12 Volt Switch

I'd suggest to visit Walmart and get a marine/deep cycle battery with number designation "DC-**". The "DC" designation has larger plates inside than the other Walmart offerings. Try to get the largest battery that will fit the case. While you're there shop for a battery master disconnect switch. You want this so you can flip a switch rather than disconnecting a battery terminal every time you put the trailer in storage. Without disconnecting the battery, the trailer's parasitic loads like circuit boards, radio memory. and alarms will suck your new battery dead in a week or two. Do that a few times and your new battery will be your old dead battery.

SRM24 is the size (srm is an Interstate designatIon, I believe, sizes are spec'd as Group (G). Common deep cycle 12 volt sizes are G24, G27, G29, and G31.

For deep cycle use, you are interested in the amp hour capacity, mca, or marine cranking amps is really not directly relavent.

The 31 is physically bigger? It looks like it fits in a plastic housing and I don't think larger would work?

what about 24 volts? is it not 12 volts? what is srm?

where does 690 mca come into play?

cs2kplus wrote:
I'm gonna show my dumbness with electronics now......why are the batteries 24V???

srm-24 means 24 volts right?

550 cca i think is for non cranking

690 mca - is marine....yada yada....don't get it.

550 cca means "cold cranking amps"


You have a Megatron, 12 volt, RV/Marine dual purpose battery, group size 24.
Replace it with a group 31, if you have enough space to accommodate it.

I'm gonna show my dumbness with electronics now......why are the batteries 24V???

srm-24 means 24 volts right?

550 cca i think is for non cranking

690 mca - is marine....yada yada....don't get it.

makes sense Dakota. Thanks so much for the great info!

cs2kplus wrote:
what does deep cycle mean?

Deep cycle battery:

A deep-cycle battery is a lead-acid battery designed to be regularly deeply discharged using most of its capacity. ( No more than 50% of it's total capacity is best ) In contrast, starter batteries (e.g. most automotive batteries) are designed to deliver short, high-current bursts for cranking the engine, thus frequently discharging only a small part of their capacity.

There are also AGM type deep cycle batteries.

You can purchase any RV/ Marine type deep cycle battery & that will be adequate for your needs. If possible get a group 31 size, if you have space for it in the battery compartment. It appears that the current battery you have is a group 24, the smallest.

what does deep cycle mean?

Chris Bryant wrote:
You basically want a deep cycle- I would look at Trojan first- a good, solid battery, not the best, but possibly the best price/performance. Look here for a nearby dealer who will likely be a battery place, and have a large selection.
The battery you have is an Interstate- also OK, generally. You can find their dealers here.
Walmart does have OK batteries for an OK price, and there is a Walmart within like 2 miles of everywhere now :).

I bought a Walmart battery a few years ago. It's was identical to the Interstate it replaced with the exception of the color and stickers. It's the same battery.

Where is the converter?

If you have a single door you open to reset a breaker or replace a fuse odds are right behind that panel in fact part of it.,

If you have two Separate doors one for breakers one for fuses good luck

If you have the one door set up and there is a make/model on the door.. Please post what they are.. IE: Parallex 7300