Could be related to the cold? Batteries do not like absorbing energy when they are very cold, and it's been below zero overnight for a couple of nights now.

 

Temperature

 

Yeah, it's the cold temperatures at the moment. Very low temperatures degrade the battery's ability to take on as charge (and that charge can be as much as 13 kW with heavy stopping).

Having said that, I do think that the MG is pretty poor in this respect. Zoe never really showed the same losses in regen. I've seen recently that the MG's regen has dropped to around 20% below the zero mark (on the right hand dial) to recover later after several regen events to the usual 35 - 40%. I'm assuming that this is because the previous regen events have warmed the battery. YMMV

 

Very low temperatures degrade the battery's ability to take on as charge (and that charge can be as much as 13 kW with heavy stopping).

This is surprisingly low, I've seen my i3S report nigh on ~50kw charge rate in full regen (and I heard earlier cars were much more brutal)!

 

Yes, it will be the temperature then. Its been consistently between -5 and -2 Deg C overnight for the past week. It was particularly cold this morning taking a downhill run into town. I did notice a lack of regen. During the day the temperature has stayed at -2 Deg C and after a short drive of a few miles this afternoon, there have been no such warnings. Battery must have been sufficiently warmed up.

The plus side of this cold weather is a chance to see how the car performs in the snow and ice on single track roads in the hills here. Put some snow chains in the boot the other day and headed up a small ice covered road. I was impressed that I didn't need the snow chains to get up some quite steep sections. The traction control system kicked in a few times and was effective. I have lived and worked in the Alps for several years so used to snow driving and I must say it performs pretty well!

Very reliable starting up in the morning and jump started a diesel Subaru with a dead battery this afternoon without a problem.

 

The plus side of this cold weather is a chance to see how the car performs in the snow and ice on single track roads in the hills here.

Do you have the standard tyres on it? On my old banger Hyundai I had a set of snow tyres on wheels which safely took me to the Alps but with my new car I haven't splashed out yet! Thanks for your separate account elsewhere of your trip to Geneva, and suspect many of us would welcome more such accounts.

 

The ZS battery is meant to be insulated but I'm not convinced - it is in a big flat aluminium pack exposed to undercar airflow. It seems to cool down a lot overnight and take a while to heat up once driving (having a battery temperature gauge would be nice, along with SoC %age....)

I think last winter was very mild, thinking back, and I wonder if the car is simply behaving as intended in a colder winter spell - I have noticed weaker regen and the power is certainly withheld at higher SoC (when cold can be limited to 60% at 40-50% SoC) than last winter.

 

I have noticed weaker regen

Hi @CasperStorm .
I started to notice the reduction in regen strength about a week ago.
I have always driven in the default mode of Max regen level 3 and "Normal" for the driving mode, therefore spotting the reduction in strength was very quickly picked up when driving.
I find myself using the footbrake a little more over the last week or so, because of the reduction in the Max regen strength.
The ZS EV has a pretty strong regen strength when in level 3.
In the summer time, even after a full charge.
As soon as there was space in the HV pack, the strong regen would return.
Now the regen feels weaker, a little like the battery is almost full, when it fact it is only half charged to capacity.
Now I think about it, my previous PHEV was the same in cold weather if I remember correctly.
My car is parked on the drive at all times, it is currently sitting there with about three inches of snow on the roof !.
Even on short journeys to the local supermarket, it consumes the energy from the HV pack at a high rate.
Mind you, everything in the car is running almost flat out.
Cabin heater and the blower motor of course, heated seats, side lights, head lights, wipers etc etc.
You soon get use to that Max regen feeling, I both love and miss the power of it right now !.

 

I agree, last winter was much milder so these new observations are cold related. The battery is supposed to be insulated true, there is also a flat plastic panel to deflect the air underneath, and the aluminium battery pack also has a covering to protect from road chips and damage which probably helps a little with insulation.

I just looked up the owner's manual ...

Effects of Ambient Temperature

The working performance of the high-voltage battery
pack fitted to your vehicle is related to the ambient
temperature, this battery powers the vehicle power
system and therefore it is recommended that where
possible the vehicle should be used within the temperature
range of -15 to 45. This will ensure that the vehicle is at
the optimum working state, and help extend the service
life of high-voltage battery pack. Extremely high or low
temperatures will affect the performance of high-voltage
battery pack and vehicle.

 

Has the ZS not got battery warming/pre condition that can be programmed?

 

Not programmable. There is a software update to allow manual control but it was only really meant for Nordic countries.

Without being able to see pack temp (thanks MG - similar for no SoC %age....) we don't know when the automatic pack warmer kicks in.

The overall low usage and sustained freezing temps is very different to last year. Li-ion at feeezing cannot effectively be charged safely, and can only be discharged at a reduced rate.

Would be great if one the OVMS crew could post pack temp and rate of charge from a freezing start (though I suspect the charge drawn would be a mix of amps to battery and amps to heating circuit if on).

 

I think this might be sorted with the new BMS update that @Miles Roberts mentioned the other day.

The duff BMS is throwing up a lot of strange behaviour. I personally think it’s all related.

But yes, this winter is much colder than last winter so far.

 

Interesting to hear how the new BMS affects the battery preheat setup on you car. Assume you’ll be getting the new BMS as soon as it’s released?

 

I have the standard Michelin Primacy 3 tyres on the car. I may go for Michelin Cross Climate all weather tyres when they need replaced. They are supposed to be even better on snow and ice but not sure if they are as efficient or long lasting in summer conditions.

 

I’ve got Goodyear Vector 4 Sesons (Gen 2) fitted on mine since 1st December, I’ve not noticed any noticeable change to range (I had CrossClimates on my Soul, Leaf and E-Golf and in all cases I think it seemed to change summer range about 3% compared to what others were reporting, but then again everyone’s driving style and drive is different so hard to truly compare). The Goodyear’s have been good, you still get a little wheelspin on ice thanks to the traction control kicking in (turned regen down to 1 to avoid that being a contributing factor), but last weekend I happened on a car park that was complete black ice. Two cars were already stranded at the bottom of the car park and they were waving at me to stop coming in further (it had a 20% slope) I manage to do a 3 point turn and get out and they probably thought I had a fancy 4WD car to get out.

 

To be fair a fully frozen car takes 3 minutes to have clear glass and be toasty inside.

 

Think I've seen up to 60-65 amps (@400+ volts) on regen 3, so more like 25-30kW peak (with warm car/battery and not on 8 blobs of course)

5.5 eh?

Here's my 6.1 (from central Edinburgh to N.Berwick - lots of crawling and waiting at traffic lights, then 40-45 in a big snake of traffic between Musselburgh and NB)

Average since the car was serviced in November is currently 2.9....

 

so more like 25-30kW peak

Yeah, I would imagine that it would be in that region. Zoe would do this quite easily. It's just that it's easier to see on the Zoe. I'll give the MG a go when things are better

 

I was doing some testing on this yesterday, coming back down the steep hill into my town which goes 50-40-30. The highest regen I saw when I purposefully slowed from around 42 to a stop (as there are lights just after the 30 zone starts, this was in N Kers 3 with lift off and then brake pedal applied) was 430v and 50 amps which works out at 21.5kW.

 

Ah, on the i3 you would have to use an app to get these numbers, but there's a battery flow, kw, statistic can be read via an OBD dongle. Nice app called "Electrified" displays this and a bunch of other really interesting stats for i3s on android. Now if only it drew graphs .. !

 

Went to the shops today and on the way back at a quiet point I took my foot of completely at about 25 mph, 2c and fairly flat. Screen showed 416v and 42 amps = 17.5 kW (approx) then rapidly slowed until regen stopped.

We had been charging on a Tesco PodPoint about 10 minutes before, so the battery may have been a little warmer than usual.

 

Not had a decently warmed up battery for a while - too many freezing starts.

I think max regen is with the needle between 'R' and 'G' on the dial. Even with a half-empty battery I've not seen much better than an 'A' in recent weeks!