Comments on disabled regen in the cold

[cinergi]

Oh. In that case maybe there's something that could be done in firmware. Like an option to automatically preheat the pack at a prescribed time, so it can be toasty and ready to go at the end of your workday.

A similar feature for pack cooling would be great too, for those hot summer days.

I wonder how much energy it would take to maintain the pack at 40F when 0F outside for 10 hours. Would love an option when I exited the car to do so.

 

[user497]

It's a little disconcerting...

I agree 100% with cinergi's first post. I live in NY and yesterday the regen didn't kick in when I went to work. It's such a different driving experience than when regen is on. It feels to me that when I let go of the accelerator, the car slows down a lot slower than a gas car. It almost feels like it tries to maintain the speed a little. The first time I experienced this I imagined what it must have been like to be in one of those Toyotas that accelerated on its own. I thought to myself "this is a death trap" Of course, a couple drives later I am completely used to it but I agree that it makes the driving experience much less enjoyable. It also takes me about 15 minutes for the regen to kick back on. Too bad my commute is 20 minutes I will try driving in performance mode tomorrow to see if it does make a difference. If they could find a way to simulate the regen even if they don't do anything useful with the energy, it would be great. Is it me or did it get real cold real quick?

 

[Jaff]

Just curious guys...is anyone plugged in to a 110v when at work (and letting the car sit outside in the cold for 8-10 hours)?

If so, is the 110v plug in keeping the pack warm thus keeping the regen working from the start on your ride home?...or does it make no difference at all?

Thanks!

 

[Alan]

If a lack of regen bothers you on cold days then you could always use the timer function in the charging menu to ensure that charging starts x hours before you want to use the car (where X is just enough to fully charge before use). As long as the car has been charging in the last hour or so the battery pack will be warm enough for regen.

 

[user497]

If a lack of regen bothers you on cold days then you could always use the timer function in the charging menu to ensure that charging starts x hours before you want to use the car (where X is just enough to fully charge before use). As long as the car has been charging in the last hour or so the battery pack will be warm enough for regen.

Hmmm, I don't think that is true. This morning the car was still charging with the 110 when I left to go into work and the regen wasn't working. I don't charge at work so I don't know what impact that would have although it is obviously a lot warmer during the day than at night so that would certainly factor as well.

 

[Alan]

Thats interesting. I thought the whole point of the battery heater is to warm the pack up to a point when it can accept a charge. You would assume that if the pack if warm enough to accept a charge via the charger it would be warm enough to accept a charge via regen.

When I charge at home using 240V / 30A and that warms it up enough to allow regen when we got to -7C / 19F. Perhaps a 110V charge does not warm up the pack as much and there is a difference between the pack temperature for an external charge and regen.

 

[mpt]

Hmmm, I don't think that is true. This morning the car was still charging with the 110 when I left to go into work and the regen wasn't working. I don't charge at work so I don't know what impact that would have although it is obviously a lot warmer during the day than at night so that would certainly factor as well.

Just checking; were you in standard, range or performance mode charge?

I ask as regen is disabled at the end of a range mode charge as, well, it's full.

 

[user497]

Just checking; were you in standard, range or performance mode charge?

I ask as regen is disabled at the end of a range mode charge as, well, it's full.

I was charging in standard mode with the 110 V charger and it was still charging when I left (I had been pretty low the day before).

 

[mpt]

Have we stumbled upon something? If the heater is 2Kw per cinergi, at 110v 12A there isn't 2Kw... No pack warming on 110v? Or, is cinergi slightly off and it's 1.5Kw which is all you get from 115v. Was user497 still heating, not heating but trickle charging?

My MINI e doesn't heat the pack, at low temperatures the charge rate drops to a dribble, it didn't fully charge last night at -8c. I have a timed start at 3am so it only got 4hrs which put in 70% - this could be an issue for leaf if it doesn't heat.

 

[doug]

The Leaf is supposed to have an option for a cold weather package which likely heats the battery.

I remember hearing that when it's warm and charging via 120VAC, the Roadster alternates between cooling the pack and charging since it doesn't have enough power to do both at the same time. (This behavior may have changed with firmware updates.) Perhaps it does something similar in terms of heating the pack.

 

[cinergi]

Have we stumbled upon something? If the heater is 2Kw per cinergi, at 110v 12A there isn't 2Kw... No pack warming on 110v? Or, is cinergi slightly off and it's 1.5Kw which is all you get from 115v. Was user497 still heating, not heating but trickle charging?

My MINI e doesn't heat the pack, at low temperatures the charge rate drops to a dribble, it didn't fully charge last night at -8c. I have a timed start at 3am so it only got 4hrs which put in 70% - this could be an issue for leaf if it doesn't heat.

If I could open my trunk, I'd try charging with 110 to see what happened with respect to heating & charging (viewing amperage draw on the screen), but alas, my trunk is frozen shut :-\
I'd assume it ran the heater at less than 2Kw which obviously means longer heating time but should still work. Would be nice to know the actual temperature of the battery coolant. Again, I can't get to it to manually check (heck, for all I know, I'm running low!)
Wonder if some of this data is the in logs. I keep meaning to do that ...

 

[cinergi]

interesting. Not at all the behavior I have. Is all off or all on. I didn't check to see if my amperage is 0 vs 8 while coasting with the heat on. I'll try to do that next chance I get.

Btw I'd assume the motor won't create voltage for regen when it's off since the pem wouldn't be inducing a magnetic wave in the rotor

I tested this last night. +8 amps (heat full blast) when my foot was off the accelerator and I was rolling forward with regen off. Also no difference between neutral and regen being off.

 

[user497]

It was warmer this morning (35 degrees) and I worked from home until noon so the regen was working. I'll keep track of this next week when I leave earlier. I'll look at current outside temperature, car charging or not and miles until regen kicks in. Anything else? I wonder if this info is already in the logs? I haven't downloaded them yet but that is on my list of things to do in the next few weeks.

 

[cinergi]

Use the log parser tool to extract the "Sleep" record and plot the battery temperature vs time. Then see how long it takes for the battery to cool down to the "no-regen" point (or send me a log and I'll do it for you)

Assuming ess_min_temp is the right field (for sleep record) and is in Celsius, the absolute minimum of all my sleep records is 0.96. I've had the car parked, unplugged, for 8 hours in -10C ... weird. 0.96 would indicate to me the ESS hasn't gone below freezing, so why was regen off? In particular, for the day in question (12/6), the minimum for the entire day is 1.47. For the Drive1m records, I see a coolant_temp field, which was 0.5 when I started driving. Within 1 minute, it was 2.5. Regen didn't kick in (first 0x2c/Brake/RGbrk row) until 40 minutes later, with coolant_temp on the drive1m saying 6.5 ...
The following day I started out with coolant at 1.5, regen kicked on 3 minute later at coolant at 6. And moving on to 12/8, start = 2.5, regen 18 minutes later at 6.5. Seems like 6 is the magic number... Do I have all this right? First time I've ever looked at logs and I'm just making educated guesses on the data I see here ...

 

[mpt]

Cinergi: Ah, you were measuring the current draw for the cabin heater from the battery; I thought you were measuring the current draw from the utility feed to the charger with an external tool.

I understand that the cabin heater is 4KW and I believe that the Ammeter on the dash shows only half the total current. I think that the battery is configured as a 150-0-150 pack to make AC easy to create and that the ammeter is only on one leg. I suspect that the heater is AC 300V.

Evidence? If the heater is 4Kw, you should see 15A @ 300v not 8A. When charging, the meter shows half the charge current, i.e. 30A charging, the meter shows 15A. When Camille Ricketts chatted with what's-his-name with the chin (forgotten) she said that the accessories; heat, etc. used 20A. We never see more than 9A right? When driving the power meter shows 50Kw yet the meter shows ~80A not the 150+ we should see.

Obviously, the meter is connected to a 300V system so the numbers don't match perfectly, i.e. we're charging at 30A @240v but for the meter to only show 15A we'd need to be at 480v into the battery.

I think that the coolant heater is a completely different heater to the cabin.

 

[cinergi]

Cinergi: Ah, you were measuring the current draw for the cabin heater from the battery; I thought you were measuring the current draw from the utility feed to the charger with an external tool.

I understand that the cabin heater is 4KW and I believe that the Ammeter on the dash shows only half the total current. I think that the battery is configured as a 150-0-150 pack to make AC easy to create and that the ammeter is only on one leg. I suspect that the heater is AC 300V.

Evidence? If the heater is 4Kw, you should see 15A @ 300v not 8A. When charging, the meter shows half the charge current, i.e. 30A charging, the meter shows 15A. When Camille Ricketts chatted with what's-his-name with the chin (forgotten) she said that the accessories; heat, etc. used 20A. We never see more than 9A right? When driving the power meter shows 50Kw yet the meter shows ~80A not the 150+ we should see.

Obviously, the meter is connected to a 300V system so the numbers don't match perfectly, i.e. we're charging at 30A @240v but for the meter to only show 15A we'd need to be at 480v into the battery.

I think that the coolant heater is a completely different heater to the cabin.

I thought I'd checked that the ammeter matched the KW meters ... I'll double check that again.
The "2KW" from 8A at 240 was for the battery heater. For the cabin heater, I've only ever made note of how many amps the in-car ammeter showed. If the ammeter shows 15A while charging at 30A/240, then the reverse should be true -- the ammeter should show the actual amperage draw from the ESS, no? I'll go play with that later today. BTW the nominal pack voltage is 400V (e.g. when fully charged). The A/C is a 400V system, and I'd suspect the heater is designed for 400V ... of course this is about power so we'll have to factor in both actual ESS V and A.

 

[mpt]

No, wait, my previous post was indeed bollocks. I've just checked. Charging at 12A @240v the car registers 5A on the dash amp meter (charge then turn on key to see).

If the battery system is 400V then that's about right; it's about 2-&-change KW.

Under hard acceleration, the meter shows 600A plus which also makes sense.

The dash display make sense... hopefully I do too now.

 

[cinergi]

No, wait, my previous post was indeed bollocks. I've just checked. Charging at 12A @240v the car registers 5A on the dash amp meter (charge then turn on key to see).

If the battery system is 400V then that's about right; it's about 2-&-change KW.

Under hard acceleration, the meter shows 600A plus which also makes sense.

The dash display make sense... hopefully I do too now.

Yeah 25 KW on the needle is 65A on the ammeter; ESS should have been around 380V as I had a full standard-mode charge so that's effectively 24.7 KW ... I also remember seeing charging 40A @ 240 registering as about 20A on the ammeter but haven't done that today.

 

[Doug_G]

Relevant firmware update

Noticed this in the firmware release notes:

Release 4.2.30 / 4.2.34

Charging

When plugged in to charge in Standard, Range, or
Performance (not Storage) mode, the battery
heater will be used (in very low ambient conditions)
to keep the battery temperature high enough to
maintain regenerative braking. This feature
ensures regenerative braking while driving at any
ambient temperature.

Good to know...

 

[doug]

Brings up the question again of how much energy is used heating the battery. How does that compare to the temporary missed opportunity for regen.