Whack-A-Mole time - Is it worth it? How many more miles might I expect.....

whack a mole is worth it if you do it yourself and treat it as a learning experience. If you are looking for reliable transportation, then it's not worth it.

 

That about covers it.

 

How much time have you got to devote to this?

 

Go and give it a try. You could try balancing the pack when you’re done. Many people selling used prolong charger systems, could be worth it to do it right

 

That's the dream, "just a year or so" of reliable service for under $100 and almost no time invested. It CAN happen- it just seems to be a low chance of that occuring. so do you feel lucky?

Posted via the PriusChat mobile app.

 

The outlook isn't so bleak.
I replaced 2 bad cells in my battery pack 5 years ago, and it's still running beautifully. I do one reconditioning on it every spring with a Prolong set.
You can get longer term results with a little luck, and if you are meticulous in your work.
Good Luck.

 

My 15 year old traction battery finally threw a P0A80 code. Dr. Prius app shows module #4 more than 1v lower than the others when the pack is discharging (no consistent difference when charging though). The rest of the modules seem healthy enough, so I'm planning to replace 1 or both of the blades in module #4, balance voltages, and see if that solves it. If it doesn't, or fails a second time, I guess I'll get one of @2k1Toaster 's batteries. I plan to drive the car for many more years.

 

If your car is in good running condition and your plan is to drive it many more years, you should just save your time and money from doing this repair over again later. Buy a new battery now

 

It is a 2007 with 228,000miles, but besides the traction battery, it runs well, maybe loses 0.5quarts of oil every 5,000miles. I think the battery failed because it sat for 3 weeks while I repaired damage from hitting a deer, (welding in new radiator frame, new radiator assembly, hood, headlights) and then another 2 weeks shortly afterwards while I replaced my stolen catalytic converter.

It is the nicest car I've ever owned, and I'd be happy to drive it for another decade or more if it will last. I've been doing the recommended maintenance (transmission fluid, coolant flush, etc). and there's barely any rust, so it might very well last another decade. I realize the logical decision would be to get a new battery..... but.... it is so tempting as an electrical engineer to just replace that one failed blade and restore the battery to new life! But at 15 years (I looked on Carfax, there is no record of the traction battery ever being replaced), would replacing blades just quickly devolve into whack-a-mole?

And of course, a new NewPriusBattery would likely last at least 10 years, probably longer than I will be using the car, and there is no way replacing blades will work for that long, so.... yeah.

 

Well after a major repair like what you did, I would just do whack a mole and get the car running. After you can verify everything is put back and runs good, then spring for a new battery when it fails again

 

That's fair. I have already ordered 2 "refurbished" blades, so we'll see how that goes. It drives quite nicely, no wheel alignment issues from the deer hit or codes from replacing the converter.

Regarding replacing blades, I've read a lot of posts about how to do it, but they tend to go into the weeds of "reconditioning" modules via fully charging and discharging. I might have access to 1 or 2 RC chargers, but I'd like to complete this project in a single day. To that end, this is the plan I have.

1. Instantaneous load test all cells with a headlight (does it actually need to be 2 minutes? according to the app, the voltage disparities show up practically instantly)
2. Discard the bad blade (or blades if both in module #4 are actually bad) and replace with a "refurbished" one
3. Discharge new blade(s) to similar voltage as the others (with headlight) (assuming blades from the car will be around 50-70% SOC)
4. Wire all blades in parallel to equalize voltages (how long does this usually take?)
5. Repeat instantaneous load test on all blades and note voltage drop for each
6. re-equalize voltages.
7. Pair into modules such that the combined voltage drops are as equal as possible.

Does this make sense? Am I missing something essential?

I should add, I cleared the P0A80 code and have continued to drive the car (2 days and counting). The RTOD has not reappeared, but module #4 often dips as much as 1.29v below the other modules.

 

Given the price of an alternative vehicle, if you can keep it running for a couple of thousand dollars for five more years, that would be prudent. Major front end damage repair is always problematic on a Prius though. Hopefully only the radiator and lights.

 

I'd forget about step 4 (and step 6, if that means repeating step 4). This 'equalization' process doesn't do anything useful, so save your time and energy. If you are concerned to match the voltage just use your charger or discharger to get the module (what you're calling a blade) to the same voltage.

A comment on step two, there is not really such a thing as a refurbished module. Any module you get that will match your existing ones will likely be of a similar vintage. All your modules are at the point where they are closer to failure than not. You cannot defy the laws of chemistry. Batteries get old and die.

Limiting yourself to trying to get this done in a day is not really feasible (if you want a job to last at least a few weeks) so work out a plan that would allow you to work on this for up to two weeks if you insist on module swapping. And, yes, this will devolve quite quickly into whack-a-mole.

if you want to spend only a day doing battery work, then you need a 'once and done' solution which is to replace the whole battery with new. There is the newpriusbatteries solution – which you know about, but don't overlook getting a price from a Toyota dealer (shop around if you have that choice), use online parts if you can, but ultimately you need to pick the battery up so it will need to be in traveling distance.

You have a bit of time (but not much) with being able to clear the P0A80, so use that to plan for a new battery.

Balancing up what I said, this might be a prudent interim step, so you can truly evaluate that your car has no further issues resulting from the collision and the assisted repairs.

 

@dolj , thanks for the advice. I am aware that "refurbished" at best means "charge cycled a few times and load tested" and at worst means "yup, she measures at 7.9v alright" and always means the battery is old used stock. So replacing a few modules still leaves the same risk of another module (even one of the replacements) failing again.

Regarding module balancing, I had thought that wiring them all in parallel was merely a simple and effective way to make sure they are all at the same voltage. Are you implying that this isn't necessary? If most modules are at say 7.2v and the replacements are at 8v, I would think that means their state of charge is wildly different and they won't work together well. Bringing the new ones down to 7.2v with a load seems like a good system, but wouldn't it be hard to get them all closer than 0.1v that way?

The triangle came back driving home yesterday. I didn't clear the code and today driving in to work I noticed that the Dr Prius app shows SOC at almost 100%, well over the 80% norm. Does this mean that continuing to drive the car risks overcharging and reversing more cells?

Sounds like an actually new battery is the way to go in the long run. Even if the car dies before the battery, I could probably still sell the battery and recoup a portion of the cost. However, I do have the replacement modules arriving Wednesday, so I might as well try the whack-a-mole fix at least one time. If(when) it fails again, that's when I'll buy a whole new battery.

Have dealer prices actually come down close to the $1.6k that NewPriusBatteries cost? I thought they were well over $2k, not even counting their labor which you are required to use (since they won't just let you take it home).

 

The problem is that there is not enough potential difference between each module to effectively move enough electrons around so it is largely a waste of your time and energy. I'm not implying it, I'm saying it outright. In fact, a much better way is to top balance all modules in the pack at the same time (i. e. grid charge) and then let it sit for 4-7 days then measure the static voltage. All the good modules will cluster around the same voltage – give or take a few tenths of a volt – and the bad ones will be significantly lower.

It is not so important for the static voltage to be exactly the same voltage when you assemble the battery, as long as they are within 0.1 to 0.2 V of each other. More important is how each module behaves under load, both charging and discharging. Well-matched modules of similar capacity will go up and down together. Bad modules will shoot up way more under charge and the same modules will dive down under discharge. You can monitor for this with your Dr. Prius app or in Techstream (or another professional-level scan tool like a high-end Autel or Snap-On).

I can't comment on what's happening there as I have never monitored that but you won't reverse cells by charging to 100% or above. That can only happen on discharging unbalanced cells and a low cell (or cells) discharges down below 0 V. Maybe what you are observing is the battery control doing a top balancing charge but that's just a guess as I don't know if the Gen 2 does that. I know it has been reported that the Gen 1 appears to do some sort of balance charge or calibration from time to time.

... or you could swap the battery into a replacement Gen 2/3. The Gen 2 would be a straight swap. A Gen 3 swap would involve disassembling both batteries and swapping all the modules over.

Yep, nothing to lose except the time it takes.

You can get a price of between $1,650 and $1,950 plus taxes (and a refundable $1,350 core deposit) by shopping around dealers. I believe $1,950 is the recommended retail price. FL dealers recently ran a sale on the HV battery for $1,2xx or $1,3xx just recently and sold out super quickly. There are dealers that will sell the battery assembly to Joe Public but you have to collect it from the parts counter, so again shop around. I guess it helps to be confident that you know what you're doing with it.

 

Well, you've convinced me.

Finally realized that there is almost no way to know how much relative charge the modules have when they are at 50%, since the voltage curve is almost flat there. So, replacing a single module without charging all of them would likely result in an unbalanced pack, and I don't want to spend weeks charging the modules 1 at a time. Final straw was when the module ship date got moved out to May 5th

The new pack from NewPriusBatteries should ship around May 10th. Is there any risk that driving for 1 month with a failed module would damage other systems or modules? Surprisingly, MPG appears about the same as it was before the RTOD, about 42-44mpg depending on the weather (30-50deg F). Instantaneous power is about the same as well, just the engine runs more often, and the charge indicator goes all over the place except for when cruising on the freeway.

After I install the brand new battery, I may take the time to individually charge and load test the old modules for resale, unless someone can recommend a buyer who would take the whole set as-is for over $15 a module.

 

If you already ordered replacement modules for the failed ones, just stick them in and drive until your new batteries arrive