Battery System Upgrade

[G-man]

Looking for some advise. In early Sept. I will be dry camping for two weeks in Shenandoah National Park. In preparing for no electricity for that time ( I do have a 2000 watt pure sine generator to charge the battery ) I am contemplating upgrading my battery system
I have purchased a brand new 12 volt 92 ah deep cycle battery to replace my main 5th wheel battery. The old batter is a 1 year old Interstate deep cycle battery.
Reference to the diagram I have attached, I want to use a WirthCo #20092 battery doctor to hook the two batteries together. The goal is to be able to charge both batteries when I am plugged into my generator. Knowing that you should never hook a new battery and an old batter together in parallel this battery doctor would prevent that.
The other thing I am trying to accomplish is using the two batteries together when I am leveling the trailer with the landing gear and rear supports as well as deploying the two slides.
The battery doctor has a jump start button that hooks both batteries together temporarily for this purpose.
Questions:
Will this work as I want it to
What size cables should I use for cable #1 and cable #2
Should cable #1 have a fuse in it
Does battery #2 (the Interstate) need to be grounded for it to work in parallel with battery 1to temporarily provide more battery when setting up and breaking down the fifth wheel. I don't think it needs grounded for just the inverter.
Hope I have made sense. Thanks for you help.

[NewBlackDak]

You would be much better off just buying a paid of GC2 6V batteries, and wiring them up in series. You’re making it over complicated trying to keep that cheap battery that came with the trailer in there.

[Mustang65]

HEy G-man



Based on what your have for battery power and the method for utilizing that battery power, I do not think you will not be very successful for 2 weeks of dry camping.

Personally, dump the 12Volt batteries, of which will have about 160ish Amp hours total, for (2) 6 volt Trojan T105's or equivalent that will give you 230 Amp hours.

Oh, of the 160 ish Ah's you can only use 80 of those Ah's... the 50% battery rule. Have you ever dropped the original battery voltage below 10.5 volts, if so I would not recommend connecting them together for charging or loads.

If you are only charging your cell phones get a 400 watt inverter, they use less internal power. You can not use the batteries you have to do anything but charge your cell phone batteries, run the heat for a only a night or 2 max, some showers and LED lights. If you connect those 2 batteries in parallel to charge them one will probably be overcharged the other undercharged. If you connect them together for loads, the older battery will draw down the new battery to its level in no time.

Do you have a Digital Voltage Display to keep tract of your battery voltage so you can STOP using your batteries when they hit 12.2 Volts (there again the battery 50% rule). At that point they need to be charged again. I would venture to say that you will need to run the generator fro at least 3 hrs a day to get the batteries up to at around 80%.

Your best bet is not to complicate matters and stick to the battery basics if you want to have a GREAT time for those 2 weeks. Otherwise you will be devoting your time to troubleshooting or taking drastic actions to keep the electrical system running to meet your needs.

I assume that you will not be using a TV or microwave because those batteries do not have enough power to keep them going for any length of time.


When you are leveling the TT or putting the slides out leave the TT connected to the TV with the engine running and the power will come from the TV, saving your battery power for a better use.


Good luck
Don
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[DrSmart]

Regarding your diagram. You do need to ground the 2nd battery to power the levellers and slides and for the converter charger to charge the 2nd battery. There needs to be positive and negative path from both batteries. The switching unit doesn't show a negative link to the 2nd battery.

[whaffner]

if it were me, I wouldn't use the battery doctor. I would simply wire (parallel) the two batteries together, using 6 ga wire. The 1 year old battery should still be good, unless you've let it discharge. I would also do away with the inverter, and simply charge cell phones , ect. from 12 volt receptacles in the trailer. You can purchase receptacles that include usb ports as well as voltage meters cheap. You will need to run the generator as much as needed, dependent upon how much power you are using.

[Screwby]

Your going to be sorely disappointed with 96ah batteries for boondocking. One of my Duracell 6v batteries has more amp hours that both those 12vs together. If your going to boondock a lot, ditch the 12v batteries. Wire up some 6 volts, add some solar, and only use an inverter if you absolutely need it. Your better off with 12v accessories than converting 12v to 120v with an inverter. I use an inverter for things if I absolutely need it but I also have a 420ah battery bank and a lot of solar so I’m less worried about it.

[G-man]

Thanks all for the great info. I have always been a little gun shy of 6 volt batteries due to loosing all of the power if 1 battery goes bad
I don’t boondocks much at all as this is a special trip for my wife to hike the Appalachian Trail through Shenandoah NP. That’s why I was trying to work with what I have.
Again lots of great ideas. Thanks for your input

[Mustang65]

Originally Posted by G-man

Thanks all for the great info. I have always been a little gun shy of 6 volt batteries due to loosing all of the power if 1 battery goes bad
I don’t boondocks much at all as this is a special trip for my wife to hike the Appalachian Trail through Shenandoah NP. That’s why I was trying to work with what I have.
Again lots of great ideas. Thanks for your input

I am on year 7 with 2 Trojan T145 (260Ah) 6 volt batteries. They are showing their age (current Ah's are a lot less than the original 260- Ah's and will be replacing them soon. If you take care of the 6 volt batteries, they hardly ever die without giving you notice... like a lot less Ah's available.


Don
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RVing with SOLAR

[Screwby]

Originally Posted by G-man

Thanks all for the great info. I have always been a little gun shy of 6 volt batteries due to loosing all of the power if 1 battery goes bad
I don’t boondocks much at all as this is a special trip for my wife to hike the Appalachian Trail through Shenandoah NP. That’s why I was trying to work with what I have.
Again lots of great ideas. Thanks for your input

I’m not sure the logic here, if one 6v dies you do lose all your power, same as if a 12v goes bad you also lose all your power. So if a battery goes bad, you do indeed lose power. 6v batteries are much more robust, and have a much longer lifespan than 12v batteries. They have much thicker lead plates in them and are designed to be worked hard unlike 12v batteries. Understood if you don’t need to boondock and don’t care to build a battery system to do so. Don’t be scared of 6v in the future, they are awesome.

[Siamese]

Originally Posted by Screwby

I’m not sure the logic here, if one 6v dies you do lose all your power, same as if a 12v goes bad you also lose all your power. So if a battery goes bad, you do indeed lose power. 6v batteries are much more robust, and have a much longer lifespan than 12v batteries. They have much thicker lead plates in them and are designed to be worked hard unlike 12v batteries. Understood if you don’t need to boondock and don’t care to build a battery system to do so. Don’t be scared of 6v in the future, they are awesome.

The OP is saying that with two 12v batteries, if one fails, he can take it out of the system, and continue with a single 12v battery. I would say that having this marginally useful redundancy is keeping him from having a pair of 6v, which would be the much better setup.

Agree that ditching the existing 12v is a given. Would be inefficient having what would essentially be two battery banks with switching. KISS.

[ALJO]

Never mix different battery group systems together on the converter charging system.
2- 6 volt deep cycle batteries give (approx.) double what 2- 12 volt group 27 supplies (amp hours).

[Screwby]

Originally Posted by Siamese

The OP is saying that with two 12v batteries, if one fails, he can take it out of the system, and continue with a single 12v battery. I would say that having this marginally useful redundancy is keeping him from having a pair of 6v, which would be the much better setup.

Agree that ditching the existing 12v is a given. Would be inefficient having what would essentially be two battery banks with switching. KISS.

Ahhhh that makes more sense if your using two batteries isolated from each other. Kicking the dead horse, I wouldn’t bother spending the money going that route. OP says he doesn’t need a boondocking setup so I digress

[NewBlackDak]

Originally Posted by Siamese

The OP is saying that with two 12v batteries, if one fails, he can take it out of the system, and continue with a single 12v battery. I would say that having this marginally useful redundancy is keeping him from having a pair of 6v, which would be the much better setup.



Agree that ditching the existing 12v is a given. Would be inefficient having what would essentially be two battery banks with switching. KISS.

In reality…
A pair of 12v batteries wired together will fail together. One will go bad, and kill the other rather quickly.

[GHen]

Another option is to keep the 12 and add a couple 6v batteries.
I have two 12 volts (150 total amps) that came to my rig, I figure they have at least another year of life left.
I just added two 6 volts (210 total amps) and also added 2 100watt solar panels.

I have the two batteries sets wired to a switch, A, B, Both and Off. Don’t want to use the “both” settings. This way I don’t waste the life left in my 12 volt system, I just switch between the 6v and 12 v as needed.
Just finished Boondocking for 5 days, The new CG2 6 volt system is much robust than the 12v side. Had a nice sunny spot and the panels keep them charged.
My results were the 6v would easily last a couple days, the 12v were pretty weak after just 24hrs, but I don’t like taking either set below much below 12.4, I just like to have that reserve power if I need the heat on.

[videoarizona]

I'm running 2 golf cart (gc) 6 volt batts. 210amphrs. Also bought a 100 watt solar suitcase from Renogy that attaches to terminals on the battery cases. Have a Honda 2.2kw generator for those cloudy days. 1 week trips so far and never got even 1/4 down on the batteries. BTW, GC batteries are true deep cycle...you can take them down all the way without damage. Think about it.... On a golf course they go all day under heavy load! Far better set up than 2 -12 volts that can only go down 50% without damage.

[rtaylor]

I had a number of RV friends tell me to set up my new trailer with two 6-volt batteries. I was reluctant to spend the extra cash so I jumped into my "let's research the crap out of this" mode. Let me save somebody else the trouble. The science and the user experience with 2 x 6-volt batteries greatly exceeds the additional cost. So when I purchased my trailer this spring I upgraded to 2 6-volt batteries and a battery shutoff switch. I received a credit for the 12 volt battery they usually send them out the door with. So glad I did.
The two 6-volt system is amazing. Granted....just my wife and I and our electric use is minimal. We use the LED lights in the trailer, the water pump, and occasionally the furnace fan. I think the refrigerator even on propane requires a slight amount of 12 volt power. We have boondocked for 4 days a couple of times and my battery indicator never comes off of 4 out of 4 bars. I had planned to get a portable solar system (and probably will at some point) but if we can go that long with minimal depletion there is no rush.
In my humble opinionated opinion.....install a couple of 6-volt batteries.

[Isaacs]

You could go the 6V battery route and throw the new 12V into the bed of your truck to be hooked up in case of an emergency.

[Wayne44]

Thanks for the information.it’s a Start.
I need some more in depth info. AGM 6 Volt batteries.(Source) What Brand ? Price, Amp hours. What type disconnect switch? Most of all,Where to put this battery bank on my 2017 Redhawk?
Wayne44

[trento]

Originally Posted by G-man

Looking for some advise. In early Sept. I will be dry camping for two weeks in Shenandoah National Park. In preparing for no electricity for that time ( I do have a 2000 watt pure sine generator to charge the battery ) I am contemplating upgrading my battery system
I have purchased a brand new 12 volt 92 ah deep cycle battery to replace my main 5th wheel battery. The old batter is a 1 year old Interstate deep cycle battery.
Reference to the diagram I have attached, I want to use a WirthCo #20092 battery doctor to hook the two batteries together. The goal is to be able to charge both batteries when I am plugged into my generator. Knowing that you should never hook a new battery and an old batter together in parallel this battery doctor would prevent that.
The other thing I am trying to accomplish is using the two batteries together when I am leveling the trailer with the landing gear and rear supports as well as deploying the two slides.
The battery doctor has a jump start button that hooks both batteries together temporarily for this purpose.
Questions:
Will this work as I want it to
What size cables should I use for cable #1 and cable #2
Should cable #1 have a fuse in it
Does battery #2 (the Interstate) need to be grounded for it to work in parallel with battery 1to temporarily provide more battery when setting up and breaking down the fifth wheel. I don't think it needs grounded for just the inverter.
Hope I have made sense. Thanks for you help.

I just did that mod myself.two 6 volt golf cart batteries 180 AH each.Wired in series.now when dry camping i use my generator once every 3 or 4 days.they hold a constant 12.9 volt charge.I never had it so good.IT's a simple modification and well worth it.or if you want to spend the money go for lithium ion battery.expensive but would virtually last forever.Very good technology.interstate batteries are junk.thats what i replaced.would never buy again.

[Mustang65]

Originally Posted by rtaylor

The two 6-volt battery system is amazing. Granted....just my wife and I and our electric use is minimal. We use the LED lights in the trailer, the water pump, and occasionally the furnace fan. I think the refrigerator even on propane requires a slight amount of 12 volt power. We have boondocked for 4 days a couple of times and my battery indicator never comes off of 4 out of 4 bars.

Yes, 6 volt batteries are great! But the "Idiot" lights (60's car term) that come with trailers are useless. The last thing you want to monitor your expensive battery investment with is those lights.


Get a battery monitoring display. There are some inexpensive options to insure that you do not let your battery voltage drop below 12.2Volts. There are a few options below.


Don
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