OVMS (Again)

[dragon2611]

Sure there was a thread about this before but can't seem to find it now

I might grab the hardware as it looks like the work being done for the MK2 ZS will also lead to it being able to talk to the MG5

MG ZS EV (2020) SOC and estimated km wrong after BMS update · Issue #724 · openvehicles/Open-Vehicle-Monitoring-System-3

During the maintenance they updated the software versions as well as the BMS to 1027630EU4 which adds delayed charging and battery heating. Very nice but OVMS can't handle the changes all though th...

github.com

Well that was unexpected, OVMS trying to poll the GWM causes the drivers dash to completely shut off.

Peter over at MVEV hackers gave me a new build to try, this one looks a lot more promsing, OVMS was able to get the SOC (It was off by a couple % vs the dashboard). Dash did misbehave when switching car types but I don't know if that was from the old profile upsetting it as it returned to normal when I disconnected the OVMS hardware and then continued to behave itself after i'd reconnected it.

Will re-connect the OVMS again later (Disconnected it as haven't mounted it yet and didn't want to leave it overnight)

 

[Gomev]

Peter over at MVEV hackers gave me a new build to try, this one looks a lot more promsing, OVMS was able to get the SOC (It was off by a couple % vs the dashboard). Dash did misbehave when switching car types but I don't know if that was from the old profile upsetting it as it returned to normal when I disconnected the OVMS hardware and then continued to behave itself after i'd reconnected it.

Will re-connect the OVMS again later (Disconnected it as haven't mounted it yet and didn't want to leave it overnight)

That will be showing you the real full sized battery percentage. 100% on the dash is the usable percentage. So 100% on dash will be about 97% of full (OVMS).

 

[dragon2611]

Need to connect it again and see if the dashboard behaves itself

 

[Squidder]

Hey Dragon, did you get any more on this?
I bought myself a bluetooth OBD2 module a while back, Im curious about OVMS however. Interesting is my current plug, if left in, will trigger the vehicle alarm if I attempt to query it while the car is locked. How do OVMS get around this do you know?

 

[dragon2611]

Last build I tried was displaying a werid SOC when the car was off (was showing something like 7000%), also there was some issues with the sleep logic so I didn't want to leave it connected as it will probably drain the 12v as it's thinking the car is charging the 12v when it's not and then keeps trying to poll. (which fails because the GWM goes into a locked state)

Regarding the alarm it happens if you attempt certain actions when the cars locked, the way to avoid it seems to be not to poll certain PIDs I think, that does limit what data you can request when the cars in the locked state. I think based on some of the OVMS docs for the ZS EV polling the BMS (So cell voltages.etc) sets off the alarm.

Hopefully Peter will make another build soon as he seems to be the only one working on it at the moment.

 

[dragon2611]

Ok so the reason it’s sometimes trying to poll when the car is asleep is my 12v is still quite high just after the car is turned off it’s seeing at 13v.

Still got the issue where I get a very off Soc reading when the cars off it currently shows 7159% vs 75% when the car is in ready state.

lastly I need to find somewhere to mount the ovms unit, it’s just sitting alongside my seat atm but thats Because I’ve only been testing with the car stationary.

it looks like the side panel of the centre console near the obd port could come off wondering if I could go behind there.

Edit: Yep there’s room on top of one of the control modules behind there.

Edit2: I think I’ve solved the polling when the cars asleep issue by calibrating the 12v reading to be closer to the dash reading.

 

[aled]

Very helpful and much a much better place for it than unplugged in the pocket behind the seat still waiting for me to set it up ?

 

[dragon2611]

Very helpful and much a much better place for it than unplugged in the pocket behind the seat still waiting for me to set it up ?

Be careful I think the zombie mode mitigation still sets off the alarm.

Also don’t run the release build it will upset the dash you need peters build

 

[aled]

Be careful I think the zombie mode mitigation still sets off the alarm.

Also don’t run the release build it will upset the dash you need peters build

Thanks.
For the 12v stuff there is a possible alarm issue if the car tops up the 12v battery while locked. If you keep an eye on the voltage either through ovms or just a multimeter to make sure the battery doesn't get too drained before the car decides to top it up you could fiddle with that. Or unplug it if you are leaving the car locked and unattended (I'm thinking of situations like a week if you are on holiday without the car).

 

[dragon2611]

Thanks.
For the 12v stuff there is a possible alarm issue if the car tops up the 12v battery while locked. If you keep an eye on the voltage either through ovms or just a multimeter to make sure the battery doesn't get too drained before the car decides to top it up you could fiddle with that. Or unplug it if you are leaving the car locked and unattended (I'm thinking of situations like a week if you are on holiday without the car).

It will be interesting to see if it sets the alarm off when the car is locked but charging.

I hope not as that’s actually one of the scenarios I wanted ovms for (i.e to check on the soc when stopped on a public charger)

edit: unplugged the module from the obd2 when I got home just in case it sets the alarm off again it’s one thing to do it during the day but I’d not be popular if it did it in the middle of the night

 

[Gomev]

...

Still got the issue where I get a very off Soc reading when the cars off it currently shows 7159% vs 75% when the car is in ready state.

...

That's probably 71.59% and represents the %age of the full unbuffered battery whereas the 75% represents the %age of the useable battery.

 

[dragon2611]

That's probably 71.59% and represents the %age of the full unbuffered battery whereas the 75% represents the %age of the useable battery.

It’s a strange behaviour either way as the values look about right when the car is on.

When it’s off the voltage reads over 1000v and the soc/soc raw sometimes goes to that silly reading.

Only happens sometimes if ovms tries to pool when the car is locked hasn’t done it since I calibrated the 12v and ovms goes to sleep when the cars off.

 

[dragon2611]

Thanks.
For the 12v stuff there is a possible alarm issue if the car tops up the 12v battery while locked. If you keep an eye on the voltage either through ovms or just a multimeter to make sure the battery doesn't get too drained before the car decides to top it up you could fiddle with that. Or unplug it if you are leaving the car locked and unattended (I'm thinking of situations like a week if you are on holiday without the car).

Thus far i've not been able to start a charging session with the car locked without setting off the alarm, I suspect the neighbors must love me. (I pretty much know when it's going to do it when testing and catch it quickly as well as making sure to only test during the day but still)

Wondering if there's an accessible fuse that I could pull to disable the horn to allow for more aggressive testing without disturbing everyone.

I don't know if once the alarm has gone off if you can continue polling without setting it off again, Don't really want to leave it just in case.

 

[EWD]

 

[dragon2611]

Ah thanks I’ll have a look at see if I can pull that fuse

 

[emmrecs]

Ah thanks I’ll have a look at see if I can pull that fuse

Just don't forget to put it back before you next drive the car!!

 

[dragon2611]

Just don't forget to put it back before you next drive the car!!

Indeed, whilst I rarely use the horn I believe it's a requirement for it to be in working order.

 

[emmrecs]

Indeed, whilst I rarely use the horn I believe it's a requirement for it to be in working order.

It's certainly an MOT fail if it isn't!

 

[dragon2611]

Indeed, I'll have to see what happens with OVMS as at the moment whilst it can get data from the car polling when the car is locked sets off the alarm. Which is a problem for my use case as I wanted to monitor charging when on public chargers.

 

[aled]

Although it's been a while I do recall the keep awake thing being mentioned (tester present pin on obd2 port maybe?). The reason not to use it was it kept the car awake and the power draw could drain the 12v. Since that wouldn't be a problem on a charger you might find a way to make use of it. Otherwise you could set it to record the can messages to micro sd during a charge session then see if it already transmits the % during charges so that the ovms could listen without polling.