replacing 6V deep cycle marine trailer batteries

[rvshrinker]

Hello, my trailer purchased oct 2017 has its original two “GC2 Deep Cycle Extreme” Interstate batteries “115 mins @ 75 amps 225 Ah @ 20 Hr” wired in series and even though we haven’t had any performance problems I figure it’s time to replace them. 

Costco has 3 options, i believe one doesn’t fit but i’ll know better when I get into the store.

The first option is “24DC AGM” 930 MCA and from what I read I do not need the benefit of AGM and don’t need to spend the extra money.

The second option is “24DC 700 MCA” and the third option is “27DC 750 MCA” both Interstate batteries. I think the 27 is not the right size, so I think 24 is it.

Is this the correct batter replacement? The info on the old battery “115 min @ 75 amps 225 Ah @ 20 hr” isn’t comparable to what’s on the Costco battery.

I don’t know why it’s bolding, sorry for that.

[StirCrazy]

the costco GC2 are 208Ah@20h so a very comparable battery to what you have.  I wouldnt install new batteries untill you get the feeling they are not holding as much power though as a well maintained ^V deep cycles can last a lot more than 6 years.  

[rvshrinker]

Thanks, I did go ahead with the new Costco ones since we usually dry camp and finding out the batteries are dead could be a real issue. The old ones had also run dry a couple times before I knew how to maintain them properly. With the new ones I water them monthly and will keep them in good shape.

[Grit_dog]

Golf cart batteries aren’t rated in cranking amps. And Costco only has one golf cart battery. 

[rvshrinker]

thank you!

 i've been happy with these Interstates, lasted six good years with minimal maintenance and gave us up to five days off grid. where can i find something comparable? 

[mkirsch]

You can find something comparable at any Interstate battery dealer. In fact you should be able to find the exact model batteries you currently have, or an improved version.

[opnspaces]

I looked again and I see that Costco does indeed list more than one GC2 battery. But all of them are little ATV batteries aside from the one 6 volt I linked and an 8 volt which you can't use. If you walk into Costco and look at the batteries on the rack it should be obvious which one you  are looking for. It will say golf cart on the label and have 3 water fill caps and it will weigh almost twice what the 12v batteries weigh.

[opnspaces]

If you're looking to stay with the 6 volts like we've been discussing in the other post then the above are the wrong batteries as they are 12 volts and would have to be wired in parallel not series. Costco typically only has one 6 volt battery, the GC2. I'll link it but if the link fails, search Costco for GC2 battery.
Link