Any issues with 4 12 volt batteries?

Lyrikz wrote:
Just purchased a new toy hauler. Has 2 new 12 volt batteries installed. Right before i sold my other trailer i purchased 2 12 volt batteries. I want to run all 4. When they die, i will swap them out for 6 volt batteries.

There is nothing wrong with using 4 12 volt batteries wired in parallel correct???

i figure i cant return them, might as well get some good use out of them...

Lyrikz
My MH came with 4 Interstate 12V deep cycle house batteries.
The originals lasted 10 years, (79k miles).. the 2nd set is now 8 years old.
Mel
'96 Sahara

I have been running multiple 12VDC batteries in my OFF-ROAD POPUP setup since 2009. My trailer came with two each standard issue GP24 12VDC Interstate Deep Cycle batteries. I added wring for two additional 12VDC batteries but only installed one as the 255Ah capacity was allowing me to camp off the power grid like we was wanting to do. Just never added the fourth Interstate battery.

I also added a new smart mode PD9260C 60 AMP converter/charger unit so that I could connect my trailer 30AMP Shore Power cable using a RV30A-15A adapter to my 2KW Honda Generator 120VAC Receptacle at 8AM each morning and recharge my three 12VDC Interstate batteries to their 90% charge state in a short three hour generator run time period.

Been doing this since 2009 and we are very successful camping off the power grid running some 120VAC items from an 600WATT PSW Inverter and many other 12VDC item direct connected to the three 12VDC batteries.

All of this took some planning so that my three batteries would be at the 12.0VDC level at 8AM each morning which is approximately the 50% charge state. My three batteries are still going great since 2009 and are just now staring to show some drop in performance. I am planning to start replacing them this season.

My real success was being able to monitor my batteries operations inside my trailer using a BATTERY MONITOR DC METER setup I can tell at a glance my approximate BATTERY BANK CHARGE STATUS using the chart. With my DC Monitor Panel I usually see around 52-53AMPS DC when in boost 14.4VDC charge mode for around 15-20 minutes and then it starts dropping back to around 8AMP after two hours of charge. Then the PD9260C will drop back to its 13.6VDC charge mode and my DC current drops down to around 6AMPS of charge for the remaining one more hour of charging.



This is a photo and diagram of my setup to support the additional 12VDC batteries mounted on the trailer frame between the Propane tanks and the front trailer deck. The batteries are sitting on a 1X1 metal angle strip going across the top of the frame extending out on both side as shown. With a longer angle strip this would support four batteries easily.


Since my original WFCO WF8945 converter/charger was new I elected to add my PD9260C 60AMP converter/charger in series with the 4AWG cables feeding the battery switches. This is a backup as I can just flip the 120VAC Circuit breaker to power up the converter/charger unit I want to use. I could never get my WFCO WF8945 45AMP converter/charger to go into smart mode charging so it is just used as a backup to give 45AMPS capacity of 13.6VDC if needed. This allowed me to install my PD9260C 60AMP converter/charger stand alone much closer to the battery switches. I am using a 600WATT PSW Inverter verses the 1500WATT PSW shown in the diagram..


Note using the BLUE SEA 4-position Battery switches allows me complete control of which batteries are selected for use. This also allowed me to use same length battery cables to help keep the DC current flow as close as possible in operation. The three Blue Sea switches also provides a complete disconnect of all batteries when placed in the OFF position.



My 12VDC Battery hookup
Roy Ken

Tiger4x4RV wrote:
Where will these batteries be housed? I am assuming that the 2 existing batteries fill up the battery space on your TH. Except for AGM's, batteries must be vented to the outside and cannot be in your living space.

I have a HUUUGE battery storage area..
Im making a rack.
It is vented.
They will fit.

Where will these batteries be housed? I am assuming that the 2 existing batteries fill up the battery space on your TH. Except for AGM's, batteries must be vented to the outside and cannot be in your living space.

If you are going to jump in with both feet you might as well get yourself an inverter/charger & be finished with it. Take the cheap & nasty single stage converter/charger & toss it.

Do a bit of educating yourself first. It is not that simple but not that complicated either. If you have the space for additional batteries you might think about installing a battery switch for multiple banks, as you would find in a boat. You might also think about no maintenance batterys like AGMs. You can put them anywhere there is space. No worrys about venting.

wa8yxm wrote:
The only "Issue" as such is re-charge time ..

First You have one battery Bank, It does not matter if it is 2 Six volt in series, or 1,2,3,4,20 12's in parallel, it is one 12 volt battery bank, All you are doing when you add more "Jars" as someone around here calls 'em is adding amp hours, that's a good thing.

You may wish to put in a bigger converter.. Depending on your converter this may best be done by putting it in a compartment near the batteries and direct connecting with starter cable. or not.

NOTE that unless you are using LIfeline AGM, The larger converter is optional.. Just with 2x the batteries you will need 2x the recharge time but they will last 2x as long.

The only Danger.. And Ive been there And I run 4 12 volt, is if a battery shorts out.. With 4 that's 4 that can short out... Turns out it was not as bad as I feared. I isolated and replaced the one with the shorted cell and everything worked.

Good info.
I only boondock for about 2 days, sometimes 3 days at a time. When we run the microwave it is mostly with the generator on. At night the heat runs and that fan is ran off the batteries. Only once have i needed to run the generator and that was when it was really cold out and the heat ran a long amount of time, but that was with 2 batteries...
I eventually would like to get a couple solar panels to help extend that 3 day to 4 days or so...

Thanks for the information.

The only "Issue" as such is re-charge time ..

First You have one battery Bank, It does not matter if it is 2 Six volt in series, or 1,2,3,4,20 12's in parallel, it is one 12 volt battery bank, All you are doing when you add more "Jars" as someone around here calls 'em is adding amp hours, that's a good thing.

You may wish to put in a bigger converter.. Depending on your converter this may best be done by putting it in a compartment near the batteries and direct connecting with starter cable. or not.

NOTE that unless you are using LIfeline AGM, The larger converter is optional.. Just with 2x the batteries you will need 2x the recharge time but they will last 2x as long.

The only Danger.. And Ive been there And I run 4 12 volt, is if a battery shorts out.. With 4 that's 4 that can short out... Turns out it was not as bad as I feared. I isolated and replaced the one with the shorted cell and everything worked.

Post the charger model number and you'll get additional input. A larger 3 stage charger can shorten charging time and increase battery life. Might be desirable especially with future 6V batteries. Really only comes into play with more boon docking.

One option is to disable the current charger and add the new one close to the batteries.

CA Traveler wrote:
No problem but wire them Balanced. I'd probably compromise and use Method 2 considering your situation. Consider a larger charger.

The charger i have i guess it what comes stock on the unit.

I dont really know how to upgrade that...

No problem but wire them Balanced. I'd probably compromise and use Method 2 considering your situation. Consider a larger charger.