Help on deciphering hybrid battery inspection sheet

It looks reasonable but those values do not really give a pass fail. You look for the min max differences to be small, ideally as low as 0.05v but 0.10v is reasonable. Some believe an app like Dr. Prius with a bluetooth Obd2 scanner is better because they can test the battery with a forced charge and then turn on loads to determine how fast it discharges.

In reality, a significantly bad battery will throw a code and warning light. Looking at the min max difference then may show a bigger difference with one or two of the modules to blame. Age is usually a sign as well, use in high ambient locations seems to shorten life, clogged up battery cooling fans may simulate high ambients, fast discharge at traffic lights is a bad sign, reduced mpg is common with a weak battery, etc. Usually specific codes and symptoms you notice like fast discharges and reduced mpg are the only real warnings before specific battery codes.

No symptoms and a new battery three years ago is a good sign; codes, warning lights and the original high voltage battery deserves caution. It is easy for a seller to reset warning lights. It may take a week for the same warnings to reappear. On a 2013 with an original battery, I would factor in a new hv battery in the next year.

There are other issues on these models. The power brakes (brake booster system), oil consumption and head gasket issues are common. A plus if oil changes were done every 5k miles or less without fail.

how do you read dr. prius app | PriusChat

 

Your battery is made of 28 modules connected together. The computer monitors their voltages in pairs, called blocks. The 28 modules are actually 14 blocks to the ecu.

Techstream is the software Toyota uses for communicating with the car computers and taking snapshots of car data.
The data in the report is from one of these snapshots.
Line one means the block with the highest voltage reads 16.05 volts
Line two means the block with the lowest voltage reads 15.95 volts.
Line 3 means there are 14 blocks (some cars have up to 19 and some as low as 10)
The other numbers are the voltages of the individual 14 blocks.
Cooling fan is running at 39% of full speed.



Those numbers don't match up very well. I realize this is likely from a Techstream snapshot, but when the Max and min block voltages are documented as 16.05 and 15.95 volts at the top of the report, yet the individual blocks in the same snapshot show 16.02 and 15.17 for max and min, something seems a bit sketchy to me. Those numbers rarely ever match up perfect, but that 15.95/15.17 window is a lot larger than I usually see.

 

What I can tell you is that Toyota puts a 10 to 20% (non usable) buffer in the (traction batteries) SoC both bottom and top. So when the car shows 100% SoC on the dash SoC gauge, in reality that is somewhere between 80 and 90% of the traction batteries true SoC. And likewise at the bottom, when the cars SoC gauge shows 0% SoC in reality it is somewhere between 10 to 20% of the traction batteries true SoC.

Another snapshot or 2 would help both Us reading this thread and you understand it better.
Using the DrPrius battery health tests can also reveal more.

 

There is no "inspection" or "test" modes built in that are available via the obd2 scanner. There is no capacity remaining test result either. As stated previously, Dr Prius makes an attempt at capacity but I would not trust it.

The min max voltage values are likely synced snapshots but the individual module readings are scanned one at a time. The battery state of charge numbers are largely irrelevant unless the hv battery has failed and the car won't start. As the car operates there is always a load on the high voltage system and often a concurrent charge as well. So the battery modules continually change voltage making the scanner speed and turnaround important.

It does not look like the seller used Techstream, it shows Launch, another general purpose, all brand scanner that is sequentially polling hundreds of data points. Bottom line: these results are largely meaningless as a true indicator of hv battery health but look reasonable at best. Symptoms and history are better indicators, guaranteed. If it throws codes, it is weeks or months from limp home mode. The hv battery will need replacing in your ownership, its just a matter of when.

Frankly a $2,000 new battery is expected after eight or more years. A $2,500 brake booster or $3,500 head gasket is not "expected" but is way too common on these models. Many have changed or repaired all three making their "gas saving" 2010-2015 Prius a bad used car investment.

The gen3s are also known for Inverter fails, a several thousand dollar repair that is still covered by Toyota in the US. However being stranded without warning by a flawed inverter is no fun. Ask me how I know. I always suggest going conventional when buying used.

Launch Tech Co., Ltd

 

Here is a reliable low cost used vehicle option.

 

Correct. This is mismatch and self contradictory report. It is certain this battery will fail very soon with 0.88v difference.