[SeeWhy]

We're having some trouble getting any kind of decent charge rate on our Zoe (R90) - rarely above 11kw recently (on 22kw chargers). I've see that wonderful spreadsheet showing expected charge current for temperature and charge status and it leads me to ask an obvious question...

Would I expect the cell temperature change during the charge cycle and is there a way to (positively) influence the battery temperature during charging in low ambient conditions (<10C)?

All the chat appears to focus on how to keep the temperature down but, living in Scotland, for most of the year I want to increase the battery temperature
I know that driving the vehicle will increase the temperature, but there's something counter intuitive about making a long enough journey (or driving like an eejit) prior to charging just to get a higher rate of charge.

I have CanZE (Oh thank you SO MUCH for developing that!) but haven't yet worked out if / how to map or log historical charging rates and cell temperatures - I have a nice list from ChargePlaceScotland of all the charge session I've made on their network and worked out the average rate for each charge, but I can't cross refer that to SOC and cell temperature to see if there's a pattern emerging.

The importance of this comes with trying to use the vehicle in the real world where I might not want to spend 3 hours waiting for the car to charge enough, or hope that it really does charge more quickly if I've given the battery a cuddle first...

Do I have a problem with my Zoe or do I have to live with this as one of the realities of EV ownership?

Of course I can always charge it slowly overnight at home, but if I am not at home, this is not an option.

 

[Matthew]

If you can leave your R90 on a 22kW charger before a big trip a heater inside the battery pack and a fan kicks in near the rear wheel arches (you'll be able to hear it).. the cells will be warmed up.. so when you do your drive and then plug into charge it will be able to charge at a better rate later. The pack does keep heat for quite a while so if you can leave it to warm up to the point it clicks out (either 8oC or around 14oC depending on software version), your car will be warmer than not around 24hrs later. I have easy access to a 7kW charger now and I am observing the Zoe draw around 1kW but it seems to only want to keep the cells at 8oC at home.

Still that would be better in this 1oC / -1oC weather.. so if you have home charging I would suggest you leave it plugged in overnight to help with charging speeds when you are actually driving it somewhere. It is also possible to accelerate / brake more aggressively etc (@yoh-there ’s “stiff drive”) .. but this is likely to just cause you to lose more charge than is worth unless on a very low State of Charge (SoC).

 

[SeeWhy]

Hi Matthew,
Thanks for your detailed response. Interesting that the battery temperature can be regulated to 8 or 14C by heating (I think ours must be the 8C version!) - the fan does kick in sometimes when plugged in to our 7Kw charger, but I suspect there is a problem that means it is not reliably bringing the battery up to temperature. The vehicle is going for a service next week and this issue is going to be investigated at the same time. It's always helpful to be armed with specific information that might open a door or two towards a solution.

 

[Matthew]

Hi Matthew,
Thanks for your detailed response. Interesting that the battery temperature can be regulated to 8 or 14C by heating (I think ours must be the 8C version!) - the fan does kick in sometimes when plugged in to our 7Kw charger, but I suspect there is a problem that means it is not reliably bringing the battery up to temperature. The vehicle is going for a service next week and this issue is going to be investigated at the same time. It's always helpful to be armed with specific information that might open a door or two towards a solution.

If you have a smart meter with an In Home Display, you should see that even when the car has officially stopped charging that it will intermittently when it’s cold out (and it’s actually only when the cells are cold which are 2 often linked but still slightly different things) use 1kW of energy above what your house normally uses and it will stay awake. This will be the battery warming (and with the fan drawing in air across the pack, “heat spreading”). I’m not observing the same behaviour with the ZE50 so I’m doing some more research on that. A lot more stays asleep with the ZE50.

I only noticed the ZE40 warming the cells even further than 8oC when plugged into a 22kW charging post one day.. and this was immediately after I had my 3yo car have all its software updated after it was in the garage for a repair (the friendly garage proposed updating all the software after they replaced a part, the electric motor, just to be sure it wouldn’t be damaged again).. then I noticed the battery heating performance had changed.. but when I took it to a 7kW post the fans were softer and it cut out sooner at around 8oC avg.. so it is specifically linked to which type of post I am plugged into now. If I were to take a complete guess then I would imagine they know most 7kW are home chargers and so would begrudge using electricity above the odd kW.. and also it may be in this state stuck on a drive for a while.. meanwhile a 22kW post was seen as ”Accelerated” charging and likely on the road, therefore the better and more aggressive (both duration and current) battery warming would have big payoffs on your big drive. Plus you likely don’t care how many kW extra it’s using to soak the battery in heat. Especially if you happen to be charging at the same time and the more aggressive heating is leading to a faster charge time ”on the road”.

Leaving your car plugged in even after it has finished charging should achieve your goal even on a 7kW home charger of ensuring the cells aren’t dropping below 8oC - which means you’ll at least get 8oC charging rates on the road for a little while. The cells die if they get much below freezing and the car’s acceleration performance is a little off (dangerously in my opinion) when the cells are cold anyway, so I’ve always been a bit precious about ensuring the cells are kept warm if outside is around freezing. I didn’t have realistic access to a home charger until yesterday so that’s why I am very aware of what the car is like when it’s cold and what it likes to do when in a Sainsbury’s car park on charge.

See also : What does your Zoe do while on timer charge. and within that I also link to : PSA : Battery Care in Cold Temperatures

 

[SeeWhy]

Thanks for the further information and links - interesting reading. Having bought out the battery recently I will pay attention to charging rates and cell temperatures, but there are probably some compromises to be made, particularly for our situation...

I've noted from those discussions that the low temperature is mainly an issue for performance of the battery rather than storage (some issues about charging if they are below 0C), so maybe we need to think more about that. Our local authority has just (this week) started charging per kwh to plug in, so more often we'll be trickling it at home (cheaper), and if we need to recharge on the go, it sounds like recharging at the end of a journey is the way to go to get the most effective charge rates...

We don't use vehicles daily and often it's for journeys of under 20 miles (hence the EV instead of ICE), so keeping the battery at 8C for long periods might not be practical and could have a negative impact on our overall energy use over periods of winter when temperatures are frequently and extensively below 8C (we're on Ecotricity and solar panels, but even so...). I think there's good advice in terms of letting the batteries warm up before giving them a hard time, but keeping it plugged in constantly might not be viable for us. Might be worth us using our Zappi on eco-mode so it just runs at 1.3kw if we're charging it on a chilly day... and crank it up to 7kw if / when the cells are warm enough. It would be helpful if we could be confident that the Zoe could manage the charge rates and cell temperatures to make sure we stupid drivers don't damage them...

Thanks for sharing your knowledge and experience.

 

[yoh-there]

it sounds like recharging at the end of a journey is the way to go to get the most effective charge rates...

Yes, and start at a low state of charge, especially when going for the fast chargers. This is of course to reduce your waiting discomfort: you can be ABSOLUTELY confident ZOE protects it's battery, There is literally nothing you need to do.

BTW, low temperature does not affect discharging very much, you still have "punch". It's mostly charging that's affected.

 

[SeeWhy]

Yes, and start at a low state of charge, especially when going for the fast chargers. This is of course to reduce your waiting discomfort: you can be ABSOLUTELY confident ZOE protects it's battery, There is literally nothing you need to do.

BTW, low temperature does not affect discharging very much, you still have "punch". It's mostly charging that's affected.

Thanks for the reassurance.

So, it's sunny here (for a change!) but relatively cold (-1C) and I've plugged the Zoe into the Zappi in Eco-mode to match the solar panel output (c1.5kw peak this morning). Using that fabulous CanZE app I can see that the car is taking in 1.1kw and using 0.8 for charging - so that would match the 300w heater element? The rear battery fan ran briefly when the Zoe was plugged in but then it was all quiet.

A couple of hours and a massive 2.6kwh of sunny input later (according to Zappi), the mean battery temp had shot up to 1C. Interestingly after unplugging the Zoe, CanZE showed -0.3kw in the DC power, so presumably the heater was still running. Another check half an hour afterwards and it still shows -0.2kw of DC Power... Let's hope that it doesn't all leak away keeping the battery cosy.

Interesting for me that the Max battery charge rate is 4.7kw - the magic spreadsheet indicates that at 0C it might take between 6 and 7kw (depending if that's based on the usable or real state of charge.). At unplugging the Max battery charge was showing 5.2kw at 65 / 69%, which is closer to the chart's 6kw estimate at 1C.

 

[yoh-there]

Don't forget other losses. The car being "on" in itself draws in the order of 40 watts on the computers, which is being fed through the DCDC converter. Then there are the losses in the charger circuits themselves. As it's running at the far end of it's design specs it's efficiency won't be fantastic, so another 100-200 watts "lost". An R90, to my knowledge, does not have a battery heater, unless it's a Nordic model, but your numbers still make sense to me.

 

[SeeWhy]

An R90, to my knowledge, does not have a battery heater, unless it's a Nordic model, but your numbers still make sense to me.

I know you have more knowledge than me so I'll wait until I've been to the dealer to get a definitive answer, but I'm just going by this post (in the 'timer charge' thread linked above):

Confirmed here …..

View attachment 111264

I'm hoping that this is right...

Thanks for highlighting the losses in the system - that makes sense. I can cope with them given that, if it were to be exported to the grid, my 1.1kw of solar power would probably have just been 'losses' anyway!

 

[Timberr]

No heater for the R90. I assume that this also applies to the ZE50. The car has forced air cooling of the traction battery - can it or should I say does it have forced air heating?
The reason I asked - for the last 10 days or so I get the 'cold battery - limited regen' banner every time I switch to B mode. The GOM (bless) has also lost all sense of direction. Same thing after 30/40 mile trip - can never get the battery warm.

 

[Matthew]

Sorry but most of you in this thread are wrong and I am the only one who is right (including my technical idol @yoh-there 😮).

The R90 (well specifically when it’s a ZE40.. I believe there may be some ZE20 22kWh Zoes that also have R90 engine instead of the R240? But either way no 22kWh model will have a battery heater unless nordic/“very cold countries”) does have a battery heater.

https://twitter.com/i/web/status/1028899658805006336

The document on Google Docs goes into further detail (and even shows you where the heater and HV HVAC is located!):
”In nominal mode, PTC is used when the battery is too cold. The power delivered is 1000W with a resolution of 330W (0W= None relay activated, 333W= POE Relay 1 activated, 666W= POE relay 2 activated, 1000W=POE relay 1 & 2 activated)”

@SeeWhy If you are interested in the HV Bat conditioning, you may wish to look at the ”Climate” screen in CanZE specifically “HV Bat conditioning mode”, you will see “Heat cond req” when it is running and/or in this weather you may even see under “Climate loop mode” the message “AC deiceing” (only triggered that twice and it has a surreal running tap sound). The Heat cond req will run up until the mean value of all the cells is around 8oC on a 7kW charging post.. and on a 22kW I think it was 14oC (if you have recent firmware). I think the params are also shown in CanZE All Data but I can’t remember which to hand. If you aren’t plugged into the car OBD then the easiest way to tell is from a soft or medium fan noise coming from the rear wheel arches. This will come on irrespective of whether the ZE40 is actually charging or not and will cut off when the desired temperature is reached.

As for the ZE50, from what I can tell when the car is done charging it will go to sleep. It does seem to have HV battery conditioning (fan comes on in the cold when I plug in to charge even on 99%) but I need to do some more testing. I am wondering given they had issues waking up parts of the car to precondition whether the HV battery conditioning also shutting down with the car is intentional or not. CanZE ZE50 also does not indicate the battery is heating.. which I’m not yet sure if that’s a CanZE bug, a car one or whether the fan comes on because it just uses charging warmth to heat rather than an actual heater... I also spotted in CanZE All Data that the car thinks it’s a Left Hand Drive when it’s a Right Hand Drive... To be honest the ZE50 has a load of weird DTCs on mine, it was randomly beeping while I sat in it while it was asleep and I know I’m an early adopter of this car which has had tonnes of little quirks that I fully expect some of which will need to be ironed out with a firmware update as one becomes available.

 

[Matthew]

New post, new info.. I am starting to think that keeping the cells warm isn't for the benefit of the cells longevity themselves but it's actually purely to help with the charging speed / imminent post-charging driving performance.

My reasoning? Well even on ZE40 the car only stays awake heating for a period of time after charging then after warming up the cells then goes to sleep and doesn't appear to wake up again without human interaction; allowing the cell temperatures to plummet again. My cells were then 4oC when I checked them yesterday morning after leaving the cable in overnight. The EVSE also did not indicate a charge was in session (which it does when the car stays awake for battery heating). Pressing the pre-condition button this morning showed a 5kW draw which would appear to be the pre-condition.. but once that had tailed off I was still seeing the residual 1kW draw of battery heating again

So actually the ZE50 behaviour might be more efficient / correct if the cell warming is purely to assist with charging or an imminent drive after charging (especially if charging while on the road). On a ZE40 while public charging in the cold there is some value in not rushing back to unplug.. but on a ZE50 as soon as the charge has finished you might as well go unplug. While at home I would probably still leave the cable in (on both models) and do a cheeky little pre-condition when it's cold for the benefit of yourself (in-cabin comfort, acceleration performance at roundabouts, unlocking regen when disabled) and the battery (both their heat and not draining/wearing them from the precondition load).

I'm going to rule out an "emergency" wakeup and a lower "when sleeping" cell temp threshold of 3/4oC by monitoring my smart meter usage a bit more.. but at this point it's just to rule it out rather than any evidence indicating this is a thing.

 

[Matthew]

Hmmm ZE50 :

764.624225.24,CH_WithHVBattCond,1:1d - Without HV Batt Cond,
764.62441c.24,VH_HVBatConditionningMode,0:NoRequest,
764.624424.24,IH_HVBattEvapTempSetPoint,8.0,°C
764.62442a.24,IH_HVbatteryTemperature,4,°C

Wonder if this is just for the cabin:

764.62421e.24,CH_WithAirHVPTC,2:2d - With Air HV PTC Low,

but then again...maybe this is sometimes nonsense:

764.624219.24,CH_SteeringType,2:2d - LHD steering,

And ZE40:

7ec.6234a8.29 Battery Heating System Type:1:Air PTC by evc Power n°1(2relays)
7ec.6234f4.24,($34F4) Threshold for HVBattery conditioning received from BMS,28,°C
7ec.6234f5.24,($34F5) Threshold for HVBattery conditioning received from BMS (01),26,°C
7ec.6234f6.24,($34F6) Threshold for HVBattery conditioning received from BMS (02),33,°C
7ec.6234f7.24,($34F7) Threshold for battery thermal management,10,°C
7ec.6234f8.24,($34F8) Threshold for HVBattery conditioning received from BMS (03),10,°C

 

[SeeWhy]

Hi @Matthew
Thanks for these additional nuggets (I do like being on the 'right' side for once - ours is indeed a ZE40 R90). I had seen the HV Bat Conditioning field on CanZE - I think it was showing as 'no request' at 0C in this case, so that's where I want Renault to look into the behaviour of charging and this discussion is incredibly useful from that perspective. My motto appears to include 'a little bit of knowledge is very dangerous!'. I've already had a chat with the EV Tech at the 'new dealer' and he's been helpful (the 'other dealer' was not so great, so we're not going back there even though they are MUCH closer!), so I'm hoping that he will be able to let me know what's going on in the black box(es). I will report back anything that might be useful.

 

[Spike]

This has been covered several times before. I’ve posted about it Using CanZE when you have a timed charge set and 5e car plugged in, you can see the power draw for the battery heater on the ZE40 as it tries to heat the cells up to 8oC before going to sleep, ahead of the timed charge. You can see 300, 600 or 1000w being drawn and hear the low hum of fans at the back of the pack.

I wonder if the ZE50 has something similar. The last two times my wife has plugged the ZE50 in ahead of an overnight charge, some quite loud fans kick off at the front of the car for several minutes, before the car shuts down before the charge starts. It’s been around zero here for the past week, so the pack is cold and we get limited B mode warnings.

 

[Matthew]

Hi @Matthew
Thanks for these additional nuggets (I do like being on the 'right' side for once - ours is indeed a ZE40 R90). I had seen the HV Bat Conditioning field on CanZE - I think it was showing as 'no request' at 0C in this case, so that's where I want Renault to look into the behaviour of charging and this discussion is incredibly useful from that perspective. My motto appears to include 'a little bit of knowledge is very dangerous!'. I've already had a chat with the EV Tech at the 'new dealer' and he's been helpful (the 'other dealer' was not so great, so we're not going back there even though they are MUCH closer!), so I'm hoping that he will be able to let me know what's going on in the black box(es). I will report back anything that might be useful.

I wonder if this was due to the Zappi being set to give less than the car needed to click on a heater and everything else? Also You'll see "No Request" if you're not plugged in. Some of the Renault dealers are brilliant.. I can throughly recommend SJ Cook & Sons in Bristol. Much better service than even my friend is getting with VW right now. From the docs the High Voltage (HV) Battery HVAC is just underneath the boot next to the wheel arches (which is funnily enough why we can hear it best there)

This has been covered several times before. I’ve posted about it Using CanZE when you have a timed charge set and 5e car plugged in, you can see the power draw for the battery heater on the ZE40 as it tries to heat the cells up to 8oC before going to sleep, ahead of the timed charge. You can see 300, 600 or 1000w being drawn and hear the low hum of fans at the back of the pack.

I wonder if the ZE50 has something similar. The last two times my wife has plugged the ZE50 in ahead of an overnight charge, some quite loud fans kick off at the front of the car for several minutes, before the car shuts down before the charge starts. It’s been around zero here for the past week, so the pack is cold and we get limited B mode warnings.

Oh I know, these forum posts do tend to get a bit samey after a while and the same myths get peddled (no, the ZE40 does not get an update twice a year to make the aircon more powerful ).. the battery heating isn't new to me either.. but what I am finding out fresh is that the battery heater gives up after a while and the car goes asleep.. I always assumed the battery heater was for preserving the battery but it looks like it's more to speed up a charge / make a drive more performant. I'm also still trying to locate where on the CAN the 333/666/1000W is indicated. I'm not entirely sure the battery heating has anything to do with a timed charge either. I have never set a timed charge yet the battery heater performs as you describe. Additionally, if I set the timed charge for 6am.. from what I observe the car will have cut out heating the battery approx 2 hours after being left alone the night before.

As for the ZE50 I have one of those too and I am observing the battery heating to exist only for the duration of a charge session.

 

[Spike]

I think the connection with the timed charge is that you can see the power draw when the vehicle isn’t actually charging. It seems to me that as long as it gets the battery up to 8oC it’s happy and then goes to sleep. With our ZE40, we found it would sometimes stay awake for an hour or longer if the battery was really cold. I suspect that when it wakes to charge, if the temp has dropped, it heats the battery again. I’m sure this is just to help charge speed, although if it’s using 1kW for a while to heat, the battery will only take 6kW less conversion losses from a home charger.

 

[yoh-there]

Yup, I am pretty sure it's ONLY to assist charging. Discharging is not very affected by temperature. Also, heating when plugging is way too late, the heater working (only?) when on scheduled charging makes sense to me. As a sidenote, I have always been a staunch promotor of NOT using scheduled charging controlled by the car. Too much trouble, bugs, cell coverage issues and not realizing it's on when the car refuses to charge. I might need to reconsider that position, especially in winter, as it enables the car to do smart battery heater things.

But not yet (with my Q210 ;-) )

 

[Spike]

We have used timed charging most of the time over the past three years. We’ve never had a missed charge because the timer didn’t work. Now we have the ZE50, I get the sense that it works with the timer without relying on the Renault server to tell it to start charging. Remembering to turn it off when out and about has caught me out though. A simple button like the Leaf has to turn timer on and off would be simpler than digging through screen menus to switch between modes.

 

[AndrewC]

.. A simple button like the Leaf has to turn timer on and off would be simpler than digging through screen menus to switch between modes.

@Spike Could the app help with that - as you can switch between instantaneous and customised. Although I haven't tried it.