Battery Replacement?

JeffGeb

It's time to replace my battery on my T@B 320 CS-S. I'm planning on sticking with the Marine/RV 24M, but does the CCA number matter? I understand that this is a "cold cranking" figure, but since "cranking" isn't necessary - is there a difference? I'm looking at a battery with a 550 CCA or an 800 CCA. Oddly, both are the same price. 800 sounds better than 550, but is there a difference?

Sharon_is_SAM

@JeffGeb - look at the 20 amp hr rating.  That is a better unit of measure to be able to compare one brand battery to another brand battery.  Cold cranking numbers are irrelevant - they are important for batteries that are used as “starter” batteries.  The very important feature for RV batteries is the ability to run it down and have it effectively recharge.  So, make sure it says “deep cycle”, too.

Here is a link to convert reserve capacity to amps.  https://sciencing.com/how-8681870-convert-reserve-capacity-amp-hours.html

pthomas745

Every battery can have a CCA/MCA rating.  For a deep cycle battery that we need in the trailer, it is irrelevant.  Battery manufacturers send up tremendous layers of smoke to confuse the issue.  You want a deep cycle battery.  This battery FAQ gets into it a bit in their description of what a deep cycle is.

https://www.solar-electric.com/learning-center/deep-cycle-battery-faq.html/

elbereth

Like @Sharon_is_SAM said, the number to care about is capacity at 20h rate, which is listed in “Ah.”  A standard Group 24 is going to be around 80. 

Ignore CCA - that’s the maximum charge that can be delivered in an instant to start an engine.  The design of the lead plates to start an engine quickly is different than to supply power over days and then be recharged - so the “dual purpose” batteries are always a compromise, and will have a shorter lifespan than a true “deep cycle” battery.

If all it has is “reserve capacity” listed you can calculate the capacity in Ah - but a manufacturer that has designed the battery to deep cycle will almost always list the 20h capacity in Ah.  So lean toward the one that is more of a true deep cycle so it has a longer life.