Costco 24DC Interstate Battery

[gypsydan]

Does anyone have any experience with the Costco Interstate 12 volt 24DC Battery ?  How reliable are they?  How long do they last?  Are they true Deep Cycle batteries? 

Since they are marketed as Marine/RV bateries, I'm tending to believe you should not discharge them below 50%.  I'm just beginning to learn about the differences in batteries, so am not clear as to which batteries should not be discharged below 50%, and which can be discharge down to 80%.

Interstate also markets the 24DC battery.  Nowhere on fact sheets at Interstae or Costco does it state the batteries AMP HOURS, but in talking with Interstate I'm told it is an 81 amp hour battery.  This seems unusual, since Costco is sellling them for $73.00. 

I'm therefore confused as to whether or not the 24DC battery, at $73.00, is a good buy and will last more than a year as compared to batteries in the $200 range. I'm looking at the 24DC as the battery compartment on my class C will only hold a group 24 battery. I am planning on putting solar on my RV to help in keeping them charged.

Thank you in advance for any help.

[Yarome]

The 24DC 12v is a hybrid marine/deep cycle (vs. true deep cycle) battery with... if I remember correctly... ~60ah capacity. Typically, any battery that has a CCA rating on it is going to be a starter or hybrid.

Let me double check.....  Yup. 58ah capacity (140min@25a).

Any wet cell battery shouldn't be discharged below 50%SOC in order to maintain optimal battery health. That's not to say that you "can't" draw them down more than that. If you're just looking for a single 1-year "trasher" battery then, really, anything goes. I would still try and get something with a higher capacity (or 2 lower capacity batteries)... basically...  buy as many ah's you can for your dollar and then don't worry about SOC's. The main thing being to charge them immediately after use and not "leave" them severely depleted.

Bang for your buck-wise... it's not a great value, but if the bucks are limited it's perfectly fine to get whatever you can afford and keeps you rolling, right!?

Ie., 2x $73 60ah DC24's ($146 total) would get you ~120ah (60ah@50%). Alternatively, 2x $90 6v GC true deep cycles ($180) would get you 220ah's (110ah@50%). So... for $40 more you nearly double your ah capacity and  get a longer term battery. The flip side....  you can't run a single $90 6v battery by itself and if you only have $70 in your budget it's moot anyway. You buy whatever will keep the lights on. 

Edited March 16, 2018 by Yarome

[Yarome]

First step would really be to measure out the battery compartment to see what will actually fit in there. A group-24 is going to be a about an 11x7x9.5 battery, but odds are... it will hold something bigger.

Edited February 8, 2018 by Yarome

[gypsydan]

8 minutes ago, Yarome said:

Let me double check.....  Yup. 58ah capacity (140min@25a).

Yarome, may I ask where you read the 58ah, as the mfg said they were 81ah?

[Yarome]

45 minutes ago, gypsydan said:

Yarome, may I ask where you read the 58ah, as the mfg said they were 81ah?

Not at all! Specs on the 24DC 12V are listed with a reserve capacity of 140 minutes @ a discharge rate of 25amps. Quick and dirty math.... 140min/60min =  2.33hours. 2.33hrs@25amps = 58.25ah's capacity.

[Yarome]

I'll add... for the "techie's"... the more accurate way to get to AH capacity of a wet cell is RC x .4167 (assuming a standard 25a 80degrees spec), but in smaller batteries it doesn't make much difference. Ie., 58.25ah's vs. 58.34ah in this case.

Just sayin' before someone points out, "that's not how you do it!". 

[gypsydan]

Thanks for all the input, Yarome. I ended up getting 2 grp 27 batteries, until I can find a way to install agm's or golf cart's. They will last for the summer, at least.

[Yarome]

13 minutes ago, gypsydan said:

They will last for the summer, at least.

They'll last quite a while longer than that. As long as your needs are being met and keeps you rolling within your budget... they're the "perfect" battery! 

[oldjohnt]

On ‎2‎/‎8‎/‎2018 at 12:45 PM, Yarome said:

"that's not how you do it!". 

Gee Yarome, "that's not how you do it"   LOL LOL   Just kidding

I have to agree with your good advice, those relatively cheaper batteries labeled RV/Marine or those that talk about CCA and never Amp Hours, are often semi and NOT true Deep Cycle like a golf cart battery which are described in Amp Hours moreso then CCA. Their purpose is to have sufficient CCA to crank a big marine engine and then run the trolling motor a good period. 

Dan, That being said in my younger or broke days (prior to extended dry camping) I ran plenty of those RV/Marine batteries and got by fine, so once installed I wouldn't bother to upgrade until such time they totally failed (may be a long time if kept charged up and not discharged over 50% often) orrrrrrrrrr you upgrade and plan on a lot of extended dry camping.

That's my story n Ima stickin to it

John T

[hemsteadc]

On 2/8/2018 at 6:41 AM, gypsydan said:

.  I'm just beginning to learn about the differences in batteries, so am not clear as to which batteries should not be discharged below 50%, and which can be discharge down to 80%.

80% is for Lithiums.

[bigbillsd]

And for true deep cycles like my Crown CR260 batteries.  Factory said 750 cycles @ 80% draw down.  Bill

[Yarome]

2 hours ago, bigbillsd said:

Factory said 750 cycles @ 80% draw down.  Bill

Although there are a number of factors at play, the main reason it is recommended to not discharge "any" deep cycle (wet cell) battery below 50% is because that is the average SOC that most deep cells will be capable of maintaining maximum expected life. Beyond that, most batteries will start to have an increasing rate of loss. Not all batteries are created equal though. Some will only maintain optimal life capacity above 60% SOC. However, it's easier to use a general "rule of thumb" and the additional rate of decrease is still "marginal" considering that, in the course of using the 50% "rule", folks don't typically drop to 50%SOC. They are more likely to begin a charge cycle (or have their charger thresholds set) at 50+ (ie., 55 or 60). That gray "marginal" range is less frequently visited and helps mitigate unnecessary losses.

What we see is, for example, a 3000lc battery dropping to 1500lc's (50%) @ 50%DOD. If we drop that down to 25%SOC (75%DOD) we wouldn't see 750lc's, but likely only 680 or less. The higher the DOD the faster the lifecycles decline. More importantly... the total AH capacity will also decline at an accelerated rate so it's really a double edged sword.

Of course you can discharge them down to 20% (80%DOD). Just realize that your battery banks working AH capacity and lifecycles will decrease at a much faster rate than staying above 50%.

Talking Crown's CR260 specifically... specs show 3000@20%DOD, 1500@40%DOD (50% of max), 1200@50%DOD (40% of max). Ideally, what you would want to see in a true deep cycle would be 50% of max rated lifecycles @ 50%DOD/SOC. That doesn't make them a bad battery, but it might be something to keep in the back of your mind and lean more toward staying in the 40%DOD range for optimal life... and in practical terms... adjust your charger thresholds accordingly.

[billr]

Good info Yarome! Thanks

[bigbillsd]

As I said, Crown states we would get 750 cycles at 80% DOD.  I will probably never get mine down that low, but it piece of mind knowing that if I had to I could keep doing it every day for more than two years.  And yes, if brought them only down to 50% DOD i would double the number of charge cycles it can handle.    -Bill

[Gap]

How do I charge that hybrid Costco battery? My charger has four settings: Standard, AGM, Deep cycle, and Gel. The charger’s directions indicate that using the wrong setting could shorten the battery’s life. Isn’t Costco remiss in not ID-ing their product?