Question about Hybrid Battery

Yes, your HV battery is on the way out. It had a good long life! You can try preventative maintenance by getting a grid charger and balance charging it periodically (not just one time). Most folks here use the Prolong system (easiest, most $$$) but a few try DIY hobby (RC cars) chargers (cheaper but lots of labor and time). This may revive that one bad module or it may not. The only sure repair is a new Toyota battery ($$$$).

 

I don't know what's going on...but a couple things:
(1) check/clean your hybrid batt cooling fan, maybe that dust got bumped in the mishap
(2) consider new 12v

About the green bar thing - in summer you will see green bars much less often as A/C drains the HV batt. In winter the need for heat causes the ICE to run and you get more green days. Also I feel like a good 12v gives you more green, but that could be my imagination.

 

Yes, swapping out the bad module for a known good one is preferable IMO; that's what I had to do. Grid charging balances the whole pack together so it's not advised to just charge one module and put it back in. That's why hobby charging takes so long plus the pack needs to be removed from the car and disassembled each time. Some folks buy multiple chargers to speed up charging all 28 modules.

Reconditioning the entire pack (three charge/discharges cycles) takes several days with a grid charger. I can't imagine how long it would take with one hobby charger.

 

136,000 miles is pretty low for a Prius.
At some point, of you need a reliable car you will need to replace the battery.

But in the mean time if you are not so concerned about reliability and you could swap in a replacement module yourself. I sell them to customers regularly. ($90 for a set of 2 delivered).

This would likely get you back on the road.... For a while, until you need to do it again.

To increase your chance of success you could build a charger/discharger. Or you could buy a pre-made charger/discharger. Or buy a hobby charger.
But all these things cost time and money.

If you have a lot of free time, and don't need a reliable car, then open it up, swap in a module and be done with it. Knowing that you'll just do it again in the future. Could be weeks. Could be months. But hey, it'd be cheap.

A replacement pack will cost 20 to 30 times more than modules. But it will. Be reliable and come with a warranty.

This is the same situation that owners of older Prius face. Part of the territory.

I'm happy to discuss ideas with you one the phone. Feel free to call.

 

Watch the voltage live. See how it plays with the others.
Is it always lower than the rest? Well maybe it just needs to be topped off.

Is it the first to go low when discharging and the first to go high when charging? That's bad.

If it is a bad pack and this is a commuter car that must be reliable, then you'll have to decide if you want to spend the thousands of dollars for a new pack.

If there really is a problem, then it won't magically fix itself.

 

This sounds like a case of post hoc ergo propter hoc reasoning. Never underestimate the power of coincidence.

You have a 13-yo chemical battery that is finally starting to show some weakness. Several thousand dollars to replace it is probably the only truly reliable way to go.

Heed erickbecky's advice about commuting with this car, and consider the cost to your career and paycheck of repeated breakdowns in the near future. Also consider the cost of another car in otherwise good shape with less than 140K miles. And a good Gen2 battery has some portability, easily transplanted to another old car.