Should you disconnect the solar panel’s at the port to keep power from reaching a Victron 100/30 MPPT while in storage? Note, I don’t have a disconnect switch. I’ve read conflicting information. Some people say the MPPT will not overcharge the batteries and keeping the panels connected to the system will function like a trickle charger. What is the best practice? I installed Battle Born batteries.
If you have sun in storage…definitively leave it on.
Not sure you will have to contact Battle Born about storing them. How long will you be doing it?
The MPPT will charge it from the rest voltage, which could be around 13.6V up to the charge voltage of 14.4V. It will do this every day. It’s not like an AC charger that is on 24/7 and has a storage mode to stop any discharge at the storage voltage.
It might be feasible to set the charge, float and storage voltage the same, maybe 13.4V to limit the high charge voltage.
Let us know what you find out. The battery will self-discharge, but is very low with lithium and depends on the draw of the BMS.
I store lead acid and AGM, but with an AC charger connected to the boat or car. All my lithium is ESS so is cycled daily.
The self consumption of lithium is so low that you can store them disonnected for a couple of months.
That’s the problem. Battle Born advised me to disconnect the solar. The professional installer, where I purchased all of my Victron equipment from, told me to leave the panels connected and the MPPT would not over charge the batteries etc. It is designed to cycle on and off as needed. He also stated that many of the BB reps don’t know what they are talking about and provide inaccurate information. The batteries have a built in BMS. I will call BB again to see if I get the same answer.
They have a blog here, How to Winterize and Store LiFePO4 Batteries | Battle Born Batteries
Looks like 2-3% a month so you can disconnect everything and let them sit for months at a time.
You can experiment leaving solar on but there is no need charging them from a rest voltage to absortion voltage everyday. The degradation in lithium at a high SOC is measurable. Like I mentioned it might be feasable to lower the charge, absorbtion and float voltages to just below the resting voltage.