Hey There! Just Got Started Rebuilding Hybrid Battery

I would say your pack is beyond rebuilding. Any module that has self discharged below 7.2 volts is non recoverable junk. You have at least 13 modules below that level. With that many having fallen off the voltage cliff it's unlikely that the rest of the modules are in very good shape.

 

Your pack is unsalvagable.. I'd like the remaining packs that are good on ebay, toss the rest, and get this: http://newpriusbatteries.com/ 1600 shipped. Call it a day, otherwise you're going to be putting tons of money on replacing the 12+ bad modules.. with other used modules that will fail within a year anyways. Don't waste your time and in extension your money. Life in short.

 

Battery modules that have at least a couple volts in them after sitting for years I've been able to revive and they run great without much problem if you're patient. But start with very lightly charge and discharges on them first and then slowly ramp up to higher voltage&amperage. I myself have never seen 0.0 volts on a module if there's no load on it, so that module/block is likely dead.

But contrary to all the commenters above I recommend going from the least expensive fix to most expensive fix. If there wasn't a Pandemic I'd be visiting my elderly Dad in Napa near you this time of year and I could loan you my rig. But...

Judging from the high quality of your tools in the photos, you won't mind spending a little money. So get yourself one or more of these chargers: https://www.walmart.com/ip/SKYRC-iMAX-B6-V2-Balance-60W-6A-DC-DC-Converter-Compatible-with-Mavic-Inspire-Intelligent-Battery-NiMH-NiCd-LiPo-LiHV-LiFe-Li-ION-Battery/214060609 and then use 55watt standard headlight bulbs for discharging, as well as for 2 minute load tests to figure out which modules are bad, or are going bad. Then if you deep cycle each module 3 times at increasing lower discharges the capacity will be restored.

Let me know if you have any questions? Or want to know who the most reliable person to buy modules from, etc.

 

You would do better to have left it in D and applied a little brake pedal to hold your speed. It would have put more charge in the battery and quicker, too. A quicker way to do what you're trying to do is just stay stationary and "force-charge" the HV battery.

This is very dangerous if you don't know what you're doing and don't have an external grid charger to get you out of the doo-doo if you get in trouble by discharging too low.

There is not much you can do in-car that would be useful. The HV (hybrid vehicle) Control system ensures the battery is only charged/discharged in the 40% – 80% range and to achieve what you want would require exercising the HV battery outside of this range, with the exception of the dangerous behavior you mentioned above where you could discharge the battery to beyond the point that is can start ICE.

Having said all of that, I would just run with the battery as is, it obviously can start the car and if it is not exhibiting any problems, leave well alone. You don't say the age of the crash vehicle, but if it was a fairly recent model and the battery was in good shape a the time of the crash, a couple of months is nothing to worry about.

I don't see a link to a battery charger, but if it is the HA prolong system you have, you could use that to do a series charge/discharge cycles to recondition the HV battery if you were seeing anything that gave you cause you to worry.

 

Congrats! I recommend you rebuild the pack that's not in the car so you have a loaner pack... When the weather heats up in late Spring there's lots of owners of older Prius who will be told by the stealership that it will cost $5K to fix and then you show up and put in your loaner pack in less than an hour and they will be so pleased with your low price to solve their problem that you'll get a huge tip!

As for charging the pack in the car... B mode is an unnecessary function, but it's an expected safety system to use the engine to slow the car if the brakes overheat, but that's super rare thanks to regenerative breaking doing most of the work. Never once heard of that being a problem with a Prius. And B-mode has nothing to do with charging the pack.

But you can charge the pack in the car by putting it in drive, emergency brake on, push brake pedal all the way down and then gas pedal all the way down. But this is something you only want to do on rare occasion prior to pulling a pack to work on it, or to get out of a jam of some sort and safely get home. It's not good for MPG or anything else to do this on a regular basis. Though I know one guy who races his Gen3 and he does this alot prior to racing and it hasn't created too much of a problem yet.

To do it right you need a high voltage trickle charger that uses the NiMH algorithm and doesn't pump more than amp into the car's pack. There's one system online that does 1/4 amp trickle charge without algorithm and the best system is Prolong which cycles through 0 to 1 amp based on battery feedback and algorithm: Prolong Battery Systems | Hybrid Automotive California, USA Both of these systems will balance all modules to the exact same voltage.

Alternatively, get those SkyRC charger and charge up all the modules individually... I usually do this on packs to get self discharge numbers. As in do a max charge on all modules, then wait three days or longer and check voltage of each module. Some modules will self discharge more than others, which is a good hint as to which ones are going bad.

Also deep cycling the modules is essential to restoring capacity from 50% to 96%. In the process of doing that you might find some modules that discharge much faster than others so you can swap 'em out before they go bad... Learn more here: BU-807: How to Restore Nickel-based Batteries – Battery University I set my system up so I can watch 5 modules discharge at the same time... Kind like a race, with the slowest one to discharge being the best module and the fastest ones being the word. Of course until you complete three rounds of progressively deeper cycling (5v, 3v & below 1v) you won't get a good measure of weak vs. strong modules.

Use lots of fans to keep everything from overheating especially on the final charge after the deepest discharge. Also a thermal imaging camera is helpful to find a bad cell that's overheating before it gets to the point it fails, explodes, etc..

I put all this data into a spread sheet if you want to see one?

 

Nice job on the good find and smart fix. I see you also have a Tacoma and dirtbike. Thats the same setup as me and the prius fits the bill for a cheap commuter car. It sure does save alot of gas money when the gas prices shoot back up to $4+ a gal. Makes me feel less guilty when im towing my trailer getting 10mpg on the weekends


I picked up a 2008 with 242k miles for $3500. Drove it for 10k before the main battery was showing signs of dieing so I picked up OEM toyota battery for $1800 and installed myself. Im sure she is good for another 200k miles at least. Just keep an eye on the engine oil as mine burns roughly 1qt every 3k miles.

 

The good thing about having a second working pack is you don't have to buy 4 or 6 chargers to do the rebuild. 1 will work but its going to take time, plus your in the game for like 35 bucks.

 

I would look for threads from @TMR-JWAP He rejuvenates modules all the time for fun and profit, a true master. My advice would be to attempt to rejuvenate most of your existing modules first, then get replacements from a reliable source here. E-Bay is not a good source for modules, and most junk yards wont sell individual modules. Any battery advice from @strawbrad , or @PriusCamper would be good advice.