Reconditioning Prius Battery with a hobby charger

Hi everybody! First post here. Been following the forum for a few years now.

I have a 2004 Toyota Prius with almost 400k km (about 250k miles). It's still running with the original battery, almost 16 years now. Using Dr. Prius for testing i get 63% in the life expectancy test.

The HV battery holds the charge ok, but when it's discharging in the test, from about 50% it goes down to 40% really quick. Probably due to loss of capacity because of the aging modules. No error codes on the HV battery yet, because everything is balanced. The cells have about the same voltage. Error might show up in the near future, if nothing is done.

I would buy a Prolongue system, but it's to expensive for me. I have this charger -> SKYRC Extreme 2X150W 7A Dual DC Balance Charger Discharger (cannot post links yet, still new here). I plan on cleaning the bus bars and to try and recondition the modules. Would it work if i wire a few cells in parallel (4 would work) and discharge - charge them 3 times to get rid of the memory effect and restore some capacity? The charger can discharge at 5A and charge at 7A. So i can set it to discharge at 4A and that would be 1A / modules and charge at 7A would be 1.75A / module. Given the fact that the charger is dual, it could do 8 modules at once. I could get another one to do 16 at once. It would be a lot better if i have the time to take the modules one by one and see exactly what capacity they have and what i can gain, but i don't have the time.

Is there an option to wire all the pack in parallel and charge / discharge? Although that would be painfully slow at about 0.25A charge / module and 0.17A discharge, that would be more than 24h to charge and even more to discharge. So probably close to a week for 3 cycles. Has anyone tried something like this?

Is it necessary to bring the voltages back down after everything is finished? So they don't remain at 100% when reconnecting back everything.

I did work on smaller 48V li-ion battery packs for electric bikes. I'm trying to see if i can do it safely with my knowledge and your help.

Or i can just drive until it fails and get newer modules. I've seen modules from 2015 Toyota Yaris being sold for 550$. Would that be an alternative to buying a new battery pack?

Thank you!

 

Great info, thank you. It looks like i will use a Prolonque after all, a friend of mine bought one and he can help me.

I will try to get more chargers and do it manually later.

 

I took the battery to my friend who has the Prolongue charger and discharger. He did a clean-up on the battery terminals and bus bars. Also he cleaned the fan. The battery was about 59% in dr. Prius. After cleaning and Prolongue it jumped to 128%.

I will post some pictures soon.

 

Thank you. Here's how bad the situation was. Also, he wrapped the steering wheel with new leather. In the battery, all the modules were the original ones, nothing was replaced in almost 16 years.