Two 6 volt batt or Two 12 volt batt

DonaandDon · 10-20-2017, 06:48 PM

So my dealer installed one 12 volt battery and it is not enough for my 2017 NP 381 DLQS. It has the res fridge and a 1000watt inverter. After traveling 6+ hours the DW told me the inverter was flashing at 11.8 volts. Discussing this at the campfire, I was told to go with two 6 volt batteries. I told him I do not boondock and his response was I bet your first truck wasn't a diesel either. Help please...

Robbbyr · 10-20-2017, 06:58 PM

While an identical battery will help your situation, it is very likely your existing battery is a "dual-purpose" battery, not a true deep-cycle battery. A true deep-cycle battery (most often 6-volts in RV situations) has much thicker lead plates and better tolerates discharge/recharge cycles. I have never seen a 12-volt battery ever installed from the factory/dealer that are "real" deep-cycle batteries.

There are a number of owners frequently on JOF who are far more versed in battery technology, hopefully they will weigh in and give you some good information to consider.

Bookemdanno · 10-20-2017, 07:40 PM

We don't boondock either, but I have three (3) 12 volt batteries (not the one that the dealer installed) to power the res fridge while traveling in our NP 377. Haven't had a problem since.

DonaandDon · 10-20-2017, 08:28 PM

Bookemdano: If running three 12s are they all the same? I've heard 12 volts are not true deep cycles.

Ringneks · 10-20-2017, 08:47 PM

I'm running 4 Trojan six volt batteries, but we mostly dry camp. Everyone we've talked into going to six volts will never go back, like I said above though we all dry camp mostly.

Murff · 10-20-2017, 08:52 PM

Two six volt batteries have more storage than two 12 volt. I would go with the 6 volt.

Murff

rodro123 · 10-21-2017, 04:12 AM

Most 12 volt "deep cycle marine/rv" batteries are not truly DEEP cycle batteries, they are a hybrid between a deep cycle and a starting battery. If the battery has a CCA (cold cranking amps) rating it IS NOT really a deep cycle battery. Instead look for AMP/HOUR ratings.
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The deep cycle marine/rv batteries will work well in most peoples application - limited boondocking. However, if you plan to boondock much, you should consider true deep cycle batteries. I believe virtually all 6 volt batteries are true deep cycle batteries.
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Regarding 12 volt or 6 volt.... Assuming both have the same amp/hour ratings .... both will give you exactly the same storage capacity. Where the difference between 12 and 6 comes into play is the internal resistance and the connection resistance of each battery. These will never be exactly the same for both batteries resulting in one battery getting a higher charge (or discharge) than the other so you end up with one 'working harder" than the other.
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With two 6 volt batteries ALL the charge (or discharge) current passes through BOTH batteries and is equal resulting in both "working" equally.
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**Mustang65** · 10-21-2017, 05:14 AM

Most RV buyers are unaware of what the issue is when they purchase the RESIDENTIAL fridge with all its space inside, and find that their batteries and TV can not keep up with the battery drain caused by the fridge. I attached a link to another post here that we dig into the problem (45Amp drain) and the fix that is working perfectly. The fridge type was a Frigidaire, but the same issue and fix can be done to any residential fridge.

Bare minimum, I personally would go with the TRUE deep cycle 6 volt batteries, will need 4 to ensure enough power, based on the findings.

Best solution, 4 true deep cycle batteries and 500 watts of SOLAR power with MPPT SOLAR Charge controller (will add about 40 Amps, with sun). This will cover your travels and keep the batteries topped off. This fix is a "MUST" for anyone that dry-camps or spends a night between CG's. I have 2 Trojan T-145 6 volt batteries (260Ah), and for 5 years they are working GREAT!

Adding the modification would be your best bet. Contact Klassic (member) for more information on his install.

For more Residential Fridge info you can search "Residential Fridge" using the above search.

https://www.jaycoowners.com/forums/f...mod-47511.html

Good luck,

Don

My Registry

RVing with SOLAR

Bookemdanno · 10-21-2017, 07:25 AM

Quote:

Originally Posted by DonaandDon

Bookemdano: If running three 12s are they all the same? I've heard 12 volts are not true deep cycles.

Sorry just now seeing your question. No, they are not "true" deep cycle...you'll need the 6 volt batteries if that's what your looking for. All 3 of mine are the same 12 volt. They are the blue top Optima's.

Sent from my iPhone using Tapatalk

DonaandDon · 10-21-2017, 08:03 AM

Great information as always and thanks. Better to have and not need than to need and not have. 6 volt batteries it is.

Rock · 10-21-2017, 08:26 AM

You can get either a deep cycle 12 or a deep cycle/start. Like said the 6 volt wired together have way more capacity. I have gas fridge and just use two 12 deep cycle.
Rock

DonaandDon · 10-21-2017, 08:32 AM

When Amazon looks bad. Price is to high and shipping rate looks like a Sunday delivery. Hahaha.

https://www.amazon.com/Trojan-T-145-...eries+%28260Ah

I have found a local dealer at my destination so I think I'll wait till I get there.

Marine71-76 · 10-21-2017, 10:17 AM

We have the residential fridge in our Pinnacle. We also have 6 6 volt batteries - yes 6. No we do not normally dry camp but on our recent trip to upper Michigan, pulled into Walmart to sleep for the night. Without starting the truck, was able to put the bedroom slide out that night, back in the next morning & run the fridge without any issues.

Last year the truck/trailer had an issue and we had 4 batteries then. The trailer was left at a service center and the next morning the inverter was peeping. Yes we left the fridge on because we were on our way back home.

Would definitely recommend 6 volt batteries and if you can afford & have the space, more than 2.

DonaandDon · 10-21-2017, 10:20 AM

Wow. What type of batteries did you have back then? What do you run now?

Marine71-76 · 10-21-2017, 10:24 AM

Quote:

Originally Posted by DonaandDon

Wow. What type of batteries did you have back then? What do you run now?

Last year the unit was new & we replaced what the dealer put in with Interstate. We added 2 more after we picked up the trailer and then picked up 2 more after the trip.

**Mustang65** · 10-21-2017, 10:31 AM

If you are interested here is a link to an inexpensive inline Amp/Voltage meter. It is not difficult to install, instructions are in one of the posts on our "RVing with SOLAR" social group 9link below). Some of the members have installed them and are happy with them. Here is the thread I started a while back regarding the meter. https://www.jaycoowners.com/forums/f...vel-32652.html

You mount the shunt resister between your negative battery cable and the frame ground. Easiest way is to buy a 6" black battery cable (automotive parts store) with bolt hole lugs on both end. Disconnect the negative battery cable at the negative battery terminal. Remove the ground bolt with the negative battery cable at the frame. Connect one side of the 6" battery cable to the frame where the original ground wire was connected. Connect the other side of the 6" cable to the shunt. Connect the end of the negative battery cable that was terminated on the frame to the other side of the shunt. You will need some old telephone wire (4 wires needed) to go between the shunt meter terminals and the actual meter. There is a wiring diagram if you want to switch between monitoring battery discharging or charging. Very simple project. If you purchase 2 of these meters you can use the same shunt just revers the wires for the 2nd meter at the shunt or on the back of the meter.

Don

My Registry

RVing with SOLAR

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