I had our RV dealership install 1450w of solar panels, 2 LiFePO 460amp batteries, a Victron MultiPlus II inverter/charger, 2 Victron MPPT solar controllers, a Victron Smart Shunt 500a, and the Victron CCGX monitor screen. We started having issues with the system on our first trip after install.
First, the Victron CCGX monitor screen would not show the same SOC% (state of charge) for the batteries as the VictronConnect App showed. We overnighted several times without connecting to shore power in order to try out the batteries and observe the rate we were discharging the battery bank. The readings differed by a little over 10%. After connecting to shore power to recharge the batteries, both readings would eventually get to 100% SOC.
One night we decided to disconnect from shore power to try out the new system again. Before disconnecting, SOC was at 100%. We started our Furrion A/C (13500 btu) on FAN mode only. Our plan was to make sure we could run it all night. We also watched a little TV before turning in for the night. At 4am the next morning we were awakened by an alarm on the CCGX monitor panel. It indicated a low power warning and then ALL power to the RV went off.
I hooked up to shore power and power was restored to the RV. The monitor showed a SOC of 86%. I then checked the VictronConnect app which showed a SOC of 58%.
Questions: 1. Why the difference in SOC %? 2. Why would we get an alarm (and power shut down) when SOC is 86%, or even 58%? I was under the impression lithium batteries could be safely discharged to 0%. 3. How could running the FAN only that night for roughly 7 hours drop the SOC from 100% to 86%?
I am a novice at RVing and certainly on the topic of Solar and Lithium systems. Unfortunately, I am not getting much/any help from the installer. Ideas, comments, and mockings are much appreciated!