Heating my EVs

I'm sure I've covered the heating in both of my EVs, the cars at least, in previous posts, but I though I'd write a new one about them and how they've been doing.

As you may or may not know, I heat both of the cars with ethanol. In Finland it's easy to get locally produced bioethanol, which is made from biowaste, so it's basically free energy in the sense that it only requires a little work to make a burnable liquid from it. It doesn't add to the carbon burden on our climate, because it's not something stored underground and pumped into the air. It's already here and it's just recycled into something useful.

The C-Zero obviously has a electric liquid heater already, but it's not very powerful and yet it consumes a lot of power. It can take up to 5 kW and when you consider that the car only has a 16 kWh (nominal) battery, you can see that it will easily eat up a third of the pack capacity in an hour. To make matters worse, any used EV will not have it's full capacity left, like mine which only has about 14 kWh left, so it's even worse. And it doesn't even really get your toes warm even if you have it on full blast. It'll keep you a alive, for a short moment, but that's about it.



The heater I have in the C-Zero is a Binar 5B from Autoterm:
https://autoterm.eu/en/shop/engine-preheaters/binar-5b-12v-bensiini/

It's made in Russia and meant for Siberian winters. I'm not sure if they've completely managed to hit that target or is it because I've been using ethanol only, but so far in the 15 months I've had it, I've had to replace he glow plug twice and I'm just about to replace the fuel pump. It may be that especially in the most harsh winter conditions we've had here I might have been better off using gasoline. I had left the car sitting outside for three weeks during the holidays and when I got back the fuel pump wouldn't work anymore. Ok, it had come down to -25˚C, so it wasn't exactly sunny, but still. I was a little disappointed. Why I've had to replace the glow plug twice, I have no idea. I do think that the ethanol is not as flammable as gasoline (I couldn't get a bonfire started with ethanol), so maybe that's it.

In any case, Autoterm has a 2-year guarantee on their products and they've come through nicely. I've got new plugs from them and a new fuel pump just arrived today for free, so it's mostly only been the annoyance of the heater being broken and having to fix it. Then again having to fix stuff is something I've known to have taken pleasure in.



In the Xsara I'm burning the same bioethanol, but with a different heater, a german product called Webasto Thermo Top E. This one I got from a junk yard for 150€, so it was very affordable. Actually the first one I got didn't work at all, but they let me just swap it for another, which did work right away. The fuel pump didn't come with the burner, so I had to buy it separate from ebay, which added about 50€ to the cost. The burner is also a gasoline model and this manufacturer doesn't guarantee it to work with ethanol, unlike Binar, but I just tried it and haven't had any problems with it.

Actually this burner has been the most reliable of the two. Even though it had seen some heavy use for several years and the pump was a used one too, there has been zero problems with this one. It's also smaller than the Binar and the water pump is right there at the device. It has sort of made me regret that I didn't try to look for a used Webasto for the C-Zero as well, but then again it sort of made sense to use a new part in a newish vehicle. I also might not have been able to find another for such a good price. Usually they ask Binar-like prices for even used Webasto brand burners and the spare parts are expensive as well.



The Binar does have a couple of other things going for it as well. It has a display (in the picture) which shows the "coolant" temperature, so you know what's happening. It's also more powerful than the Webasto, 5 kW vs. 4 kW. The Binar hasn't had a problem getting up to 70-80 ˚C in any weather, whereas I think the Webasto might not have been quite powerful enough in the coldest days. On the other hand it doesn't show the temperatures so it's a bit more based on a gut feeling and it's the only method of heat in the Xsara as well. Additionally, the coolant pipes in the Xsara were quite long and exposed, so I just added some insulation on them the other day, which might also make a difference. I could also test if gasoline would improve it's heat output. In any case when it's not been terribly cold it has been more than enough.

One thing you need to keep in mind with these heaters is that they're not going to keep the coolant at a set temperature at all times. They will cycle so that first they will run on full blast to get the coolant to 70-80˚C and then go to a low power mode and restart the full power if the liquid temperature goes down to 40-50˚C. So they heat output is not going to be exactly the same at all times.

The way the heat works in the C-Zero (and all i-MiEV based cars) is that when you have the temperature knob on hot (or previously had it on hot before setting it to neutral) it will blast all the heat it gets from the heat exchanger. It will not mix any cold air into it. So you need to regulate the hot airflow with fan speed if you have a burner. The idea originally has been that the knob's heat setting directly controls the coolant target temperature of the car's own electric heater. If you turn the temperature knob to cold and either keep it there or turn to neutral without going on hot, it will only put out cold air into the cabin and no heat from the heat exchanger. Also the car's original coolant pump only runs when the knob is on the hot area. The burners I have also have their own pump, so they don't need that car's pump to be running, but it's something to keep in mind. I haven't had any problems with having two coolant pumps in the system running independently.

What I generally do is that on a really cold morning I keep the temperature knob on neutral (having had it on hot previously thus keeping the air going through the heat exchanger) and only start the ethanol burner. Once it's up to temperature, I may switch the temperature knob to one step into hot, just to make both coolant pumps run. It's not strictly necessary though. If the burner is stopped (manually or by it's timer) I can then leave the know on 1st heat step, let the car's pump circulate the still hot liquid to get the most of it's heat into the cabin and perhaps let the electric heater to keep the liquid lukewarm once it's cooled down. Sometimes I might also immediately have both on, with the heat on 1st step, to get some heat into the cabin as soon as possible, but still leaving most of the heavy heating for the burner.

Update: The heaters will burn about 0,5 to 1 liter of ethanol per hour.

What's up

It's been a little slow on this blog lately. Which doesn't mean I haven't been busy. Let's start with the converted Xsara. It's 12 V aux battery woes have continued. Also contributing to the issue is your's truly, forgetting the vehicle running and so on. So it seems I killed another lead acid battery. Maybe it's a hint I really should take and just not use them anymore at all anywhere again. To replace it I put in four of the worse 40 Ah SE40AHA lithium cells I had around. Worse because they don't really keep their voltage really well and are at least a little soft shorted inside, but not completely.

With those four cells in the can serving the purpose of aux battery I set off to the local inspection office to have the vehicle checked, as is required every year. This time I had no less than three officers looking under the hood and asking questions about the electric powertrain. The brakes have seen better days, but the car still passed. I should still take them apart and at least try to salvage the discs.

It seems there were no pictures taken of the battery swap or the inspection itself, but there are pictures of something I did a little earlier. The repaired 87.6 volt charger gave up the ghost again and this time I pretty much gave up on it. Again, I suppose, but not willing to pour any more money into it.

So thinking about how to solve the issue again, I decided I'd add some more batteries into the vehicle. It has 60Ah cells, but since I have those abused 40 Ah cells around from the motorcycle, I decided to augment the pack with a couple of them in parallel. Turns out I can just about get away with a string of 27 cells with the AXE 7245 controller in the car. It has a maximum voltage of 90 volts, but it will start if the voltage, as presented by Cycle Analyst, is less than 91 volts. With the 27 LiFePO4 cells in series and fully charged, I end up a little over 91 volts, but if I let the DC/DC converter run for a bit the AXE will relent and start up. This gives me about 400 Wh more to drive around with bringing the pack total a little over 5 kWh.

It's a bit of a mess, but there they are. I was sort of hoping I could use my 102.2 volt charger directly when increasing the cell count, but I had to put into a bit of monitoring in the end. It looks at 20 cells in the middle of the pack and makes sure they stay within 3.5 volts on average and then it tells the 102.2 volt TCCH/ElCon charger to stop charging until the voltage goes back down. Not optimal, again, but it works for now.

On the C-Zero I received a shifter cover panel from Ben Nelson, who has a flooded i-MiEV his parting out now. It took a little bit of fiddling to get it in the car, but I managed to do it and now it really looks the part. Thanks a lot for part, Ben!

Last, and probably least as well, but still quite important is the addition of two new USB charging ports I added to the C-Zero. I can turn them on or off with the switch. They're always connected to the car's aux 12 V battery, so I can provide power to some devices even though th car is not running. Very handy for CaniOn, which I've also configured to turn on when the phone which is permanently in the vehicle gets power, so I can always easily see what's really going on with the battery.

More "gears" to our C-Zero

Thanks to the great great folks at My i-MiEV forum I got a tip that PSA may actually have just mechanically blocked two of the shifter positions on the Citroën C-Zero and Peugeot iOn. It didn't take much convincing to make me crack open the cover on mine and behold, it was true. I quickly found out that even the screen would show the new B and C modes. On with the drilling and I had some new "gears" to play with.

I'll still need to modify or acquire a suitable cover plate with all the shifter positions.

A quick check using CaniOn and it looks like the difference from B to C is about 10 kW in regen power, with B having the strongest and C the least regen. Normal D right in the middle of those two. Letting the accelerator pedal go at 70 km/h gave about 10 kW regen at C, 15 kW at D and 20 kW at B. I finally have the low regen "C" option for cruising long distance. Good times!

Back to the original charger

The cheap charge controller I had installed gave up the ghost - or more like stopped reading the pack voltage correctly - and the next option, installing a PowerLog 6S to monitor the pack, also ended up with some smoke escaping and thus rendering that device inoperational as well. They run on the magic smoke, as you know. I now have some more electronic junk to be taken to recyling.

Cheap and readily available options exhausted, I figured what the hell, perhaps a local electronics repair shop could fix the original charger. The one that actually charges to a correct voltage right away. And what do you know, a couple of days in the care of Porin Radiohuolto and I once again had a working charger. Had to depart 85 euros for the job, but it's well worth it. These chargers do run at least around 500 € from China.

It had blown a fuse and a couple of caps had swollen, so they had replaced those. I had already suspected that I might have in fact aided in it's downtime by having it connected to the pack permanently, even while driving. It may have gotten on those caps a little and caused the fuse to blow.

So installing the charger back into the vehicle now, I added an 80 amp 12 VDC contactor, which only closes and connects the charger to the pack when the car is plugged into the mains. In the same power inlet as the main charger I just have a 12 VDC PSU originally from a Linksys router, which activates the contactor. I had a timer circuit as well, but decided to leave that out, just to keep it simple. In addition to the charger and the PSU there is also a aux battery charger, which keeps the small 12 VDC lead acid battery of the vehicle topped up.

Added insulation

I've been planning to add some insulation to the doors of my C-Zero. Insulation for the cold winter and also some sound dampening to reduce noise. Today I finally got it done. All four doors got some 1 cm thick foam with a sticky side and a side with aluminium foil.

Driver side front door before and after.

Passenger side rear door. Not as pretty, since I used leftover pieces.

Same door. Now you can see the foil in the unused speaker opening instead of cold steel.

On a quick test drive I noticed two things. The sound of the electric motor was more audible than before. I guess when you reduce other noises you start hearing others. I also noticed that the bass frequencies sounded louder on the car stereo. To be expected, since adding the insulation makes the doors perform better as speaker enclosures.

I'm also planning to add some anti-stone chip shield behind the front wheels. There doesn't seem to be much to speak of. It could also make the car quieter. At least concerning noises made by flying stones, if nothing else.

Update on charge controller

Noticed something nasty with the charge controller setup in my previous post. I really should have thought of this, but the 100V voltmeter is not isolated. It will connect your high voltage pack negative to your 12V negative, which is your vehicle ground. Not cool. In fact so not cool, that it seems to have killed at least one, probably two 12V lead batteries I used in the vehicle as the aux battery.

So, lesson learned, again, always check your pack isolation after you install anything that connects to it. Check voltage between both positive and negative ends of you high voltage and the vehicle chassis. If you see the pack voltage or something like it, you have a problem. If you get some fluctuating, small voltage, you probably don't have a problem. Note that with a brushed motor, you can end up having dust from the brushes build up and create a short, so it's not a bad idea to check even if you don't install anything new.

Charge controller

Went ahead and installed the simple 100V solar controller. It takes 12 volts and the pack voltage. When pack voltage reaches a set value, it will disengage a relay. It's set to disengage at 88 volts, which is a little over 3.5 volts per cell. The relay then controls the Elcon/TCCH charger's Enable pin, which will instruct the charger to stop charging.

Of course as the pack voltage drops, the controller will re-engage the relay and the charger will resume charging. This will make the pack voltage bounce back and forth pretty much forever, so it's not a perfect solution, but it should make sure the charger doesn't overcharge the pack right away. On the other hand there's no CV phase, so the bouncing is kind of necessary to get the pack full.

In any case, this solution will have to do for now.

It's dead, Jim

First things first. Godspeed, Mr. Leonard Nimoy and GNU Terry Pratchett. Also dead is my 2kW KP charger. Coincidence? Maybe, maybe not. In any case, I'm a little short on chargers (and great minds). Luckily, I have the Elcon/TCCH 2500W charger from my temporarily defunct electric motorcycle.

As it happens, the Elcon charger is set for 102.2 V, which is way too high for the 25 cell pack in the car, but it will still start charging although the initial voltage is lower than expected. For the 25 cells the 102.2V would be about 4.1 volts per cell. Not into dangerous territory, but not very good for the cells either. So you either need to watch the voltage carefully while charging or device something to end the charge earlier.

Knowing my tendency to forget things, an automatic shutoff would be much safer. Luckily I've had some experience with one of these voltmeters. It can measure up to 100V and control a relay based on that, among other things. I have one in my bottom balancer, but I'm reluctant to take that well functioning setup apart, which is why I've put another on order from ebay. Once it arrives I'll set it up to control the ENABLE wire on the Elcon charger, so that it will end charging at 87-88 volts. Actually it will bounce back and forth, but at least it will give me more time to pull the plug.

Or, as I just recalled, I also have a CellLog 6S, which I haven't come up with a use for yet. I could also set that one up so that it would monitor five series of five cells and control the charger as well. In that case the cutoff voltage would be 17.5 volts for five cells. It would even be more accurate, since it would monitor five cells at a time, instead of the whole 25. Certainly something to consider. On the con side, it does require more wiring, but maybe it would be worth it. We'll see.

Technically, the Cycle Analyst display could also do the job, but it would require opening the CA case, adding some wires, using a solid state relay and so on. A lot more work, all in all.

Update on cell testing

Just a quick update regarding my previous posts on the SE40AHA cells that seemed to be fine after all. So far, in testing the cells by draining them to about 2.6 volts I've found that out of the 33 cells I have, nine seem to have internal shorts. I can tell this by leaving the cells at 2.6 volts and monitoring their voltage. The bad cells have gone down in voltage, some already below 2 volts. They must therefore have internal shorts. The better cells have bounced back a little and then kept their voltage.

So it looks like I might have 24 usable cells. Unfortunately this doesn't really match anything I have in use. The car, Xsara or kWsara, has 25 cells in series, and the motorcycle, kWsaki, is set up for 29 cells with it's 102.2 volt charger. So it's either figure out something else to do with the cells, get a new charger perhaps, or try to find a couple of SE40AHA cells. Unfortunately GWL Power doesn't list them anymore. They are a couple of generations old now, so it's understandable that they'll be unavailable. Sinopoly has similar black 40 Ah cells, which might do just fine, though.

Regarding winter range

One of the questions I often get asked at the quick charge stations during the winter is how does the winter affect your range. It depends. That's the answer. Turns out, it doesn't just depend on one thing either. It depends on a lot of things.

The most obvious one, and the one people are most aware of, is the fact that current batteries perform better when they are in optimal temperature. That's usually around room temperature, or perhaps body temperature. Much above and you get into trouble. Freezing and below charging becomes slower and they're not quite as willling to part with their charge either. How much this matters on my C-Zero I don't really know. I've done most of my long trips in less than optimal conditions, so I don't really know well it will perform come summer. If I'd have to guess, I'd say it's in the 10-20 % range.

The second rather well known factor is heating. Electric cars tend to use the electricity in their batteries not just for driving but also for heating. In the C-Zero the heater can use around 5 kW. With a 16 kWh battery, with some usually left in reserve, it's not too hard to figure out that the heater can suck up a third of the range in an hour. Generally when I have 100 km range on the gauge, turning heat on will drop it to 70 km, which is probably quite accurate. So I'd say 30 %. In my car I've installed an ethanol heater, so I don't have to suffer this drop in range or the cold either. Some newer vehicles also have heat pumps, which should be able to reduce the consumption to around 1 kW in optimal conditions while still providing enough heat.

Some people are also aware of rolling resistance. Winter tires are designed to grip on snow and ice. And you can't have perfect grip with perfect rolling resistance. In other words, your summer tires will roll easier and winter tires will decrease your range. My guess, 5-10 %.

What I haven't seen anyone recognize is air resistance. If I've done my math right, going from room temperature to something like -20˚C can increase the air resistance or drag as much as 10 %. Simply because cold air is heavier than hot. That's quite a bit for something most drivers don't even think about.

I'll leave it to you to figure out how much all of these could dimish your range.