Xilebo

Think about fitting an external 20s balancer. It is not expensive. It is quite small there is a chance to hide it in the wheel. And it will keep the balance permanently in the battery. You plug it next to BMS without balancer or with broken one I have another question... after how many km/time did you change the tyre on the v8? Or did you do it after it got damaged? I've done about 2500 km on mine. I'm considering whether to change the tyre or wait. It still looks pretty good. But it costs a fortune to repair the teeth. The tyre is not that expensive

Yes, that is why I am testing my solution. Locking the battery charge at a certain level of charge. The disadvantage is that it will never charge to 100%, the plus is to create a "cushion" for recharging during the descent . But there is a chance that the developers of inmotion have taken this problem into account. It is possible to start from a high hill with a charged battery. Then the battery will overcharge anyway. I don't know if such protection is included, but it should be.

So you ARE circumventing the bms. That introduces some risk like if you let your powerbank bring the battery to full voltage 84v. I do not avoid any BMS. That would require great interference with the inmotion batteries. Just cheats the Electronics of the wheel. BMS works 100% of the time. It allows me to discharge and recharge the inmotion. The assumption was that the communication between the inmotion battery BMS and the caster electronics is not as tight and as multi-directional as it generally seems. That the BMS of the inmotion battery at some level is primitive. And so far my assumptions are coming true 100%. Yes battery overcharging has been my concern. I am testing with great success a protection against this. This is my risk... Initially I disconnected the battery charging on descents. I made it so that it disconnects itself after pulling the cable. It comes in handy during accidents. For example, when a wheel goes off on an invisible kerb and I run straight out Then the battery is discharged automatically with a jerk. Everything is on test. So I am not telling you anything, I need to go through some tests then everything will become clear. I am similarly concerned about the minimum battery condition and safety qualities. I have not yet been able to get to that level in tests... The most I have discharged the battery was 50% Also, what happens with the dc-dc converter in the powerbank, when you're braking on the wheel? Could it get damaged? The DC-DC converter is protected. These are the preconditions to start testing Nothing is burning I plan to make a command and control system with sensors in the final version. I have a preliminary vision of the control program. But for today it is just a vision I am thinking whether to do cell communication or to do a simple control panel on a cable. Problems like overheating of the system or cells I plan to notify with a beep. These are important warnings so I don't care about comfort ITD..

Did you write how you enabled charging while riding? I connect the appropriate adapted electronics in parallel to the high voltage (72-84V) of the inmotion battery. Through a small fuse, so that in case of any short circuit / trouble, the additional circuit automatically disconnects without causing power failure and collapse. So far the 3.15A fuse is coping. You make it sound like the riding characteristic has changed while you're charging. Why is that? The driving characteristics do not change. But the circuit puts less strain on the battery when accelerating and recharges more frequently. This gives the effect of a long charged battery and unlimited driving. Yesterday I drove 32km for a test with an average speed of 23km/h and a top speed of 29.1km/h. It was a ride half upwind on rough forest roads. I had 50% battery left. I consider this an excellent result for an inmotion V8. Today, I rode 22.64km with an average speed of 14.4km/h and a top speed of 24.7km/h. It was a mixed ride some in the woods some in the city. After the route I had 87% of battery left. As for me it is very satisfying The slightly higher voltage should actually make the wheel feel a tiny bit zippier. There is no higher voltage. The voltage is within the limits of battery operation. Higher could damage inmotion. There is only higher possible current to be drawn by the wheel.

The main power connector on the inmotion V8 battery works in 2 directions. The issue is where the higher voltage is. When the voltage is higher on the battery output it gives back energy. When the voltage is higher on the source connected to the battery it charges the battery. When my energy bank is plugged into the wheel at rest, it has a higher voltage and charges the battery. When in motion, when the motor is drawing over 1.5A, this is exactly what the energy bank is giving out, the rest is coming from the Inmotion battery. So, when I am driving and the wheel draws 4A, 1.5A comes from the energy bank, the rest is 2.5A from the inmotion battery. From my small but experience I can say that it has a nice effect on battery performance. Smaller "jerks" of current and frequent gentle charging improves stability of the main battery. My experience is a few days and a few tens of kilometres. But it looks optimistic.

I was thinking of plugging in an extra battery with BMS for 72-84V. But as you mentioned it gives a lot of problems. If you connect them in not perfectly the same state of charge there will be a rapid equalization of battery states, which in extreme case may even damage cells or at least reduce their life. As for me it could be done by connecting discharged cells and charging them in pack. But this is only a theoretically good idea. The differences between the packs could make this very difficult. I have generally rejected this idea. Instead, I decided to make a power supply with a constant charging current and an adjusting voltage. This is an electronic circuit between an additional battery and the inmotion battery. This allows you to plug it in at any time just like the original charger for the inmotion. Because the charging current will not rise above the current limit. The voltage naturally adapts to the battery as when charging from a charger. In my case the power bank runs on 24V is charged from 12V and gives 84V max 1.5A. I was planning this as a car charger/energy bank for inmotion. It was only recently that I came up with the idea of another application. As the energy bank charges separately there is no problem with the original charger. The battery from the inmotion has its own BMS and can handle the charging and discharging of the battery via the downhill energy recovery function. I predict that it is a matter of charging parameters. When combining packs with not equal potentials I predict that the Inmotion BMS may block. But I have not tested this. For that I have tested that with the charging parameters of the original charger is supported.

Everything works perfectly. You can see a clear increase in the range of the inmotion V8. I did tests today at higher speed so more load. They were not as impressive as at an average speed of about 15km/h. I analysed the logs from the route. They show that when driving calmly the average current consumption was above 2A. Sometimes it was 15A sometimes 0.1A and sometimes -1A. That's why a continuous power supply of 1.5A had such a spectacular effect. A fast route gave an average current draw of 3-4A. Then the 1.5A charge is less impressive. Although it is still noticeable. Especially when driving around town. Where standing at traffic lights you can see the battery charge bar climbing upwards. This is very nice. A couple of issues still concern me. What happens when the extra constant charge charges the battery to full. And I have a way down the hill? Will it overcharge the cells to keep the braking ability ? Another question is how will it behave with minimal battery. Will it keep all safety rules. But I am optimistic. I have ideas to solve all the problems. I don't know if these problems exist though. I am now going to investigate these issues and build a new more powerful power bank to at least double the range of my wheel. To do this I am considering increasing the charge current to 2-3A. My priority was to interfere as little as possible with the inmotion power system. Hence the current dilemmas... And slow quiet steps. To solve them.

I was wondering how to increase the range of the inmotion without cutting, unsoldering and losing the warranty. I made a mobile power bank for the inmotion. It has operating parameters consistent with the original power supply. 84V 1.5A. Its cells in test version (almost free) last for 1/3 - 1/2 of inmotion V8 battery. It works perfectly. I tested it on an inmotion V5 and an inmotion V8. Cool. Allows you to reach the maximum range of the battery, take a rest there and connect the Inmotion wheel for charging. But you have to wait for a considerable charging time to have enough energy for the way back. Today I made a breakthrough. I figured out how to charge while driving. I did the first tests at home. It works. The Inmotion V8 was running on handle mode, so with low current consumption. With such a low current draw, the charging of the battery was clearly visible. If everything works as I plan it will be perfect. It uses the cells of the original battery. Does not require interference with the battery or inmotion electronics. Allows you to systematically provide energy to the wheel, or if it uses less than what the extra cell will give charge the internal battery (something like when riding downhill). Soon I am planning long distance tests. Then I will know if this project meets my expectations

Thank you for your quick reply. I have some experience with notebook batteries. There they use specialised chips with quite standard communication over I2c protocol. I wonder if inmotion was breaking down the open door and creating something of their own ? I assume that he used some proven solution, and if I find out what chips are on the BMS board, there will be a chance to find documentation for them. That is why I ask for good quality photos This is an example of a chip for notebooks: https://www.datasheetq.com/BQ8030DBT-doc-Unspecified . For these circuits is created whole interface to change parameters and reset. I trust that something similar is possible for inmotion.

The inmotion V8 battery has 2 connectors: 2 pin (power supply) and 7 pin (unknown). Does anyone know what signals are on the 7 pin connector ? My guess is that it is some kind of communication between the battery and the motherboard. But does anyone have knowledge which one more precisely. Or has good quality pictures of the inmotion motherboard and battery BMS. So that it would be possible to trace where the paths lead? The main limitation is the cannibalism of the BMS. I am thinking how to make a compatible BMS alternative. Power, is not a problem. Voltage similarly. I see the problem only in communication between BMS and inmotion motherboard. I would appreciate any information on this topic.