I have two Sunpower 50-watt panels connected in series, creating a 100-watt setup. I mounted them to a DIY frame that I can place on my small Teardrop trailer and remove and place in the sun if needed. The battery is a 240 ah lithium. When I first put this to use in 2022, I got a solid 75 watts plus on sunny days when positioning the panels at optimal angles toward the sun and, on numerous occasions, got it up to over 90 watts. Once the battery reached full, the system would kick into the Absorb state and radically reduce the wattage going into the battery, which I believe is normal behavior. This summer, I’ve not been able to get more than 40 watts from the panels, no matter how well I’ve placed them. Then, this last weekend, I had my battery fully charged before driving to a 5-hour destination. While driving on a full sunny day, mid-way there, I checked the app and noticed the battery voltage was 14.5 volts and still the Bulk state. The wattage coming in was around 30 watts. I’m not sure what this means, but I think it means it’s not operating correctly. Note that the system seems to top off the battery enough each day, so reserved power storage isn’t an issue. I run a Dometic CFX-55 12v fridge, charge our phones, and use normal LED illumination in the evening hours. I have Firmware vs 1.64. Thoughts? Thanks, Devin
If the battery voltage is 14.5, then it looks fully charged.
The system can revert to bulk state if the charge is interrupted or the battery voltage drops briefly.
Thing to do is use Victron Connect to check the chargers voltage parameters.