LaserEdge

My Gotway Tesla V2 along with the accessories has been sold.

Have lowered the price and open to serious offers.

Hi Hecticc. The Charge Doctor I have is V2 of the Dual Input GX16 model. I am not interested in selling it separately. Thanks.

I have a Tesla V2 84V 1020Wh/2000W which I purchased as new late this past summer. It only has 40 miles on it. I am beginner to EUC riding so the wheel has some scrapes. The wheel works perfectly fine. I can message you with links to more pictures and video of me riding it if you are interested. Included with the wheel are the following: Charger and packaging that came with the Tesla V2 Roll.nz Bodygaurd for Tesla V2 84V / 5 amp fast charger charger Dual Input GX16 Charge Doctor Price $950. You pay shipping. Pics of the Tesla V2 and its accessories below.

My only concern with the LG M50T 21700 batteries is battery sag. The discharge rating on them is 7.3A. Substantially lower than 10A. It might translate to increased chance for cutoffs.

That's what I am thinking. The PCBs Ryan is showing has one central PCB for the BMS, the small one with the ASICs and the FETs. The other PCB is for wiring the cells in 10s4p configuration. Each battery pack will have one of those larger PCBs. Yes, no equalizing currents will flow through the BMS PCB, only the larger PCB shown. I agree such a design should be fine.

To be clear the PCB RyanEUC has shown is totally different than the one Pingouin showed me. It is likely Pingouin has an earlier design of the 1480Wh Tesla V2.

Pingouin from France owns one of the 1480Wh Telsa V2. He opened one of the battery packs and took pictures. He sent the pictures to me via PM. He hasn't posted them in this thread. From his pictures and the information he shared over PM I was able to determine the configuration of the BMS is 20s4p with the 1480Wh design. For the 1480Wh design there is definitely only one PCB for both battery packs. That PCB has both the charging cutoff FETs and the charge balancing resistors. I agree as the cells age the equalizing currents between the cells increase. Based on the pictures I saw from Pingouin the equalizing currents are not flowing through the PCB. The PCB is only handling 4.2V charge shunting, overvoltage and undervoltage. The equalizing currents is being handle from the way they have wired the cells in the battery packs.

Thanks for the pic RyanEUC. Hard to tell from just looking at one side of that PCB. I am guessing the other side has another set of 20 pads to connect to the cells. There should be markings for B11 through B20. Must be broken English. The 1020Wh Tesla V2 didn't change BMS design. The same Gotway BMS PCB is used for all of the 84V battery packs.

Had a long back an forth with Pingouin today over PM. He opened one of the battery packs to his 1480Wh Tesla V2. I will summarize our findings. The 1480Wh Tesla V2 is using a passive battery management system. We confirmed that the 1480Wh Tesla V2 only has one BMS for both battery packs. The passive charge balancing is done on the on the PCB already pictured in this thread. The configuration of passive balancing is 20s4p meaning there are 20 sets of 4 Li-ion cells connected in parallel which are connected in series. For each BMS in a 1020Wh Tesla V2 it uses a configuration of 20s2p meaning 20 sets of 2 cells in parallel wired in series. So what does this mean? Having a BMS per battery pack has one significant advantage, it will increase the peak charge voltage achieved with each full charge overtime versus the design with just one BMS. The 1480Wh Tesla V2 will reduce its peak charge voltage with each successive charge cycle faster than a 1020Wh Tesla V2. Another advantage the two BMS design has is that the 1020Wh Tesla V2 will charge and discharge balance faster since the number of cells in parallel is smaller. Passive BMS designs don't load balance across the cells wired in series, only those cell which are in parallel. An advantage that the 1480Wh Tesla V2 configuration has is better ability to handle dead cells since it has more cells wired in parallel. Considering this point the 1480Wh Tesla V2 batteries should give more total charge cycles. I am curious if anyone has tried a faster charger with the 1480Wh Tesla V2. One potential issue is that the higher number of cells in parallel could potentially indicate charging is finished when in fact the cells need time to load balance. To confirm use the faster charger and let the wheel charge to the point the charger says it is full. Unplug the fast charger. Check the charge level with an app. Wait for an hour. Check the charge level again. If the charge level went down it means the cells were not 100% full charged due to charge balancing issues. Driving differences: Besides the peak charge voltage I don't think anyone is going to notice much difference. I don't see any fire hazards with this single BMS design. Well that is a summary of what we discovered. I will leave it to Pingouin if he wants to share the pictures. They are his pictures after all.

One way of determining the quality of the BMS would be to get the modded Tesla V2 to low charge (under 20%) and measuring the top speed as charge decreases. Create a graph from the data. Repeat the experiment with an unmodded Tesla V2 and compare the data. Such a test could make for an interesting video.

Good point. If a wheel is only going to get 200 or less charge cycles for the lifetime the design, the BMS isn't as important as other parts of the system. Really just need something to charge the batteries without them getting very hot. The other main aspect of BMS focuses on increasing the life span of the batteries by balancing the charge and drain. As you point out not really a concern for the typical usage of a wheel. A highly stressed li-ion battery by a poor BMS will likely yield around 300 charge cycles. An average BMS will yield around 500+ charge cycles. A great one over 1000+ charge cycles.

500 or so charge cycles would definitely prove the design. Doubtful it will cause a fire for just you. If the battery packs aren't getting very hot during charging or frequent heavy breaking whatever design they have is good enough.

The FETs on the board pictured look to be for switching in and out of charge mode. The smaller red lines look to be charge rails. Doesn't look to be anything actively regulating the charge rails. The board pictured is too simple for that. They could possibly have put another PCB in the packs that uses a passive balancing approach. Such an approach would bleed off excessive charge with a weak cell through a resistor. Would have to open one of the battery packs to know. Measuring the voltage and current of the charge rails would confirm a few things about the design.

I am new to EUCs. Based on my research the GotWay Tesla V2 is an excellent choice for someone new to EUCs. I came across this thread while learning about the Tesla V2. Being both and electrical and computer engineer I can tell you from the photos those cells are not being load balanced properly. The balance wires from each cell pack should go to its own BMS. Each cell needs to be isolated for proper load balancing. The mod that they have done will definitely shorten the life span of the cells. Over time the cells will become increasingly unbalanced with this mod. As they become more unbalanced they will heat up even more during charging and discharging. Would it start a fire? Possibly if there is enough unbalance and the cells are driven hard enough. If the battery packs are getting really hot during peak charging and discharging it is a sign there is a risk of fire. It only takes one extremely weak cell to cause a major unbalanced situation.