Upgrading present system

Re: Upgrading present system

Well guys, I think I'm beginning to get the drift of some things. However, I do have a question that's been plagueing me for sometime. I will have 312 amp. hr. capacity when I finish with this re-installation. Roughly, when finished I will be sending approx. a little better than 9% charge to those batteries. I think that's alright. They are AGM Concorde Sun Xtender 1040T's. The question is: First, don't laugh me off the forum, I realize that these, or any other battery's shouldn't be discharged below the 50% level. I have never gone below 25%, and that was twice in almost 6 years of using these batteries. Are you ready?

Why does one need to worry about charging to the full capacity when they're only using 1/2 of the capacity? In other words, is there any reason I can't calculate my usage, and the recharge that should follow to charge only 145 or 150 amp. hrs? After all, that's all I've used. I alway's attempt to replace what was taken out, and have succeeded thus far. So please explain the reason behind the math calculations to recharge the battery's at 100% of it's original capacity.