My Gotway MSX Battery Repair Journey

[Garrie Lim]

Link: https://www.facebook.com/groups/GotWay/permalink/2477689168956057/

My Gotway MSX (84V) Battery Repair Journey

Background: 

https://www.facebook.com/groups/GotWay/permalink/2465864426805198?sfns=mo

As stated previously, I came back from a one week holiday and encountered an issue with my Gotway MSX. I realised my battery was depleting very fast despite starting my ride with a full charge. Turns out my battery has an issue and was unable to reach the full charge of 83.7V(as indicated by my own voltmeter).

It was able to charge to 79.4V and my stock charger would turn green indicating full charge. Using my 3A and 5A charger did not “continue” the charge as well(both green lights), which meant all my chargers were functioning. 

This would only mean that one cell probably died somewhere, since the difference was almost 4.2V, the typical full charge of a 18650 cell. 

As I pondered what to do, either riding it as it is and risk deteriorating the battery further, or importing a brand new 20S3P 800wh pack for S$900(US$650), I realised I should check with the many reputable battery builders in Singapore. 

As you know, we have a lot of escooters in Singapore, and there are some people out there who have been making batteries since eons ago. 

I decided to go with Xoda, a custom battery builder in Singapore who has experience in building custom batteries way before we got into electric unicycles.

I dropped him a message and, despite his busy schedule, he told me to just walk in anytime. 

When I arrived at 1100hrs, he got to work straight away diagnosing my pack even though it’s his first time working with an EUC battery. 

He found that one cell had indeed died and affected the surrounding cells, so 3 cells had to be replaced. It was a good thing he has Panasonic/Sanyo GA cells in stock as well. 

He proceeded to remove the BMS and remove the affected cells. Did a quick charge of the 3 new cells before repeating the process in reverse. Using nickel to spot weld the cells back together. Then he helped to put my pack together and gave it a new heat shrink wrap in black and then a final full charge of the whole pack. It took 1.5hrs for him to do everything and hand me back my battery pack. 

Back home, the first thing I did was to charge the unaffected pack on the other side of my wheel first before connecting my repaired pack. Once it was almost full, I connected back the repaired pack and reassembled my wheel cover and pedals. 

Then I used my stock charger to continue the charge of both packs. 

This is one of those times where I’m glad Singapore is a small country and glad that we have people who have the experience and know how to fix things at short notice, no matter how niche a market may be. 

I started my day at 10am, did a bunch of stuff, had lunch, and was ready to go wheeling by evening for a sumptuous dinner with my friends

A big thanks to those who gave valuable advice along the way, notably Mathias Gran and Marty Backe

[Arbolest]

That was quite the experience, and it ended far better than I ever would have expected it to! You must have felt amazing afterwards coming out of what could easily have ended up as a day-ruining catastrophe.

Edited August 6, 2019 by Arbolest

[Garrie Lim]

5 minutes ago, Arbolest said:

That was quite the experience, and it ended far better than I ever would have expected it to! You must have felt amazing afterwards coming out of what could easily have ended up as a day-ruining catastrophe.

Yes it was. And I forgot to mention the cost of repair. 

It was a double digit sum for 1.5hrs of work plus all materials used and time spent.  

 

Way less than what what I would expect to pay. 

[Arbolest]

Fantastc!