RV Batteries

[Morelli]

Howdy All, 

Question for everyone, what battery are you using in your 5th wheel ??  Anyone using AGM ?  Anyone change from 6V to 12V with multiple batteries in parrallel ?

Thanks !

[Yarome]

That's an extremely vague question. Many use 6V, 12v, flooded cells and AGM's. Some use lithium and most use multiple batteries. About the only "most common" denominator is to use true deep cycle batteries when installing wet cells (vs. starter or hybrid marine/RV batteries).

It all depends on what you are trying to accomplish, your budget, size of your battery compartment, supporting equipment, energy requirements and how you plan to replace the energy used from your battery bank.

In the most general terms, many find that 6V flooded wet cell golf cart batteries from Costco/Sam's club provide the best bang for your buck for semi to light usage.

What is your intended usage and what exactly are you trying to determine ?

[Morelli]

Thanks for the fast response.  I have a newmar kountry aire and the batteries are all the way in the back in the spare tire draw.  The draw by default holds two battiers, but with a slight modification can hold at least 4.

Reason for asking it currently uses 6V flooded batteries and with all the tossing about, acid caused lots of rust damage.  I am thinking about cleaning everything up and remove the flooded batteries and replace them with AGM and leaning towards 12v swtich over.   Also thought about 6V AGM golf cart batteries in 6V and putting in 4 ...  All thoughts and seeing what others have done.  We are not full timer.

Hope that helps.

[Chalkie]

27 minutes ago, Pug said:

Reason for asking it currently uses 6V flooded batteries and with all the tossing about, acid caused lots of rust damage.

I think I would examine how the batteries are secured. They should not be getting tossed around enough to spill any of the fluid any more than they would be tossed around in a car (well, unless you are doing some hard core extreme off road driving).

[Chad Heiser]

AGM batteries have advantages over wet cell lead acid batteries, but they are more expensive so you are paying for those advantages.  They are basically set it and forget it type installs.  You really only need to check connections once a year or so.  With wet cells, you need to regularly check fluid levels.  AGM's can also accept a charge at a higher/faster rate than wet cells.  They also typically have more life cycles than wet cells.  AGM's do not off gas like a wet cell does so they can be installed in the same compartment as your electronics or even in your living area without fear of hazardous gasses causing issues.  There are other differences as well, but these are the highlights.  I had wet cells in my last RV and I have AGM's in my current RV.  They both have their place.  It really comes down to what will work best for your situation and what you can afford. I personally prefer the AGM's.

As for 6 volt vs 12 volt, that comes down to the space you have and the wiring you are willing to do.  As long as the batteries are true deep cycle batteries and are not hybrid RV/Marine batteries, there is no significant difference between two 6 volt batteries in series and an equivalent 12 volt battery.  The wet cells in my last RV were 6 volts.  The AGM's in my current RV are 12 volts.  My 12 volt AGM's have the same basic footprint as two 6 volt batteries sitting end to end. Look at the ratings of the batteries and go with whichever gives you the best bang for the buck in the footprint you have available for installation.

[Al F]

To add to the discussion, when buying inexpensive 12V batteries, you usually get a combination starting battery.  Many are labeled "Marine Battery", which are NOT a true deep cycle battery.  The 6V golf cart batteries from Costco, Sam's are typically deep cycle. 

However if you don't stay at places w/o elect for more than 1 or two nights at a time and don't run an inverter, the Marine battery will work just fine for your needs. 

If you do plan on staying places w/o elect for days at a time, have an inverter to power the TV, coffee maker, microwave then that is a different requirement. 

[Yarome]

That makes better sense now. To start... I highly doubt you're getting actual acid spillage. More likely is just off gassing in an inadequately ventilated space. High temperatures or excessive charging can contribute to that, but regardless, AGM's "would" solve that issue completely.

Good advice from Al. Before "sizing" a new battery bank it's a good idea to really determine what your requirements are. You mentioned the possibility of 4-6v. That's quite a lot of juice, weight, and cost that may be completely unecessary if they only see light overnight or point A to point B travel usage.

[Helipilot]

I just replaced the 12v factory battery with two 6 v T-105 Trojans with a Magnum 2000 watt pure sine inverter and installed a Samsung RF18 residential french door refrigerator (a  lot more room in the freezer and the box as well).  The new batteries and inverter will run the refer 24 hours without issue.  Planning to add solar this winter after I save up some coins for the conversion.  Our DRV is already pre-wired for the solar conversion.

[SWharton]

We are switching to 12v AGM(that is all that  will fit) due to a poor location and no slideout tray(cannot be installed). Twice I have left the water get too low since I needed to remove the batteries to check them.  Going with Sams club AGM(Duracell) due to price($179) and have upgraded the remote so we can better monitor the batteries. 

Challenge was getting enough batteries. We needed 4 and had to go to 2 different Sams Clubs.

[Al F]

7 hours ago, Helipilot said:

I just replaced the 12v factory battery with two 6 v T-105 Trojans with a Magnum 2000 watt pure sine inverter and installed a Samsung RF18 residential french door refrigerator (a  lot more room in the freezer and the box as well).  The new batteries and inverter will run the refer 24 hours without issue.  Planning to add solar this winter after I save up some coins for the conversion.  Our DRV is already pre-wired for the solar conversion.

Not sure what your experience is with RV 12V electrical systems and batteries are.  Since you have only have 2 golf cart batteries I strongly recommend you read the following informational websites:

http://www.marxrv.com/12volt/12volt.htm

http://www.marxrv.com/12volt/12volta.htm

http://www.jackdanmayer.com/rv_electrical_and_solar.htm

http://www.jackdanmayer.com/Batteries_and_charging.html

Pay close attention to charging/discharging requirements for the batteries.  Also look at the wire size information for the wiring coming from your future solar panels down to the area of your batteries. 

Some concerns I have about your setup:

--  With only about 230AH of battery capacity 24 hours of running the fridge and other 12V needs will likely discharge your pair of batteries to below 50%.  Life cycles of Trojan is around 3000 cycles if discharged to 75% full (using only 25% of the capacity) going to 50% drops the life to around 1500 cycles, going below 50% rapidly decreases the life of the batteries.

--  Batteries really need to be frequently charged to 100% every several days, around 4-7 days or so.  Not a problem as long as you don't dry camp or boondock more than a few days between having elect hookups.

Many or most solar pre-wiring in RV's has too small of wire size and therefore a larger voltage drop from the panels to the solar controller than is optimal for charging.  Be sure to check the wire size and distance.  Then use a wire size calculator to be sure your voltage drop is less than 2%-3%.  1% is best. 

If you don't have a battery monitor such as a Trimetric, your really  need to install one so you know for sure just how much your batteries are being discharged/charged. 

[Helipilot]

Good post Al.  Thanks for the information and I will study it in detail. 

That is one reason I carry the Honda 3000 generator in case we need to charge or top off the batteries.  We are usually in a park with 50 amp power available but wanted some ability to keep going in the event of some short term situation such as a major traffic jam or road closure that would prevent us from having shore power.

The solar wiring will be sized by the solar installer when we are ready to install the panels and other related electrical equipment.  They are here in Little Rock and have a good reputation for quality work having installed solar systems for several cities in the area and businesses as well.  If we need to replace the existing wire in the unit we will

Edited October 6, 2017 by Helipilot

[RBH]

On 10/6/2017 at 12:15 AM, Helipilot said:

 

The solar wiring will be sized by the solar installer when we are ready to install the panels and other related electrical equipment.  They are here in Little Rock and have a good reputation for quality work having installed solar systems for several cities in the area and businesses as well.  If we need to replace the existing wire in the unit we will

I would still double check to make sure the wire they are using is adequate. Wire size calculators are easily found on the internet.  If in doubt go to the next heavier gauge as there is no problem with too heavy a wire but big problems with too light a gauge and the price difference is not that much of a factor.

[Ronbo]

Since you are going with AGM, this does not apply, but for others you can install a watering system. This is great especially for hard to reach batteries. It has a bulb pump and you pump until it gets hard. The batteries are full. Di this once a month. You will be shocked how much water they use. Once a year is just often enough to be replacing batteries quite often.

[Al F]

11 hours ago, jamesph said:

Because 12 Volt batteries are utilized in parallel circuitry, there is no limit to the number of 12 Volt batteries that can be connected to increase amp hours. It is feasible to keep adding 12 Volt batteries, but you must be careful of their size and space requirements. 

In addition there is no limit to the number of pairs of 6V batteries, that are wired in series, so each pair makes up a 12V battery, that can be wired in parallel.  

There is a practical limit in dealing with the wire size or bus bars to carry the huge numbers of amps a large number of batteries can supply to the inverter or the amount of amps coming from the charger to get all those batteries charged. 

It is one thing to build a battery bank that can, for example, run two air conditioners in an RV for 10-12 hours.  

It very much a different situation when you try to have enough solar panels or other charging source to put all those amps back into the batteries.  

[harriotle]

where I can find best batteries for RV? is this link will be work?

Edited April 2, 2022 by harriotle

[Kirk W]

Are you thinking of batteries for the RV's 12V system or for the chassis of a motorized RV?  Assuming that you are looking at the 12V system then it depends to some degree on how you use those batteries, but if you have a single battery then you need a 12V, deep cycle battery. If you have 2 batteries then a pair of 6V golf cart batteries connected in series would be a good way to go. There are also AGM batteries and lithium batteries that some who do a lot of dry camping prefer. As to where to buy them, if you have access to Sam's Club they would be a good source for the deep cycle or the golf cart batteries. 

[Ray,IN]

Since you seldom dry camp I'd go with AGM 12V deep cycle batteries. I have 3 and have yet to run them down overnight. No need to haul the extra weight of 6V deep cycle batteries.

[Lou Schneider]

1 hour ago, Ray,IN said:

Since you seldom dry camp I'd go with AGM 12V deep cycle batteries. I have 3 and have yet to run them down overnight. No need to haul the extra weight of 6V deep cycle batteries.

Actually, on a watt-hour basis both AGM and flooded lead acid (golf cart) batteries weigh about the same.   Makes sense since they're essentially the same lead acid technology.

A Renogy 12 volt 100 amp-hour AGM weighs 66 lbs, a NAPA 6 volt 230 amp-hour golf cart battery weighs 64 lbs.  You'll need two of each to have a roughly equivilent amount of storage.

Lithium batteries are where you get weight savings.   A 100 amp-hour 12 volt BattleBorn weighs less than half that much, 31 lbs. and you can use the full rated capacity.

Edited March 26, 2022 by Lou Schneider

[Ray,IN]

On 3/25/2022 at 10:48 PM, Lou Schneider said:

Actually, on a watt-hour basis both AGM and flooded lead acid (golf cart) batteries weigh about the same.   Makes sense since they're essentially the same lead acid technology.

A Renogy 12 volt 100 amp-hour AGM weighs 66 lbs, a NAPA 6 volt 230 amp-hour golf cart battery weighs 64 lbs.  You'll need two of each to have a roughly equivilent amount of storage.

Lithium batteries are where you get weight savings.   A 100 amp-hour 12 volt BattleBorn weighs less than half that much, 31 lbs. and you can use the full rated capacity.

Golf cart batteries are touted as having heaver, thicker lead plates thus the comment about weight.

Edited March 28, 2022 by Ray,IN

[Jaydrvr]

46 minutes ago, Ray,IN said:

Golf cart batteries are touted as having heaver, thicker lead plates thus the comment about weight.

This is true, but the corollary of that means that in the same space, there are fewer plates. Often, you can reasonably compare lead acid batteries just by comparing their weights. Deep cycle batteries are generally designed with thicker plates for longer deep cycle life, while starting batteries have much thinner plates for the higher starting currents needed. Jay