Battery drained fast even though the sun was doing its job

[VictorGen]

I had one of those days where the numbers just did not add up. Solar stayed steady all morning here in Hawaii, no clouds, no weird dips, everything looked normal. But my battery still drained quicker than it should have. I kept checking the app thinking maybe there was a delay or a glitch but nope, the battery kept sliding down.

Nothing heavy was running. Even the usual devices were quiet. It felt like the battery was losing charge faster than the solar could replace it and I cannot tell if it is a BMS thing, a balancing issue, or some hidden load I am missing.

If anyone has had this happen, what was the reason in your case? Trying to decide if I should investigate or wait to see if it goes back to normal tomorrow.

 

[HughB2]

I’d double-check for a ghost load. I’ve had days where something tiny left running all morning ended up pulling way more than I thought. If the solar was steady and it still dipped fast, it’s either a stray appliance or the BMS doing a quiet rebalance cycle.

 

[Skuld_Union]

I’ve had days like that too and it corrected itself the next day. Sometimes the system just has an off rhythm. I usually watch it for another cycle before digging too deep.

 

[Alan]

That’s usually either a hidden load or the system doing something behind the scenes like balancing or inverter self-consumption. In Hawaii, a sneaky one is anything with a heating element or compressor that cycles quietly. Water heater, fridge, mini split, pool pump. If your app shows it, I’d check inverter output vs house load vs battery flow for a 30 minute window and see what is actually pulling.

 

[blu3 li4m]

if it's not a hidden load, then it can be bcs of battery cell imbalance. so, if cells aren't balanced, the BMS can't use all the battery's capacity, making it seem like it's draining faster or not charging fully