I have 2x 200Ah Dakota litium batteries. The solar panel leave me at the beginning of the evening with 85% full
At night I draw 200w combined between ac and dc loads - fridge, freezer, fans.
Is that why I end up at 0%?
asked
Lithium battery running to empty
Assuming 12V at the battery.
200W/12V gives a drain current of about 8-9A.
200Ah * 85% is 170 Ah.
170/9=19 hours (approx).
So unless you have very long nights, the answer is no. Basing the calcs on 12V gives a shorter time range than actual,
You'll need to confirm the actual loads are about 200W. Also whether or not the 85% figure is correct. If it's not coming from a properly configured battery monitor or smartshunt, good chance this is not correct.
We are talking about 2 batteries, so approx 38 hours might be correct.
As far as I could see, the 200Ah Dakota litium batteries do not have a BMS with app. So you can not check or change anything in the battery's settings. Like @kevgermany wrote; you might need to focus on the Victron Smart Shunt, or battery monitor, if their settings are correct for the batteries used. This also counts for the charger and MPPT, to check if they are correctly set to LFP battery.
If you are using a Victron Smart Shunt, and the settings are changed in the correct way, then charge the batteries till 100% SOC, so that the Smart Shunt can reset it self, and start monitoring correct.
unfortunately I messed around with the SOC before reading this and set it to 100% in the settings w/o knowing if the batteries were actually fully charged...
See my reply in your other thread. I'm going to edit it to say smartshunt instead of BMV.
