Replacing individual traction battery cells w/o balancing?

First of all, They are modules with each one having 6 cell in series.

Second, it is difficult to reliably obtain "good" module as most sources that do not properly test salvaged modules and Toyota (Panasonic) does not sell replacement modules.

Third, All 28 modules have to form a matches set as a voltage offset of more than 0.3 volts (Max-Min) of monitored module pair voltages will cause another battery alert.

If you use multiple DC6 type charger/rebalancers (they are relatively inexpensive, about $25 each), the time can be significantly reduced. You also need to test each module under load to determine its health as all of them should exhibit the same voltage drop under load.

Just replacing a few modules without going through the process will usually mean repeating the effort again when the symptoms reappear.

JeffD

 

this is why rebuilt packs are expensive, labor intensive.

 

Simply buying a couple of random modules and slapping them in may be all your friend is looking for.
It won't be reliable long term and you will be doing the same process again soon. But it may at least get the car running.

What's the goal for your friend? Does he expect a professional job, or just a quick bandaid fix?

Feel free to call me if you want to talk through things or bounce around ideas.