Traction Battery Display Question

You would have to acquire some software for your phone or laptop to check the state of the traction battery.

That indicator you mentioned is a state of charge (SOC) indicator. One bar on that indicator is 40% charged and 8 bars is 80% charged. As you drive the car, the number of bars will fluctuate.

Light acceleration will draw power from the traction battery to drive an electric motor which moves the vehicle. Heavy acceleration will start the internal combustion engine (ICE) which will assist the electric motor in moving the vehicle. Braking will switch off the ICE and the electric motor becomes a generator (regenerative braking) to capture energy while slowing the car. It will use that braking energy to charge the traction battery.

 

Wow. I just looked at the manual for the Prius c and it doesn't explain anything about the battery indicator as far as I could tell other than one little diagram that shows full, mid, low or something like that.

The quick answer is that it is just a state of charge indicator like a fuel gauge. It has nothing to do with wear and tear or with replacing anything. The dealer should have explained this along with lots of other things, but most of them work very hard to remain ignorant of anything having to do with the Prius.

The longer answer is that if it shows all bars filled, that's still not 100% SOC and no bars is not 0% because the car won't let it go that high or low. It reserves charge at the top and bottom that you can't see or use in order to protect the battery. Most of the time, it should stay in the middle or a little above the middle. Big down hill slopes or repeated braking might fill the indicator. It should be very rare for it to get all the way "full" or "empty."

 

congrats and welcome!
it is simply showing you the relative state of charge. it charges and discharges on its own when the car is made 'ready'.
it doesnt really mean much, but can be useful as an indicator of a battery nearing the end of its useful life if you see repetitive swings between one bar and 8 bars.

your battery has an 8/100 warranty

all the best!

 

In California it's a 10/150 warranty.

OOPS!! I looked it up and the c doesn't have the CARB warranty.

 

on the c?

 

Nice catch, Bisco. I didn't know that about the c. I looked it up from Toyota's online manuals and you're absolutely right.

 

i was surprised when i learned that, from ray i think. the nuances of warranties are frustrating

 

The RX450H battery is also 8/100.

But just because the batteries warranty is shorter, doesn’t mean it’s less reliable .

Just how the car is classified. Since they use the same technology, why wouldn’t it last equivalently ?

That’s what I’m operating on anyway.

We just did our SoCal trip in the RX450h this time and the battery did very well. Even in LA traffic the battery seemed brand new but is 2.5 years old and 31k miles seasoned.

 

Just one thing to add

All of what Ronald mentioned above is right, but regenerative braking is not always easy to understand, especially when moving into a hybrid from and ICE car.

Regeneration is handled by the computers in the car, much like the SOC state of charge of the Prius C "traction pack" battery.

With regenerative breaking, the electric motor will regenerate "traction pack" SOC state of charge, All the time you are braking,

but the " Prii"

also has regular disc breaks, and they are used as well, by the computers to determine when and how the regular disc breaks are used.

It's a computer control thing,
Like Ronald say above,

The computers use regeneration while you are driving regularly too,
which is one of the reasons why Hybrid cars slow down different than normal ICE car slow down.

 

I agree with what you say Vvillovv.

The Prius is a front wheel drive car so regenerative braking can only be applied to the front wheels. The rear brakes on the Prius are mechanical (friction) and can only assist the front.

Up to 75% of a cars braking force comes from the front brakes which is why vehicle front rotors are always larger than the rear rotors. It is the job of the braking computer to maintain the balance of front-to-rear braking force (proportional braking).The harder you brake, the more the front of the car dips down and the rear of the car raises. That means more braking force needs to be transferred from the rear brakes to the front brakes or else the rear brakes would lock up.

The braking computer also has to account for how much regenerative braking is being applied to the front wheels and release an equal amount of mechanical braking from the front brakes to maintain the front-rear brake balance.

Next there is the regeneration current limit. Increasing the pressure on the brake pedal increases this regeneration current up to and beyond the 110 amp limit. Braking harder than the 110 amp limit just adds more mechanical braking into the mix and that energy is lost as heat in the rotors. Since batteries don't charge instantaneously, gradual braking keeps the regeneration below the 110 amp limit and the longer charge time allows the traction battery to recover the maximum amount of electrical energy.

Finally, the regenerative braking is switched off below 8 mph. Below 8 mph the Prius brakes are just like any other car.

That has to be some pretty amazing software. Hats off to the engineers that developed it.

 

Holy crap - You all are aware that your replying to yourselves I hope.

The original poster hasn't been back. Probably won't, but you never know. If he/she did return, they'll probably be so confused they'll never return until panic sets in down the road when the car breaks. Gotta keep it simple. All this SOC / ICE / Regenerative braking and the technicalities behind it all will most likely completely overwhelm and thoroughly confuse a 1st time Prius owner.

 

I have been a car enthusiast since I was a teenager. I read every hot rod magazine I could get my hands on. Rebuilt engines and transmissions and built racing engines for a few of my friends cars. I put a turbocharger and water injection on a "Sleeper" economy car that I owned that was fun to drive in the "stoplight gran prix". I do all my own work on our cars as well as any electrical, plumbing or mechanical work on our home. I am fairly new to Prius but I want to know every detail of how my cars and everything else works. I just took my wife to an Urgent Care and sat in our Odyssey reading the 300 page owners manual while she was waiting to be seen. I learned a few things. OK, so I am a geek.

My wife on the other hand is not the least bit interested in anything mechanical. She is smarter and has way more people skills than me but her only mechanical curiosity is seeing how long she can drive the car with the "low gas" light on.

I assume that we have some new Prius owners like myself, some like my wife and then there are many in between.

 

I have to admit, I wan't thinking much about the OP in my post above.
I was trying to explain that most people don't understand what regenerative braking is or how it work due mostly to the way
it's been explained to drivers since the beginning of hybrid regenerative braking systems

I still see post here where drivers actually believe the regeneration is being done by the disc brakes somehow.

 

Just in case the original poster does come back, an “8/100” warranty means the hybrid traction battery is warranted to be free of material defects for 8 years or 100,000 miles, whichever comes first.