Hello!
I have a question about charging for my solar set up. It’s as follows: System is 600 W of solar panels, Victron multi +3000, Victron smart solar MPPT 150 charge controller, Touch 50, and two 200 amp hour lithium batteries
My batteries are at 37% state of charge but the BMV and Touch 50 are saying that it’s at 100%.
It’s 20 ish degrees outside and has been cold for quite a while.
What happened:
We had a snowstorm and I did not have the Airstream plugged in to shore power, and the batteries depleted to 40% because of snow covering the solar panels. I plugged into shore power this morning with the state of charge at 37%, and got a fault on my touch 50 saying that the DC Voltage was too high. I lowered the input voltage from 15 to 14 because it kept faulting when it was trying to go into bulk charge.
Somehow, at that point, the system reset and said I have 100% charge on the batteries, when in reality they are sitting at 37%. The problem is the multi plus will not go into bulk charge because it thinks that the batteries are at 100%. It’s stuck in absorption phase. Also no solar charge because it believes it has fully charged the batteries.
How do I change this so that I can charge my batteries to full capacity? I think this has happened in the past but I don’t remember how to change it. If I recall correctly it was some fluke in the system that reset some parameters and I had to reconfigure it all again.
I’ve looked at my settings and they seem to be correct. When would my batteries equalize with the system saying it’s 100%?
Can I change the SoC manually so they charge?
@71airstream 0.5% is too low for some lithium batteries, the choice can be based on observations but at the moment I would not change your setting as this is not the problem, I will explain below, but once sorted see what your tail current drops to and consider reducing it a bit if need be.
Here is what I think happened. The SOC jumping to 100% is not because of erroneous settings, this happens when you have a voltage higher than 14.3V and a current lower than 4% of your battery capacity, so below 16Amps. You had a good voltage but no charging current so it wen to 100% as planned. The question is why you had no charging current.
You have to remember that the BMV is only a monitor, it does not control anything, if it say 100% the charger should just charge anyway based on the battery voltage.
The clue is in your write up
Which I take it to mean 20degF, remember most of us are European so may have skipped that, I do not know but that is -7 degC so your batteries have likely stopped charging because they are cold. The chargers then tried to charge but the batteries would not accept any charge so the voltage went a bit high and no current could flow so the BMV reset to 100%.
The batteries need to warm up to allow charge.
You tell us nothing about your batteries, are they drop in type that do not communicate or do they have some form of communication with the rest of the system. Do they control the chargers via DVCC or do the chargers just run themselves. It sounds like it is the latter, drop ins that do not control the charge.
It was definitely due to temperature. My apologies for the lack of clarity with temp. It was and has been below 20* Fahrenheit. I forgot about the cutoff due to temperature but was still perplexed how it could reset to 100% charge.
Is there a way to keep it from resetting to 100% SoC in these circumstances?
Stay as you are and accept that occasionally you may need to manually reset the SOC if it goes high due to BMS shutdown. There is no simple setting to stop this. The trouble is if you do not notice you think you have more energy than you do.
Increase the charged voltage setting on the BMV to something like 16.0V to stop automatic synchronisation from occurring. The purpose of automatic synchronisation is to remove the drift that can occur in the SOC because the measurements are not perfect. Without it over a period of weeks, the SOC can become less accurate so you may have to adjust it manually. You can also change the charge efficiency factor to try and keep it from drifting as much.
