FoxESS Community - Owners & Installers Forum

I have an h1 6kw g2 inverter, 4xEP12 batteries and charge with home assistant through Intelligent octopus Go. After the success of getting the home assistant to work and charge batteries when the off peak tariff triggers I am now getting very strange behaviour in that the inverter is switching to grid import randomly ( my EV is not plugged in) and also not hitting 100% charge and throttling back sometime two hours before the end of the off peak charging period. Any thoughts

The first and third graphs it looks like there was just not enough time in the charge slot to reach 100%, a full charge from 10% SoC of 4x EP12 with a 6kW inverter in a 6 hour slot is a bit of a stretch, you would need at least 7 hours to charge from 10 to 100%. The throttling as you near 100% is most likely the BMS performing balancing of cell charge.
Do you have battery heating enabled? If "charge from grid" is set then if SoC is less than 40% and battery cell temp drops below the trigger level then that may explain your random imports. With 4x EP12 you may see about 1.5kW going into the battery when heating from grid (based on what I see with 2x EP11)

Take a look at this post Jonathan viewtopic.php?p=13135#p13135

And set the date back to the pictures above, you definitely want the Min Cell Temp. and you can then tick in what you want to measure alongside.

As nrb501 has mentioned, you are going to struggle with the 6kW x 6hrs to fill 4xEP12's from empty to full. You can get around 36kWh added, that you see on the 17th, it didn't make 100% SoC. The other times you either had an extra bump from IOG, or just had a little more left at 23:29 that got you to 100% SoC

Thanks super helpful, I have the home assistant working but for some reason my Audi sometimes decides to unlock itself from the charge cable which means no out of hours.

I also have a second 6kw inverter being prepared to be installed. I think I might drop the battery warm up temp trigger by a degree and see if that resolves the discharge gaps.

Let’s see - again as always super helpful and will configure home assistant for temp tracking - by the way can home assistant have remote access or does it always need to be on the home network

Kr
j

VAG group and IOG integration is not the most stable on the planet from my reading on it, if you have IOG integrated to the charger, then that can rule out the disconnects. My IOG controls the charger, and works fine for the most part, it has hiccups, but that's just how it goes sometimes.

Here is a video from Will, it might be worth a look and compare your charge rates vs. temperature. (5m 30s in for chart)
Caveat, these values may have been changed with new battery FW's but you can see rate changes with temperature with HA logs.


That 2nd Inverter might make a World of difference, and you will probably be in a much better position, as long as the power limits are set correctly.

I believe you can check HA remotely, but you would need to look this up for certain, something like Tailscale would be something to look at if you can have this running on HA.

With my EP11 (1.011 FW) on a KH7

5.5 Amps up to 10.9°C
10.0 Amps from 11°C to 15.9°C
13.0 Amps from 16°C to 20.9°C? (I hit 90% SoC so current drops 18.8°C for reference)

This is why I always have my heater start temp set at 9°C as my lowest value.
albie999 the "beta tester it seems" has got a different range on a newer FW (reads as 0.013)
viewtopic.php?p=12235#p12235

If you had the latest FW, you might want to keep yours above 11°C to keep in the sweet spot for your charging needs.


ETA: Tailscale is an option you can add to your HA, so that would make your setup/security much better than opening a port on your router.

Within HA there is a cloud option but is a subscription service costing £65 annually, personally I use a VPN back to my home network (some routers provide VPN server capability).

With the four EP12 on one inverter low temp charge limiting will not be much of a problem unless it gets very cold, at 6kW charge each EP12 will only be getting 4A at most. Keep the temp above 5°C and you should be ok, when you get the second inverter online with two batteries on each using 8 or 9°C as the low temp limit should be fine, the batteries will self heat as they charge.

Thanks everyone, I can see absolutely that the discharge stop happened exactly as my battery warm up schedule switches on so that makes a lot of sense.

J

Glad you found your reason for the charging mystery.