How long do 'Module Replacement' on Prius batteries last?=Does this cheap fix work?

there is no precise time, but the more you do to balance the pack, the longer it will last.
is it worth it? it's a ton of time vs a ton of money.

 

It may last 1 week, 1 month, or maybe 1 year.
Hard to say.

Unfortunately there is no "industry standard" when it comes to Craigslist battery folks.

Ultimately you will probably get what you pay for.

If you don't need a reliable car and have plenty of free time in case the car is broken down for a few days while you do the job again, module replacement might be an option.

Most reliable, but most expensive is a pack with new cells from Toyota. Probably $3,300 or so depending on the dealer. Probably a bit less from an independent shop.

 

Here's an example of what can happen when Mr. $400 Craigslist ad shows up at your door, claiming they're going to fix all your problems in just a few hours by swapping out a bad "cell" or two and balancing the battery. They claim everything in the world about how they're going to test everything and it's going to be like brand new. I'd love to see how they balance a battery in 2 hours. Oh, wait...they probably don't.

Not long ago, I installed a Gen 2 battery built using low mileage Gen 3 modules into a members car in northeast Florida. This replaced a $400 rebuilt battery that had failed after 6 months. Block 6 was showing as the obvious problem. Another CL rebuilder probably would have replaced this module or block and called it good. I took the old battery and did some initial measurements. I documented module voltage after sitting for a few days and did a discharge test (D1) to see how much energy was stored in each module at the point of being removed from the car. The numbers under D1 are mAh. A perfect battery would have all 28 modules with the same exact amount of energy. When I perform this test on a nice low mileage 2016 battery, the modules are typically within a ~200 mAh band. Look at the results from this battery....



Block 6 was showing weak. Lets make the assumption that Mr CL replaces both modules in block 6 (17,18 in chart). You pay your 400 bucks and the car is working again (or at least it isn't coding out). How long do you think it will be before #24 causes a code? What about #14, or #8 or #10 or #20? This battery did not get this jacked up in just 6 months. It was most likely all over the place since the day it got "built".

NO ONE on CL that swaps a module or 2 in your driveway is going to test and detect those modules as being a problem. Even the voltages would be effectively useless because they wouldn't have even settled out yet. Somewhere down the road, most likely after your 30 day warranty is expired, the next one codes out and you're right back where you started. Hence the term whack-a-mole. This could be no big deal if you're a hav'in fun DIY'er like many of us here, but if you're not, then it makes life miserable, and expensive.

 

ok here's the big thing,
#1 if someone tells you he's gonna do it in your driveway unless he's swapping your whole battery forget about it!!!!!!
#2 depending on your mileage driven you may end up with a worse battery than you actually have right now sans the code.
#3 it's really hard to source good modules honestly, so the DIY route might cost you 300 bucks in modules before you get the right ones.
#4 if you buy it online and can find one near you several online vendors (toyota dealers but you have to order online and then pickup or it's 1950) sell a new battery(without the computer modules and stuff you swap from yours fairly straight forward.) for like 1750 bucks i.e. 1658 + tax but a 1300 core charge so depending on your state you might lose the sales tax on the core charge. i.e another 100 bucks. still not 3 grand only like around 1850 and you'll be good for another 125k-200k miles
#5 I had to go the hard way(cheap) because of the lack of funds, but in the long run I have spent about 1300 bucks and well I'm still getting less than 40mpg overall would get 50 with a new battery. If the prices were this low when I started having trouble I would have saved myself a lot of anguish by just getting that extra 500 bucks together.
#6 I am so desperate at this time I will be starting to experiment on re-hydration because I just dun have the funds. If I had all the money I spent on rebuilding well I would be able to get a new battery. But then again I wouldn't have had a drive able car till I got the money together so your mileage may vary.
#7 If your car is under 140k as a second gen and you did not live in death valley or the nevada/ arizona / new mexico desert I would say go for it it might just be a fluke module. Otherwise if you come up with the money it's like owning a brand new prius (well almost you'll still be burning more oil lol).
My $.02
terramir
PS: the thing is my car had 130k on the odometer when I bought it I found out that it had more like 170k miles on it this is why I had so much trouble. That dam combo meter flaw cost me dearly.

 

Without proper equipment and capacity testing modules it depends on how good your old pack was and how good the part is that you're putting in, then it depends on how well you matched the replacement part to the rest of the pack. Once in a while I get lucky, a single module in the entire pack needs replacing and the rest of the pack has over 1000wh capacity after reconditioning. Other times some of the modules are at different levels of degradation and you end up tossing 12 to 15 modules one after another, an entire week of charging/discharging.