maanantai 26. syyskuuta 2016

A little improvement to the Leaf heater switch

I added a little hack to the Leaf heater on/off/half power switch I installed earlier. The Leaf hacker who made the switch into a kit published a video about some improvements to the system and mentioned that there could be a way to bypass the switch when the car was pre-heated. I pretty much immediately figured that if I were to add a relay powered by the 12V AUX outlet that would do it. The AUX outlet only has power when the car is on, but not for example while pre-heat is activated. He later went on describe the same idea on video.

Today I finally got around to adding the relay. The wires going to the 12V outlet were a bit hard to get to, but I managed to add a vampire clip to the positive wire. The negative wire I ended up connecting to the ground on one of the bolts holding the infotainment screen in place. Then it was just a matter of running two of the wires going to the switch (not the brown one) through the relay and that was it. Come to think of it, I guess I could also have run just the brown one, but the end result is the same.

Now I don't have to worry about which position I left the switch - pre-heating will always work. The very useful hack is now even more useful and user friendly. It's good to have less things to worry about and it might just save me a couple of trips to the car which I would have done just to check the switch position.

Oh, I also added a switch the EVSE I made. I can now switch between 6 and 16 amps using that EVSE. Together with the original 10 A cable I now have three levels of power to choose from and still have a backup cable in case one of them breaks. Good times.

tiistai 30. elokuuta 2016

Improving the Leaf

"If it's broken, fix it.
If it's not broken, improve it."

That goes for electric cars too. I've done a couple of little things to our Leaf so far. Let's have a look.

Right off the bat, I just had to have a 16 A charging cable. The car came with a 10 A cable, which is fine for overnight charging, but when you're charging at work or on the road you just want to get the full speed (our Leaf only has a 3.6 kW charger). The EVSE is a kit from GWL Power and the plug with lead is from Works like a charm and is very light so it doesn't put a strain on the Schuko plug. I've since replaced the Schuko plug with an angled one to make it even better.

The Leaf's heater control has a major flaw in that the only way to turn off the electric liquid heater in the car is to use the Climate Control Off button, which stops all fans, but also for some reason directs the natural airflow into your feet. That's not what you want in the winter. You want to be able to control the air (mainly direct it to the windscreen) and still turn off the heater for maximum range. Even better, this kit will let you turn off the heater or have it not heat the liquid as hot as it usually does. The only problem is that you need to remember to switch it back on for pre-heating to work, but I'm working on that as well (you need to add a relay driven by the aux 12V plug, but more on that later).

As an additional source of heat I've put together a somewhat portable heating kit, which includes a 1.5 kWh pack of LiFePO4 cells and a 1000W heater from a Citroën C5 along with some fans. It doesn't quite put out the whole 1000W, but a good 750W anyway, which means two hours of heat into the cabin while not using any from the traction pack. Might come in handy in the winter. You can direct it to the windscreen, which might just be enough to keep it from fogging and freezing. We'll see.

To keep the heat where it's needed we came up with this mattress-based solution. I cut a new 200x120cm mattress into a shape which fits snugly behind the front seats. The piece is 150x120cm at the widest, so you will need a 120cm mattress. My better half even sewed the cover back on so it looks nice. She's a keeper.

Turns out the cut mattress is also pretty much exactly the right size to fit in the boot with the seats folded down. This might also come in handy if a quick charger is out of order and you need to spend a bit more time charging than you had planned, for example if it's getting late already.

Last, but not the least, definitely not if you consider the amount of work, I wrapped the heating pipes under the hood with some Armaflex XG tube to keep the heat inside the pipes as much as possible. For some bizarre reason the heating system in these early Leafs with liquid heat is not insulated in any way, which lets a lot of the heat just escape and makes the heating terribly inefficient. At least now I've covered most of the pipes. I had to take out the 12V battery, not forgetting to cover the solar panel. Some of the piping below was still unreachable so everything's not perfectly insulated, but I did the best I could. The heater itself has no insulation either and it's sitting right behind one of the cooling fans and a radiator. What were they thinking. Even if this was quite a bit of work, it was the cheapest of the modifications. The tube and the aluminium tape cost 12.10€.

Anyway, with these modifications, mainly related to winter driving, I'll see if I can manage a winter without installing a fuel burning liquid heater which I had in my previous car, the C-Zero. Hopefully I don't have to go there, but I won't be afraid to do it if I have to.

tiistai 5. heinäkuuta 2016

A Leaf among other things

So, yeah, got a Leaf. Traded in the C-Zero. It was a nice little car, but more range is more range. Something like 50% more. The Leaf I got can get about 19 kWh on a full charge and 18 kWh from a quick charge. Much more than the C-Zero, which was down to something like 14 kWh, making the usable kWh between quick charges aroung 12 kWh. Plenty for in town, but not so much between towns.

I also kinda sorta started putting the electric kWsaki motorcycle back together. I've been bottom balancing the 40 Ah cells I have left. Looks like I might be able to put together 29 anyway, even though many of them bloated previously. They seem to hold voltage now, so I'll just have to drive them to see if they keep working ok. Eight of them have been in the Xsara, four as an extra battery to take it from 25 to 27 cells (two 40 Ahs in parallel, since it has 60 Ah cells) and two as it's 12 volt battery. 

Having a higher voltage on the Xsara might have caused it's DC/DC converter to blow up, but as is often the case with something blowing up I've also learned something. Turns out the issue I had with the 12 volt system was caused by the DC/DC converter. It was quietly draining the 12 volt battery when it didn't have high voltage connected, thus causing me to loose a few lead acid batteries. Well, now I know not to leave a DC/DC converter always connected. You need to disconnect them from high voltage to keep them draining the traction battery and from the 12 volt battery for the same reason. Nasty buggers. I've also learned that I don't really need a DC/DC converter in the car. At least with four LiFePO4 40 Ah cells in series it works fine without and the battery stays full instead of the car draining it.

Also the 2000 W 87.6 V charger I originally had in the car seems to be ok as well. It just had blown a fuse when I last had it in the car. D'oh. Well, I replaced the fuse and it's working again. Very happy about that. Now I just have to decide what to do with the controllers. I have the better 120 V 600 A controller in the car, but the higher voltage pack available for the motorcycle as well as a 102.2 V charger for it. Not sure if the 72 V (90 V max) AXE7245 I had in the car and before it in the motorcycle is completely functional though. It started go offline while driving, which is why I put the 600 A Kelly into the car. I guess I'll figure it out eventually. I haven't been driving the Xsara after I got the Leaf though, so I might just store it and put the better controller into the motorcycle anyway.

lauantai 6. helmikuuta 2016

C-Zero 12V battery relocation

I don't think I've actually told you where I relocated the 12V aux battery in our C-Zero. I did put the fuel burning heater where the 12V lead acid battery usually is. From there, and the positive battery terminal, I ran a 16 mm2 red cable into the cabin thru the grommet below the center console and under the back seat. I took out the styrofoam box containing the tyre fixing equipment and put a 12V 20Ah LiFePO4 battery there. It has a 100 A fuse on it, which is plenty

The battery in question is one of these:

It's been functioning perfectly so far. It usually sits at 13.3 V when the temperature is normal, a little less when frozen. The car keeps the 12V bus at about 14.5 volts when it's running or charging. That's about 3.6 V per cell, which is quite ok. The cells are as they came, I didn't do a bottom balance on them myself. I think they ship these 12V batteries with balanced cells.

perjantai 15. tammikuuta 2016

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:

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.