Prius Hybrid Battery Failure Analysis 

Prius Hybrid Battery Failure Analysis

Prius Hybrid Battery Failure Analysis
Prius Hybrid Battery Failure Analysis

We’ve seen Civic batteries that are of Gen1 and their several Insight fail. To Honda’s credit, the bulk of them were covered beneath the extended or common warranty. We’re currently discovering Hondas coming back due to their next battery substitute out of guarantee.

We’ve seen lots of Prius battery problems; I’d think we’ve observed now. That will look like a whole lot, but it’s a drop in the container in comparison to other forms of repairs that are costly. Therefore we’ve lots of Gen1s however arriving, We’re in Berkeley and we’re still viewing a minumum of one poor battery per month. it continues to be 12 years because the 2003 that was last bought, so none are covered anymore, although initially most of the batteries were protected under warranty. The batteries that are Gen1 had a lot of problems with chemical leaking past the terminals. They were all recalled to be cleaned. This “fix”’s success counted a great deal on the technician’s expertise and the energy he put in the job. You’ll find benefits to presenting construction done in a manufacturer setting lady or by way of a gentleman that does nothing but assemble batteries all day long. Quite a few fairly badly performed resealing jobs were noticed by I’ve. I don’t know if the mistake lies with “flatrate” or expertise time force. Anyhow, I imagine the “fix” saved some batteries and triggered premature failure on others. Regardless of the battery issues that are Gen1s, it has been unusual to determine one fail sooner than 100,000 miles — that is pretty good for me, especially when you think about the Prius will be the first hybrid that sold at this kind of high volume.

The Gen2 Prius batteries are currently doing a lot better than the Gen1. Gen2s was noticed by I’ve with 200K around the original battery.

The actual R&R (remove & replace) is pretty fast. About 45 minute for elimination and one hour for adding it back in. The remaining 1.75 hours is for switching elements from your old battery pack for the battery pack.

Thus now you understand “How extended ?” and “How much?”, if your Prius battery is beginning to crash which leaves “How are you able to tell?”

The HV ECU monitors battery issue, and certainly will alert you that the battery effectiveness has deteriorated below an acceptable performance patience having a warning light. But it appears that is not adequate enough for those who have been in the marketplace to get a cross that is used. For screening battery problem for them, I’ve created a way. Well, that’s not entirely accurate. It’s really likewise test process of the confirming a P3006 is legit. I simply found a nice way to graph it on the TechStream, and took some test information on a few automobiles with identified battery situations — one-with a fresh battery, one-with a negative battery, and one using a 60K / 7-year old battery that had no problems.

Here comes the tub technology! (Like “bathtub cheese”, or “bathtub gin”, “bathtub science” is home-made, by people without professional teaching, and might be of questionable quality.)

The Prius battery includes a couple of individual battery blocks sent in series. Each battery stop is approximately 15V. The HV Battery ECU watches every specific block’s voltage. Most of the block voltages differ somewhat. Whatever stop has the lowest voltage is described in a PID (Parameter identity) called Battery Minimum Stop Voltage. This PID may bounce to whatever block may be the lowest at the moment, therefore it may be the voltage for stop 10 one second prevent 13 the following second. There’s also a PID named Battery Maximum Block Voltage. Except the stop that’s the greatest voltage is reported by it It’s just like the Minimum Stop PID.

Both of these PIDs can be used to determine the battery pack’s situation. Temperature can affects battery stop efficiency and I’m different variables that were confident also. So just how is it possible to tell if a battery stop is performing adequately given its present condition? Easy, you go through the identical battery blocks next to it, which are currently performing underneath the exact same situations. If the others are not doing something wildly different than one block in the group , something’s not right. The HV Battery ECU can judge the healthiness of the battery pack, by looking at the best and lowest blocks.

The image below is actually a recording around the Toyota TechStream scanner. I’ve graphed the Max Stop Voltage as well as the Minute Block Voltage having an overlapping graph. Car-running amplitude has turned off and set identical minimum and maximum size prices for both PIDs. If you utilize the standard configurations, you wind up using a very worthless graph.

The length of the record is 5 minutes, consequently each division is approximately 30 seconds. The catch trigger was setto “10% before”, meaning prior to the switch was pressed, that when the trigger key was pressed, the saving began about 30 seconds.

The thing of the test will be to eliminate the battery and take notice of the variation between the Max Block V as well as your Minute Stop V while the battery is stressed. Therefore, how will you discharge a Prius battery?


The check goes such as this — allow it to warm up and Start the automobile. Set it backwards. Await the motor to stop running (if it’s not already running, await it to begin, then wait for it to avoid running). Press on the trigger key and simultaneously phase about brake and the fuel in the same period.


By doing this you’re discharging the battery using the MG2, which will be wanting to throw you backwards, nevertheless the wheels (preferably!) are preventing you from moving. THE ENGINE (SNOW) HAS TO BE OFF! Once the ICE is currently running, the battery is receiving. That’s the last thing you want when you are currently attempting to release the battery. This is actually the principle for the examination: ICE on = throttle down. ICE throttle on. You are currently wanting to launch and refresh the batterypack while watching the currents.


In the data below, MAX & the MINUTE are quite near when the SNOW is running. But as soon as the SNOW closes down as well as the battery is laden with MG2 & the throttle, a main split is made by the currents! There are about 7 divisions between your MINUTE along with each team and the MAX is.5 volts. The maximum allowable difference is 1.2V. This battery pack is very, very poor. Realize that the voltages keep coming back together pretty easily after the SNOW restarts and also the throttle is released. Furthermore realize the SNOW needed to start as well as that the battery-pack was cleared in only 1 minute 45 seconds. Finally, take a peek the amplitude — 18V is reached by the MAX and 14.5V is dropped down to by the MINIMUM.



Now let’s take a look at a recording taken on the same car, with a brand new battery. The graph setup is exactly the same, and the test was done in the same way.

There are quite a few differences. First, the MIN and MAX remain within a 1/4 volt from each other during the entire discharge cycle. That’s pretty different from the bad battery’s performance, where the MIN and MAX drifted apart 3.5V under load.

Also notice how long the discharge cycle lasted. Under the exact same load conditions, the new battery was able to discharge for over 4 1/2 minutes before the ICE kicked on to start recharging. That’s about 2.5 times the capacity of the bad battery.

Finally, take a look at the amplitude. The fully charged voltage is just over 16V and drops to just under 15V. Compare that to the bad battery where the range was 18V to 14.5V



i am definately not a battery pro, but of the three variations — divorce between Min Block V / Max Block V, time for you to discharge, and divorce between fully charged voltage and entirely discharged voltage — personally I think that the divorce involving the Minimum Stop Voltage and the Max Stop Voltage would be the most reliable signal of total batterypack issue.


So let’s take a peek in a known great battery-pack that’s been in service for some time. This recording is from a 2001 Prius, just like the two tracks that are other. The car is 7 yrs old, just as the additional two Priuses that had batteries that are bad, nevertheless the mileage is dramatically lower; this vehicle has 58,000 kilometers on the odometer. This car got set for a 5K service and the owner had no problems to report.


Thus, just like the new battery along with the negative battery, the maximum difference between your Minimum Block Voltage and the Max Stop Voltage reaches the conclusion of the release pattern. The brand new battery had a variation of about 0.16V, the battery had a maximum variation of about 3.5V, the good battery (when you can see below) had a variation of 0.28V. The Toyota exam describes a maximum difference of 1.2V.



Strangely, the Prius together with the undesirable battery’s MWL light had simply comeon, which begs the concern — so far as self-diagnosis and the difficulty code P3006 are worried, does the MWL genuinely come on if you have a difference of 1.2V involving the Min Block Voltage and also the Max Stop voltage? Often the conditions for establishing a P3006 is actually much more lax as opposed to 1.2V spec, OR, the battery power suddenly deteriorated quickly, proceeding from a 1.2V difference to a 3.5V variation in only one-day, OR, the voltage difference between Minute Block Voltage and Max Stop Voltage is less pronounced in daily driving than when energy braking inside the bay.


Whatever the response, I do believe 1.2V is a great “good/bad” slice point for battery power testing. So, for hybrid customers who would like to realize, “It the battery in shape that is good?”, I recommend these.


0.20V = 100% efficiency that is adequate

0.45V = 75% satisfactory efficiency

0.70V = 50% acceptable efficiency

0.95V = 25% acceptable efficiency

1.20V = 0% efficiency that is acceptable


I had actually entered the data above with “% life remaining”. However, I think it’s almost certain that battery damage won’t be that linear. I’m guaranteed Panasonic and Toyota have inked studies as well as their designers no doubt have piles of data, but I don’t have access to it, so my screening and conclusions over a sample of three must do for that second.

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