Also, I notice for the Gen 2 Prius, the install of the harness seems easier, connecting the Prolong harness to the battery side of the battery disconnect relay per step 18 in the below:

2004 - 2009 Toyota Prius Plug-and-Play Car Harness Installation Instru – Hybrid Automotive

For the Camry, per the Product Guide, the harness had to be connected directly to the battery (I didn't check to see if connecting to the battery side of the relay would be a possibility without having to open the battery cover). This also seems to be how it would be for the 2010 Prius per the below:

2010 - 2015 Toyota Prius (non plug-in) Plug-and-Play Car Harness Insta – Hybrid Automotive

I presume the Gen 2 install is easier than the Gen 3 and the Camry. But if I see I could connect to the battery side of the disconnect relay for the 2010 Prius, any reason I shouldn't attempt it?

Thanks.

 

Install per the instructions. The 2010 Prius is easier than the Camry because you can easily remove the cover without removing the relay or any of the attached hardware.

 

Hi Keith,

I neglected to do any more maintenance on the battery for the last about 2 years since the reconditioning. The car has been driven normally in town with occassional highway trips. I just did a Hybrid Assistant battery health check and attached is the report. I would be grateful for your perusal and advice.

Thanks,

srivenkat

 

Battery health section

Voltage delta chart. Climb from about 0.2 to about 0.4 is a sign of a deteriorated battery.

Global stats table:
"Estimated Capacity": 3.52 Ah vs. rated of 6.5; 3.52/6.5 = 54%

54% does not imply that you have 1/2 battery life remaining. Very common for pack failures to occur in the 35-40% range.

 

Thanks for the perusal and advice, Keith. I would be grateful for advice on what you suggest be done now out of the below action plan you suggested 2 years ago, which regretfully I couldn't follow. Should I do "SINGLE reconditioning cycle (charge for 24 hours, discharge to 163V)":

------------------
Moving forward:

30, 60 and 90 days: repeat the discharge test and see how it holds up
90 days: conduct an overnight (8-12 hour) grid charge to top the battery off.
Every 90 days thereafter: discharge tests and overnight (8-12 hr) grid charge
Every 12 months: conduct a SINGLE reconditioning cycle (charge for 24 hours, discharge to 163V) [ should restore almost all of your lost capacity.

If at any time the discharge tests show a marked decrease in capacity or significant increase in voltage deviation, repeat test to confirm results. If confirmed, conduct a single 24 hr charge/discharge to 163V cycle.

Essentially, monitor and react. Do not charge or discharge any more than is necessary to maintain performance.

Should you experience cell failure, you can now have confidence in the module replacement option provided you get the modules from a reliable source.
-----------------

 

That probably still works, but the most important is the periodic evaluation.

I would recommend ONLY the evaluation routinely.

If the evaluation demonstrates clear deterioration, single reconditioning cycle WITHOUT the 24 hour charge:

1. Overnight 8-12 hr charge from about 60% SoC
2. SINGLE discharge to 163V
3. 4 hour charge
4. Idle charge to engine off
5. Very light driving until battery at ~60%.

Approximately 7 days/200 miles after reconditioning cycle, repeat discharge test to evaluate effect.

It's very easy to "over-use" a grid charger to the pack's detriment.

 

Thanks for the suggestion, Keith. I will perform the single discharge to 163V. So, I am understanding the steps correctly:

1. In step 4, "Idle charge to engine off": Start the engine and wait for it to automatically shut off after it brings up the charge to 2 bars.
2. Then per step 5, "Very light driving until battery at ~60%", the battery will start off with 2 bars from step 4, but slowly bring it up to 60% SOC by gentle (very light) driving.

If you can confirm I have understood these correctly, I would be grateful. Also, the below bulb schedule is what you would still recommend, right?
Above 224V, up to 200W
Above 204V, up to 100W
Below 204V, up to 40W

 

You understand #1 and #2.

I don't get too hung up on bulbs much anymore with the shallow discharges, but you likely have a lot of capacity disparity across the modules meaning they will all have notably different capacities. I'd just run 60-100W for the whole thing. Just don't leave it unattended for more than an hour. If you're in a rush, whatever you want above 245. Below 245, 100W max.

If I haven't mentioned it before, you can also expedite the process by doing a discharge test PRIOR to using bulbs. Just leave it in N until the car actually shuts off.

 

Thanks for the advice, Mr. Keith. Will try this and report back.

Separately, a friend's 2007 TCH had battery issues and he tried to resurrent it using my Prolong system and the procedure earlier in this thread and it didn't work; clearly one module is bad and he isn't able to invest the time and effort to go the module-replacement route. From your advice earlier in this thread, he has decided to get a new Toyota battery. We called a few places near here and the below (3 hours away) is offering the battery for $2900 but says the 12-month warranty applies only to dealer installations. I am wondering if this is true. If it is true, buying a battery not knowing if it has a manufacturing defect seems risky. Local dealer is asking $4k+ including installation.

https://parts.bommaritotoyota.net/p/...951033010.html

 

No amount of grid charging/discharging will fix a failed cell or modules that have grossly deteriorated capacity.

All replacement parts sold by Toyota carry the standard parts warranty, 12 month/12000 mile. Some parts may have different warranties for different situations, but they are usually longer. The hybrid batteries receive a longer warranty when installed by the dealership.

EVEN IF they maintain there is no warranty, the likelihood of an entire battery going bad is zero. I've seen TWO < 4 year old packs fail. In both cases, it was a module that physically leaked, and replacing that single module was all that was needed. I would not hesitate to replace a failed module on a recently new pack.