quasimatter wrote:
SJ-Chris wrote:
But when I need batteries from time to time, I have been buying from Walmart. You can get what appear to be pretty good 29Ds for less than $100 each which seems like a good value.
-Chris
Quick question - If I want to add a second battery - do I need to replace them both (i.e., get matching ones?) (Current one is 100AH and seems OK - the Walmart one is 85AH - is it OK to connect two different capacity batteries in parallel?).
If you are adding a 2nd battery, most people will tell you that you should make sure both batteries are identical in terms of size, AH, and purchase date. Basically, you should buy 2 identical batteries at the same time.
I would imagine if they were of different sizes/capacity/AH it would present an issue. It could be that two different batteries will likely have two different charging requirements and since there is only one charger charging BOTH at the same time it becomes problematic. Could this be the biggest reason for them to be identical? Quite possibly.
There could be another issue if you are using batteries of different ages. Eventually, the older one will likely die. When it does, since it is connected in parallel with your "good" battery, there is a good chance that it will damage/kill the good battery. For example, lets say that eventually your bad battery stops holding a charge. Well, that is going to drain your good battery since they are connected and soon your Good battery will no longer be good.
So.....If you are adding a 2nd battery I would replace both with new ones at the same time. I suppose if your existing battery is only a year old and you could buy another identical one right now, you'd probably be (mostly) okay.
Note: Walmart has different sized deep cycle RV/Marine batteries. The larger ones are 29D sized and I believe have 100-110AH of capacity. I've seen these recently for $89 each.
Good luck!
Chris
