OHME Charger - what is it doing?

[JodyS21]

I finally have my Ohme charger (with 32amp commando plug) setup.
Am trying to figure out what it's doing and why with the scheduling.
Does anyone actually know?

I wish Ohme would provide proper details on how it figures out how to calculate the charge schedule to use, plus the ZS specifics used.

Am using "ZS Exclusive (latest firmware)(2019)".
I've setup the tariff details: off peak 12:30am - 7:00am.

My car is at about 75% charged, but obviously the Ohme can't know that.
So I've just told it to add 100miles, to be finished by 6:30 and to not charge above the off-peak price. (I know it doesn't need to add that much I'm playing it safe)
Plugged it in at 4:40pm.
Attached is the charge schedule graph it's is using.

I don't really understand why it would not just start the charge at 12:30 (or 15mins after to be on safe side) when my off-peak period starts. Instead it seems to work directly backwards from the target finish time working out how long it thinks it will take and starts the charge from then i.e. around 2:30am.
This just seems frankly a silly thing to do.
For instance, what if it actually takes longer to put the specified charge into the car etc - it could be cold or something restricting what charge the car will pull, thus it risks the car not having the required state of charge when specified.

The charging schedule graph also shows that it starts to charge the car a little bit at around 1am, before actually doing the main charging a couple of hours later.
Is this to do with the ZS's 10 hours that I've read about, does the car have to be woken up within 10 hours of it being plugged in and then kept trickle charging, otherwise it cannot be woken up by the charger? I plugged it in at 4:40ish.
It looks like this is the case and, this is the work around that despite the cars firmware updates, is still necessary to do a "smart" charge.

My other concern is regarding the Ohme allowing the car to balance as necessary.
I've send Ohme a support question about this.
I don't particularly care if it does this during off-peak rate as it's not using much power, but I want the Ohme to allow the car to balance for how ever many hours it may want to after it's finished charging. Is it going to allow this i.e. let the car carry on pulling power after the scheduled end time?


I'm also wondering.
Does the Ohme stop the charge as soon as the car has taken on the amount of kWh that I effectively specify (calculated from by set range %/miles to add), or does it just go by it's calculated start/end schedule and allow the car to pull the max power for that time period it has calculated (as that should be sufficient).


I'm not convinced this super smart charger is actually going to do what is best for me (it maybe great for Octopus agile tariff)
Realistically, I just want it to allow the car to start charging as soon as my off-peak commences and allow it to fully charge followed by any necessary balancing.
Usually I'm going to need it to be fully charged by 6:30am, which will always be successfully done if it starts when my off-peak tariff commences (potentially it may not always have finished balancing by 6:30am but that's fine occasionally)


Lots to digest there, if anyone has the Ohme and real experience/knowledge of it please share it with me!
thanks Jody

 

[Chrispydoc]

I'm not into timed charging..it makes things much to complicated for me. I also have solar panels, so I figure if the sun is shining, my charges cost very little.

Every time I come home, I plug in. Either on the Granny charger, or as yesterday, we arrived home from a long trip 160 mile trip with just 20 miles range..i used my pod-point charger. I've been following this practive for the last year and a half. The GOM's estimated range has remained very constant, at about 170 miles for the last 16 months.

I like having my car with a "full tank".........i'm sure there will be a lot of folk jumping up and down telling me i'm wrecking by battery life.....but its working fine and the battery is warranted anyway.....its just fine.

 

[notdodgy]

I finally have my Ohme charger (with 32amp commando plug) setup.
Am trying to figure out what it's doing and why with the scheduling.
Does anyone actually know?

I wish Ohme would provide proper details on how it figures out how to calculate the charge schedule to use, plus the ZS specifics used.

Am using "ZS Exclusive (latest firmware)(2019)".
I've setup the tariff details: off peak 12:30am - 7:00am.

My car is at about 75% charged, but obviously the Ohme can't know that.
So I've just told it to add 100miles, to be finished by 6:30 and to not charge above the off-peak price. (I know it doesn't need to add that much I'm playing it safe)
Plugged it in at 4:40pm.
Attached is the charge schedule graph it's is using.

I don't really understand why it would not just start the charge at 12:30 (or 15mins after to be on safe side) when my off-peak period starts. Instead it seems to work directly backwards from the target finish time working out how long it thinks it will take and starts the charge from then i.e. around 2:30am.
This just seems frankly a silly thing to do.
For instance, what if it actually takes longer to put the specified charge into the car etc - it could be cold or something restricting what charge the car will pull, thus it risks the car not having the required state of charge when specified.

The charging schedule graph also shows that it starts to charge the car a little bit at around 1am, before actually doing the main charging a couple of hours later.
Is this to do with the ZS's 10 hours that I've read about, does the car have to be woken up within 10 hours of it being plugged in and then kept trickle charging, otherwise it cannot be woken up by the charger? I plugged it in at 4:40ish.
It looks like this is the case and, this is the work around that despite the cars firmware updates, is still necessary to do a "smart" charge.

My other concern is regarding the Ohme allowing the car to balance as necessary.
I've send Ohme a support question about this.
I don't particularly care if it does this during off-peak rate as it's not using much power, but I want the Ohme to allow the car to balance for how ever many hours it may want to after it's finished charging. Is it going to allow this i.e. let the car carry on pulling power after the scheduled end time?


I'm also wondering.
Does the Ohme stop the charge as soon as the car has taken on the amount of kWh that I effectively specify (calculated from by set range %/miles to add), or does it just go by it's calculated start/end schedule and allow the car to pull the max power for that time period it has calculated (as that should be sufficient).


I'm not convinced this super smart charger is actually going to do what is best for me (it maybe great for Octopus agile tariff)
Realistically, I just want it to allow the car to start charging as soon as my off-peak commences and allow it to fully charge followed by any necessary balancing.
Usually I'm going to need it to be fully charged by 6:30am, which will always be successfully done if it starts when my off-peak tariff commences (potentially it may not always have finished balancing by 6:30am but that's fine occasionally)


Lots to digest there, if anyone has the Ohme and real experience/knowledge of it please share it with me!
thanks Jody

As you worked out correctly, the charger has no awareness of the state of charge, so all we can do is have a schedule that adds a number of miles or %charge.

It's obvious that it is designed for cars that do have an API.

It does seem to work backwards from the target time, in order to guess when to start, which means the risk of not having enough charge is higher.

I have noticed it runs at full charge for a could of minutes when plugged in. I don't have a time based tariff, but the 2 minute "verification charge" you mention is consistent with this.

It used to report when the car was not charging as expected. This happened at 97% charge when the current drops to 16Amps.

To balance charge, override the active schedule and select max charge. This seems to work.

 

[JodyS21]

I have noticed it runs at full charge for a could of minutes when plugged in. I don't have a time based tariff, but the 2 minute "verification charge" you mention is consistent with this.

It used to report when the car was not charging as expected. This happened at 97% charge when the current drops to 16Amps.

To balance charge, override the active schedule and select max charge. This seems to work.

I did notice when I first plugged it in, on the Ohme screens it said it was putting 6amps into the car, I'll have to keep an eye on this. Maybe it does it to check it can communicate with the car so there's less chance of it failing to start the charge later on?

I was expecting to see some sort of graph showing the power being pulled by the car and the accumulative power supplied over the charge period.
I'm very disappointed it doesn't do this, I'd have liked to have seen that it was pulling the full 7kWh, then if it reduces towards the final few percent of the charge, followed by it using low power during balancing.

 

[JodyS21]

So, I ended up setting the following charge schedule.
It would appear that because the car didn't take on the full "100miles" by the specified end time (4:59am), as it wasn't that empty; It doesn't just end the charge, it extends it to the next off-peak time the following morning (for some reason between about 4:45 - 5:42 not at the start of the off-peak period).

I've checked my security camera that's facing the MG badge, it started charging at 00:30, ended at 02:43, balanced until 05:44.

I don't like this and, the graph it provides it pretty useless - especially the time scale.