They are essentially the same car and may be even be exactly the same for all intents and purposes, but the "C" is sold in the states and the Aqua is not.

You can get some insight into the actual state of the C's battery as follows:

Get an android phone/tablet
Get an - linked to the one I use on Amazon
Install "Hybrid Assistant" and "Hybrid Reporter"
Conduct a battery test EXCEPT do it in "N" until the car gets p!ssed and tells you to switch out of neutral.
Terminate test
Place in P
Evaluate the block voltage behavior

The above can give you confidence if the battery is suffering from either voltage depression, that can be improved with reconditioning, or if it is suffering from widespread damage.

 

Finally had the time to get a couple of battery tests in. There was quite a bit of learning curve when using this app. I've inserted two separate tests. One of them show an incorrect actual capacity I think due to the car getting pissed and stopping. I can conduct more tests if you think I should.

First attempt

Actual SoC error?

 

There is some inherent loss of capacity, and it becomes most evident below 40% SoC when testing in "N". The second test avoided that region.

You should be able to export the raw data and an html report from tests. I don't remember how, but you can find it on your phone/tablet and upload it. I think you have to use Hybrid Reporter to generate the report.

Your actual battery capacity is likely somewhere in between those two extrapolated values - about 3.75Ah or a little over 50%.

The detailed data from the tests can give clues as to whether it's from capacity loss that can benefit from reconditioning, or if it's permanent damage.

 

Here are a couple of tests I performed in N using the hybrid assistant. I don't think I've still figured out how to use the app as I've conducted more tests than this. The reporter app is very nitpicky in what it logs.

 

The 2/24 test was too short. I have attached a zipped spreadsheet of the earlier test - just the discharge portion. Refer to the chart in the workbook. The circled area is where you have lost capacity that might be gained by reconditioning. Since it's 40-45% SoC, you may only have some small capacity loss - certainly not enough to affect performance. The very low dV between the blocks suggests that there is little or no damage, but possibly simple capacity loss that can be reclaimed by reconditioning.

The real issue is with the extremely low current used. You need to maximize the electric load. Need to increase current by following test instructions:

http://hybridassistant.blogspot.com/...check.html?m=1

If it's cold where you are, A/C won't be effective, but you can increase current using the defroster on HI. This will force the engine to run for the heat demand, but it won't start charging the battery until you hit 40% SoC. This also adds the spark plug load, so you might see 10A or so of current, which is a much more effective test.

 

So I've done one test. I had headlights, A/C and phone charging during the test and the battery didnt last long at all this time. Im having trouble opening this file on my phone so hopefully you can.

 

That's more like it. Note that the USABLE capacity of the hybrid battery is approximately the same as the TOTAL capacity of the little 12V battery, so reconsider your expectations. The HV battery is not sized to permit extended EV driving but to act as a kinetic energy recovery and release mechanism. You have a gas car with electric assist.

The attached zip file contains an excel sheet. The chart shows SoC, current, capacity extracted and maximum voltage delta. I only plotted the portion down to 20% SoC because the car cut to the current (likely disabled the A/C compressor).

You can see the SoC curve abruptly changes slope around 55% SoC (circled in red), but the dV is under 0.2V on this chart as well as the lower SoC values in the sheet (not plotted). This is a sign of reduced capacity. Since the dV is small, there's a good chance some of this lost capacity can be recovered with grid charging/discharging.

I've highlighted the region between 55 and 65% SoC. this is the typical operating SoC range of the car. You can see you're operating in the more shallow slope of the SoC curve. This means that your battery deterioration is likely NOT causing any issues with drive-ability or economy.

You extracted 1.264Ah of capacity between 66.7 and 19.2% SoC. The extrapolated capacity is 1.264/(.667-.192) = 2.66Ah or 41% of rated capacity (6.5Ah)

If you limit the evaluation to the 40% SoC level (that's what the car normally uses), the extrapolated capacity is 3.77Ah or 58% of rated capacity. This is probably a better measure of the battery's actual health since the deeper discharge includes more of the steep sloped portion of the SoC curve.

To summarize, your battery is showing signs of significant capacity loss. The small voltage deviations across all 10 blocks suggest that this capacity loss is more likely due to conditions that can be improved via grid charge/discharge vs. permanent cycle or heat damage.

 

Well, that is better news than I expected. You cranked out that spread sheet rather quickly. You got some macros that formats all that?
I've read into your posts about grid recharging. Is there a particular model of charger or equipment you suggest for my 2012 Prius c?
Thanks for all your input, it's greatly appreciated.

 

You might guess I've done dozens of those. No macro.

I am an authorized installer for Hybrid Automotive Prolong systems, so naturally I recommend them. I know the owner personally, and he stands behind his product.

https://hybridautomotive.com/product...oning-package/

The automatic discharger is awesome. No babysitting light bulbs.

IN MY EXPERIENCE/OPINION, the Toyota packs benefit from grid charging much less than Hondas. Hondas go out of balance if you look at them funny. The Prius rarely has this problem. AGAIN, MY EXPERIENCE, nobody else's.

Discharging is the key to restoring capacity. Unfortunately, you have to discharge BELOW empty to get benefits, so a grid charger is needed to restore the battery to a working state of charge. The prolong discharger is top notch. My neighbor just acquired his 3rd Gen2 Prius, and it's battery looked very much like yours, except the slope change was around 60% SoC, and it was impacting his economy... struggling to get over 40 mpg. After a single discharge to the highest voltage, he effortlessly gets 45mpg.

With the Prius' ability to force charge the battery, the process can be expedited, and the extended grid charging sessions can be avoided.

 

I was wondering if you could elaborate on what metrics we should focus on in other to determine if the loss of capacity is due to irreversible vs reversible damage. Are voltage deviations the only metric by which this is determined? You mentioned that the dV of .2v is considered 'small' , in your opinion what is the largest dV that you would consider acceptable?