2006 Prius High Voltage Battery

Especially in hot summer weather where the AC compressor is running (and therefore putting a load on the traction battery), it would be normal for the traction battery SOC to move around as you described.

 

If you find it's mostly dropping to 2 bars soon after cold starts then try letting it warm for about 50 second before taking off. This will fix the problem and is the kindest thing you can do for your battery.

 

Yup fluctuations are normal.

The easiest test is if you are doing around town driving every time you accelerate it goes to 1 or 2 bars and every time you stop it goes to completely full green. If it does that, your battery is on its last legs. The bars might (most probably) drop when accelerating and go up when braking but it should not swing full charge.

 

Things I noticed just before my battery tanked:

• Bars would fluctuate from pink to green back to pink in a matter of a few minutes
• Gas engine would occasionally have a short jolt of powerlessness in the morning
• battery fan ran a lot

 

IF your battery were to die, and I don't think it sounds like it is, you are currently within that threshold that Toyota seems to be helping out with a replacement. I think I have seen it up to 112K where someone calls customer center and Toyota agreed to pay for half of the replacement. Keep that in mind, just in case.
Mine was at 140K, so no help for me.

 

Jeff,

In reference to "a matter of a few minutes", could you please give a actual number? Also, did it seem to make any difference depending on how much load you running at the time ie: A/C and fan running etc.?

Ron

 

I wish that I could give better specifics. Prior to it failing, I didn't pay too much attention to SOC. The first clue I noticed was the gas engine loss of power. This usually happened first thing in the morning. I would leave the driveway, hit the pedal and there would be a sudden sharp drop in power, followed by a gradual uptick.

I wish I did more specific tests to see how long my HV was holding a charge. Once the triangle came, it was up and down like crazy.

With P0A80 code, it seemed to continue to run fairly normal, though it relied much more on the gas engine. If I had to guess, I would say that it only took a matter of 2 minutes of normal (for me) driving for the battery to drop from 7 to 2. When I started getting cell specific codes (P3017) that's when I noticed my Prius would go into limp mode. Then I would pull over, let it cool for a minute, and it would start back up and run fine.

 

Remember that after the vehicle just starts it tries to warm up the engine without using it for motive power. Even a healthy pack will experience lower power and slight jerkiness when going from puttering acceleration to high power acceleration, like mashing the pedal. When the battery has almost no capacity this will be exaggerated. The minute or two will be the warmup period and vary based on temperature.

 

Thanks Jeff and 2K1 for the replies and the info.

I am under the impression based on what other's have written that it seems that the charge swing is just in a couple of minutes (2 or 3). As 2K1 stated, when the Prius is in "Stage 1", the system uses the traction battery the most which at times will pull down the SOC if it is not close to 6 bars. I do believe it is normal for the ICE to seem to have less power when the traction battery SOC is low (pink - 1 or 2 bars). I believe it is due to the fact that the system is actually pushing more power towards the traction battery than MG2 hence the feeling of the ICE having less power.

So far, I have yet to hear the fan running fast but there have been times when I have run the pack down. That seems to happen to me if I am running the A/C a lot (high ambient temps) while the Prius is parked. I have timed it several times. It seems to be consistent and it averages about 15 minutes between cycles if I am not moving and the Prius is parked in direct sunlight with a ambient temp of 92 or higher. If I turn the air off, I then note it takes about 23 to 25 minutes before the ICE cycles on.

Ron

 

From everything you have said, it appears your battery is healthy and happy with many tens of thousands of miles ahead of it.