PV generating and Battery charging in the early morning hours (i.e. at night)

[Sysiphus]

PV + Battery Morning of 31/01/2026

Grid + Load Morning of 31/01/2026

Can anyone explain how the PV is generating, intermitently, even tiny amounts at night? And also why the battery is charging when the load is greater than the amount the PV is generating?

Probably another stupid question, but I'm curious as to why this is happening - it's the first time I've seen it since installation.

Could it be the reflected light from the Moon?? The Moon and Jupiter (According to Stellarium) would have been alongside each other) and been high in the WSW sky. And, in the opinion of the Met Office, the skies over Milton Keynes would have been relatively clear from around midnight. Moon Set for my house (with the panels oriented to the WSW) would have been at about 00:04.

Best regards and grateful for any answers.

Derrick.

[retsplines]

It’s not completely beyond the realms of possibility.

If you view the voltage data on a clear night with a full moon, you will certainly see higher string voltages than a cloudy night or a night with a new moon.

Whether moonlight is enough to start the MPPTs and produce any energy at all, I’m more sceptical about! Not something I’ve seen. I’d guess something else is going on here maybe… but I could be wrong.

[Sysiphus]

Thanks for the reply, retsplines,

As to "something else is going on here maybe… but I could be wrong" it's my thinking also, but I am a little curious about what mechanism is at work.

Given what I've seen in the replies from MaterialBarracuda48 regarding the Battery Cell voltages and the variation shown in the graphs supplied I, as a total solar numpty (but computer and IT past career), would tend to think it's something to do with the firmware/software struggling to make sense of things.

It is, to me, a bit intriguing and it would be nice if Fox could provide an explanation.

Best regards,

Derrick.

[MaterialBarracuda48]

You probably had a visit from NPAS helicopter with 40 Million candle power "Nightsun"

Anyhow, jokes aside, there would not be enough to fire up the Inverter into making juice, no idea why your system was thinking it had solar though.

Here are two HA graphs, to follow on from what retsplines mentioned in his logs.
The Voltage present on Moonless night, is most likely the Inverter sending a little to check string(s) is connected or something like that.

18th Jan, Moonless night

31st Jan, almost Full Moon (1st Feb)
Only a small bump in Voltage, but you can probably see more action as clouds roll over.