Class 27 Battery recommendations

[Almost There]

Friend who needs to replace a pair of deader than a doornail Interstate Deep Cycle Marine batteries...yah, yah, I know! She didn't know any better.

She tried to buy better batteries only to find that they wouldn't fit under the step in the Class C (brand new, new owner, regretful owner...  

What can we put in there that will be a better battery.

Maximum height is 8 1/2", length about 12"

Vehicle still under warranty and she's not sure if she's going to keep it (it's been a lemon so far) so doesn't want to go to the expense of getting welding done to alter the battery shelf.

 

[RVtrek]

If she's not sure if she's going to keep it, and she killed the last set of batteries, wouldn't it make sense to buy whatever the cheapest battery out there that will fit in the space? If she decides to keep the RV and doesn't kill this set right away, then eventually she can make other modifications (like going lithium).

 

[drysailor]

Friend who needs to replace a pair of deader than a doornail Interstate Deep Cycle Marine batteries...yah, yah, I know! She didn't know any better.
Maximum height is 8 1/2", length about 12"

I'm guessing you already know this but, the 8 1/2" height dimension here is the real issue. Only the very smallest deep cycle batteries are that short (32AH). If modifying the existing space is not likely, is it possible to relocate the batteries? If you google, "battery case sizes" you can get a better feel.

 

[tx2sturgis]

Interstate batteries are good quality, normally, so this makes me wonder what the charging system is doing (or not doing) that killed the batteries.

Or maybe she is boondocking with no solar?

Most Class C's, certainly most new ones, come with a generator and a 120v-12v converter....are these working as they should?

 

[John61CT]

If you mean BCI Group #27, that is already over 9" high

G31 is only a 1/4" higher, more choices there, so try measuring as precisely as possible.

Or even better go to the auto supply when they're not busy, and bribe a guy to lug a couple samples out to see if they can be made to fit.

Otherwise locate inside the living space, or have a box made that can be made removable?

And yes Interstate brand's not great (maker is JCI) for hard deep cycling use, but they should still last at least 2-3 years if properly cared for.

So best to get that issue fixed before too long, FLA better than sealed also so you can learn to use a hydrometer.

 

[Almost There]

Oh, we do know how she killed them and that's about to be remedied!

Standard case of not understanding the relationship between production of energy and the use of energy....

The problem still remains that modifying the battery case is not desirable and relocating the battery bank would be a bitch of a job given the design of the RV...stupid manufacturers have even made the access to the charger/converter none accessible to the owner...only access is to rip the bed apart...  

Not looking for best ever, just best possible given the parameters.

 

[tx2sturgis]

And yes Interstate brand's not great (maker is JCI) for hard deep cycling use, but they should still last at least 2-3 years if properly cared for.

At least.

I have an older Interstate Deep Cycle AGM battery that is probably 10-15 years old in emcomm float service, (not deep cycled regularly, only a couple of times a year).

Still going like the energizer bunny!

 

[rayrey]

I had a interstate grp 27 for 6 years and it was still was kicking when I gave it to a member at the RTR a year ago. He did not have enough solar to cover his needs so he decided to get four 6 volts, those lasted a month. Maybe he should have gotten Interstate 6 volts instead. lol

IF set up properly a awful brand like interstate can last a long time. If not set up right the best brand out there will die a quick death. In that case, buy a cheap battery and use the savings to buy some more solar.

 

[jimindenver]

I had a Interstate grp 27 last over 6 years at which point it was put into service by another member. He did not have enough solar to cover his needs so he bought four 6 volts that lasted a month.

So treated right a Interstate battery can last a long time. Treated badly the best battery is junk in a month. My suggestion is to buy the cheap battery and use the savings to add solar.

 

[John61CT]

Your choice is

A short-term batt in the too-small space

B relocate and get a bigger decent bank

For A, if you know G31 or G27 won't fit, you can just roll up to Interstate shop or auto supply, tell em you want biggest best "deep cycling" they can get to fit.

Will only be pseudo.

Or with AGM you could maybe stack sideways Group U1 size, 7.71" 5.18" 6.89" 

e.g. Lifeline GPL-U1T

If you can't physically try at a shop, then you need precise measurement of the space available.

 

[John61CT]

At least.

I have an older Interstate Deep Cycle AGM battery that is probably 10-15 years old in emcomm float service, (not deep cycled regularly, only a couple of times a year).

Still going like the energizer bunny!

Sure, float service is a completely different use case from regular deep cycling.

It's not the years with the latter, performance is measured at number of 50% DoD cycles. And standard end of life point 80% AH capacity SoH.

Lesser vendors cheat that spec by defining EoL at 70% or even 60%.

Many real-life users keep going until the batt is obviously failing, sometimes below 50% SoH, but then the odds of unexpected even catastrophic failure are much higher.

 

[drysailor]

The problem still remains that modifying the battery case is not desirable and relocating the battery bank would be a bitch of a job given the design of the RV...stupid manufacturers have even made the access to the charger/converter none accessible to the owner...only access is to rip the bed apart...

So, no real way to add a 1" spacer under whatever is the top of the battery case?

 

[rm.w/aview]

Crown Battery dimensions of their Crown One line of deep cycle batteries:
Group 24 (12V) 80ah... Length 11.26" Width 6.75" Height 8.12"... Standard Terminal Height 9.38"
Group 27 (12V) 98ah... Length 13" Width 6.75" Height 8.12"... Standard Terminal Height 9.38"
Group 6V-27 (6V) 215ah... Length 12.05" Width 6.89" Height 7.98"... Inserted Terminal Height 8.08"
You can see how precise battery compartment measurements can be helpful.

 

[drysailor]

...

 

[John61CT]

And Crown is a great quality marque for automotive form-factor FLA, along with US Battery, maybe better than Trojan these days.

Unlike most mfg in that market, the rating specs from these three can be trusted.

Still about half the cycles of their GCs though.

 

[rm.w/aview]

^They're a tad large for her at this point, barring relocation...
GC2 (6V) 220ah... Length 10.25" Width 7.06" Height 9.7" Standard Terminal Height 10.94"
GC2H (6V) 260ah... Length 10.25 Width 7.06" Height 10.37" Standard Terminal Height 11.38"
although may be the better choice by providing more of a buffer for her power consumption.

 

[Weight]

The existing batteries have a number. Get the same number and they will be the same size. Go to walmart and get their low price label.

 

[Almost There]

Crown Battery dimensions of their Crown One line of deep cycle batteries:
Group 24 (12V) 80ah... Length 11.26" Width 6.75" Height 8.12"... Standard Terminal Height 9.38"
Group 27 (12V) 98ah... Length 13" Width 6.75" Height 8.12"... Standard Terminal Height 9.38"
Group 6V-27 (6V) 215ah... Length 12.05" Width 6.89" Height 7.98"... Inserted Terminal Height 8.08"
You can see how precise battery compartment measurements can be helpful.

More precise measurement coming up!

Thank you ever so much for the information Rick.

Once she's got solar and a good protocol for keeping her batteries charged she'll be much happier and so will her new batteries.

Those Group 6V-27 look promising.

Battery sizing and specs are not part of my day to day vocabulary. I chose to put in the Trojans 2 years ago, didn't have any size limitations and never studied up on the subject...

 

[John61CT]

Key words for googling the various standard sizes is "BCI Group".

Nice thing about "standards" there are so many of them.

And of course different mfg may not follow them closely, anyone building custom enclosures should always go a bit bigger, any slack space can always be taken up by shims.

 

[drysailor]

More precise measurement coming up!

Thank you ever so much for the information Rick.

Once she's got solar and a good protocol for keeping her batteries charged she'll be much happier and so will her new batteries.

Those Group 6V-27 look promising.

Battery sizing and specs are not part of my day to day vocabulary. I chose to put in the Trojans 2 years ago, didn't have any size limitations and never studied up on the subject...

Think there's a typo in the dimension given for the 6V27; height should read 9.98, not 7.98. Apologies if I'm wrong...