FoxESS Community - Owners & Installers Forum

Batteries drained this morning by charging the EV, an unintended consequence of removing the Ohme Pro price cap. Anyone else has this?

So.. previous setup (which I’ll probably revert back to):-
IO smart charging via Ohme. Price cap set at 7.5p. IO send the smart charge schedule to charge the car between 23:30-05:30.

Fox batteries set to charge between 23:30 and 05:30.

This has worked well. It does mean if the car is completely empty it may not fully charge but that’s not an issue for us.

New setup. Ohme updated their app in past few weeks and the advice was to remove the price cap setting as this will extend your off peak 7.5p period if required to ensure the car is fully charged up.

What’s actually happened is that the car wasn’t fully charged up by 05:30 and the car has taken the remaining juice it needed from the battery! Arghh!

Obviously the Fox setup is to charge the battery between 23:00 and 05:30 and NOT to discharge during this period. Works as intended. However it started discharging as soon as it got to 05:31 and finished off topping that car up due to this price cap setting in Ohme.

I’ve now switched the Ohme price cap setting back on which should resolve the issue. I can’t think of another way around it?

Other than what you have done, there are only 2 other ways to 'fix' this - both take a bit of work.

If you have a home assistant it is possible for it to dynamically set charge periods when it detects your Ohme charging, I know quite a few people that do this with EV's / Ohme chargers.

But by far the simplest option takes the most work (cost) - you need an electrician to move your EV charger feed so that the inverter doesn't see it anymore - this is usually done by splitting the live feed from the smart meter on a henley block and feeding the house and inverter from one feed and the EV charger from the other. Once this is done your inverter will never see the Ohme charger anymore and so whatever it does won't flatten the batteries.

Thanks Dave. I think I’ll just revert to the original settings because they work and it avoids any cost.

I can see though that if you need a fully charged car every day for a commute then your options would need to be considered! Thanks

I’m having a similar issue, I’ve set the battery to charge between the same hours as I’ve set the Zappi to charge the car so as not to wake up to an empty battery.

I’m curious as to whether I could use the scheduler function? Ideally, I’m happy for the car to take maybe 50% of the battery whilst charging, so was wondering if I could schedule the battery to discharge to 50% SOC between 00:00 and 05:30 when the car is on charge, and then between 05:30 and 07:00 set the battery to be able to discharge again down to say 20% to keep the house running until the solar comes back online and runs the house/recharges the battery?

Any help would be appreciated.

Thanks

Aston170 wrote: ↑Wed Sep 04, 2024 12:13 am I’m having a similar issue, I’ve set the battery to charge between the same hours as I’ve set the Zappi to charge the car so as not to wake up to an empty battery.

I’m curious as to whether I could use the scheduler function? Ideally, I’m happy for the car to take maybe 50% of the battery whilst charging, so was wondering if I could schedule the battery to discharge to 50% SOC between 00:00 and 05:30 when the car is on charge, and then between 05:30 and 07:00 set the battery to be able to discharge again down to say 20% to keep the house running until the solar comes back online and runs the house/recharges the battery?

Any help would be appreciated.

Thanks

If you are using the 'old' charge periods you could set the time between 00:00 and 05:30 but leave the charge from grid switch off - that will not allow your batteries to discharge but they won't charge either - that way your not unnecessarily pushing energy into and out of your battery if you don't need it.

You could also do what you have said, or if your inverter has the 'Backup' work mode (earlier ones did), it would be simpler to use scheduler to change the work mode between certain times which also stops the batteries discharging.

Or you could set a schedule to put the inverter into work mode Self-Use but change the minimum soc to be 50% between 00:00 and 05:29 and then set a work mode of Self Use between 05:30 and 07:00 with a minimum soc of 20% - but remember to add a final schedule to change it back to your 'normal' desired setting as it stays whatever it was last set to in the schedules.

Can I suggest a possible alternative solution.

I am not sure what Car you are using or what make of home charger. Some home chargers have a scheduling function that allows you to program when to charge the car. Your car may have the same function. If the car does not fully charge in that period, this function will at least stop the charge and not drain your battery.

I have a Hypervolt charger. I set the charging schedule to charge during the off peak period. I also set the Inverter to not use battery power during the same period.

Sure the car does not always fully charge during that window but it is enough for the day and I can always plug it in again the next day to top up.

Hope that helps