Newbie here. I’m on economy 7. I’ve set my battery to charge overnight at off peak rate. It stops charging at 7am when it starts supplying the house. Today, when demand was low around 10am and my panels were covering house use, my system started exporting to the grid rather than topping up the battery which was by now half depleted. If I have excess from the panels I want them to charge the battery not export. How can I do this?
Hi - Have you looked at your settings on the inverter page on the portal? 'Eco' should be enabled. You might also want to check that the Timed Export section is disabled. You might also want to look at Remote Control and see what the General - Export Power priority is (choice between Load First, Battery First and Grid First) On mine this is usually set at Load First.
HTH
Hi, thanks for the reply. Eco was enabled, Timed export was disabled but there was nothing set for Power export priority. I’ve set it to Load First and I’ll see what happens! Cheers 🍻
Kim911t is this a new install? Or has it been behaving correctly for a while and has suddenly changed?
Hi, this is a new install, I’m trying to get to grips with how it works. I was expecting any PV generation the house isn’t using to top the battery up. I have the battery set to charge 1am to 7am whilst I’m on off peak. I also set timed discharge to 7am to midnight so that the battery didn’t power the house while I’m on off peak. The battery had been powering the house until about 10am during the coldest weather, then the grid took over. But as the temperature has risen and the PV has started powering the house, if the PV generation is more than the house needs, the battery seems to be discharging to the grid… I’m not on an export tariff yet as I’m trying to work out which will be best for my set-up.
I have smart electric heaters so daytime use is likely to be quite high… if I’ve gobbled up lots of off peak energy I don’t want to be exporting it back to the grid…
Kim911t I also set timed discharge to 7am to midnight so that the battery didn’t power the house while I’m on off peak.
Just fyi that's not really necessary - battery cannot power the house while on grid charge (even once it's full - it will hold charge until end of timer).
Kim911t But as the temperature has risen and the PV has started powering the house, if the PV generation is more than the house needs, the battery seems to be discharging to the grid…
I'm not seeing that on the graph you've posted. There's a few small spikes of export, but that's usually just a sampling error - measurements are taken every 5 mins, and are snapshots, not averages over the last 5 minutes.
DD Thanks, so is the grid export from the PV? If so, why didn’t it top the battery up rather than export to the grid?
DD That’s odd, mine definitely did… perhaps my system is an hour out? It was set to charge battery until 7am but started powering the house around 6am…
Kim911t That’s odd, mine definitely did… perhaps my system is an hour out? It was set to charge battery until 7am but started powering the house around 6am…
Notice, though, that battery was fully charged by around 3am, but the house continued to run from grid rather than battery, even though battery was no longer charging
And it's odd that after it started discharging, it then switched to charging again. Was that just before 7?
I'd experiment a bit - change charging end time to 630 or 730 and see what happens.
It started charging at 1, so that seems to rule out a clock error.
DD Kim911t That’s odd, mine definitely did… perhaps my system is an hour out? It was set to charge battery until 7am but started powering the house around 6am…
Notice, though, that battery was fully charged by around 3am, but the house continued to run from grid rather than battery, even though battery was no longer charging
that’s exactly what will happen. If you set a charge to run to 7am then the battery will charge up to full and hold the charge at that level until the end time you specify. The house will run off grid whilst there is a charge active
Kim911t Thanks, so is the grid export from the PV? If so, why didn’t it top the battery up rather than export to the grid?
Solar rarely exceeded home demand on that chart. When it did prior to noon, the excess was going to the battery, not the grid.
The brief periods of export appear to coincide with abrupt drops in consumption - the inverter can only respond to changes after they happen, it cannot anticipate them. So when your heating or kettle turns off, it takes a short while for the inverter to notice and reduce battery discharge rate. (The house can't pull what it needs from the battery - the inverter must actively calculate how much DC to convert to AC to cover the inferred consumption, and that varies from second to second. Accidental export happens when consumption drops but inverter has not reduced how much AC it is generating.)
Thanks guys, that all makes sense. Today it all worked as I hoped and the excess charged the battery. I can see there will be anomalies when appliances turn on and off and the demand changes instantly.
Now I just need to work out which tariff and supplier will suit my setup best! Kim
geoffreycoan The house will run off grid whilst there is a charge active
Which is more efficient that running off the battery as there would be 2 lots of conversion losses. This is exactly what I do - I keep the battery on charge for the whole of the cheap period so that the house (and any appliances that were load-shifted) will run directly from the grid