Winter EV operation

Does anyone know if there is a heater core from the ICE that can be used for heating the cabin? I ask because I just finished a 270+ mile trip in HV mode and got 44.7 MPG on the last 135 mile leg with a battery at about 6 miles of range at the start with an air temp of about 30F and the heater on.

Nice to see that actual milage agrees or is slightly better than the sticker rating. The only problem is that the car seems to think that I have 248 miles of range with a depleted battery and slightly more than a half tank of gas (44mpg x 4gal = 176 miles of range)...

 

Based on other posts, it does not appear that we can use waste ICE heat from its coolant loop to heat the cabin. So I’ll bet you started off with more than the 6 miles of EV range you ended with.
As to the HV range, welcome to the Guess O Meter Club. Some posters are seeing HV ranges in the thousands. I’ve only put 2 gal in since driving away from dealer w a full tank and I’m already up to 558. It seem to be a common problem and will only get worse (increase) every time you put gas in the tank.
Refer to this post for more info
https://www.insideevsforum.com/community/index.php?threads/let’s-get-the-hv-range-problem-fixed-here’s-how-and-a-poll-to-track-it.871/

 

I didn't realize that. Are you saying the only heat for the cabin is electrical. Can you direct me to the posts that indicate there is no cabin heat from the ICE?

 

Hi bpratt, here are some posts from earlier in this thread.
Hope this helps.

 

Bpratt, now that I think on it, I realize that although we have resistance heat for EV mode when there is no ice heat does that mean that the car is able/unable to stop resistance heater and switch to warm coolant from the ice when it is warmed up? I have no idea.

 

I realize the PHEV has a resistance heater that appears to heat engine coolant in the heater core. I also realize the PHEV has no heat pump. I assumed the heater core and resistance heater were in a closed loop when the engine is not running and the loop would open to engine heat when the engine was running. Anyone know for sure how that works?

 

Well, I did find this in this article:
https://carswithplugs.wordpress.com/2018/03/17/electric-car-heaters-honda-clarity/

The Honda Clarity PHEV uses a coolant based electric heater that works like an on demand water heater. If you ask for heat it will heat the coolant and flow it through the heater core in the cabin (just like a gas engine would). Given that this is a coolant system, it is surprisingly quick to heat the air. It switches to using the engine for heat at very low temperatures (less than about 5 F (-15 C) or so, seems related more to battery temperature than air temperature).

 

In Canada, in the cold of winter it looks like the range will be ~45km based on user experience.

But for planning purposes I always use an estimated winter EV range of only 50% and then ask myself if that will work for my circumstance.

If I can make due with only 50%, everything else is a bonus and puts a smile on my face rather than a frown in winter.


Sent from my iPhone using Inside EVs

 

I live in Wisconsin. We have been having some bitterly cold days. I work a 9 hour day and my car sits on the north side of the building with a direct west exposure as well. A few days ago, I got in my car to go home and it made a noise similar to the seat belt alarm. It was nearly fully charged. I got an error message that said: Engine System Problem. Power Generation Not Available. Vehicle will stop in 16.4 miles." That message alternated with another that told me to find a safe place to pull over and stop the car. I drove the 5 miles to my house and called the dealer. Seeing as I was the first Clarity purchaser from them (and maybe the only?), they had no idea what to do. They told me to park my car in the garage and plug it in. I did and the next day it worked. My issue is the forecast is calling for wind chills of -50F for later in the week. And even if I had a battery warmer on my car, we have no plugs at work. Any suggestions?

 

Diane Williamson

Below is a link to one of several threads on cold weather starts etc.

As a FYI...actual temps not wind chill temps are what you need to be concerned with and monitor.

https://insideevsforum.com/community/index.php?threads/cold-start-thoughts.4447/

Hope this helps.

Good luck

 

The message seems to indicate your Clarity would travel only under EV power--something I don't believe anyone's ever reported on this forum before. I wonder what temperature-related problem would keep the ICE from starting? Did you try to start the engine by selecting HV Mode on your 5-mile drive home? I wonder if that would have produced a different warning message?

Your incident would persuade me to purchase an OBD-II scanner to see if the problem produced any trouble codes. Of course, your dealer can check for trouble codes, too.

 

Suggestions:
1 Move south, waaaay south!!!!
On a more serious level,
2 If work allows, could you use a heavy duty extension cord (from the building) and the OEM Level 1 EVSE? That might help keep the 12v and HV battery fully charged. But boy would that Canadian battery heater come in handy. Ranting here, but IMHO Honda should have given all of us battery warming. It can’t be that much of a weight penalty.
3. Periodically call for preconditioning. I don’t know for sure, but this might cause the ICE to start up at those low temps. If it doesn’t, then you wouldn’t want to do it and drain your HV battery. So I’m not sure if this will help the error codes or with the battery cold soaking outside. You might just have to try it and see. And I’m not sure how often you’d have to do it if it did help. Might not be feasible.
4 Carpool or Uber during the worst of this Polar Vortex so you don’t get stranded.

Best wishes and hoping you get through it ok.

 

There's a good post over in the other thread on cold starting about wind chill, and a quick mention of it above. Just to reiterate in this thread too, wind chill acts to cool things that are warm, but does not lower temperatures below ambient actual. So, for the purposes of starting and running an electric vehicle, what matters is the actual temp, not the wind chill temp.

 

I have a lot of unresolved questions about this general topic of EV battery cold weather behavior. As another piece of data, we had a very cold day in MA last week (~0 F; -17 C), and I was attempting to charge at an outdoor public ChargePoint L2 station, which in moderate temperatures charges at 6.0 kW, and during the past couple of cold months it is typically at 4.0 - 4.3 kW, but on this extra cold day it was 1.4 kW. So I put on the precondition in the hopes that it would warm the battery enough to charge at at least 4 kW, but no such luck. I had preconditioning on and off for 4 times over the course of the 3 hours of charging and it did not change the rate of charge at all - it was still around 1.4 kW, no matter how hot the cabin got. (Note that during the preconditioning the kW spiked up to 6 kW and drifted between there and ~5 kW during cabin heating; but after turning it off or if it shut off naturally, the base charging rate was still 1.4 kW).

So I understand that the heat/cooling of the battery is independent of the cabin HVAC. So my conclusion is that preconditioning seems to have little or no impact on the battery charge rate. Still, even without the cabin preconditioning you'd think that 3 hours of charging at 1.4 kW would be enough to raise the EV battery temperature to where it would be comfortable to raise the charging rate.

If anyone can shed any light on the Canadian battery warmer I am all ears. Is it in the engine bay somewhere? Is it truly heating the EV battery or is it possibly a battery heater for the 12V battery? The mentions of 'battery' seem to be at times somewhat interchangeable and thus I wonder if they mean a battery warmer for the 12V battery, but it is interpreted by many as a warmer for the EV battery. If it really is a warmer for the EV battery, is this something that can be jerry-rigged with an aftermarket heater? It is hardly worth my while as we rarely have really nasty cold days in MA, but I wonder if in my garage if I pointed my little ceramic space heater at the radiator, would it help to keep the battery temperature from chilling too much?

If the Canadian battery warmer is for the EV and is integrated into the battery / power infrastructure somewhere deep in the car (unlikely), I wonder if it is built into all North American models, but is only 'hooked up' on the Canadian ones. Crazy to think so, but I remember when people post the output of the PDI battery check that one of the line items above the battery Ah, are mentions of 'Battery Heater Contactor'. It may be a ubiquitous code that is only active for the Canadian models. But I recall in the early PC CPU days that Intel or AMD had a math coprocessor on all the chips, and on the cheaper ones it was just disconnected, lol.

Anyway, I'd be interested to hear more details about the Canadian heater or any details at all about how the heat for the cabin vs the waste heat from the ICE vs the heat to/from the EV battery are interconnected or not. Presumably, the Clarity Electric (EV) model and the Fuel Cell model handle heating for the battery in slightly different ways without the ICE; or maybe not.

I have seen the SAE paper on the EV cooling system for thermal management (someone posted on here somewhere), but the references to battery warming are only with regard to the warmth that is self-generated during charging. There is no reference to the Canadian heater in that document as it is all about cooling really.

 

A car out overnight on a clear night can get maybe 5-10 degrees below the ambient temperature due to it being metal and radiating to the sky whose temperature is much colder. Wind actually reduces this effect. http://www.asterism.org/tutorials/tut37%20Radiative%20Cooling.pdf

 

@Ray B, I suggested the preconditioning might help only because I thought it might force the ICE to come on and perhaps warm the battery indirectly or at least make it easier to start. But that may be a long shot. But if the trigger event for not allowing start up is ambient temp or HV battery temp, then upon reflection, I’m not sure anything will help an American model with no battery heater left out long enough and unplugged in sub -23 F conditions.

 

I was thinking the same thing last week, when I saw how low the charging rate was. I was sure that heating the cabin would help speed up the charging, but after 3 hours of trying I figured there was no easy/direct link between the cabin heat and the temperature of the EV battery.

Perhaps if the L2 was disconnected, and then I preconditioned, it would draw enough load from the battery that it would heat up on its own from churning out so much current, and then after that when connecting up the L2 it would accept the higher level of charging, but it is a trade off because I am using up EV battery charge to heat up the battery so that it will charge faster. So in the end it may not save any time.

 

It's highly ironic that I installed my level-2 charger on one of the coldest days of the year and am observing the same thing that you are seeing - charge rates that are similar to the level-1 charger. I am not surprised that charging at that rate does not heat the battery. Even if 1.4 kW was going into the battery 100% as heat, given the mass of the battery and the fact that it is transferring heat to a very cold environment, you wouldn't see a lot of actual temperature change in the battery. And only a small fraction of that 1.4 kW is producing heat; the rest is charging the battery, so I don't think that charging is going to get better as it proceeds. It's kind of a catch-22 in the sense that a cold battery is not accepting much power, so there is not much to heat it.

The battery is under the rear seat. Heating the engine compartment will have no effect. I have no personal experience with the Canadian battery heater option, but it has to be in/at the battery to have any effect. It's not the 12v battery. I suspect that you could rig something where you have a heater that you park on top of that would then heat the battery from below. That seems expensive and potentially dangerous, so not something I would pursue.

I do not think there is any connection between the engine coolant and the battery coolant. That would seem to be a reasonable way to heat the battery, but the logistics would be difficult since the more common need is to cool, rather than heat, the battery.

 

Good point! And that much additional cooling might be the difference in whether or not the car will run. Another good reason to park inside!

As an aside, my uncle supervised the electrical lab in Indiana that built the device that first detected the hole in the ozone layer over Antarctica. I remember him telling me they cooled the unit as it orbited the earth by pointing it at the darkest spot in the sky to take advantage of radiation cooling.

 

We're supposed to hit 0 F in MA sometime this week, so I'm sure we can try out some theories. I did something similar by trying to precondition while the car was charging at a L2, but although the preconditioning drew power from the L2 at a good pace, the battery did not charge fast at all.

I think it's almost purely a function of how warm the battery is at the time of charge. So when it's the coldest this week, prior to charging I'm going to drive on the highway in ICE mode for at least 15-20 minutes, so that the rest of the car (including the battery) is at a decent temperature, and plug in immediately afterwards and hope that the charging rate doesn't get too slow.