Battery charge slowly going down even with PV input

I just hooked up my EP500 Pro to 2 Renogy 200W panels. Everything is working but after 3 days the battery % is actually slightly less. The weather has been overcast so I understand it will be slow and I’m getting a range of input watts. When it was sunny for a few hours I was getting 280W so it seems like its charging. Any idea why the battery % is going down? Does the EP500 draw down battery power when its “on” and receiving PV inputs?

Yes it will draw power to be on. If ac and dc is switched on also then it can really use quite a bit.

I think 1% per hour. So 4 days from 100% to flat.

This happens on most big inverters on all brands.
Some hybrids are 60w hour idle.

I think somewhere there is a idle load chart for all bluetti series.

If possible get at a minimum of 10x200watt panels.
2x200w if not super sunny is not going to get you much power. Even better get some 500w panels.

Then again just check max input pv you can have with voc and amps first. Im not sure how much it can take.

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Hi @FQRobert , machine will have no-load power consumption.
The no-load power consumption of EP500PRO (standby, AC and DC are not turned on) is about 19.6W. The no-load power consumption when AC/DC is turned on is about 50.4W.

EP500PRO supports up to 2400W PV input. 2 x 200W solar panels may be a bit low for EP500PRO. May I know what is the open circuit voltage of your Renogy 200W panels please?

Thanks for the responses - very helpful
I actually have 5 200W solar cells but have only hooked up the 2 Renogy ones so far. My other 3 are Bluetti PV200’s.
The Renogy spec says the short circuit current is 9.66A.
On a overcast day with some sun I was seeing 180W from both panels and 44 Volts