Like two peas in a pod

 

Mazda MX-30 eSkyactiv 2020 and my Citroen Xsara 1997/2014 conversion.

Gave up and installed a BMS

Yes, it's true. I gave up and installed a BMS. A Battery Monitoring System, that is. Not the kind that drains a few of your cells and then their buddies destroy them at the earliest opportunity. No, the kind the measures two voltages. Whole pack voltage and half pack (more or less).

 The brains of my BMS.

In my case the half pack is the first 13 cells. What this gives me is four interesting figures:

• Average cell voltage (total voltage divided by number of cells)
• Average cell voltage for the first 13 cells (their total voltage divided by 13)
• Average cell voltage for the last 12 cells (total voltage minus first 13 cells divided by 12)
• Difference in average voltage between first 13 and last 12 cells.

That last bit of information is very interesting, because if it is more than say 0.2 volts, there must be a problem with one of the cells in either part of the pack. All data goes to my Zabbix server, which can alert me, if that happens. I also have Grafana set up, so I can some pretty graphs too.

Now you may ask how do I measure the first 13 cells and not cause an imbalance? Well done, my young Padawan, that is the right question. Well, I have a relay in the loop, which only connects the first 13 cells for a very short time, less than a second, currently every three minutes. The load imposed on the first 13 cells is also something like 0.1 watts. This should not cause a problem even in the long run. And if it does, I'll know about it.

I've used a LinkIt Smart 7688 Duo for a couple of IoT things now, so that's what I used here too. You can get easy to user Grove parts with sensors and the like from Seeed. They're really quite handy if you're as lazy as me and don't want to be soldering every last thing yourself.

Solar controller for charging the car.

I also now charge the car on solar. I have a couple of panels installed which actually charge my motorcycle first and from there I can charge the car, if it pleases me. But more on that later. The motorcycle has had a bit of a make-over as well. It's been about two years since the last post, so if you waited this long, perhaps you can wait a bit more for those as well. Anyway, good times.

ps. Don't pay attention to the grounding cable on the battery box. I've been meaning to hide it for six years now. It's going to happen any day now. Really. Maybe.

Showing off

I got caught on video, mostly about the car conversion. Finnish only, I'm afraid.

The link to the video here has been removed due to the maker of the video becoming an antivaxxer and even harrassing children about it. I will not promote any of his work on any of my platforms.

Mystery box

Disclaimer: I take no responsibility of anything. What you do with the information on this blog is completely up to you. In fact, do not try this at home or anywhere.

So this mystery box appeared out of nowhere. It seems to have a couple of connectors. One red male and one black female. I wonder what's inside?

Looks like it has a contactor, a piece of PCB with some components for generating a PWM signal and a switch for doing something. The parts could be these:

• https://www.aliexpress.com/item/ZWET-IEC-62196-Type2-3-Phases-Charging-Socket-European-standard-EV-charging-Type-2-connector-for/32805447401.html
• https://www.aliexpress.com/item/TOCT1-4P-25A-220V-230V-50-60HZ-Din-rail-Household-ac-contactor-4NO/32790911085.html
• https://www.ev-power.eu/Electric-Cars/EVSE-Kit-V1-1-for-EV-charging-station-cable-Wallbox-kit-only.html

Looks like this is the manual for the board: https://www.i4wifi.cz/img.asp/?attid=325360

There seem to be no protective components, like an RCBO. One has to assume that if one was to plug this in one would have to make sure the inlet already has all the required protections in place.

Anyone with a keen interest should probably really dig into the board manual to figure out how the things are connected and how to limit the current of the device. There seems to be more than one way to do that. The way it's done in these pictures seems dubious. Perhaps there's a better way?

Still alive

Zoe has been working great. I have well over 10.000 km on the clock now and the only issue I've had is the "Check ELECTRIC System" error which occasionally pops up on the display, but apparently it's much less serious than it sounds and nothing to do with the high voltage system. I'll mention in the first service next year, but that's all. Also funny are some of the translations from french, for example pre-heat is pre-soak. Well, the weather has been quite a soak this fall. The 40+ kWh battery is amazing and I've actually pretty much stopped looking at the range meter. It's more like with an ICE car where you just know or notice that it's time to fill up instead of continously monitoring the state of charge.

The converted Citroën Xsara is also working as usual. Had to have it's yearly inspection done and still nothing to fix on it. The brakes could be better, but they still get the job done in city driving. I did notice that the ethanol heater I have in the car wasn't putting out much heat, but turned out I just had to bleed the "cooling" system. Luckily it's really easy to do and the heat was back right away.

EV meet-up and time for a Zoe

First of all, it's alive! kWsaki was revived today for an EV meet-up at the Pori Energia offices. We have SuomiAreena summer happening in Pori now, so there's a lot of people around. This makes a good time to have a little get together. The bike is still working great, although the non-EV bits would seem to need a bit of attention. Brakes don't feel great and there's something weird about the steering.

In any case, the bike is alive, currently with 21 cells for about 70 volts of electric power. I tested the bike and the top speed was around 90 km/h with this voltage. I've had it up to 29 cells or 97 volts, which resulted in about 130 km/h top speed. That's about 4.5 km/h per cell or 1.3 km/h per volt.

We had a lot of good discussions, also with Minister for Foreign Trade and Development Kai Mykkänen, who visited us and talked about what the government is doing to further the EV cause.

In other news, the Leaf is gone. That's right, we decided to invest in a little bigger battery. Quite a lot bigger actually, so we went ahead and got us a Renault Zoe with the  new 41 kWh battery.

I have to say the car is really great and range anxiety is gone. Completely. The bigger battery means I can manage my journeys with ease and the ubiquitous Type 2 charging points together with the 22 kW on-board charger of the Zoe means charging is possible almost everywhere, quite often also completely free of charge. So, once again, good times!

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.

Improving the Leaf

"If it's broken, fix it.

If it's not broken, improve it."

--The Fixer's Manifesto by Sugru

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 EVBitz.uk. 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.

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.

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:

http://www.ev-power.eu/LiFeYPO4-batteries-12V-1-1/Lithium-Battery-LiFePO4-12V-20Ah.html

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.