A missing mile.

[Lovemyev]

True, without knowing what parameters the GOM is using it really is a black box. It could be anything from battery SOH, temperature, time-of-day, tyre pressure, previous usage just to think of a few. I think It's fair to say its precision is greater than it's accuracy.
It's effectively saying "nnn miles available +/- nn.nnn miles"

It’s all in the title :- GOM !.
It is precisely that, it could not have been given a better name is you tried.
The name is a LOT more accurate than the prediction of the gauge that’s for sure .
A battery percentage gauge would be better, but hey ho, it is what it is I GUESS !.
See the poor “Dad” joke at the end there ( guess ) - sorry folks !.
Better than nothing, but only just .

 

[Kithmo]

I must learn to control my OCD.

 

[SCB86]

I always get 161 miles range estimate after recharging and with the HVAC on, 179 with no HVAC on.

 

[Lovemyev]

I always get 161 miles range estimate after recharging and with the HVAC on, 179 with no HVAC on.

Running on the OEM software then !.

 

[SCB86]

It was updated in January (I think, might have been February) it now shows 449V when charged compared to the dodgy 455V software.

 

[Lovemyev]

It was updated in January (I think, might have been February) it now shows 449V when charged compared to the dodgy 455V software.

Reset both of your trip recorders before your next charge and then see what the predicted range is on boot up, when it has completed.
I doubt it will be anyway close to 178 miles then.
New BMS and you should see around 448 - 450 volts on the pack, with a predicted range of around 163 miles at best.
This with everything turned off of course !.
A strange feature of the latest BMS upgrade, is that continues to build up your “Predicted” range against the accumulative trip until reset.
Which will give an inflated value of the cars range, even with only a short distance recorded from a previous made trip.
Yesterday I had around 125 miles of accumulative miles recorded from a previous trip.
I then did a overnight charge to 100% and balanced, but with NO trips reset.
The car was predicting a range on boot up of around 180 miles.
A quick reset of the trips and the predicted range dropped to a more realistic range of 156 miles.
This strange condition has been witnessed by many owners with the recent upgrade.
It’s not a problem at all, it just can be a little misleading if you are expected to actually cover that amount of distance quoted.
That 125 mile journey return a 5.0 m/kWh in efficiency OBTW.
Although not necessary, I do personally prefer to reset BOTH of the trips before setting out.
I don’t want to see a over inflated prediction figure thank you very much !.

 

[SCB86]

I ALWAYS reset my trip after a charge, otherwise the GOM is even more wildly inaccurate.
After resetting both with no HVAC I always get 179 and 161 with HVAC on.

 

[Kithmo]

I ALWAYS reset my trip after a charge, otherwise the GOM is even more wildly inaccurate.
After resetting both with no HVAC I always get 179 and 161 with HVAC on.

I think I'm going to start resetting it each time I do a full charge and balance from now on.
The extra miles I mentioned in my first post has stayed at just over 2 miles more on the trip, over what the GOM has dropped so far, so it looks like I'm actually going to get just over 164 miles to a charge. The m/kWh is still reading a bit weird saying 4.2 now.

 

[JodyS21]

I ALWAYS reset my trip after a charge, otherwise the GOM is even more wildly inaccurate.
After resetting both with no HVAC I always get 179 and 161 with HVAC on.

To confirm and put this in context, I presume you must be talking about the GOM in Eco mode for those figures?

Generally when we talk about the GOM figures we always state the Normal(3) mode readings for comparison purposes. (Plus with the HV battery off/car started without brake pedal pressed)

 

[Lovemyev]

To confirm and put this in context, I presume you must be talking about the GOM in Eco mode for those figures?

Generally when we talk about the GOM figures we always state the Normal(3) mode readings for comparison purposes. (Plus with the HV battery off/car started without brake pedal pressed)

Absolutely @JodyS21 .
It also depends on what software you are running on also.
Latest BMS after a full charge, expect to see 448 - 450 volts on the pack, with both trips reset and nothing turned on in the back ground.
Car booted into READY status with NO pressure applied to the foot brake.
Car in default mode of normal and Regen level 3.
Predicted range on the GOM will be in the region of anything between 157 - 163 miles depending on the age / mileage covered by the car.
If you don’t clear the trips, the car will quote an inflated range prediction on the GOM.
Last week I performed a full charge & balance and reset the trips before a journey.
The voltage on the pack was 449 volts and the predicted range was 157.
We covered 125 miles and when I returned, I checked the car’s efficiency.
It ( we ) where achieving 5.0 m/kWh which is pretty good in my mind, as some of the journey passed through the Welsh hills.
Returned home with around 70 miles of range still remaining on the GOM.
This was predicted against the good efficiency of course.
Had I reset the trips, I am sure this would reduced !.
If the car is reporting an inflated range after a charge, then the trip needs resetting.
A prediction of above 200 miles is just not actually achievable in the real world !.

 

[BarryH]

Kithmo.
Been experimenting and mine has gone other way , answer to your question , I've got it

That's my experience too after 18 months and 10,513 miles. Last week 3 hours after finishing a balancing charge I had 215 miles on the GOM in Eco and 195 miles in Normal and 185 miles in Sport with 100% showing. I have a Dongle and using the free version of "EV Watchdog" it reports Cell #61 as low at 4.14 volts and Cell #108 as highest at 4.156 volts. The State of Health is shown as 95.4%.

Each time I test whether before or after a Balancing charge Cell #61 is always significantly lower than any other and will therefore be the range limiting cell voltage. I wonder at what point it becomes a performance-limiting constraint and the cell needs replacing? The Cell data shows that the pack is made up of 9 groups of 12 cells and the lowest cell number in each group has the lowest charge and the highest numbered cell has the highest voltage reported.
ie, #1 low at 4.146v and #12 high at 4.155v
#13 at 4.415v - #24 at 4.152v
#25 at 4.148v - #36 at 6.154v
and so on until
#97 at4.146 - #108 at 4.156v

If anyone else has tried EV Watchdog I'd be interested to know how your readings compare?

Barry
Save on Utilities and to share £100 with me (50:50) go to:
share.octopus.energy/zappy-guppy-175

 

[Lovemyev]

That's my experience too after 18 months and 10,513 miles. Last week 3 hours after finishing a balancing charge I had 215 miles on the GOM in Eco and 195 miles in Normal and 185 miles in Sport with 100% showing.

I can assume from this that you are running on the original factory software and that your car has not received the latest BMS software update released 15th Jan 2020.

 

[SCB86]

To confirm and put this in context, I presume you must be talking about the GOM in Eco mode for those figures?

Generally when we talk about the GOM figures we always state the Normal(3) mode readings for comparison purposes. (Plus with the HV battery off/car started without brake pedal pressed)

I always drive in Eco, can't personally see the point in having an EV with such a low range and not trying to eke out the most miles. That's just my personal preference however.
The car is also much smoother to drive in Eco and the ACC is also much less aggressive when accelerating back up to your set speed.
I never use Normal mode. It sometimes gets flicked into Sport if I'm driving through the mountains or country lanes though.

 

[Gomev]

That's my experience too after 18 months and 10,513 miles. Last week 3 hours after finishing a balancing charge I had 215 miles on the GOM in Eco and 195 miles in Normal and 185 miles in Sport with 100% showing. I have a Dongle and using the free version of "EV Watchdog" it reports Cell #61 as low at 4.14 volts and Cell #108 as highest at 4.156 volts. The State of Health is shown as 95.4%.

Each time I test whether before or after a Balancing charge Cell #61 is always significantly lower than any other and will therefore be the range limiting cell voltage. I wonder at what point it becomes a performance-limiting constraint and the cell needs replacing? The Cell data shows that the pack is made up of 9 groups of 12 cells and the lowest cell number in each group has the lowest charge and the highest numbered cell has the highest voltage reported.
ie, #1 low at 4.146v and #12 high at 4.155v
#13 at 4.415v - #24 at 4.152v
#25 at 4.148v - #36 at 6.154v
and so on until
#97 at4.146 - #108 at 4.156v

If anyone else has tried EV Watchdog I'd be interested to know how your readings compare?

Barry
Save on Utilities and to share £100 with me (50:50) go to:
share.octopus.energy/zappy-guppy-175

Just had a look and on Play store in the app description it says the EV Watchdog app only supports Kia/Hyundai.

As you are using it, I take it that is not true ?

 

[JodyS21]

That's my experience too after 18 months and 10,513 miles. Last week 3 hours after finishing a balancing charge I had 215 miles on the GOM in Eco and 195 miles in Normal and 185 miles in Sport with 100% showing. I have a Dongle and using the free version of "EV Watchdog" it reports Cell #61 as low at 4.14 volts and Cell #108 as highest at 4.156 volts. The State of Health is shown as 95.4%.

Each time I test whether before or after a Balancing charge Cell #61 is always significantly lower than any other and will therefore be the range limiting cell voltage. I wonder at what point it becomes a performance-limiting constraint and the cell needs replacing? The Cell data shows that the pack is made up of 9 groups of 12 cells and the lowest cell number in each group has the lowest charge and the highest numbered cell has the highest voltage reported.
ie, #1 low at 4.146v and #12 high at 4.155v
#13 at 4.415v - #24 at 4.152v
#25 at 4.148v - #36 at 6.154v
and so on until
#97 at4.146 - #108 at 4.156v

If anyone else has tried EV Watchdog I'd be interested to know how your readings compare?

Barry
Save on Utilities and to share £100 with me (50:50) go to:
share.octopus.energy/zappy-guppy-175

I’m beta testing EV Watchdog for the developer.
I’m not 100% but the very latest version for public download may support the ZS.

The battery cells page could be a bit misleading, it’d be interesting to get your views and I can pass them on.
Not each (108) cell voltage can actually be obtained. The developer has obtained each of the 9 cell pack min / max voltages, he’s then filled in the other cells with the in between values, if that makes sense.
I was going to recommend he changes it to only show the real data that obtained, but would be good to know what others think about this

 

[BarryH]

Just had a look and on Play store in the app description it says the EV Watchdog app only supports Kia/Hyundai.

As you are using it, I take it that is not true ?

If you download and install EV Watchdog and use one of the recommended OBDII (OBD2) Bluetooth or WiFi Dongles it will pull data from the car and display MG ZS EV as the vehicle. The developer would prefer at this time as it is in Beta that I stick with the Free rather than Paid For version although I'd happily pay the £13:49 or whatever it is for the full function set. I tried a couple of Dongles and the first, a cheap Chinese Knock-off Clone, didn't recognise the MG or fetch data but the Konnwei KW902 did work although is slow (as the developer states on the website). Beware Cheap Knock-off Clones but by all means, give it a shot.

Barry
Save on Utilities and to share £100 with me (50:50) go to:
share.octopus.energy/zappy-guppy-175

 

[JodyS21]

That's my experience too after 18 months and 10,513 miles. Last week 3 hours after finishing a balancing charge I had 215 miles on the GOM in Eco and 195 miles in Normal and 185 miles in Sport with 100% showing. I have a Dongle and using the free version of "EV Watchdog" it reports Cell #61 as low at 4.14 volts and Cell #108 as highest at 4.156 volts. The State of Health is shown as 95.4%.

Each time I test whether before or after a Balancing charge Cell #61 is always significantly lower than any other and will therefore be the range limiting cell voltage. I wonder at what point it becomes a performance-limiting constraint and the cell needs replacing? The Cell data shows that the pack is made up of 9 groups of 12 cells and the lowest cell number in each group has the lowest charge and the highest numbered cell has the highest voltage reported.
ie, #1 low at 4.146v and #12 high at 4.155v
#13 at 4.415v - #24 at 4.152v
#25 at 4.148v - #36 at 6.154v
and so on until
#97 at4.146 - #108 at 4.156v

If anyone else has tried EV Watchdog I'd be interested to know how your readings compare?

Barry
Save on Utilities and to share £100 with me (50:50) go to:
share.octopus.energy/zappy-guppy-175

@BarryH I’ve just noticed what you’ve said your SOH is, 95.4%, having done only 10.5k miles.
Very interesting, another recent thread in SOH, someone has not much different SOH and they’ve done 35k miles.
Mine today says 97.27% SOH @ 10.5k miles, 8months old.

 

[BarryH]

@BarryH I’ve just noticed what you’ve said your SOH is, 95.4%, having done only 10.5k miles.
Very interesting, another recent thread in SOH, someone has not much different SOH and they’ve done 35k miles.
Mine today says 97.27% SOH @ 10.5k miles, 8months old.

Thanks for your SoH info. I wonder how much the lowest cell voltage impacts the system's reported SoH? Maybe I can get a comment from @MilesperkWh in this evening's Podcast?

 

[JodyS21]

Thanks for your SoH info. I wonder how much the lowest cell voltage impacts the system's reported SoH? Maybe I can get a comment from @MilesperkWh in this evening's Podcast?

To be honest, I doubt Miles would know the algorithm used for the SOH.

I don't think it is anything really to do with the lowest cell voltage that affects the SOH. My voltages haven't really changed from what I've seen and my SOH has dropped.
I believe it's more likely, the BMS monitors how many kWh have been drawn from the battery between when it was at X voltage to Y voltage range. They know how much power should be discharged over the voltage range on a new battery, and monitor accordingly.
I don't believe the max and min voltages change for a 100%SOH battery to a 70%SOH battery, it's just how much power is stored, if that makes sense.

 

[Alan5]

I am using the EV watchdog app at the moment and I like it a lot at first I thought some of the information may not be quite right like average MilesperkWh as it's more than the car shows but it does seem to work out correct at 6.4 mpkwh for the trip home from work this afternoon the car shows 4.5 mpkwh , i did 8.8 miles and used 1.3 kwh , the trip home is downhill and flat roads for about 80% of the journey , I like the instant and average mpkwh as it updates much quicker than the car and helps a lot with efficient driving and it's good to see how much kwh there is in the battery pack at any given percentage , fully charged mine was 41.6 kwh at 93% which is about right for what we know is the usable kwh for the car