Only getting a fraction of battery capacity

[angelakelly]

Two more questions- and sorry to be continually taking up your time.

Regarding stratification, I was reading that the mixing of the electrolyte isn't as much of an issue if your system is in an rv/camper and you are driving around, as normal driving will do the mixing for you. Is that accurate, to your knowledge? If so, that might be a load off my mind as I do a good bit of driving, usually going into town every day or two for supplies, etc- or even just exploring mountain roads.

Second, I've been reading this particular post over and over again: https://www.solarpaneltalk.com/forum...your-batteries. If I am understanding it, it's really just applying as much current as possible and hoping to find a voltage you can set at that will have your batteries charged at the end of the day. Do I have this right? If so, does it damage the battery not to have the absorb stage where the current tapers down toward the end?

[Bala]

This is my opinion based on my experience. I had flooded batteries for 13 years and now have sealed batteries which are frowned upon for off grid on this forum. But my life is as much about convenience rather that $ per kwh to power my house.

You may be able to get a better hydrometer but this one is telling you all cells are the same and you have a reading for discharge after a night. I would be getting them up to a known state of full charge so you have a hydrometer reading for that. Then you can work with Voltage and charge current as your indicators.

As I cant take SG from my batteries I use a combination of things to gauge my battery SOC and what to do for the next day/night. Voltage, charge current, what the weather was and is going to be, if we are going to be home or not. I know that when charging if I have a good sun and my charge current is down to single digits i am good, that will change as the batteries age.

IMO you have a good grasp of what your system is doing. What you do now really comes down to longer term cost. The ideal for long battery life is to minimize discharge and return to 100% ASAP. You can do nothing and budget for new batteries often or you could spend a lot of money on charging systems to extend battery life. Only you know your budget and lifestyle so only you can decide on where to go from here.

I would be looking to connect the car alternator to the house bank for charge while driving. If that can be done with a VSR then it will not be a big expense.

[angelakelly]

Okay, I'm going to mark this as solved.

As Bala suggested, the system hasn't been getting fully charged. I believe I -am- putting about as much in as I take out (100Wh out vs 135Wh in), but the issue is that when the CCs switch to float (they're on a timer, I verified), I'm generally only about 80% charged. So over the last few months, there have been clouds, etc that kept me from replacing all my used power, and I probably started with less than a full charged to begin with.I believe the effect has been cumulitive, a little loss here, a little there, adding up over the past few months, so I'm not hovering between 65 percent charge to 80 percent charge. A 15% usage is much more what I expected to see from a single night. The math adds up now.

Going forward, I'm going to work to start getting more charge in, even if I can only do it once a week or so. I may also switch to a mppt controller or even add another panel, but at least I know what's going on now, and I know what I need to do to fix it- the question will be as Bala posed, how much is it worth it to me? Throw good money after bad, or make the best compromises with what I have and plan better next time? Either way, it's working for me.

Thank you to everyone who replied. I got a lot of good advice, and you were all so patient with me as I grappled with concepts that don't tend to show up when you're looking at pure, ideal numbers.

Angela

[Mike90250]

Stratification and Sulfation do not show up in voltage readings.

Stratification is an abnormally low SG reading, because all the heavy acid settled to the bottom of the cell. Drive around and mix the battery juice up.

Sulfation shows up as reduced capacity (I should be getting 80A but I only get 20A) and a weak SG reading ( because the sulfur is locked up in the crystals on the plates instead of in the acid) It also shows as a "low battery charges right up", since it's really only a 20A battery now instead of 80A