Batteries discharging to 11.9v at night

[Tjbrancher]

Hello. I'm new to solar and have set up my own system. It's been running well for a year, but now it's discharging to 11.9v even when not in use. The panels are still hooked up and will charge to about 12.2 during the day but by night falls to 11.9.

My configuration is:
2 x 100w Rich Solar panels
40amp mppt Controller
4 x Mighty Max Battery 6V 200AH SLA Battery (purchased new on Amazon)

Ghost Load?

Thanks for the help

 

[Bob B]

Charging to 12.2 is not nearly good enough .... you are operating those batteries in the bottom end of their charge. That will soon ruin SLA batteries.

 

[RCinFLA]

If you have been running with such low state of charge for last year your batteries are likely sulfated and yielding less capacity.

 

[Tjbrancher]

They've been holding at about a 100% for a year or have recovered quickly to 100% after running a Maxx fan and led lights for about 5hrs. This issue is recent. Could my settings be wrong on the renogy app I use to monitor? I didn't change from factory settings.

 

[RCinFLA]

You should be charging to at least 13.5v daily and a good absorb at 14.2-14.5v at least once a week.

Two 100 watt panels are not enough for 12v 400 AH battery. You should have 4 to 5 times the amount of PV power.

If using an inverter, do you know what its no load idle power consumption is?

 

[Tjbrancher]

I don't understand why it's no longer charging to those voltages? It was doing fine. I'm pretty sure I oversized my system to what I'm actually using. It was holding at 11.9 for about a week. I didn't use it cause I didn't want it to drop any more. Yesterday it was charging again. Faulty controller? I'm so out of my element here.

 

[Don B. Cilly]

If you've been doing that for a year, your batteries are probably giving up.
For lead-acid, 12.2 is not 100%, it's more like 60%

 

[Tjbrancher]

It's been running fine for a year. I put the system together last September. Within the last two weeks things have changed to my current desperate condition.

 

[boondox]

It seemed like it was running fine. But you were quietly giving your batteries a Sh!tkicking. The were dying a slow painful death while you went about your business. Up your charge levels as recommended by the manufacturer. You might try a light equalization charge even though you aren't supposed to with SLA but you have nothing to lose. If not, get some more batteries. And as also mentioned, I'd throw a little more solar at the problem too.

 

[Don B. Cilly]

It's been running fine for a year.

No, it hasn't :·)
It's been running - from what we can gather - between pretty low and pretty dismal SOC. That is supposed to damage the batteries - and probably has. Being new, they have a good chance of recovering - at least partially. But you'd better find a way to charge them properly, soon.

 

[Don B. Cilly]

As to why they're not charging properly... you say you "didn't change from factory settings." What settings did you charge at?
Because, with 200W of panels, in summer, you might have got a decent charge often enough. This season, probably not.

 

[Tjbrancher]

No, it hasn't :·)
It's been running - from what we can gather - between pretty low and pretty dismal SOC. That is supposed to damage the batteries - and probably has. Being new, they have a good chance of recovering - at least partially. But you'd better find a way to charge them properly, soon.

So if it's been holding a 100% or near 100% charge for a year; that doesn't mean it's been charging correctly? I need a degree for this stuff! ?

 

[RCinFLA]

Unless you have a generator or grid to get out of deficient battery discharging, with such feeble amount of PV capability you are on a downward spiral that will kill the batteries.

 

[Tjbrancher]

As to why they're not charging properly... you say you "didn't change from factory settings." What settings did you charge at?
Because, with 200W of panels, in summer, you might have got a decent charge often enough. This season, probably not.

 

[Tjbrancher]

Heres the settings. I did change battery type recently cause I noticed it was set to "flooded"

 

[Tjbrancher]

Unless you have a generator or grid to get out of deficient battery discharging, with such feeble amount of PV capability you are on a downward spiral that will kill the batteries.

Does consumption not play a part? My set up is DC only and I'm producing more than I'm consuming, so I think.

 

[RCinFLA]

Two 100 watts panels is appropriate for 100 AH 12v battery. Having larger AH batteries just means more self discharge power to replace at 10% capacity per month loss. It is human nature if you have the battery capacity you will use it from time to time. Once you do it will be very difficult to get out of the deficient hole with insufficient PV recharging capability.

 

[740GLE]

You have a shunt to prove your using less that you charge?

What’s the whr your getting from PV array on a good day? You’d notice a sharp decline if something recently went south with a connector or something.

Seeing the voltage hasn’t been getting up to >13v each day from day one you may have caused issues.

 

[Tjbrancher]

Two 100 watts panels is appropriate for 100 AH 12v battery. Having larger AH batteries just means more self discharge power to replace at 10% capacity per month loss. It is human nature if you have the battery capacity you will use it from time to time. Once you do it will be very difficult to get out of the deficient hole with insufficient PV recharging capability.

Does that mean I need more panels or less batteries?

 

[Tjbrancher]

You have a shunt to prove your using less that you charge?

What’s the whr your getting from PV array on a good day? You’d notice a sharp decline if something recently went south with a connector or something.

No shunt. The controller tells me what's coming in and what's going out. Is that good enough or do I need a shunt?