How to load hybrid battery to 100%

[CesarD]

Hello.

I have a brand new Yaris Style since a couple months ago and can't help but notice that the hybrid Battery never loads to 100%: even if I try to keep it on fuel or use the breaking periods for as much as possible to charge it, at some point the car keeps using the electric motor for something and the Battery starts to discharge again (of course).

Is there any way to charge the Battery at 100% at all?

Thanks.

[bathtub tom]

I believe Toyota don't allow the Battery to be charged to 100% as this extends the Battery life.

[FROSTYBALLS]

Quote from Toyota on the hybrid system:

"The hybrid Battery (and the battery-power management system) has been designed to maximize Battery life. In part this is done by keeping the Battery at an optimum charge level – never fully draining it and never fully recharging it."

[CPN]

50 minutes ago, CesarD said:

Is there any way to charge the battery at 100% at all?

In a word, no. The HV Battery is managed by the system as a whole and kept between the lower limit of 40% (although I have seen it go lower than that briefly under load) and the upper limit of 80% since this has been proven to extend the Battery life with Lithium-Ion and Nickel Metal Hydrite batteries. It's the same for your Smartphone actually (most use Lithium-Ion) and it also benefits from not being charged to 100% all the time.

Anecdotally, Chalmers University of Technology, Sweden, reports that using a reduced charge level of 50% SOC increases the lifetime expectancy of the vehicle Li-ion Battery by 44–130% and I notice that with our new 2020-21 model Yaris, it does hover closer to that 50% sweet spot more often than my previous (2017 - using Nickel Metal Hydrite) Yaris ever did.

[MikeSh]

1 hour ago, CesarD said:

the hybrid battery never loads to 100%

This happens with most pure EVs too, though to a lesser extent (much bigger batteries). 100% is not a good place for the Battery and also means you have no capacity for regenerative braking.

Since the latter is crucial for much of the economy of a hybrid it obviously needs to be prioritised, so you won't get near 100% except perhaps on an extended downhill section.

[Catlover]

Cesar, you say “even if I try to keep it on fuel or use the breaking periods for as much as possible to charge it, at some point the car keeps using the electric motor for something”.  That “something” is to propel the vehicle by electric power.  What did you buy the car for?  Because it uses less petrol, tight.  So if you using less petrol to do the same miles, “something” is replacing the petrol and that is electric power.  I know I have stated the obvious, but sometimes we can’t see the obvious.

Just relax, let the computer do the work, enjoy the drive. Toyota have been developing hybrid cars fro more then 20 years, their engineers know a few things by now.  It is true the driver can help get better fuel consumption by using “hybrid driving techniques” but the computer does a brilliant job.

[TonyHSD]

Hi,

it’s all explained well above regarding the hybrid Battery, all managed by the car and you don’t have to worry about. Even you bring the Battery soc to 100% or close to the car will run the ice to discharge the Battery to more acceptable levels which most likely been between 40-80%. With Toyota hybrids all you need to think about is to have sufficient amount of fuel in the tank, don’t let it run dry and you will never have any troubles. Going long downhills can fully charge your battery or coming out of motorways slip roads at higher speeds, when that happens you will notice your ice is running to discharge,. fully discharge your battery is a problem that you have to worry about and this can happen when run out of petrol and continue to drive on electric until you kill your battery, then your car will not start even after you fill up with petrol and you will need to transport your car to a dealer. 👍

[PeteB]

In fact the Battery display is only showing a 'window' of the charge state.  If it ever got to fully empty (almost impossible), there's still about a 40% charge, and on the very rare occasions all 8 bars are lit and the Battery is considered 'maxed out' (that is, won't accept any more regen charge - it still does for a while after the 8th bar lights up) the true State of Charge is about 80%.

I experienced Maxed Out state on a Gen 1 Prius descending some very long hills (like 5-6 miles at 20% gradient) in Scotland a long time ago, and also on a Gen 3 Prius in Devon.  At that point, B mode becomes more useful (it uses engine pumping without injecting any fuel to help control speed), and braking with the with the footbrake is 100% using the friction brakes.

The attached link shows a graph that someone worked out a long time ago for a Gen 2 Prius.  The numbers may have changed slightly on more recent Hybrids, but probably not by very much.

 

[CesarD]

Hi guys. Thanks everyone for taking the time to reply 🙂 Much appreciated.

My main concern regarding this topic was because every time I intend to switch to "EV Mode"  (with the button that is next to the Drive Mode switch and such), it tells me that there's not enough charge on the Battery to switch to EV Mode... So I wondered "hmmm, ok, so how could I charge it up to a decent level where I could experience the full EV mode without switching to petrol for a while? 🤔". I understand that the car would normally try to balance fuel and Battery usage and that's great, but if I can't get much charge on the Battery to switch to EV Mode, then why is that mode even there, and in what aspect would it differ from the regular driving where I only accelerate up to the limit of the ECO zone so it only uses electric motor and prevent the petrol one from kicking in?

[Trewithy]

I only use EV mode when reversing out of the garage, or if the car has been parked on the drive, to drive into the garage.  Once I'm on the move it's into Normal Mode.  The car will go into electric drive whenever it can and I have to say it does a good job of managing the whole process. That is the benefit of Toyota developing their cars and software over many years.

[TonyHSD]

38 minutes ago, CesarD said:

Hi guys. Thanks everyone for taking the time to reply 🙂 Much appreciated.

My main concern regarding this topic was because every time I intend to switch to "EV Mode"  (with the button that is next to the Drive Mode switch and such), it tells me that there's not enough charge on the battery to switch to EV Mode... So I wondered "hmmm, ok, so how could I charge it up to a decent level where I could experience the full EV mode without switching to petrol for a while? 🤔". I understand that the car would normally try to balance fuel and battery usage and that's great, but if I can't get much charge on the battery to switch to EV Mode, then why is that mode even there, and in what aspect would it differ from the regular driving where I only accelerate up to the limit of the ECO zone so it only uses electric motor and prevent the petrol one from kicking in?

Here is where you find out that Toyota self charging hybrid is not a plug in hybrid and it’s EV mode is only useful in very specific circumstances in ideal conditions, sometimes when your Battery is” full” as displays dashboard you still not gonna be able to drive in ev mode, you will get message “ ev mode current not available “ , since your ice is running to discharge the hybrid Battery, happens often with me since I live at the bottom of a long downhill and very often I switch to ev mode for the last few hundred meters drive and sometimes the car refuses to go in and engine kicks in and I get that message.,  well best to stick in Normal mode and enjoy your car as is. With the time and driving you will get use to and learn all tricks and quirks that hybrid has to offer, there are plenty and enjoyable. There are tricks how to drive efficiently , how to slow down more efficiently and how to accelerate faster reducing the whining noises that you may get sometimes, all with the time. 👍 or if you would like more info can search for Prius , it’s the same technology and most popular Toyota hybrid, most of the info is for that model. 
Regards 

[Catlover]

Cesar, don’t know if you found this out yet or not, but EV mode will only run up to a certain speed, my Gen3 Prius was about 18mph, my Gen4 Prius goes to about 27mph. The big Battery in your car is a compromise, more Battery is more performance, but more weight. So in a hybrid EV is a compromise. It gives you the best of a EV car and a petrol engines car. Petrol engine car emits lots of emissions, not too good mpg. A pure EV gives you limited travel (miles), but clean vehicle emissions. Hybrid gives you cleaner emissions then petrol engine, but gives you a good distance to travel, in my Prius Gen4 with 10 gallon (45 litre tank) I can do well over 600 miles, better then EV and petrol engines. Life is a compromise at times, but with a hybrid vehicle it’s a good compromise.

[Mike J.]

6 minutes ago, TonyHSD said:

.... since your ice is running to discharge the hybrid battery .... 

I don't understand this, please explain how the ICE can discharge the traction Battery (other than just starting the ICE up).

[Mike J.]

2 minutes ago, Catlover said:

Cesar, don’t know if you found this out yet or not, but EV mode will only run up to a certain speed, my Gen3 Prius was about 18mph, my Gen4 Prius goes to about 27mph.

With my Yaris Hydrid, the max. EV speed from cold was around 9 mph. When warm you could get 27 mph. It is all software controlled and uses multiple inputs (various temps, speed, load, charge, etc.) to optimise 'performance'.

[TonyHSD]

18 minutes ago, Catlover said:

Cesar, don’t know if you found this out yet or not, but EV mode will only run up to a certain speed, my Gen3 Prius was about 18mph, my Gen4 Prius goes to about 27mph. The big battery in your car is a compromise, more battery is more performance, but more weight. So in a hybrid EV is a compromise. It gives you the best of a EV car and a petrol engines car. Petrol engine car emits lots of emissions, not too good mpg. A pure EV gives you limited travel (miles), but clean vehicle emissions. Hybrid gives you cleaner emissions then petrol engine, but gives you a good distance to travel, in my Prius Gen4 with 10 gallon (45 litre tank) I can do well over 600 miles, better then EV and petrol engines. Life is a compromise at times, but with a hybrid vehicle it’s a good compromise.

Joe, you are pushing me buy a Prius with your fuel consumption figures.,  😉👌not sure I will be getting similar but probably better than the Auris. 

[TonyHSD]

18 minutes ago, Mike J. said:

I don't understand this, please explain how the ICE can discharge the traction battery (other than just starting the ICE up).

When you have full hybrid Battery the ice kicks in to rotate the crankshaft at higher speeds together with MG1 which is needed to discharge the hybrid Battery, you can drive slowly but your planetary gear set will rotate at much higher speeds , once the charge is reduced the ice will shut itself off, but if you try to accelerate even gently immediately after that the ice will kick in much sooner than if your hybrid Battery is at middle soc, you can notice that when coming to a stop from high speeds exit motorway and stop at a roundabout and your engine may run for 20 or more seconds after you had stopped completely. Here is the moment to switch to EV mode if the car let you do it, then drive for a while in ev only, it’s cool and you will drain the battery to normal level quickly. 👍

[Bos]

Only once have I seen the Battery on my Yaris on max charge, that was the last time I went down the long steep hill to Widecombe-in-the-Moor.   By the time I left and got back yo the top again it was on 4 bars.  It is usually on between 6 to 8 Bars.   I find that usually the ICE kinks in above 40mph.

[Mike J.]

I find it hard to believe that Toyota would waste Battery energy. If it wanted to lower the charge it would use MG2, the traction motor, as it always does to aid the running ICE. Note that the ICE is low torque and the motor is high torque and the software merges them in a seamless way via the gear set.

[CesarD]

Thanks a lot, guys!

I guess I was expecting for that "EV Mode" to be something else aside from the regular (for a hybrid) EV driving when you keep the acceleration in the sweet spot 😛 hehe. Don't misunderstand me, I'm fascinated with all the features and benefits the car provides, and I'm always eager to drive it everywhere I can, but perhaps I was expecting for this specific feature to be something far more special, given the way it was presented to me by the dealer when I bought it 😅
I guess I can now just let it go on this side and just keep enjoying the rest of the car 🙂 

Thanks again to everyone for your replies!

Cheers.

[Catlover]

1 hour ago, TonyHSD said:

Joe, you are pushing me buy a Prius with your fuel consumption figures.,  😉👌not sure I will be getting similar but probably better than the Auris. 

Don’t forget Tony, the wife’s car used to be mine. It’s the same age as your Auris. So I know what mpg I can get in the Auris and it is less then the Gen3 Prius and a lot less then my Gen4 Prius, and of course, the later Prius Gen4 does better mpg then earlier Gen4. I really can’t see why the Prius seems to lost a bit in popularity stakes - best car I ever had.

[TonyHSD]

11 minutes ago, Catlover said:

Don’t forget Tony, the wife’s car used to be mine. It’s the same age as your Auris. So I know what mpg I can get in the Auris and it is less then the Gen3 Prius and a lot less then my Gen4 Prius, and of course, the later Prius Gen4 does better mpg then earlier Gen4. I really can’t see why the Prius seems to lost a bit in popularity stakes - best car I ever had.

Agreed, Prius perhaps people been tired of the design of the Prius as most called too extreme., perhaps wanted something more regular looking like Corolla for example, actually it’s the only car that make real competition to the Prius. Hyundai ionic is very good car too, even  tbh I may like it more than the Prius but it doesn’t have the great hybrid drivetrain like Toyota and so Prius is unrivalled to date! I will be definitely looking at Prius 2020 or Corolla saloon or estate, just want to get two more years out of my Auris at least if survives 🤭😉👌

[Mike J.]

1 hour ago, TonyHSD said:

When you have full hybrid battery the ice kicks in to rotate the crankshaft at higher speeds together with MG1 which is needed to discharge the hybrid battery ...

Not in my experience of a first gen Yaris Hybrid. On a winter's morning with the car stationary and heating set to defrost the windscreen the ICE has to run and it will fill up the Battery. Once filled, the charging stops and you can hear the engine note change as the load is removed. The traction Battery is only really discharged by motion or the aircon electric compressor (when parked up with car on and aircon on during a hot day).

[MikeSh]

2 hours ago, Mike J. said:

I don't understand this, please explain how the ICE can discharge the traction battery (other than just starting the ICE up).

I don't think it starts the engine. As PeteB said earlier: "it uses engine pumping without injecting any fuel to help control speed".

Basically MG1 will use power to act as a brake on the sun gear thus forcing the planets, and (engine), to be turned by the ring gear (wheels). So it's using Battery power and engine friction to provide extra braking when the Battery is full.

I think ...

[Mike J.]

More info on the early Yaris Hybrid.

MG2 is the traction motor and is mechanically connected to the front wheels. It does 2 things, power the car (and aids the ICE) and charges the Battery via regenerative braking only.

MG1 is a smaller motor/generator. It does 3 things, start the ICE, charge the Battery via the ICE and tweaks the epicyclic gear box ratio for the ICE (the motor can go backward and forwards powered by the traction battery) - that is why you need lots of good software for the hybrid to work.

On the later Prius and the new Yaris MG1 has another mode because there is a 'dog clutch' (IIRC) between it and the ICE. This allows MG1 to aid MG2 and so higher EV top speeds can be achieved - MG1 is probably in starter mode, but the 'dog clutch' diverts power to the road.

[TonyHSD]

21 minutes ago, Mike J. said:

Not in my experience of a first gen Yaris Hybrid. On a winter's morning with the car stationary and heating set to defrost the windscreen the ICE has to run and it will fill up the battery. Once filled, the charging stops and you can hear the engine note change as the load is removed. The traction battery is only really discharged by motion or the aircon electric compressor (when parked up with car on and aircon on during a hot day).

This only happens in very specific circumstances and always on hot engine, let say after few hours of driving on motorway and taking off the exit long down hill braking and Battery gets full then stopping at roundabout and engine kicks in and run at least 20-30 seconds with light load, all can be felt through the car. Then engine cuts off, and when you start to drive the ice kicks in immediately and runs at certain rpm as when the car is cold during warm up process but here is exactly opposite to cool down the gearbox and discharge the hybrid Battery. Auris , Prius gen 3 , Prius plus all cars with hybrid synergy drive 1.8 engine from 2010-2018