Battery

[shark24]

What is the best and cheapest battery replacement for a 2013 21 bhs

[DavidM]

A pair of 6V golf cart batteries wired in series for 12V. Provides 220 Ah capacity. All for about $250. Costco, Batteries Plus and others. If you don't need that much capacity then a 100 AH AGM by WindyNation from Amazon is $190.

David

[Merlin]

Unfortunately, "best" and "cheapest" in batteries are mutually exclusive terms. 

David's recommendations are right on for an improvement in your battery bank. If you want a straight replacement that fits in the existing battery box, I suggest a group 24 marine/RV battery from either Interstate or Duracell. They sell quality batteries and are readily available. Check the date to make sure you get one less than 6 months old.

[DavidM]

Shark24:

Do you need more capacity? Tell us how you use your batteries and what is leading you to replacement. As Merlin notes above, there is cheap and there is good which are mostly mutually exclusive.

The simple Group 24 replacement is undoubtedly the cheapest, probably less than $100 for 70 amp hours. The pair of golf cart batteries gives the most bang for the buck at about $1 per amp hour. But it requires a new battery box and reinforcement of the mounting on the tongue. The single AGM is a more sophisticated solution, gives you about 50% more capacity and with a new $20 battery box you can probably use the existing mounting frame work.

David

[Pinstriper]

Not entirely a threadjack, but our new travel trailer (just picked up, Venture Sonic 22VBH) was equipped with a two battery rack, which the dealer put 12v batteries on in parallel. I'd have to go check the size/specs.

Point is, they said the don't like to put "maintenance free" batteries on anymore as they "don't last", by which I think they mean people don't manage them well and they stop retaining/delivering full charge.

Would Merlin/David care to provide a write-up of how to maintain the water in batteries, including any considerations for 12v parallel vs. 6v series setup ?

[DavidM]

I will give it a shot:

Maintenance free batteries can mean anything. I suspect they are referring to sealed lead acid batteries which should only used for starting. Yes those don't last in deep cycle service. Thin plates and not much room for sulfate to build up in the bottom before shorting.

Another type of battery that can be considered as maintenance free are absorbed glass matt (AGMs). These have a glass mat in between the plates which holds the electrolyte. These don't sulfate as bad and can be mounted in any direction and you don't have to add water. They are generally good in deep cycle service.

The most common deep cycle battery is flooded cell lead acid (FLAs) with filler caps. The Interstate/Duracell 12V batteries mentioned above are FLAs and so are 6V golf cart batteries. The former are ok for deep cycle use but I don't think they have the depth below the plates for sulfate buildup, and I am a little suspicious that their plates aren't as thick as GCs. But I got good service out of my Group 24 Interstate- 7+ years so far.

I checked my water level every three months and usually only needed to add water every other check. A lot depends on your converter/charger not overcharging and evaporating (well disassociating) water. With a new battery setup I would check every month until you get a handle on water usage. Realize that if you let the water level go below the top of the plates you lose as much capacity as the exposed portion.

With 6V GC batteries you have to wire two in series to get 12V. But you could also wire two 12V batteries in parallel if you needed the capacity of two. It only takes one jumper to wire two 6Vs in series vs two jumpers for two 12V batteries. I just replaced two G24s in my new MH with two G31 AGMs for more capacity.

With either GC or deep cycle 12V batteries with filler caps you can get a true state of charge reading by measuring the specific gravity of the electrolyte. It takes a simple hydrometer that you can buy for less than $20.

Did that cover the bases?

David

[nhlakes]

Agree that best bang for the buck is a pair of Costco 6volts.  That's what I have on my 21RBS.  Heavy buggers, but can take more abuse (low draw downs etc).

I'd venture the 'best' today is Lithium Ion - the more the merrier.    Suspect I'll go that route next time around just because I'm getting to the point where I don't look forward to lifting them 6 volts.

The cheapest would be that group 24 auto/marine that many campers come with...

[Merlin]

I've run 2 Duracell AGM 12V group 31 batteries in my camper for 7 years without any problems or drama. Parallel configuration is fine and 12V batteries come in way more sizes and use-types than 6V. I have not used flooded batteries (with one exception) in anything since 2003. The exception is Toyota starting batteries. They are flooded, but sealed, batteries and are the best I've found anywhere for starting batteries. Their sealing is not tight, so they can off-gas, but they have plenty of electrolyte and last many years.

So, I can't offer any thoughts on adding/checking battery water.

I can say I'm in the process of a complete conversion from lead-acid to LiFePO4 batteries in everything. My camper will be up for that conversion this fall. So, I've purchased 9 lithium batteries for various uses and consider them to be the least expensive battery out there because they last so much longer than lead-acid and it takes fewer batteries for the same KWh capacity.

[shark24]

What is the small battery for?about a 5"x5"
Where can I purchase one?

[Pinstriper]

Thanks, Boyos. Yes that pretty much answers my questions. I am pretty well stuck with what they put in, so I'll be dipping and dripping these, at least until the performance starts to lag, or I get fed up with it all and go Lithium. But I have to figure whether the converter in the Sonics can handle that chemistry, or what to change out.

So inertia will keep me with this setup for some time.

Sharkie, the early CL's had a separate battery for the breakaway brakes. Problem was, they were not hooked up correctly, so they either never got recharged and were dead after a year or so just sitting, or they were tied into the house battery and could run down in the campsite and leave you with no breakaway power on the trip home. What they really needed was an isolator that would charge from the main 12v circuit but not discharge to it, only to the breaks. Most folks took the separate battery off and just wired the breakaway off the main house battery.

[DavidM]

What is the small battery for?about a 5"x5"
Where can I purchase one?

As Pinstriper notes above, the small break away battery was always a PITA. Search the archives and you will find a couple of threads on doing away with the battery and wiring the breakaway switch directly to the trailer battery. Works fine.

David

[bcsnave]

Ok...I'm in. I need a new battery and still not quite certain even after reading this.
1) If I go with the LiFePO4 battery I see for about $900 I still only get 100Ah. Then if I do that do I need a different charger?
2) Two GC batteries what size do I get? Do they make AGM 6v GC batteries? Do I need a new box to put them in?
3) Option 3 to go with a 12v Deep cycle AGM such as  ODYSSEY band still get 100Ah

I don't know what is the best value.

Bill

[DavidM]

Short answer: The best value is that which satisfies your needs at the lowest cost. Two GC batteries at 220 Ah may be more than you need although it is the best $/Ah.

Long answer:

What battery do you have now? Is it running out of capacity too soon? How long do you camp in one spot. How far do you drive to your next campsite. What charging sources do you have: 7 pin trailer connector, solar,

After you decide how many amp hours you need then we can move to figuring out the best value. Lithiums are seductive and they are all the rage, but they may not be the best value. If you just want to add 50% then changing your existing battery to a Group 31 AGM may be the best value as it can be done for $200, 1/5 the cost of a lithium installation.

One rule of thumb which has been around for a long time is don't draw down non lithium batteries more than 50% for best life. But I have come to the conclusion that drawing down by 80% a couple of dozen times isn't going to change their life expectancy that much. Being able to draw down lithiums by 90% or more is their big advantage. But who is going to camp for 2,000 to 5,000 nights to take advantage of that capability.

So let me answer some of your specific questions:

Ok...I'm in. I need a new battery and still not quite certain even after reading this.
1) If I go with the LiFePO4 battery I see for about $900 I still only get 100Ah. Then if I do that do I need a different charger? Your existing converter will charge a lithium up to about 90% so you lose a bit of capacity unless you change out the charger.
2) Two GC batteries what size do I get? Do they make AGM 6v GC batteries? Do I need a new box to put them in? .Group GC or GC2 (a bit more capacity) batteries are always 6V and have about 210-225 Ahs. Yes you will need a dual GC box and you will have to reinforce the aluminum frame that holds it on your tongue.
3) Option 3 to go with a 12v Deep cycle AGM such as  ODYSSEY band still get 100Ah. Yes but there are lots cheaper 100Ah AGMs- WindyNation and Renogy among others.

I don't know what is the best value. See above.

Bill

[bcsnave]

Thank you David, we have a group 27 flooded battery that is just old.( was original when purchased last fall).

The battery will not hold a charge so it is time to replace. More than likely I will just buy a Duracell Platinum AGM from our local Sams Club.

Do you know if a group 31 battery and box will fit on a stock 2015 14BDS?

Bill

[DavidM]

It may or may not fit. If it is like my former 16TBS there is a rectangular frame of aluminum angle on the tongue that the battery box sets on. I think they made it and the battery box big enough for a G31 battery. But check the overall dimensions of the G31 and compare them with your box. If it won't fit, you have two choices:

Buy a G24 AGM. You won't get as many Ahs but it will fit. The other way is to modify the frame. You might have to start over with aluminum angle you get at Home Depot, etc. Just notch it and bend it to the larger rectangular shape that the G31 battery box needs. You can buy battery boxes on Amazon for about $20.

Good luck,
David