Prolong Hybrid Battery Reconditioning

[The Critic]

After a significant amount of research (and debate), I have made the decision to perform a multi-stage Prolong Hybrid Battery Reconditioning service on my 2011 Prius. My car is currently at 170,700 miles and still functions acceptably with no fault codes. However, the Hybrid Battery has begun to show some signs of deterioration. For instance, driving in-town with heavy a/c use (during hot weather conditions) will cause rapid draining of the battery. The fuel economy has also slowly deteriorated, and when test driven against other Prius with new or reconditioned battery packs, the acceleration on my vehicle is noticeably weaker.

The theory behind hybrid battery reconditioning is that you are doing a deep discharge/re-charge of the NIMH hybrid battery pack. Supposedly, when a deep discharge is performed, you are draining the battery cells beyond their voltage depression floor in order to break down the memory effect within the individual cells. When this happens, the process will allow you to regain usable capacity. This service is marketed as an on-going service and is not an one-time event; the manufacturer of the Prolong system recommends performing a full reconditioning service 2x/year on aging/deteriorated batteries.

Earlier this week, I installed the harness onto the battery and also cleaned the Hybrid Battery Fan. The process was fairly straightforward and took about 90 minutes. Some pictures are attached below. The harness was $150. I am sharing the Prolong equipment with another person which helps reduce the cost of the service. My plan is to perform either two or three discharge/recharge cycles. I am budgeting 12 hours for the initial balancing step, 6 hrs for each discharge cycle and 24 hours for each re-charge cycle. So, this service requires the vehicle to be out-of-service for four to five days.

I am not expecting miracles, but I welcome any improvement in performance and added longevity. I fully recognize that at some point, I will need to replace the hybrid battery (current list price is $2,729.35).

I will keep this thread updated throughout the process. Any thoughts or experiences about this service are welcomed.

Photos:
1) Interior disassembled to gain access to the Hybrid Battery Pack:

2) Hybrid Battery Case is opened to install the wiring harness:

3) Hybrid Battery Fan is cleaned up:

4) Installation is mostly complete:

5) My parking spot for the next four days:

 

[The Critic]

The initial balance step was started at 7:30pm on 7/29/18.



I expect this step to take up to 12 hours, but after 7 hours, the voltage is already holding steady at 241V.

 

[tomcat27]

Thanks for posting!
Very curious to see your results.

 

[eagle23]

Thanks for this. Will be watching, too. Keep us posted of how you like your results.

BTW, the corner of one photo shows the "regular" battery. Is that original?

Reason I ask is I have a 2013 Avalon hybrid. It only has about 52k, but my understanding is it (and the Camry hybrid) use Prius technology, though larger engines/transmissions to account for the heavier weight of those cars.

 

[The Critic]

Originally Posted By: eagle23
Thanks for this. Will be watching, too. Keep us posted of how you like your results.

BTW, the corner of one photo shows the "regular" battery. Is that original?

Reason I ask is I have a 2013 Avalon hybrid. It only has about 52k, but my understanding is it (and the Camry hybrid) use Prius technology, though larger engines/transmissions to account for the heavier weight of those cars.


No, my 12V auxiliary battery has been replaced before. I replaced the original one after 4 years for preventative maintenance since I regularly take long trips and need reliability. Keep in mind that any battery with the "TrueStart" label is a service-replacement battery and not a factory-installed unit.

 

[meep]

judging by the pics this unit doesn't monitor indvidual cell voltages, which means the weaker cells could see a deeper discharge, or in some cases a far deeper discharge, than the healthy cells. In RC speak it'd be a "balancing cable" "balancing circuit," or other. I'm not as familiar with niMH but would think it to be a problem. Does it have an algorithm to reduce those risks?

 

[PandaBear]

How much is this?

 

[The Critic]

Originally Posted By: meep
judging by the pics this unit doesn't monitor indvidual cell voltages, which means the weaker cells could see a deeper discharge, or in some cases a far deeper discharge, than the healthy cells. In RC speak it'd be a "balancing cable" "balancing circuit," or other. I'm not as familiar with niMH but would think it to be a problem. Does it have an algorithm to reduce those risks?


I would expect the weaker cells to have a lower voltage resting voltage to start, so they would require less of a discharge? My understanding is that the charger will balance the weaker cells during the recharge.

Originally Posted By: PandaBear
How much is this?

https://hybridautomotive.com/collections/store/products/pdr?variant=40980027919

 

[The Critic]

Discharge cycle #1 has been completed. Total time was 7 hr and 37 minutes. At the 7.5 hr Mark, I saw the voltage drop to 137V (target is 134V), and when I came back from the restroom several minutes later, the system idle light was on. It appears that the voltage bounce to 153V only takes a min or two to occur.

Charge cycle #1 has started at 3:40pm on 7/30/18.

 

[EdwardC]

Pretty interesting! I remember the memory issue with nickel based chemistries, very different now with lithium.

I'm curious, in the discharge/charge cycling, does it record and display the Ah? Does the Prius have some kind of battery status indicator? I'm mostly wondering what type of quantitative information you'll from before and after the process.

 

[eljefino]

So does this only "do" the whole pack wired in series? What if it finds a weak cell? Did you do a techstream data scan/ log before you started?

The pack "rebuilders" use a model-airplane charger to "do" each 7.5V module over and over, logging results each time.

 

[CR94]

Very interesting.

Since you're doing this in the summer, are you monitoring the battery temperature? Is the battery cooling fan running during the charge and discharge cycles?

I haven't noticed any deterioration in my battery's performance so far. Living in a hilly area, and having to park in full sun most summer days can't help, though.

Carry on, and keep us informed, please. Thanks!

 

[PandaBear]

Originally Posted By: eljefino
So does this only "do" the whole pack wired in series? What if it finds a weak cell? Did you do a techstream data scan/ log before you started?

The pack "rebuilders" use a model-airplane charger to "do" each 7.5V module over and over, logging results each time.



My guess is this "reconditioner", if works, only reduce the memory effect. The deep cycling actually makes the charge difference worse on older batteries.

 

[The Critic]

Originally Posted By: EdwardC
Pretty interesting! I remember the memory issue with nickel based chemistries, very different now with lithium.

I'm curious, in the discharge/charge cycling, does it record and display the Ah? Does the Prius have some kind of battery status indicator? I'm mostly wondering what type of quantitative information you'll from before and after the process.


The Prius has a state of charge (SOC) indicator. Unfortunately, the Prolong device does not provide any detailed information on the battery's state of health. Prior to performing the service, I did run a battery test using the Android-based Hybrid Assistant/Hybrid Reporter application. See below.

Originally Posted By: eljefino
So does this only "do" the whole pack wired in series? What if it finds a weak cell? Did you do a techstream data scan/ log before you started?

The pack "rebuilders" use a model-airplane charger to "do" each 7.5V module over and over, logging results each time.



Correct, the Prolong device works at a pack level. Performing this service at a module level with appropriate load testing (to verify capacity and true state of health) is more valuable, but requires more time and disassembly. Most of us cannot afford for the vehicle to be out of service for that long, especially for a service that is theoretically being performed on a preventative basis.

The Prolong device does not provide any detailed information on the individual blocks so you would be unable to find any information on the modules. It also does not have any testing capabilities. Prior to running the reconditioning service, I performed a test using the Hybrid Assistant/Reporter app. Obviously the results can really vary (since the test procedure is far from precise) depending on the test environment, but it did give some idea of the pack's health.



Originally Posted By: CR94
Very interesting.

Since you're doing this in the summer, are you monitoring the battery temperature? Is the battery cooling fan running during the charge and discharge cycles?

I haven't noticed any deterioration in my battery's performance so far. Living in a hilly area, and having to park in full sun most summer days can't help, though.

Carry on, and keep us informed, please. Thanks!


The Hybrid Battery fan will stay running during the reconditioning process. The fan plugs into the Prolong harness and runs off of a/c power, so the 12V battery is out of the picture. My windows are cracked about 3" each and I open the hatch during the hotter times of the day.

Originally Posted By: PandaBear

My guess is this "reconditioner", if works, only reduce the memory effect. The deep cycling actually makes the charge difference worse on older batteries.


I am not sure how weaker cells will react during the discharge cycle. However, during the charge cycle, the entire pack receives top-end balancing so all cells should be brought up to the same level of charge.

 

[Spector]

Seems to me that since you are going to be keeping the car (implied via your comments) that I simply would have replaced the battery and be done with it rather than spend the money on this effort (along with a huge amount of time) and just be done with it as you stated that eventually you will need to do so anyway.

My daughter had hers replaced, a 2008 at 142,000, now she can go on without worrying about the thing going bad etc. What we have here is an end of life issue and it seems you have traveled to Mexico to get the latest cancer treatment as a last ditch effort to stay alive.

 

[Spector]

Seems to me that since you are going to be keeping the car (implied via your comments) that I simply would have replaced the battery and be done with it rather than spend the money on this effort (along with a huge amount of time) and just be done with it as you stated that eventually you will need to do so anyway.

My daughter had hers replaced, a 2008 at 142,000, now she can go on without worrying about the thing going bad etc. What we have here is an end of life issue and it seems you have traveled to Mexico to get the latest cancer treatment as a last ditch effort to stay alive.

 

[buster]

Nice job. Very interesting. I have no idea how these Hybrids fuction.

 

[The Critic]

Originally Posted By: Spector
Seems to me that since you are going to be keeping the car (implied via your comments) that I simply would have replaced the battery and be done with it rather than spend the money on this effort (along with a huge amount of time) and just be done with it as you stated that eventually you will need to do so anyway.

My daughter had hers replaced, a 2008 at 142,000, now she can go on without worrying about the thing going bad etc. What we have here is an end of life issue and it seems you have traveled to Mexico to get the latest cancer treatment as a last ditch effort to stay alive.


I would agree with your analogy if there was a fault code and I was using reconditioning (in combination with module replacement) as a repair. But I am doing this on a preventative maintenance basis. Think of it as a replacing the trans fluid on a car that shifts a bit rough but the transmission is still working fine.

 

[The Critic]

Charge cycle #1 was stopped at 7:19am on 7/31/18. The voltage was at 239V and “within spec.” Total time elapsed was just under 16 hours.
Discharge cycle #2 was started at 7:21am. We will be going to 84V this time.

 

[spackard]

Where does it dump the 400 watts of power?
Is that green circle thing a load bank?