Hybrid battery (Traction battery) percentage charge

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SeeHR
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Re: Hybrid battery (Traction battery) percentage charge

Post by SeeHR » Mon Jul 19, 2021 11:58 am

We’re splitting hairs a bit here, aren’t we guys?

Yes, there’s a difference between “full” meaning the theoretical maximum capacity with no regard for the damage it might do to the system, versus “full” as in the maximum the system will reach during real-life operations.

If I buy a bottle of beer, the neck of the bottle is usually full of air. So the bottle is “full” according to the operational definition, but only 95% according to the theoretical maximum.

Battery cells can reach very high voltages but they’ll be toast within a cycle or two. So Toyota will have fixed a “maximum” that represents a safe limit that will preserve the life of the cells.
I think we can all relax about the bars and whether they reach “full” - some very smart engineers will have set various different voltage thresholds that seek to optimise the efficiency and the life of the system.
I suspect it temporarily allows all 8 bars to be full, but will seek to keep it between 2 and 6 as much as possible.

If it’s causing you stress, then just turn off the display and trust the car to do the hard work!

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Stormtrooper
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Re: Hybrid battery (Traction battery) percentage charge

Post by Stormtrooper » Tue Jul 20, 2021 12:46 am

I COMPLETELY understand the chemistry (more than most) and the battery life extension practices. It's the way the battery capacity is DISPLAYED which is incorrect, that's ALL I'm saying. This vehicle has been designed to be driven by people of vastly differing ages, and vastly differing mental understandings. I've had 3 different comments, from 3 completely different people, while I've been driving this car, asking why the hybrid battery isn't full. It's annoying trying to explain to people the theory behind it.
Hybrid in Stormtrooper White . . . . is it only me who can see that?

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Karmalakas
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Re: Hybrid battery (Traction battery) percentage charge

Post by Karmalakas » Tue Jul 20, 2021 7:13 am

Stormtrooper wrote:
Tue Jul 20, 2021 12:46 am
It's the way the battery capacity is DISPLAYED which is incorrect
If it's not fully (dis)charged, it shows as not fully (dis)charged. How is this incorrect?
Stormtrooper wrote:
Tue Jul 20, 2021 12:46 am
I've had 3 different comments, from 3 completely different people, while I've been driving this car, asking why the hybrid battery isn't full. It's annoying trying to explain to people the theory behind it.
So wait.. Are you pissed at Toyota, because your passengers don't understand how it works?

As someone suggested - just turn off that screen and never go back to it again. After all it's just a gimmick, which basically is completely useless. I personally don't even remember when I looked at that screen last time.
2017 HSD in Earth Bronze (a.k.a. Havana Brown)

SeeHR
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Re: Hybrid battery (Traction battery) percentage charge

Post by SeeHR » Tue Jul 20, 2021 11:03 am

Yeah I mean most people view batteries according to how they’re used in their phones - you want to charge to 100% and then use it up.

The hybrid system is all about arbitrage of energy - it passes through the battery temporarily, rather than filling it up and up. That’s how the system gives you fuel efficiency. The ideal charge of a hybrid battery is 50%. Least stress on the cell chemistry, and 50/50 headroom to charge or discharge depending on what the driver needs.

I don’t think there’s any way of displaying the hybrid battery charge that will make sense to your passengers because they’re thinking of a different concept of operation.

It’s a bit like asking for a tachometer on a horse - it just doesn’t work that way, so there’s no meaningful way of displaying that information.

Alexr
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Re: Hybrid battery (Traction battery) percentage charge

Post by Alexr » Tue Jul 20, 2021 5:16 pm

For the final time.
“ It's the way the battery capacity is DISPLAYED which is incorrect“
It is NOT INCORRECT.IT IS RIGHT.
75% full is displayed as 75% full. Full is shown as 100% full.
That is 100% correct.
All the best
Alex
------------------------
Loved driving my C-HR Excel Hybrid in Metal Stream for 4 yrs
Now loving my C-HR 2.0 Dynamic in Pearl White and black. :P

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DutCHR
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Re: Hybrid battery (Traction battery) percentage charge

Post by DutCHR » Tue Jul 20, 2021 7:09 pm

Maybe some people have to read more about the SOC.. State Of Charge of the HV battery.
Here is a very simple explanation from other Toyota forum about the SOC, the bars on your display and why Toyota did it that way.

In fact, if the gauge ever shows all 8 bars lit, and it's continued receiving charge until the Battery will not accept any more (referred to as "Maxed out" - generally some time after the 8th bar lights up), the true State of Charge (SoC) is actually 'only' about 80% full. If empty (no bars lit) it would still have about 40% SoC. The gauge displays a 'window' of usable charge ranges that the Hybrid engineers deemed safe to allow. This, along with managing rates of energy flow into and out of the Battery and cell temperatures is part of the 'secret' to the long life of the rechargeable Battery pack. When the original Prius arrived in 1997, lots of doubters predicted masses of owners regularly spending a fortune buying replacement Battery packs.

Here's a diagram showing the ranges of charge the relates to each bar of the gauge from an older Prius versions, but the principal remains on current models:



Image

A 2002 first generation Prius I once owned had some 70,000 miles on the clock before I experienced a true 'maxed out' condition for the very first time. It was on a holiday in Scotland when I encountered some 5-6 mile long 1 in 5 (20%) gradient hills, and descending those saw the Battery max out after 3-4 miles. The original Prius didn't have an EV button (nor ECO or PWR for that matter) but when I reached level ground I found I could accelerate moderately briskly up to 60 mph on electric alone, as the system tried to use up some power to make room for any further 'free' regenerated energy that could be had.

The design philosophy appears to try to stay in the range of 2-6 bars lit. Any lower and the engine works harder to add charge, any higher and it tries to use some charge up. This is so that there's always enough energy to proved extra boost for acceleration or hills when needed, and nearly always enough room to receive regenerated energy from slowing or braking.
For original post and topic see here : https://www.toyotaownersclub.com/forums ... indicator/
2017 C-HR Hybrid Metalstream Grey --- Genuine JDM styled and also a lot of sh*t from China
2019 Corolla TS 2.0 Hybrid --- 180HP Girlpower!

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Karmalakas
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Re: Hybrid battery (Traction battery) percentage charge

Post by Karmalakas » Tue Jul 20, 2021 10:10 pm

DutCHR wrote:
Tue Jul 20, 2021 7:09 pm
generally some time after the 8th bar lights up), the true State of Charge (SoC) is actually 'only' about 80% full. If empty (no bars lit) it would still have about 40% SoC.
Basically what I've said, just I remembered it in reverse :) I thought it was ~60% of real charge is shown in 8 bars, but it's actually only 40%
2017 HSD in Earth Bronze (a.k.a. Havana Brown)

SeeHR
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Re: Hybrid battery (Traction battery) percentage charge

Post by SeeHR » Wed Jul 21, 2021 10:09 am

Honestly I think it’s all moot anyway.

As @DutcHR’s excellent post confirmed, the bars represent non-linear voltage ranges that vary by temperature, and the top and bottom two bars are only allowed temporarily.
The “maximum” the system allows is only around 80% of the cell’s rated maximum (to prevent wear), and that rated maximum will be an arbitrary threshold that engineers chose as an acceptable balance between voltage and wear.

So the simple 8-bar infographic is actually trying to represent a dynamic, overlapping, conditional set of soft limits placed on top of other limits.

So it’s not really possible to have a factual conversation around binary states of being “charged” or “100%” since it’s more complex than that.

The 8-bar battery infographic is a super interesting summary, but it’s oversimplified and won’t stand up to the nitpicking we’re giving it here. There’s simply no way of representing it simply and also accurately.

AndyRC
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Re: Hybrid battery (Traction battery) percentage charge

Post by AndyRC » Fri Jul 23, 2021 8:35 am

Only having had our C-HR a few weeks I find this display the most useful when driving with economy in mind , rather than the traction battery display. When on the move keeping the blue bar above the average mark and the EV indicator on 👍

813933C9-4F9A-48F2-993D-37E97D55AF95.jpeg


ColinB
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Re: Hybrid battery (Traction battery) percentage charge

Post by ColinB » Fri Jul 23, 2021 5:26 pm

AndyRC wrote:
Fri Jul 23, 2021 8:35 am
Only having had our C-HR a few weeks I find this display the most useful when driving with economy in mind , rather than the traction battery display. When on the move keeping the blue bar above the average mark and the EV indicator on 👍 813933C9-4F9A-48F2-993D-37E97D55AF95.jpeg
This is the display that I also use as I can keep an eye on how the economy is doing, although I do have the battery display next to the satnav on the main display just out of interest. To be honest I like the way that Toyota have set up the hybrid system and just let it get on with choosing the best combination of engine and electric motor, only using the manual "gear" selector to add braking when going down long, steep hills

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