I recently had an ABS issue after I incorrectly flushed the brake fluid in my gen 2 Prius, 2009. Well I reset the ABS system myself (there is an online hack on how to do this), no more ABS issue, but ever since my hybrid battery is charging more than it did before, in a concerning way. When looking at the "Energy Monitor" screen on the main console (with audio, climate control act), the battery on the screen used to regularly drop to 2 or 3 bars, but now the lowest it drops is 1 bar down from fully charged, so essentially fully charged. The battery now regularly displays in the green, where all bars on the battery are full. On the highway it drops 1 bar for parts of the drip, or in town, but quickly goes back up to 100% charged being displayed when coming from the offramp, or going down hills. This concerns me since I don't want the battery to overcharge, and I have always been told you don't want the battery to stay fully charged (which it is often now), or the opposite, low at 1 bar too long either. Any ideas on why this would have occurred, and what I might do to normalize the charging of the hybrid battery?
Full charge in Prius OEM is ~80% You got nothing to worry about, especially with NiMH electrolyte, even at 101% charge levels!
Thanks for the reply, but being at 100% full like 60-80% of the time isnt concerning? Or that shortly after going downhill, or braking, it stays at 100% fully charged for like 5-10 minutes?
It is not 100% fully charged. To reiterate what PriusCamper said in post #2, The graphic on the Energy Monitor screen only displays the 40% (the bottom purple bar) to 80% (the top green bar) range of the battery. You should also understand that when the top bar lights, it does not mean your battery at 80% charge as this will light when the SoC is 75% and continue to accept charge until it reaches 80%. Furthermore, the second bar has an approximate range of 64% to 77%. From this you can see that the battery can never reach 100% from in-car charging. The change in behavior you describe is typical after the battery has been reconditioned, or sometimes after the 12 V battery has been disconnected (or gone flat). If that has not happened, I'm not sure what could explain the change in behavior. In any case, it is nothing to worry about, as Camper said.
Because "reset the ABS system" is not a thing, a post like this is a lot more useful if you link exactly what "online hack" you found that made you think it was—that way, other people reading have the best chance of knowing what you actually did.
If the OP can read the pack voltages with Techstream or some OBD2 dongle that might (but probably won't) show something interesting. If the sense voltages stick at 16V or higher, in normal driving on a flat surface, that would indicate that the car is charging the NiMH pretty much all the time. But if that was the case the display on the MFD should also show arrows directed into the pack, possibly even when accelerating with all green bars, which really shouldn't ever happen. Normally any acceleration on a flat surface will have the arrows moving away from the pack, with the exception of when the pack is nearly depleted, in which case the car may charge the pack even when though the driver is calling for it to accelerate. But I'm getting ahead of the data, which in all likelihood will be unremarkable.
