Hi, we had solar pv panels installed with battery storage. Since the installation the batteries have been charging to about 20% throughout the day and dropping to about 10 once the sun sets to charge the house. They have never yet hit more than 20%. During the day when the sun is strong we see that 10-15% of the solar power is released to the grid instead of charging the battery. Sometimes we also see that even when pv are producing more power than the house consumes, the battery taps power from the grid to charge. We have already disabled the grid charging in the growatt app setting, but it's still happening. Is that normal?
Is it normal for a pv installation to send some power to grid despite battery not being fully charged?
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johnb2713
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What do you have export set to?
This is difficult to judge as the solar power in these cases is incredibly low. Much easier if you are generating say 3 or 4 kw. This leads me to wonder whether your install is incredibly recent, perhaps? In the images posted, as far as I can tell, the battery would not be gaining enough power to significantly recharge from solar and would indeed need grid help. You can't sweat the 0.1 thing. BTW, that is just margin for error.
The install was done mid Jan, but there was a problem with the wiring which meant the battery was not charging at all from pv. This only got sorted out last week, so we are monitoring the situation and trying to understand if there are more problems to worry about. I know it's still winter but is this low charge (about 1kw) normal for 12 panels?
johnb2713
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I have 10 panels on a south facing roof
(+6 west facing), the 10 south facing are currently generating 2.8kW at 09:30 this morning.
johnb2713
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This mornings graph
Sorry, just seen the question. We have export to grid set to disabled.
johnb2713
Well-known member
If you have it set to disabled it will always import a small amount of energy. If you set export enabled with just a small amount it will hover around zero - small amount of export and a small amount of import.
Thanks everyone for the feedback here. It seems that it's normL that there is a bitnof residual grid charge and release. What does seem off is how little energy our pv installation produces. As of right now our 12 panels have generated 2.6kw in the entire day, while John seems to have gotten that same energy by 9:30 this morning already. I think its worth getting an independent installer come in and take a look at the whole setup.
johnb2713
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Have a look at the info logged in the inverter, it may give you an idea whats going on.
So far today, my system has generated 19.1 kWh
We have two pv cables coming from the roof, one from the back and one front the front. If I interpret this page correctly it seems that maybe one of the sides is generating 0. I've asked this of the company who installed the panels, but they just said they see nothing unusual. We've been messaging back and forth for two months now. They sent an engineer once and he did find a fault with the batteries wiring. I do think there are more problems but they are refusing to take a proper look again.
What are the roof orientations?
My own array, 3.3kw peaked at 2.6 today, and it's not at it's best time of year yet
My own array, 3.3kw peaked at 2.6 today, and it's not at it's best time of year yet
johnb2713
Well-known member
That really isnt going to work well.
We don't have the full details and it could be your panels are daisy chaining. With winter sun your only dragging from a small % through the day. If this is the case your winter production is going to be very poor. Depending on your tariff you may be better joining a supplier like octopus go and taking advantage of the low over night tariff to charge the batterys during winter. My 10kwh battery's charge from 1230am to around 3am and are fully charged. These then last approx 12-14 hours (my base line 0.5kwh ish) of the panels don't add additional charge
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