, you have enough impedance that you'll only get a slow charge. A better option to use the tow vehicle alternator would be decent jumper cables between the tow vehicle and the trailer battery more directly.

I disagree with that last statement !

A much better option would be a DC-DC battery charger. Renogy 20A or 40A. $111 - $170 on Amazon

etrippe wrote:
Trailer has 1 12v. battery, and most likely low quality.

When it dies, replace it with two 6V golf cart batteries.

[enblethen]

Refer should only use 12 volts for control of it. Very little power.
Wiring in tow vehicle is small. Charging through it is not very efficient.
Best overall is to get a genset. A small one would be good for charging battery(ies) but no air conditioning. One something like this genset

[DrewE]

Plugging into your running tow vehicle will generally not charge very quickly; by the time the current gets through all the (fairly small) wires and connectors between the alternator and the trailer battery, you have enough impedance that you'll only get a slow charge. A better option to use the tow vehicle alternator would be decent jumper cables between the tow vehicle and the trailer battery more directly.

An even better option, as mentioned, is a relatively modest solar setup if you'll be camping in a reasonably open area.

[jdc1]

A 200w solar system, in sunny conditions, will suffice. A second battery would be your next upgrade.