jdc1 wrote:
pianotuna wrote:
Unless the batteries are almost unused, adding a 3rd battery may not be a great idea. If you can afford it, replace all three.
Or, put the 4 older batteries on one bank, and the 2 new batteries on a separate bank.
I believe all the batteries are about 14 months old. To me, that makes them relatively newish. Assuming they are all in good health, I'm willing to add a 3rd battery which is brand new (same manufacturer/size/etc). If this new battery ends up eventually dying 14 months earlier than it would have normally because one of my existing batteries goes bad and takes the other two with it, I'm okay with that. When that time comes, if I still even own this RV, I'll replace all 3 batteries at that time. I've been having pretty good luck buying Group 29s (RV/Marine Deep Cycle) batteries from Walmart usually for ~$90 each which to me seems pretty cheap.
I believe the "only put batteries of the same age" mantra is really trying to protect people against a scenario where you might, for example, have one very old battery that is about to die. If you add in parallel a 2nd brand new battery in that scenario, it is likely that the bad battery will very quickly kill the good battery and then you pretty much just wasted money on that new battery.
-Chris
