2 Battery banks built from 6 volts

[Canuck_in_NJ]

Hi all, I did a quick search of the forum but couldn't find what I was looking for.

I have a 2018 17ft Jayco travel trailer. The majority of our camping is in the middle of nowhere. (boondocking) The trailer came with One 12 volt however, we swapped that out for two 6 volts from Costco.

We have One 100watt solar panel on the roof that charges the batteries through an 8 amp pwm charge controller. (plan on getting another 100watt panel this spring)

A 1000 watt inverter that is really only used to run a small tv/charge iPhones etc..

We have a 2000 watt Honda generator that we use to run the microwave and top up the batteries if needed.

I want to get another two 6 volt batteries however the space on the tongue is extremely limited. (can just fit the current batteries as it is) I do not want to store them inside due to the obvious hazard of that (and space is limited)

My thought is to install the 2 other 6 volts in the bed of my pick up, and have them as a separate second bank.

I have attached a rough drawing of our current electrical setup.

I know that if I do this I will need to use a battery selector switch and ample sized wire for to voltage drop.

Maybe I am over thinking this but exactly how would I wire this up?

My plan wouldn't be to run them on the 1+2 ever, but have the selector switch on 1 (batteries on tongue) and then when needed switch the selector to 2 which would be the batteries in my truck box.

Perhaps where I am getting hung up is how would they all charge? If the selector switch was selected to 2 (the batteries in the truck) and I fired up the generator, would that just charge those batteries? If the switch was on selector 1, would the generator just charge the trailer batteries?

How would I have it wired in order for the solar to charge the batteries?


I hope my question makes sense?

I have attached a picture at this link:
Click For Full-Size Image.

Please shed some light. Thanks so much,

Greg

[campigloo]

Slightly off topic here but a 12v TV set uses a fraction of the power and they’re not that expensive.
To save water we use a lot of hand sanitizer. Taking a shower, use a 1/2 gal milk bottle to catch water while the hot makes the trip and use that for toilet water. Get led light bulbs.

[Lwiddis]

When driving to the actual campsite, the truck’s battery will charge fully and the house batteries will receive some charge.

[ajriding]

See here for an idea, post #38 and #39.
http://www.hilotrailerforum.com/f17/hilo-renno-6007/index2.html#post42366

Your batteries do not all have to be side by side. You can have one on tongue and the other two elsewhere.

These have batteries in the dinette bunk, mostly under the floor; iceberg style. They poke into the floor about 4 inches high, but mostly are under the floor and right over the axle. They are not taking up much space inside, and by being outside can vent outside.

Cut a hole in the floor inside a cabinet or storage space, keep it over or near the axle so there is no ground clearance issues (the axle will always clear).
build a box, build a hatch door for access, run the wires…

[noteven]

I find a portable panel kit with some extension cord works pretty good in winter sun conditions. It can be set out from under the trees, or angle tilted to max output during the day.

[Canuck_in_NJ]

When not doing trips like the Oregon coast, we don't drive the truck too much. Aside from driving to the actual campsite, setting up, dropping the quads, we will take the truck into the push to load up on firewood. Then it's parked next to the trailer for the remainder of the trip.

Only have 20g of fresh water, so a limited supply. We really only use it for washing hands a quick flush of the toilet and giving the kids a sponge bath after a day of riding.

As someone else said, maybe just another 100 watt panel on the roof to give me 200 watts. Winter camping was my concern on power, but with the buddy, the furnace probably won't run too much.

[Gjac]

You got a lot of good ideas so far, but based on your setup and where you are camping I would stay with your original idea of putting the other two batteries in the truck bed and then tie them into the alternator charging system of your truck. I imagine you use the truck to site see around the area that you camp in so you will get a lot of charging in from your trucks alternator. You will not need to run your furnace with a buddy heater in a small TT so you will save a lot of battery power using it. I dry camp for a week with 2 6v GC batteries and never go below 50% SOC, but have minimal battery requirements. But after 7 days I am out of water, and wife has to do laundry so I have to move anyway. Besides lights and water pump what other requirements, will you have, TV,computer use, watching movies? The 2 batteries in the truck bed would be insurance that you never run out of battery power. How many gals of FW in your TT set up?

[Canuck_in_NJ]

Thanks for all the ideas. I don't really want to switch to sealed batteries as I have the 6's already. Also I do not have enough room under the bed as that is where our storage for all our other stuff is,

I'm sure I could come up with a mounting system on the tongue, I am just a little skeptical of weight on the tongue. I currently travel with a ATV deck that sits on the back of my truck. It is 8 foot long but can fit a 6 foot box. It over hangs off the back of my truck 2 feet (I have a short box)

In order for me to be able to back the trailer up and get into tight spots I had to get a short hitch extender so I don't crunch the deck against the trailer. That is the reason I am stuck on the tongue weight.

I know they make the super hitch system, but that's isn't cheap and really isn't in the future.

Adding another 120 lbs I'm sure will be ok, I just thought, since I have some space under the ATV deck, that would be a good spot.

I have attached a picture of the setup. In this picture the truck has been pulled away slightly from the hitch of the trailer, but should give you an idea of how the ATV deck encroaches on my trailer.

[Unyalli]

How about switching to AGM and move them inside? Mine are under the bed.
- Jeff


note: Moderator edit to fix photo URL.

[ajriding]

I never got a pic of what I did, but here is one of the result. I didnt even weld on this one.
I raised the propane tanks high enough that I could put the two batteries under the tank. It is covered with a white sheet of plastic so all you can see are the aluminum legs.



I cut pieces of aluminum square tube as legs. I then removed the double propane tank bed, it was bolted on, so I could reuse the same bolt holes in the frame. I ran a long bolt (threaded rod) from base of the tank pan through the inside of the square tubes on all four and tightened down. It was rock solid when tight. The batteries mounted under by using two angle iron pieces to hold them in place and whatever straps are made for this. I may have welded these in actually. It worked perfect. This was a few years ago and I have sold the camper. I miss the light weight, small and aerodynamic ease of towing it though…

Before there was one battery that sat in front of the propane tanks, now two sit under it. two 6-volt. Leave enough room so you can check water and work on the lugs.

[Vintage465]

Canuck_in_NJ wrote:


not a tone of room on this small tongue, but angle iron might be the trick. Didn't want to put a ton more weight on the tongue, but may be easier than the truck box.

I share your concern. I think you might get them in there, but that tongue doesn't look real stout. AM/Solar has a nice 2-wire plug set up that is 8ga. wire. It is kind of like a 2-wire version of the 7 pin plug in we all have on our trucks/trailer. You could put the "extension cord" with the male plug in the truck all hooked up to the two batteries in the back of the truck. Then have the female end mounted on the trailer and be wired in to the coach batteries. When you get on site, roll out the 6 or 8 gauge extension cord and plug it in. Not real tidy, but do able.

Wire this in to your coach batteries and mount this.......somewhere on the trailer tongue.


Put what ever amount of 6-8 gauge wire you attached to this and have it wired into your batteries in the back of your truck. Batteries in a secure box. It would be like a "power pack" to just plug into your coach batteries.


Just a thought.

[ajriding]

I did this almost exact same thing. I have posted about it, but will have to search later, or you can through my post…

I have a truck camper and the only place to have 2 6-volts were in the truck bed. The TC has a place for only one battery. I have 3 batteries (two battery banks to be more exact).

I keep them charged with solar from the camper roof. I have two dedicated solar systems. One 100 watt to charge the TC battery and two 100-watts (200) to charge the batts in the truck bed. The truck bed batteries stay with the truck all the time. I used Anderson plugs to connect them to the TC.
The solar panels stay with the camper all the time.

Before I disconnect the truck and camper from each other I have a switch to direct both the solar panel banks to charge the one TC battery. I do this per charge controller instructions to never disconnect the battery ad leave the solar panel hooked up.

When in storage I just cover one panel bank with something to block the sun. This way only one controller is charging the one battery.

To answer your question I would suggest when charging the truck bed batteries off the generator to just use a battery charger. This is faster than the weak camper DC converter anyway. When you want to charge the camper's batts then just plug the camper in as usual. If you want to charge the trucks batts and have the camper plugged in then you will need to disconnect (of flip the breaker) camper DC charger/DC power supply. I guess you can charge both at the same time though also.

Using a battery charger is a faster way to charge your camper batteries also.

At minimum l would suggest two solar panels for each of the pairs of batteries. so, that 4 panels/ 400 watts total.

With an MPPT controller you can run the panels in series (24 volts) and get more out of the limited sunlight you have so far north. The controller will know to drop the voltage for a 12 volt battery bank.
You can also run smaller gauge wire with 24 volts, or run the same gauge wire and run it longer when at 24 volts. There are charts for this.

You will need a long run to reach your truck bed batts. Seems that having the panels all on the camper roof is easiest way, so everyone here will suggest to attache the camper to the truck with Anderson plugs, get the big ones, and use big wire, like big jumper cable size wire to run up to the truck. You will need zip ties and to crawl under the truck to make the cable run.

Use a mechanical solenoid so you can also charge the bed batts off the running alternator. Use a toggle switch in the dash so you can control when of if you will charge the batteries. With solar maybe you will never need the alternator.
A big diode will work, but there is always a little bit of voltage drop with those, and you still will want to control the on/off charge selection.

I got power off my starter 12 volt bolt location. You will never be starting the motor and charging the batts at the same time, so might as well use the existing wiring. Be careful, that wire is always hot.
plan the shortest route possible, and put the solenoid (or diode) as close to the power source as possible, so you can switch off the majority of cable as possible just in case there is a short along the wire in the future.

[BarneyS]

I would get a Torklift battery box as already mentioned. It will fit all four of your batteries on the tongue which should be strong enough for the weight.

Here are some pictures of my sons former trailer with one on the tongue. He didn't have 4 batteries but used the space for other things, as you can see.
Those dividers are adjustable to any size space you need or can be removed.
Barney

[time2roll]

I don't see any issues on tongue weight.

[naturist]

Ed_Gee wrote:


LiOn batteries do not take a charge below freezing. The Original Poster does Winter camping in Canada......

That’s true, they don’t. It’s also true that they need not be located on the outside of the trailer OR that they cannot have a small, low power, heating pad attached to keep them above freezing, even in Canada in the winter.