When we talk about IP protocols and IPv6 in this particular case we think about routing over the internet. But what many do not know is that IPv6 is already playing a major role in all kinds of systems.
In this post I’m not going to explain IPv6 in detail, for many things I’ll link to external pages.
Ad-Hoc networking using Link-Local
IPv6 has a great feature where each host on a network will generate a Link Local Address (LL) which is mandatory according to the protocol.
The great thing about LL is that it allows hosts to establish communication without the need of DHCP or anything else. Just plug in a host on a Layer 2 Ethernet network and they can start communicating right away.
fe80::5054:ff:fe98:aaee is an example of a IPv6 LL address and using this address it can search for (via multicast) and communicate with other hosts in the network.
CCS is a standard for (fast charging) electric vehicles. Some years ago I stumbled upon multiple documents showing that CCS would be using a combination of PLC, IPv6, TCP/IP, UDP, HTTP, TLS and many other very common protocols for communication.
Using PowerLine Communication (PLC) the vehicle and charger will establish a Layer 2 Ethernet network over which they will communicate using IPv6 LL.
I was not able to find the exact details of the IPv6 part of the CCS standard, but it is very interesting to see that IPv6 is being used for something like charging electric vehicles.
Kudos to the people behind CCS and for using IPv6 for this!
In my opinion it’s a no-brainer to use IPv6 for such functionality as the LL addressing allow you to create networks very quickly and in a reliable manner.
You can also use a very well documented protocol and the many tools for IPv6.
It’s been almost a year that I’ve been living in my new house and proud father of a son.
Almost every parent wants to watch their little on through a camera to see them sleeping in their bed.
There are many, many, many baby monitors on the market but in my experience they are allcrap. Our house is build with a lot of concrete and none of them was able to penetrate the walls in our house and thus have a reliable video connection.
I also tried some IP/WiFi based baby monitors from for example Foscam, but these are all cheap Chinese cameras and didn’t work either. Crashing iPad apps, sending random (UDP) packets to China, half-baked UIs, etc, etc. They were all very low quality.
After a lot of frustrating I bought a Unifi Video G3 (UVC-G3-BULLET) camera and mounted it on the bed of my son.
I am using multiple Unifi video cameras around my house using Unifi Video, so for me it was just a matter of adding an additional camera to my Unifi system.
RTMP + HLS with Nginx
I also experimented with building a video stream using RTMP, ffmpeg and HLS with Nginx.
The Unifi cameras can export a RTSP stream which you can set up to live stream with Nginx. I tried this and it works for me, but with a delay of ~20s I thought it was not usable on my use-case.
It does however allow for a very easy way of building your own webcam!
In the past years I’ve said goodbye to hardware RAID controllers and mainly relied on software solutions like mdadm, LVM, Ceph and ZFS(-on-Linux) for keeping data safe.
At PCextreme we use hypervisors with local NVMe storage running in Linux’s mdadm software RAID-10. This works great! But I wasn’t satisfied with the performance for a few reasons:
It is expensive on the CPUs (Dual AMD Epyc 48-core)
It’s not super fast
We mainly use the Samsumg PM983 (1.92TB) devices and I started to look around if there is a hardware solution which could offload the RAID computation to a dedicated SoC so it wouldn’t eat up our CPU cycles.
After searching I found the Broadcom SAS3916 chip which is on the MegaRAID 9516-16i controller from Broadcom. This chipset supports NVMe devices in various RAID modes.
I wanted to benchmark Linux’s software RAID against the Broadcom controller to see if it would be faster and save us the expensive CPU cycles.
With mdadm we also looked into RAID-5/6 to have more usable space. We however found out that this eats up so many CPU cycles that it wasn’t feasible to use in production for our purposes.
Ubuntu Linux 18.04 with kernel 5.3
AMD Epyc 7302P 16-core CPU
4x Samsung PM983 1.92TB
Broadcom MegaRAID 9516-i
Benchmarking will be done using fio and the main elements we are looking for:
While replacing my router at home by a MikroTik CCR1036-8G-2S+ router I also wanted to uplink my Ubiquity switch using a Multimode (OM3) connection.
Is fiber really needed? Not really, but it saved me an additional RJ45 port on my switch which allows me to connect more.
Link up, down, up, down
The link between my MikroTik router and Unifi switch kept going up and down. In the logs on my MikroTik and Unifi switch I saw:
<14> May 26 19:19:07 SwitchPatchkast DOT1S[dot1s_task]: dot1s_sm.c(314) 454679 %% Port (26) inst(0) role changing from ROLE_DESIGNATED to ROLE_DISABLED <14> May 26 19:19:07 SwitchPatchkast DOT1S[dot1s_task]: dot1s_sm.c(314) 454677 %% Port (26) inst(0) role changing from ROLE_DISABLED to ROLE_DESIGNATED <13> May 26 19:19:07 SwitchPatchkast TRAPMGR[trapTask]: traputil.c(743) 454676 %% Link Up: 0/26 <14> May 26 19:18:58 SwitchPatchkast DOT1S[dot1s_task]: dot1s_sm.c(314) 454668 %% Port (26) inst(0) role changing from ROLE_DESIGNATED to ROLE_DISABLED <13> May 26 19:18:58 SwitchPatchkast TRAPMGR[trapTask]: traputil.c(743) 454667 %% Link Down: 0/26
19:25:12 interface,info sfp-sfpplus1 link up (speed 1G, full duplex)
19:25:20 interface,info sfp-sfpplus1 link down
19:25:21 interface,info sfp-sfpplus1 link up (speed 1G, full duplex)
19:25:29 interface,info sfp-sfpplus1 link down
19:25:30 interface,info sfp-sfpplus1 link up (speed 1G, full duplex)
19:28:48 interface,info sfp-sfpplus1 link down
I am using optics from FlexOptix which I programmed to MikroTik and Ubiquity using their programmer. (We have those at work).
After trying many things it turned out that turning off Auto Negotation on both the switch and the router resolved the issue.
On the switch I turned it off via the UI of the Unifi Controller and forced it to 1000 FDX.
On the router I turned it off using the MikroTik CLI:
Tesla’s vehicles are awesome. I own a S85 from 2013 and a S100D from 2018. I’ve driven 260.000km and 70.000km with these two vehicles and I love it.
There is however a design flaw in the early Tesla models which can become a very expensive reparation if not performed in time.
Version of of the MCU (Media Control Unit) which was installed up until early 2018 in Tesla S/X runs and is a ticking time bomb.
The problem is the Flash Memory (eMMC) which holds the Operating System of the computer. This wears out over time due to writing data to it.
Writing happens when you use the car. It caches Spotify, Google Maps and many more things. Even when the car is parked the MCU stays running and writes to the eMMC chip.
Eventually this chip will wear out. Before it does it becomes very slow and this results in the MCU becoming super sluggish, unresponsive, the screen reboots at random moments, bluetooth issues, etc, etc.
A lot has been written about this, so I won’t write to much. Short: Tesla will charge you around 2000 EUR/USD for a new MCU.
I choose to replace this eMMC chip myself and this was a lot cheaper! Total cost was <500 EUR.
Virtual Extensible LAN uses encapsulation technique to encapsulate OSI layer 2 Ethernet frames within layer 4 UDP datagrams. More on this can be found on the link provided.
For a Ceph and CloudStack environment I needed to set up a Proof-of-Concept using VXLAN and some refurbished hardware. The main purpose of this PoC is to verify that VXLAN works with CloudStack, Ceph and Ubuntu 18.04
VyOS is an open source network operating system based on Debian Linux. It supports VXLAN, so using this we were able to test VXLAN in this setup.
In production a other VXLAN capable router would be used, but for a PoC VyOS works just fine running on a regular server.
The VyOS router is connected to ‘the internet’ with one NIC and the other NIC is connected to a switch.
Using static routes a IPv4 subnet (/24) and a IPv6 subnet (/48) are routed towards the VyOS router. These are then splitted and send to multiple VLANs.
VLAN 300 on eth5 is used to route VNI 1000 and 2000 in their own multicast groups.
The MTU of eth5 is set to 9000 so that the encapsulated traffic of VXLAN can still be 1500 bytes.
To test if VXLAN was actually working on the Ubuntu 18.04 host I made a very simple script:
ip link add vxlan1000 type vxlan id 1000 dstport 4789 group 188.8.131.52 dev vlan300 ttl 5
ip link set up dev vxlan1000
ip addr add 10.0.0.11/23 dev vxlan1000
ip addr add 2a00:f10:114:1000::101/64 dev vxlan1000
That works! I can ping 10.0.0.11 and 2a00:f10:114:1000::1 from my Ubuntu 18.04 machine!
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!