Ohme limiting charging rate?
Author
Discussion

Chris-pwh9x

Original Poster:

3 posts

40 months

Yesterday (20:17)
quotequote all
Appreciate thoughts on the following.

Once or twice a week the EV does a longish trip, and on return home I'd like to be able to charge back to 80% - except the Ohme App often won't allow me to get close to that.

Example - tonight to get up to 80% will require 32kWh. But when requesting to hit 80% by 5am (end of EDF 12am-5am off-peak window) the scheduling proposes to get to 64% only (+23kWh) . And looking into the schedule that has been split as usual into 15 or so slots that cover almost every minute from 00:08 to 04:48.

Then toggling that % up by the default +5% it offers 69%, then trying again it offers 74%, then trying again 79% - but then I notice that offer is based on that being achieved by 19:30 (which is 24hrs from now). So then back in to the App and toggling both the % and time I now get an offer of 74% by 5am - which is 10% more than a few minutes ago - but only 29kWh.

The Ohme is pod is as I understand it rated to 7.4kW - and the EDF EV rate window is for 5 hours. Therefore I was assuming up to 37kWh would be available - maybe less a bit for ramp-up, cooling etc. Or less 10% for transfer losses?

Am I being too hopeful? Is a lot less than 37kWh the norm - around 20% in today's example above.
And checking the Ohme history the most we ever seem to have had in a 5 hour window is 29.5 kWh.

And regardless of the above, why is negotiation needed - why isn't 29kWh (or more) proposed? Rather than the initial 23kWh.

Or is the algorithm trying to protect the car by charging slowly and/or for less time?


Answers welcomed - thanks.
Not knowing how much power is available, and then having to negotiate is getting annoying.


Chris-pwh9x

Original Poster:

3 posts

40 months

Yesterday (20:19)
quotequote all
In case it matters I am doing the scheduling directly in the Ohme App. Although I've told it that it's on an EDF EV tariff it wasn't on the dropdown list when I set it up, therefore limits were entered manually.

And therefore I assume (maybe incorrectly) that Ohme is not speaking with EDF to agree available slots?

Or is the limit because Ohme is doing grid balancing irrespective of the energy provider?

TheDrownedApe

1,530 posts

76 months

Yesterday (20:43)
quotequote all
I have issues with my ohme home pro and volvo c40. The car will only charge at 5kw/ph.

I've tested other cars which, on my charger, pull 7kw and my car will pull far more than 5kw everywhere else.

No idea why. Ohme blame volvo, volvo blame ohme.

Meh

Chris-pwh9x

Original Poster:

3 posts

40 months

Yesterday (20:58)
quotequote all
Sorry to hear that - but interesting to know.

Car is a 2022 Renault Zoe - not tried any other permutations.

I52

38 posts

249 months

Yesterday (22:01)
quotequote all
Not sure why Ohme does throttle the charge on occasion. As well as charging loss that you mention, the charge will be limited to 32 amps, if your supply voltage is on the lower end and your installation used a reasonable length of the smallest conductors allowed, your supply voltage to the car could be in the 205-220V range, which would only give you 6.6-6.8kW to the car, quite a bit less than the nominal 7.4kW.

Martyn76

785 posts

137 months

Does your electricity supplier have their own charging app?

I'm on OVO and was using the OHME app to charge my car, it would fail regularly to achieve the desired target, usually 80% sometimes 100%. I then had to change on OVOs own charging app back in November and I have not had a missed charge since, it's a far better, more reliable charging experience.

RotorRambler

662 posts

10 months

On mine (Ohme/Octopus IOG), if the car had 20% & I want 80%, i just tell it to add 60%
Or more as the car stops it when 80% is reached.
No problems in over a year,, it does decide to slow charge various slots, but always hits by the departure time I set, 7am
All done in the Ohme app, my car isn’t integrated.