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

[Canuck_in_NJ]

Alright, lots of options. I guess one concern would be the tongue weight. Dealers website says dry hitch weight is 280 lbs. does not include water propane cargo, Dealer accessories)

so if max loaded weight is 3500, 10% can be estimated for tongue weight puts me at 350. adding the battery puts me at what? 550lbs?


My tow vehicle isn't a problem as I have a 1 ton. will the trailers tongue support that? should be fine correct?

[RLS7201]

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.

Bolt that angle iron to the tongue and mount those 6 volt batteries for and aft, for less width. After you get the iron cut and mounted you may want to stop by the local weld shop for the end pieces.

Richard

[RoyB]

I did this for a few years using three 12VDC Interstate GP24 Batteries in parallel across my trailer tongue...


Roy's image

I am now working on a BATTERY BANK of two groups of two 6VDC batteries in series using a TORKLIFT box... This extends out on both sides of my install rails... Fits perfect inside the two welded on rails on top of the trailer tongue... The torklift battery box lid slides on and this is great if your trailer has any overhang on the the tongue area.


Google image

My new setup will have two 10WATT Solar panels on the Torklift slide off lid to trickle charge each 6VDC dual Battery group...

My Dual Bank diagram will look something like this except I will be using DURACELL Batteries instead of what is shown in the drawing... All is working fine so far on the work bench will have it installed on my trailer tongue soon...


Roy's image

Roy Ken

[Ed_Gee]

naturist wrote:
Two 6-volt batteries going to four, and with concerns about weight make me suggest you might be much better served by going lithium iron phosphate. They are much smaller and lighter for their capacity, and while more expensive up front, their far longer life makes them actually cheaper that lead/acid in the long run. Just a suggestion.

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

[naturist]

Two 6-volt batteries going to four, and with concerns about weight make me suggest you might be much better served by going lithium iron phosphate. They are much smaller and lighter for their capacity, and while more expensive up front, their far longer life makes them actually cheaper that lead/acid in the long run. Just a suggestion.

[DrewE]

It looks to me like there would be space to construct a two storey battery box on the trailer tongue. That's what I would do (and have them always all connected).

With a switching arrangement, you'd in essence be just swapping batteries in and out, so whichever one is active would be active for the loads, the converter, and the solar charging, and the other would be sitting entirely disconnected, assuming you wired all the loads and such through the selector switch. If you had the inverter or whatever bypassing it, it would of course only use the battery it's connected to regardless of the switch setting. (An exception would be the 1+2 setting, which connects everything to everything else.)

[Canuck_in_NJ]

theoldwizard1 wrote:
Let's back up for a minute ! Why do you want to double your battery storage. Running a TV and some USB chargers seems like a pretty light load.

To me it sounds like you need more solar panels and maybe a better charge controller, not more batteries.

A NOCO HM426 dual battery box takes up less space.

Well we have moved back to British Columbia Canada, and are going to be camping through the winter. (big into snowmobiling and quading.

Wife likes it warm and we all know the story with how the furnace kills batteries. Don't think the sun will be out much so that cuts down on our ability to recharge via solar.

We did just buy a Mr buddy heater so that will cut down on furnace use.

[theoldwizard1]

Let's back up for a minute ! Why do you want to double your battery storage. Running a TV and some USB chargers seems like a pretty light load.

To me it sounds like you need more solar panels and maybe a better charge controller, not more batteries.

A NOCO HM426 dual battery box takes up less space.

[JRscooby]

My thoughts. A big bank in truck, charged thru a truck alternator. Long, heavy cables to the trailer. A smaller battery on trailer, that could be plugged in when the one in truck is unplugged.
We use the pickup often for sightseeing, so the batteries in truck would be re-charged often. While sightseeing, nobody in camper, so low demand for power, take long time to discharge...

[mobeewan]

It looks like you may have enough room to remove the two batteries on the tongue and add a truck bed rail storage box across the top of the tongue for all 4 batteries to fit inside of.

[Canuck_in_NJ]

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.

[Lwiddis]

Have you completed an energy use survey? Then you can buy what you need instead of guessing. And a generator is wasteful for “topping off” your batteries...absorption phase. Does ok for bulk charging however.

[Canuck_in_NJ]

miatared wrote:
One suggestion: you should switch to an MPPT solar charger/controller, you would have better performance. They're pretty cheap nowadays.

plan on doing that when I get the second panel!

[time2roll]

Get them all together on the tongue. Slap some angle steel down or grab a long aluminum storage box. Maybe someone will share a picture of their set up.

[miatared]

One suggestion: you should switch to an MPPT solar charger/controller, you would have better performance. They're pretty cheap nowadays.