Ideas to extend stay when dry camping/no generator

Driving around using the 7-pin on the spare battery in the truck bed (via an adapter you invent--not hard to do) is not going to do it for you. amps will be around 5 or 7 amps if you are lucky and in an hour they will taper down some, so think 6AH restored for an hour's drive. Forget that.

You need to run a real battery charger on that spare battery for a fast charge say at 25 to 30 amps initial till it tapers as the battery comes up. How to run that charger?

- Honda gen in truck bed with the portable charger and the battery- run that while driving around---or just park somewhere outside the campground and read a book while the battery gets done.

( your choice on swapping out the spare or leave it in the truck and connect with jumper cables as mentioned )

BTW it takes many hours for two batteries to equalize since the voltage diff is so tiny between the full one and the half full one, hardly any current flows. Tried that one.

-Don't worry about efficiency and losses--who cares? You just want to get it done and keep on camping.

Next method. You can indeed hook an inverter to your truck battery and run the truck engine at idle and that 1000w inverter will run a 35 amp smart charger. But will the campground allow you to idle the truck for an hour? I have used this method and it works great.



The limit there is
- first the inverter has to be able to handle the VA required by the charger. A 35a charger would want about 600w.
-second, the truck alternator has to be able to hold the truck battery voltage up while that draw is on it. When you load the inverter too much, the truck's voltage sags off (BTW turn off the truck's "climate control" so it is not running during this episode reducing what the alternator can handle from the inverter)

So how long are you planning to stay anyway? You get two days per 24 batt, so if you had three 24s you could do six days without recharging any. Just take some extra batteries along and recharge them all when you get home a week later. :) You can plunk the batts down on the ground by the one on the tongue and link them up with jumper cables, so for that time your trailer has three or four (pick a number) batteries. (they don't have to be 24s either, you can use big ones! )

RDMueller wrote:
put a deep cycle/house battery in the truck connected to the alternator just like is done with motorhomes. This battery would be more or less fully charged each day from driving around.

Perhaps, if the charge wire is big enough. Swapping batteries is the way to go.

The cheapest and easiest method of extending your stay is to add nice cozy comforters from home on your beds. You live in NC. The temps at this time of the year can,t be that cool at night. As Mex said, the largest draw is from your furnace. Only use it for a few minutes in the morning to take the coolness off.

Another option is a portable solar panel ,although a bit pricey at first, should be able to top off your battery every day if you are conservative with your electricity and swapped out lighting with LED,s.

Dave

"the furnace for at most a few hours a day."

That's the killer. The cheapest way out if when doing WITHOUT the furnace means no problems is to get a catalytic heater. It also means having a lot more heat with less LPG usage.

Buy a solar panel. And stick it in the sun. Your problems should be over with minimum fuss and muss.

It sounds like you've given this a lot of thought. The most efficient way is going to be swapping the batteries. Just make the battery location as easy to get at as possible.

I certainly wouldn't go the inverter route because you'll be wasting a lot of that power going from DC to AC and back to DC again.

You also won't get much of a charge hooking a full battery to a low battery.

Swapping is the most efficient (and most difficult) way, but you'll get the most use of the power you have. Driving around for an hour probably won't completely top off the battery either, but the longer you drive the better off you'll be.

The furnace is what will deplete your battery. Not running the furnace, using LED lights or being very careful with how much lighting you use, you could go for a few days on a single "good" battery.

I would recommend a second battery, charging it while you drive, and swapping them even it is a bit of effort.

The reasons are;
paralleling a charged and discharged battery means you have two discharged batteries. It is not efficient.

inverters are not power efficient. You would have losses going from 12 volts to 120 volts, and then back to 12 volts. The end result is you don't benefit from the fully charged battery.

Now having said this, how close do you park the truck to the pop up? Would it be close enough to connect a cable from the battery you have charged in the truck to the pop up? Heavy welding cable with crimped connectors would work for this. In fact, if your battery is good, this may save you from buying a new battery. Not much different then charging the pup while you are driving.

I carried one of my two batteries in the truck bed to charge when we had a PUP. Worked fine when you are driving around a lot each day. I would pull alternate batteries each day as needed.

I far prefer solar and more battery at this point.

Do you have LED lights yet?