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Goodwe 5048 utilising too much grid power


Darth Vader
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Good day all, I have a scenario where the inverter does not fully charge the batteries, even though there is sufficient PV output. For example we had an extended power failure earlier in the week with the Wapadrand substation out of action, and when running in off grid mode the batteries are at 100% around about 14h00, sometimes earlier depending on load. However, when connected to the grid, the inverter drops the PV output to match the load with the result that the batteries never reach 100%. Which configuration setting/mode can be changed to ensure the batteries are fully charged, and grid usage is minimized.

See SEMS graphs from off grid and on grid. As usual Goodwe support is MIA, any advice will be much appreciated!

PS both days full sun with no clouds

 

offgrid.png

ongrid.png

Edited by Darth Vader
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I don't see what you're describing. There is only a small chunk missing of the ideal bell curve PV output so looks like all available PV is being used. There simply wasn't enough of it to power the loads and charge the batteries to 100%. I'd say that bite out of the curve was either a cloud passing or a shadow on a panel. In the "off grid" example it looks like it drops at exactly the same time and to the same W shortly before the batteries reach 100% and the PV output drops too match the load - so a passing shadow is my best best.

Now what you may or may not want is for the battery to carry the load when the grid is present when the sun goes down. You'll be able to set the 'back to grid' SOC somewhere after which it will keep the battery above that at all times if the grid is present. Above that it will only charge higher if there is excess PV power available. You may want to set it lower, as it is currently, to minimise your Eskom bill, or higher to always be ready in case there is a blackout.

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  • 2 weeks later...

Looking at the on grid graph. Your house load was high enough such that the battery wasn't able to reach 100%. You probably have pylontech batteries, where the last 11% SOC from 89 to 100% doesn't go up until the battery is very close to fully charged. This in effect then allows the max charge amps to stay higher to allow for faster charging, but basically the batteries need to get to 99% before that 89-100% shoots up fast.

If your house load was lower, the PV production could potentially charge the batteries.

I guess since this post, your batteries might have reached 100% again if there was enough sun. But basically the house load was 2kW most of the day while your generation was about 3kW which only allowed 1kW to be used for charging.

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Thanks for the replies, and I can understand scenarios where the load is too high to leave enough output for charging. However, I attach yesterdays graph. Sun all day. Second picture shows the PV being lowered while in theory there should be more PV output due to position of the sun.

20210804a.png

20210804b.png

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The first graph you posted shows two things: 1) SOC gets to 100% 2) You have easily the lowest loads of all your samples.

OK... so that was a day when there was no grid, right? The load increases in the afternoon, but by then SOC is 100% and solar just has to service the load.

So maybe something on the non-backed up side is causing you problems. When there's no grid then that load gets nothing from your system. I run my Goodwe in general mode, and when there's grid and solar it tries to service everything from the grid, which means that the batteries can take longer to charge.

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8 minutes ago, Bobster said:

The first graph you posted shows two things: 1) SOC gets to 100% 2) You have easily the lowest loads of all your samples.

OK... so that was a day when there was no grid, right? The load increases in the afternoon, but by then SOC is 100% and solar just has to service the load.

So maybe something on the non-backed up side is causing you problems. When there's no grid then that load gets nothing from your system. I run my Goodwe in general mode, and when there's grid and solar it tries to service everything from the grid, which means that the batteries can take longer to charge.

Hmmm... This may be part of the problem but not all of it. There's the clipping that other posters here have mentioned. Now either there was bad weather for a while on those days, or there is a shadow on your panels, or the system is reducing demand for some reason. I don't think it's a shadow because that clipping doesn't happen on your first two graphs. Unless you've started flying flags or something. Observing the panels at that time will confirm the shadow or rule it out.
 

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