I'm NEW to solar with - an off-grid system.
(I also have a grid tied 15kw Enphase system)
current system:(off-grid)
- 600watt array (6X 100 watt panels in series-parallel configuration) Max voltage 60v)
- (1)JavaEnegy 12V 300Ah Lithium Battery, 3.84kWh LiFePO4 Battery, Built in 200A BMS
- (1)Victron Energy SmartSolar MPPT 100V 30 amp 12/24-Volt Solar Charge Controller
- (1)WEIZE 1200W Pure Sine Wave Inverter
I originally had an HQST MPPT Solar Charge Controller 40 Amp. I started having problems with it, and decided to try out what appears to be the best ... Victron.
When my HQST was working well, it was beginning the charging day, bulk charging, then absorption, then float as expected. During that time it would also provide power to whatever load I had provided. That was and still is about 120watt load from two attic fans - currently about 10hours a day.
With the Victron 100/50 installed - with the defaults being used; it seems to ONLY focus on charging. Once the controller gets into 'float' mode, the battery now provides almost all of the power to the load. Draining power throughout the day.
I have adjusted the absorption charge time from the default 2hrs to 6hrs, and a tail of 1amps.
This seems to have "fixed" my issue. But I don't understand how or why?
When I have full sun, the power seems to go to providing power to the load, and everything beyond that goes to absorption charging the battery. PERFECT! Except once it switches over to Float, I now see the power going to the load drop away, and the battery begins draining - to provide power for the load.
This just doesn't seem normal, nor what would be ideal.
I have since, increased the absorption time to 10hrs. (today) and so far it's working as I hoped. As long as I have sun it goes to the load, then to charge the battery if there is an excess.
Obviously, I won't have sun for 10hrs - but it covers the time needed to charge the battery to 100% SOC.
My question IS - why doesn't the default settings provide the functionality I'm expecting?
Shouldn't the mppt controller prioritize the load, then forward all excess to charging the battery as fast as possible? Then once the battery SOC is satisfied - just provide enough power to offset the load being consumed.
Thanks and hopefully my question is clear enough to understand.
