I am not a battery expert nor am I claiming to be one! I got all my information from the internet and I think designed and build my battery correctly.
Always use common sense and do not blindly trust the information I (or anybody else) am/is putting on the internet.
In 2010 I bought a Novox C20 25km/h electric scooter. Novox was (they are gone) Dutch manufacturer of electric scooters. It seems that they (partially) bought the scooters in China and rebranded them to their brand Novox. It seems that many parts of it were actually from the Chinese manufacturer Tysong.
The model I have is the 25km/h version equipped with a 2.5kW electric motor with 4 12V 40Ah batteries.
Realistically this scooter had a range of about 35 ~ 40km before running out of juice.
In the Netherlands we have two types of scooters. We call them snorfiets (25km/h, blue license plate) or bromfiets (45km/h, yellow plate). My scooter is a snorfiets which means I do not have to wear a helmet.
The primary purpose for the scooter is going to the beach in summer, use it when it’s nice weather and when I want to go somewhere which is a bit to far to go by bicycle.
4x 12V 40Ah
Originally the scooter had 4 12V 40Ah batteries which (in theory) is roughly 1.9kWh of capacity. These were lead acid batteries and each weight 12kg, so the total weight of the batteries was nearly 50kg.
Over the years the range and performance declined until the batteries died completely. After reading about DIY batteries using 18650 Lithium batteries I decided to build my own!
Designing the battery
After I decided to design and build my own battery I went out to gather information. I watched endless hours of videos on YouTube and I also bought a book:
With the information from YouTube, that book and other sources I designed a 14S15P battery.
A 14S15P configuration means 14 Cells in Series and 15 Cells Parallel. The total amount of cells would be: 210 (14*15).
The nominal voltage of the battery would be 50.4V (3.6*14) and the maximum voltage 58.8V (4.2*14).
The existing controller in the scooter would not be able to handle that voltage so I would have to swap the controller. That’s something I’ll explain in a upcoming post.
On AliExpress I searched for 18650 battery cell holders for a 14S5P pack and ordered three sets. Combining them would give me a 14S15P battery pack which would physically fit in my scooter.
During my search for the correct cell I selected the Samsung INR18650-35E cell. This cell has a capacity of 3.500mAh and 210 of them would sum up to a total capacity of 2646Wh (3.6 * 3500 * 210 / 1000) or 2.6kWh for my scooter.
Each cell can deliver 10A of current so 15 of them in parallel would be able to provide 150A of current. With a nominal voltage of 50V that would be 7500W or 7.5kW.
As the motor in my scooter is rated for 2.5kW I would only need 50A of current. 50A or 2.5kW was my design target. Anything above it would be a bonus.
After searching I found the Dutch shop Nkon which has a good reputation and was able to deliver the INR18650-35E for a good price. So I ordered 220 cells (10 spare).
Next to the cells I ordered 15m of 0.15mm Nickel strip to use when spotwelding all the cells together.
Battery Management System
The next important thing was a Battery Management System (BMS). A BMS makes sure the cells stay in a healthy state by doing various things:
Protecting them against under -or overvoltage
Protecting against a high charge or discharge current
Making sure the cells are balanced
There are good and bad BMS out there. At first I thought I’d buy one on AliExpress but after reading on the dutch forum of Tweakers in the topic about electric scooters I purchased a TinyBMS s516 from Energus Power Solutions. It’s not the cheapest, but it does do its job: Protecting my 210 cells!
In addition to the BMS I ordered:
USB programming cable
To connect all the cells together you need to use spotwelding as soldering would damage the cells badly due to the heat.
At first I bought a Sunko 709A spotwelder on AliExpress. Short story: A waste of money!
After searching a bit more I found a Arduino based spotwelder made by Malectrics in Germany.
This spotwelder works great with a Bosch 12V 44A 440A car battery. I made a short video and put it on YouTube.
In addition a picture of the spotwelder connected to the battery.
I never used a spotwelder before nor did I build a battery. I started with building a small 3S5P 12V battery to test my welding skills.
Safety First! Remember to wear gloves and eye protection when working with a spotwelder and/or batteries. Also make sure there are no loose tools or wires on your workplace and again, use common sense!
I am now using this battery as a DIY powerbank with a 12V and USB output.
After I got some practice on building the small battery I just started working on the big battery. Cutting nickel to length and I started to build the blocks.
This took a lot of time, probably over 40 hours as I slowly build my first big battery and still needed to learn.
I ended up stacking two strips of 0.15mm nickel on top of each other to handle my 50A target current.
You can also see the balancing wires of the BMS go to the positive terminal of each series. The manual of the BMS has clear instructions on how to wire them.
From the Nickel I went to 8AWG wire which I connected to a SB50 connector. Using that connector I would connect the battery Plus and Minus to the BMS and the BMS to the controller. The SB50 connector is rated for 50A and thus meets my requirements. I got the connectors from a local supplier.
Using a tape, lexan and some screw the end result (without BMS) looked like this:
And with my TinyBMS connected to it:
The tiny red wires are the balancing wires used by the BMS to monitor the cells in series and balance charge them when needed.
Using a Windows tool you can monitor and configure the BMS using a USB cable (which you have to buy).
There are various settings you can change, but the main values I set were:
Low voltage cut-off: 3.25V
High voltage cut-off: 4.15V
Maximum discharge currect: 75A
Although the cells can range from 3.2V to 4.2V I decided to take a 0.05V safety margin to increase the lifetime of the cells. I might lower the maximum voltage per cell to 4.1V in the future, but that’s something I still have to decide.
Using the BMS tool you can see the voltage of each individual series of cells and see them change while charging the battery.
Charging and Charger
To charge this battery I also needed a new charger as the old charger was not suited for Lithium and the voltage was too low.
I bought a 58.8V/5A charger on AliExpress which I’m using for now. It does seem to do the job just fine for now. The BMS isn’t complaining (yet).
Using XT90 connectors I connect my charger to the BMS although the scooter has a XLR input. But internally I’m connecting all those wires using XT90 connectors.
I got my XT90 connectors at Hobbyking as they also have a local warehouse in the Netherlands and have a good reputation.
The four old batteries had a combined weight of nearly 50kg where the new battery weighs slightly less than 12kg with everything connected.
That’s a weight reduction of 38kg! That will benefit acceleration, handling and range positively.
The end result is a 2,6kWh battery consisting out of 210 cells connected in a 14S15P configuration with a nominal/maximum voltag of 50.4V/58.8V.
My initial calculations and tests tell me that when driving ~30km/h (Yes, I did some tuning!) the motor draws about 20A. That’s about 1000W at 50V.
Since the battery is 2600Wh I should be able to drive for roughly 2 hours and 30 minutes at 30km/h before the battery is empty.
30km for 2.5 hours would mean a range of 75km which is more then enough for my driving habits with this scooter.
With the original batteries I had a range of roughly 40km, but I never tried if it actually got that far. I think I improved the range with nearly 75% with this new battery.
In this picture you see the battery installed in the scooter and hooked up to the controller. A post about the controller and connecting it all will follow later.
The total costs for the cells, BMS, wire and connectors is about EUR 940,00 which can be broken down into:
Cells: EUR 650,00
BMS: EUR 200,00
Wires: EUR 40,00
Connectors: EUR 50,00
Time: 50 hours!
For me it was a cool project and something I could learn a lot from.
There are a few people and sources I have to thank big-time for their information on the internet.
I wouldn’t have been able to do this without those people. Thanks!
The battery is currently installed in the scooter and I’m still in the process of fine-tuning the controller.
My initial test drives tell me that the performance improved a lot! Acceleration to 30km/h is a lot quicker and I feel the motor has a lot more torque than it had before. This is mainly due to the battery being able to provide the current required to power the motor. The weight reduction can also be felt clearly and also contributes to the improved acceleration.
One of the cool things is that the scooter now has regenerative breaking thanks to the new controller.
A post regarding the controller and connecting it all will follow. Stay tuned!
I didn’t write a blogpost about my roadtrip through Europe in June 2015, but you can see the route below (Prague, Austria, Slovenia, Austria, Germany, Netherlands).
I tried to draw the routes I’ve driven on a Google Maps overview.
In the threee years I still think my trips to the Arctic are the highlights for me. However, there were more highlights, so I gathered a bunch of pictures I took and added them below in a random order.
After owning a Audi A3 2.0TDI (2007), Toyota Auris Hybrid (2011) and BMW M5 E39 (1999) I can saw that Model S is the best car I’ve ever owned. I love driving it and still enjoy every KM. (Except when stuck in traffic….). Even without Autopilot it is still an amazing car!
People still come up to me to ask things about the car and are really interested.
As I said. Best car ever. Period. I will never by a car which burns fossil fuel again.
My deposit for Model 3 was made at the day they opened. Waiting!
As I wrote in my previous post we took the ferry from Moskenes to Bodø at 07:00 on Friday.
We left the cabin at 04:30 to make sure we got there on time. It was just 89km, but Google Maps told me it would take me 1 hour and 30 minutes. Due to the snow, wind and darkness it took us 1:48 to get there. In time for the ferry!
After 3 hours and 15 minutes we arrived in Bodø to head towards the SuperCharger in Grong. A 512km drive.
The trip to Grong was long. Nothing really special to mention. Ice and snow on the roads, that is mainly it. A exhausting and long drive mainly.
Fiskevägen all over again!
We took the Fiskevägen route. This time from Grong to Krokom where I took it the other way around last year.
The 240km trip took us 4 hours and 30 minutes. We took it slowly since the view is just awesome!
Halfway we stopped in Rötviken to take a break and charge. Just as last year it was just a 3,6kW charger. It added only 4km of range while we took a break. We did it mainly for the show.
Free 50kW CHAdeMO charger
Getting from the Krokom (Sweden) SuperCharger to the one in Mora (Sweden) is over 300km and I don’t like such long stretches. At home I already found a free CHAdeMO charger in Sveg which is a small town along the E45 from Krokom to Mora.
I should be just a matter of plug in and hit the start button. It was!
This charger is also part of the Green Highway. Much better than the 3,6kW charger in Rötviken!
We stayed in a Hotel in Sveg. So during our dinner in Sveg the car could fully charge.
From Sveg we followed the E45 towards Göteborg and down to Malmö and into Denmark. Slept in Bremen and drove the last 600km home.
This part of the trip was not that special. We just drove for 2 days 🙂
When I left home I hit the reset button for both trip counters. The end result is 5.571,3km with a total energy consumption of 1,179kWh. That averages to 212Wh/km.
One of the things we can for was the Aurora Borealis, also called the ‘Northern Lights’.
For two nights we had clear skies and saw a beautiful display. You can find enough pictures on the internet, so I won’t post all of them!
The route home from the Lofoten Islands is going to be 3.000km. Our guess is that it will take us 4 to 5 days. Not due to the charging, but because you simply can not drive very fast through Norway and Sweden.
Ferry from the Lofoten
We will be taking the ferry from Moskenes to Bodø. The Hurtigruten from Stamsun to Bodø was not an option this time as it leaves late at night.
This part of the trip probably won’t be very special. I hope that Fiskevägen will be as nice as it was last year. Besides from that we are not expecting any highlights anymore.
We love driving the Model S, but after driving for over 72 hours it is also nice to be ‘driven’.
That’s why we took the Hurtigruten ferry from Trondheim to Stamsund. Stamsund is a port on the Lofoten Islands just 21km from the house we rented on the Lofoten through Airbnb.
On Tuesday we boarded the MS Nordlys at 11:00 and arrived in Stamsund the next day around 19:00.
Getting of the ship was tight. With only centimeters to spare and guiduance of the crew we were able to manouvre the Model S off the ship. Yes, it is a wide car!
After leaving the ship it took us roughly 45 minutes to drive to the house in Valberg. A beautiful house at the coast looking over the fjords. What an amazing place!
We are going to stay here for a few days to see the Aurora Borealis before we continue more North on the Lofoten.
Just as last year I’m driving non studded tyres. Why? We have to pass through Germany and Denmark and studded tyres are not allowed there.
Last year I used Nokian Hakka R2 tyres which were great! This year I’m driving Hankook i-cept Evo 2 (W320) tyres and they work very good as well. The last 500m to the house is pure ice and you notice that the tyres have a hard time keeping traction. The traction control in the Model S works exceptionally good however and it works just fine.
Keep in mind: I drive a RWD Model S from September 2013. It is not a new Dual-Motor AWD Model S!
Most of the part of Norway have a 230V instead of the 400V we have in the Netherlands and other parts of Europe. This means that my UMC (Universal Mobile Connector) does not work here. This is a safety measure of the UMC.
In Norway you can recognize this by the Blue 230V label on electrical installations.
The UMC performs a check if there is 0V between Ground and Neutral, but here that’s not the case. There is 120V between GND and N which makes my UMC show a red light. It thinks there is a ground leak, which is a bad thing.
There is a special Norwegian version of the UMC, but I built my own using Smart EVSE. It does NOT perform a Ground check, but it allows me to charge.
My Model S is happily charging at 13A right now.
This means I have a new charging POI on my Model S’s screen!
Time to relax!
After being on the road for 5 days it is time to relax. Watch the Aurora, go out hiking and do nothing.
Last Saturday we left at 08:00 from Middelburg for the 1.100km drive to Hirtshals, Denmark. From there we would take the ferry to Larvik, Norway on Sunday morning.
It took us 14 hours to reach Hirtshals. Traffic was bad, very bad starting at Hamburg towards the border. Roadworks and border controls made it stop and go over almost 100km!
A short night followed since our ferry left at 08:00.
Lier South SuperCharger
After arriving in Larvik our first SuperCharger in Norway was Lier South, 100km from Larvik.
It was busy! After we parked all 8 stalls are occupied. Other Model S had to wait in the queue.
A queue is bad, but it also shows that the infrastructure is used! It’s not a charger which is rarely used. From what I understood it was also a vacation period, so that might have caused the spike in traffic.
After charging in Lier we headed to Lillehammer. We would stay the night there and charge again.
While heading to Lillehammer I stopped at a CHAdeMO from Fortum to see if I could charge there. The people from Fortum told me that I could use my Dutch phone and send a SMS to active it.
Well, that didn’t work. I borrowed a RFID tag from somebody else as a backup. On the Lofoten Islands I will need to use a Fortum charger, so I wanted to know if it worked. Lesson learned. It doesn’t.
Busy times at Lillehammer
On the E6 to Lillehammer we already spotted a lot of Model S coming from Lillehammer, so I expected the SuperCharger to be crowded.
It was! 9 of the 10 stalls we busy, so we parked at the last stall available.
As we were charging we saw more Model S arrive. We still had 100km left in the battery and we would leave the next morning. We vacated the stall and to decided to charge the next morning for the 155km drive to Dombas and Trondheim.
We checked in at the hotel and went for a dinner in Lillehammer.
SuperCharging with a cold battery
The next morning the car had been in -8C for the night. When I switched to ‘Drive’ a warning indicated that regenerative braking had been disabled. This was due to the battery being cold.
SuperCharging didn’t go very fast. When I just started it would charge with 17kW and slowly climbed to roughly 30kW before we had enough to leave for Dombas.
I have a ‘classic’ Model S from September 2013. No Auto-Pilot features or All-Wheel drive. It’s a 85kWh RWD model.
The ODO currently displays 110.000km and when we get back it won’t be long before I hit the 120.000km.
Still enjoying this car every time I drive it.
My girlfriend also wants to go to Norway to see the Aurora Borealis. She heard me telling her all the stories for over a year about how great it was and how much I like Norway.
So I said: “Why don’t we go there?”
This year the destination will be the Lofoten Islands. From what I’ve seen and heard it is about the best place to watch the Aurora Borealis!
Route to Lofoten
Our route will take us from Middelburg (Netherlands) to Hirtshals (Denmark) where we take the ferry towards Larvik (Norway). Following the Tesla SuperChargers we will drive to Bodø from where we take the ferry to the Lofoten Islands.
On the Lofoten there are no Tesla SuperChargers, so I’ll be using the CHAdeMO chargers using the CHAdeMO adapter to charge my Model S there.