Ac200p charge % dropping when off

I charge my ac200p via 3 series solar panels and it gets to 100% around 1pm. I turn it off till after dark. then I power (via ac) a 35 watt LED light for a few hours. when I go to bed, and turn the entire unit off, it reads about 96 % which I feel is reasonable given the inverter is running for 2 hours. when I power it on on the morning, it reads 68 or 69%, despite being off all night. am I mistakenly putting it on standby and the inverter is running all night? how do I tell? what is standby mode? I believe I hold the button long enough to power it off.
thanks for any help

addendum: today after another disappointing power drop overnight while off, and a couple of espressos, it was at 19%, so I turned it off, dragged it over to my panels, hooked it up to the solar panels, and it came on at 78%! so why am I getting these unreliable readings of soc?? thanks

It sounds like you are not turning it completely off. Hold the power button down for five seconds and see if your results change. A short press puts the unit in standby.

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If you haven’t done a full discharge and full charge recently try that, it can recalibrate the soc meter. I do mine at least once every 2 months or when it starts looking whacky. Even then its not very accurate (10-15%) so I rely on an external watt meter to keep track of my soc.

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yeah, interesting. after your suggestion Eric, and starting from the “0” state where it was suddenly (suspiciously for no apparent reason), i charged it via the brick and only was able to put 1100 watts into it as measured by an external watt meter. then i discharged it completely using an electric toaster oven (pulling around 1400-1600 watts). total charge output to the oven was 1650 watt hours as measured by same watt meter. so…this must be drawing on cold fusion power or something - output >input? or the soc reading was just wrong. which is backed up by the battery voltage reading (when it was at “0”% charge, battery voltage was 52.7 yet soc was 0??.) when i fully discharged it after the charge the battery voltage was 47.9 at 0 soc.
this next charge cycle is already using 1775 watts and the battery is at 75 % so much more reasonable numbers. hopefully the full charge /discharge cycle will make it as reliable as it used to be. will update.

Yep, I typically get about 1,650 wh out of mine as well so it sounds like your batteries are fine.