Other Any solar pv/battery ninjas in here?

Had the install completed yesterday. 2 day job and the system was as per the spec in my post above.

I’ve not paid a penny for electricity since the panels were connected to the MPPTs, and only the standing charge for gas too as the iboost solar diverter for the immersion did a great job of keeping the HW cylinder up to temp yesterday and we still had 50% battery at 7am when generation started to ramp up.

I’m running the system in Self-Powered mode until I receive my MCS and DNO certificates so I can move to a suitable export tariff, but I’m very happy with the decision to push ahead right now.

Thanks all for the advice and the push to get it done.

 

I have an Ohme Home Pro charger, part of the deal from the Volvo dealership when we got our EX30 last year (Twin Motor Ultra trim), and we’re on IOG also.

Octopus’ app doesn’t really control the charge point, that’s all done through the Ohme app. The car can limit charging times to specified hours, but you have to manually set that schedule in the car.

The Ohme app/charger is actually pretty good in terms of managing the charge scheduling. I can’t remember if I had to link my Ohme and Octopus accounts or not, but the app is aware of the “off-peak” times and schedules charging appropriately. I can set up “charging routines” and it creates an appropriate “smart charging schedule”. I’ve set it to have the car ready by 0650 on Mondays, Tuesdays, and Fridays, as that’s when I’m usually in the office. If I plug the car in on Sunday afternoon and I have 70% charge already, it won’t put in any charge until the wee hours of the morning; if I plugged in on Sunday afternoon with 5% remaining, it would charge right throughout the off-peak time, and if that isn’t long enough to get to 90% (charge limit recommended by Volvo for “every day driving”) by the set time, it would also charge at peak times in order to make sure it hits that deadline with 90% charge. In reality, the lowest I’ve ever let the car get is 30-something percent; I usually plug in at about 50-60%, that seems to be the optimal level to avoid charging during peak hours. Battery efficiency has gone way up over the last couple of weeks as the weather gets warmer, so I tend to worry about it even less now.

All that “smart charging” malarkey depends on the Ohme charger being aware of the battery’s state of charge. Home AC chargers don’t typically have comms between the car and the charger, so Ohme uses manufacturer APIs & services. Until a month or two ago, that was extremely flaky for me; basically every time I plugged in, the app would complain that it can’t contact the Volvo API. Sometimes I’d be able to reconnect it be removing the API integration and re-adding it, but that usually didn’t work. When that happened, it would base its schedules on an “assumed” state of charge, which was often wildly off. Or it would revert to “dumb charging” mode and just keep dumping power down the cable. But I haven’t had an issue with Volvo API integration for at least a month or so, Ohme must have made some massive stability improvements.

I’ve set the 90% charge limit in both the car’s software and the Ohme app, so that does sometimes cause some conflicts. The app will report that the car isn’t charging as expected because the car’s reached 90% and therefore refuses to charge any more; or the battery is only 88%, or 89%, instead of 90%. It’s really only a minor niggle though, and it’s due to the fact that Ohme is getting the charge percentage from a REST API and the car already knows the state of charge.

 

IOG and Eon smart drive are both using Octopus' Kraken backend for their smart charging tariff. Ohme seems to be different in the sense they do the smart tariff integration in their app. As you said, their app talks to vehicle API to figure out how much to add to reach your target 90%.

For all other charge point integration, you tell the Octopus app how much % to add (not target %) and by what time. It works out charging schedule.

For car integration, Octopus need to know your vehicle location, then it will control the car (starting and stopping charging) once it detects plugging in at home. Charge point must be in 100% dumb mode. You tell Octopus app target % and it will work out how much to add.

Personally, I prefer charge point integration as Tesla seems to wake up more often due to Octopus polling. Tesla also have more detailed privacy permissions, so I know Octopus wants to know vehicle location. But charge point integration will require constantly tweaking the % to add, I get around it by using Home Assistant to set it accurately upon plug in. So in that sense, Ohme's vehicle integration already does that for you (even better if you can restrict Ohme vehicle API access to only access vehicle SoC).

 

I just leave it at 80% and to be ready by 8am, I've never changed it, Octopus controls the charger (Zappi) but my Volvo doesn't have API control. Works great, never fiddle with anything.

Not sure how Octopus new system is going to work with but the random anytime slots were great for us as the car has a pathetic 40mile battery and charges at 3.6Kw so can take 7hrs, was nice to be able to charge it mid day etc, and switch to low rate.

 

Not sure if its relevant but got a quote from Octopus in April for the following
10x JA Solar 450 Watt Panels
1x Fox EVO Series 10kW All-in-One Inverter + 10.24kWh battery
Price included all works as required (planning, scaffolding etc.)
£9865
(Powerwall 3 was an extra £3K to replace the 10kw Fox battery)

 

My parents were doing similar, left it at +80%. Their integration with Zappi magically broke and Octopus app directed them to re-connect to the car. Renault got them to download yet ANOTHER app to connect their car. The app is so bad it was impossible to finish the tariff setup. In the end, my Dad was fed up with so needing many apps and went to dumb Octopus Go.

So perhaps in the case that both car and charge point can be integrated, not strictly setting correct +% would cause Octopus to need you to integrate with vehicle. Brand new customers, if both car and charge point can integrate, would be directed to use the car integration.

I have Home Assistant automatically set the correct +%. Both my car and charge point can integrate, I've not been disconnected yet.