rapid discharge from full green to one purple in 1/4 mile..ideas

Sounds like a weak battery pack, you can try charging it and balancing it again.

 

I've noticed similar behavior if the car is left at the airport for a week. Therefore especially in these cases I try to warm the car up in Park about 3-4 minutes. You will notice after a minute the engine comes on and another couple minutes the engine goes off, then I go.

 

Hi Beachbummm,

Do you have a Mini VCI cable? Run a charge and discharge test with the battery in the car. Art's Automotive has a good write up on how too. Or try my version. To get to live battery data run a health check, click on the battery category, then on live data.

Charge test : Engine on, set parking brake, car in drive, step on gas and brake fully. Your car will just sit still and charge. Give it about thirty seconds to a minute. The weak module pair voltages will rise faster and higher than the rest.

Discharge test: Car on and warmed up, engine off, set parking brake, car in reverse, step on the brake, give it a little gas but not so much that the gas engine turns on. The car will sit still and discharge the battery. Give it about a minute. The weak module pairs will drop in voltage faster and farther.

What did you use to run a load test out of the car?
You could have a module with high self discharge.

Brad

 

Strawbrad, I just emailed a question to Art's Automotive about this topic. I want to do a before and after testing of my battery pack and log the data into a spreadsheet and graph it to see what my HV battery looks like before and after a grid charger install (with 3 discharge cycles replicating a battery reconditioning) just for fun and to see if there was any value in the grid charger.

I was thinking about buying a techstream when an idea hit me. I own the Torque app and on the Android I can screen record as well as have a floating stopwatch, so I just made a short movie today testing what I could gather...namely discharging data without needing a techstream.

I got to the bottom of the hill today after work as normal and was using my Torque app from Android and of course I had an 82% state of charge so I let my car dwindle it's energy to 80% in the drive was expecting more rapid discharge than what I got but from my readings I had....

16.7/16.7 Max/Min Volts (Max and Min close together)

Pushing in the reverse while braking only used up 3.7 amps.

During this draining the Max/Min never varied by .1volt (which is good but maybe because the discharge was so slow?)

After doing this for 7 minutes, the SOC had only dropped to 68.6% and the Max/Min was now 15.9/15.8 volts.


I stopped the test because I had expected the discharge rate to be much faster. In the tests on Art's Automotive, he says the BAD battery discharged in only 1 and 1/2 minutes before the ICE kicks on. For the NEW battery, he saw the battery lasted 4 1/2 minutes before the ICE kicks on.

I'm not sure how he's pulling that many amps on the battery to get those results, but from my first test I must be doing something wrong because it would take me a lot longer to drain this battery down to 40%. Maybe he's talking about a GEN 1 prius or something's not right. Any ideas?

 

Beachbummm, I also have the same year car as you and my car does the same thing. I drove home from work after having the car sit for 6 hours and the battery went from full charge (80%) to 40% within a 1/4 mile area as well. I didn't charge any hills that greatly, it was pretty mellow, but I saw the voltages tumbling and I've decided I will be recording my climb up the hill each day and documenting it on my Torque Android app making a movie with timer and plotting my figures over a graph. I just bought the hybrid grid charger and will be performing the balancing and deep cycling (3 times) of the car battery when I get time during our next vacation coming up. Then I will compare my daily climb up the 700 foot hill that I must go up each day and come down each night. It is very helpful for testing purposes because my car always tops out at 80% state of charge (all green) each time I park it, and then when I leave for work it is quite drained before it gets to the top. My goal is to find out what kind of strength the deep cycling will do to prolong the voltages and not have them tumble as fast as we both have seen them tumble in only 1/4 mile.

I had been suspecting for some time that the battery was stronger when just charged to full and then driven back up the hill, but like you said....if left overnight it's "full charge" is more like a vapor (disappears but still reads full green bars) and there's not much capacity showing up when driven.

 

i wonder what happen with bb's battery.

 

I was playing around with my Torque App and did a record screen movie to see what kind of voltage differences I could get between MAX and MIN. While reviewing and pausing the movie during the parts where I floored the pedal and pulled up to 96 amps at one point and saw during those surges of electrical pull the voltage variation going up to .7 Volts at the max. I'm not sure what a new battery would have variation-wise but I'll try doing this simple test after refurbishing the battery too. Luckily my battery usually has a variation of .1 to .2 Volts normal driving, but it is interesting to see how a load test can show a different story. I'm still unclear how to best test the discharge of the battery to get a baseline for the health of the battery. When I tried the reverse/brake way of doing it, it didn't seem to pull enough amps to really "load test" the battery to see voltage variations.