12v battery maintenance, issues, etc.

[Roy124]

A philosophical question:

If a car achieves 70mpg on a journey and EV for 50% of the distance, what mpg would it achieve if the EV was not a factor?  Would it be around 35mpg?

[Graham47]

1 hour ago, Max_Headroom said:

How far will the hybrid travel in electric only mode if the battery is full, is there a maximum speed before the ICE kicks in?

I think this is my best so far …..

Start from cold (ICE for short reverse up drive) then EV, downhill, (very gentle) uphill on EV, gentle flat at 40 mph on expressway into town.  Final 0.3 mile was all slightly uphill into car park.  But for traffic I think I might have been more gentle and achieved even 100% EV !

[jthspace]

My Yaris on A road to breakfast/Aldi shop today (Sunday) and B and single track country roads back averaged 68mpg and I discovered at 48 mph it stayed on Battery most of the time. Luckily no other cars at all so 48 on a 60 road didn't pee anyone off.  Mind you, I could buy a flat cap and then it gives me permission to do that anytime 🤣😂

[jthspace]

1 hour ago, Roy124 said:

A philosophical question:

If a car achieves 70mpg on a journey and EV for 50% of the distance, what mpg would it achieve if the EV was not a factor?  Would it be around 35mpg?

Seems a reasonable thought.  Same rolling resistance etc. But the engine I expect will be working harder as no assistance from the Battery. 3 cyl 1.5L isn't designed to run "petrol only" though and was designed as a generator.  CVT helps in mitigation.

My 2L 190bhp MX5 returns low 40's on E5, mid 30's on E10 even driven "to enjoy" rather than frugal. I've seen 51mpg average on a ride-out in a group of 5 cars.

[TonyHSD]

Toyota full hybrids aren’t to be mistaken with plug in hybrids or bev. They don’t have an ev range at all.  
You can top up your hybrid Battery easily if you go downhill, 2 miles downhill even without pressing onto the brakes a lot and your Battery likely to get filled up full.
The range you can get after that in pure ev if you select ev button is max 1 mile if you drive slowly up to around 30mph and of course accelerate smoothly, otherwise the car will flip to its hybrid mode immediately. 
The ev button is very helpful for example if you like to move the car from one parking spot to another or similar circumstances, start the car to top up your tyres with 12v air compressor and you need to have enough juice in the Battery plus switch off hvac. 

One tip for those who does these dog walks ultra short trips, to get maximum efficiency best to turn off hvac completely for these journeys and crack open the windows for refreshed air. 
If hvac is off there won’t be need of heat , engine needs very little warm up to work safely, just to move the oil around inside engine and transmission, no ac ON also means no high voltage drain and you can glide in ev mostly. 👌

[TonyHSD]

1 hour ago, Roy124 said:

A philosophical question:

If a car achieves 70mpg on a journey and EV for 50% of the distance, what mpg would it achieve if the EV was not a factor?  Would it be around 35mpg?

No, it won’t be 35mpg, more like 50-55mpg I would say.  
You can’t remove the ev factor from the total power in Toyota hybrids because how they had been designed to work.. But to understand how efficient are these engines you can take an example to compare with Yaris mk4 1.5 petrol non hybrid either auto cvt or manual, cars that sadly haven’t been offered here in uk but available on other markets and these cars are doing exactly that, they run on pure petrol , use the same engine with slight modifications and delivery also great efficiency, there are data sheets available on Toyota website to compare. Here a quick look . https://www.toyota.bg/new-cars/yaris/build?path=engine/09a6531a-c3f1-4d2d-b4d3-eb45cbb35478/7b77d85b-8f26-4645-82ac-22154a7d6293/794e7377-29d0-42fb-b62e-253fbf6c9c8a

[Dezzer21]

Tried my bm monitor this morning showing 12v in acc mode in ready mode 14.1 sat in car an hour in reading manual car fired up twice for a minute or so, hopefully Battery ok.

[Cyker]

1 hour ago, Roy124 said:

A philosophical question:

If a car achieves 70mpg on a journey and EV for 50% of the distance, what mpg would it achieve if the EV was not a factor?  Would it be around 35mpg?

As others have said it's not as simple as that - The thing is, with the normal non-plugin hybrids, all the energy comes from the petrol and the engine. I would guess in a similar ballpark to Tony - 50-60mpg maybe, but very dependant on the journey (Urban/motorway, smooth/stop-start etc.).

The super clever thing about the hybrid bit is it's like a turbocharger - It captures energy that would be wasted, and that's where the efficiency boost comes from.

The M15A-FXE is rated for a peak efficiency of 41%, but that's only at a certain RPM and load - At 6000rpm it definitely *isn't* 41% efficient  but around 2000rpm seems to be the sweet spot.

That's why the engine will run at weird RPMs at a given speed (e.g. mine will run at around 2000rpm at almost all speeds if I'm only driving gently, anything from 70mph to 5mph!).

Driving at 2000rpm at 5mph would be very wasteful normally, even tho' that's the most efficient RPM, but what the hybrid system can do is take all that wasted energy and stuff it into the Battery for use later.

Unlike normal cars, where the engine is running at 3%, 5%, 10%, 20%, 30%, 5%, 20%, 5% etc. efficiency as you're accelerating/decelerating, going up and down hills, revs constantly going up and down etc., the hybrids can run at near 40% *all the time*.

That's where most of the efficiency comes from and not, say, brake regen, like a lot of the automotive press are convinced of (Brake regen actually regains surprisingly little energy in the grand scheme of things!)

That's also why diesels get such good mpg, as across their whole rev range they can stay in a 30-40% efficiency band, whereas petrol has much lower dips under e.g. hard acceleration and high rpm.

 

2 hours ago, Max_Headroom said:

How far will the hybrid travel in electric only mode if the battery is full, is there a maximum speed before the ICE kicks in?

 

TBH not very far - It only has 0.7kWh of capacity and that runs down quick, esp. at speed! It makes the EV mode button pretty pointless in the Mk4s!  On the very very very rare occasion I've gotten it to work (As opposed it saying I'm going to fast or there not being enough charge), I think I got 200-300 metres in traffic before it cut off again!  

There isn't really a maximum speed tho' - The car can run on electric-only well over 70mph, thanks to that reduction gear they added, but only if there is very little load being put on the motors. As soon as you put any significant load on to e.g. accelerate, the ICE will usually kick in as it can provide a lot more torque than MG2, thanks to MG1 faking gear ratios.

 

[Roy124]

In our engine lectures many decades ago I recall the graphs with cross over points at about 40% and 60%. 

At 40% you got best gallons/hour or endurance.

At 60% you got the best balance of speed against consumption. This was range speed. 

At higher revs you would get more speed but less range.

Translating that to a car, if journey time was unimportant,  40% would save you fuel.  If time was more important,  60% would get you there sooner and use the optimum amount of fuel.

I wonder how that would translate to EV.

[Dala]

My the best 1.7l/100 km = 165 mpg.  

 

[CruxisCore]

It's a bit sad watching reviews where most of the reviewers are like "ooh EV only mode" just for it to deactivate 200 meters later. Yet they talk almost nothing about the actual hybrid stuff.

The EV-mode might be useful when coming home late and don't want to wake up the wife when pulling into the driveway or maybe if you drive into a bit bigger garage and want to avoid emissions while in there. But mostly the button should be ignored and trust the car knows what's best.

There is also a non-hybrid version of the Yaris Cross (and Yaris mk4 too i believe), so with some digging you might be able to find their usual MPGs. 

[Cyker]

To be fair, half the reviewers still think there is an actual belt-and-cones CVT system in the car, so you can't expect much from them  

 

[CruxisCore]

3 minutes ago, Cyker said:

To be fair, half the reviewers still think there is an actual belt-and-cones CVT system in the car, so you can't expect much from them  

 

Also B is for regenerative braking 😬

EDIT: For the new people who might miss the point: it isn't.

[Dala]

the information about the possibility of charging with a longer ride will not be true

without external charging, it is not possible to keep the car Battery in the best condition

 

[Graham47]

53 minutes ago, Dala said:

@Dala

 

53 minutes ago, Dala said:

the information about the possibility of charging with a longer ride will not be true

It would be helpful if you also provided an explanation of what you are demonstrating and how you arrived at this conclusion !

without external charging, it is not possible to keep the car Battery in the best condition

[Dala]

7 hours ago, Graham47 said:

@Dala

 

the information about the possibility of charging with a longer ride will not be true

It would be helpful if you also provided an explanation of what you are demonstrating and how you arrived at this conclusion !

without external charging, it is not possible to keep the car battery in the best condition

12.3V is not a fully charged car Battery
according to the graph, 99% of the time (40 minutes, 60 minutes) of driving, the system maintains the car Battery at a voltage of 12.8V
12.8V is not a charging or floating voltage
this is not smart charging
this is a car Battery destruction system

this is probably why the current car battery does not last as long as the car battery in older cars

[Max_Headroom]

9 hours ago, Dala said:

without external charging, it is not possible to keep the car battery in the best condition

Does that include using ready mode as discussed in the thread? 

[Dala]

2 minutes ago, Max_Headroom said:

Does that include using ready mode as discussed in the thread? 

good question
I will post the "READY mode" voltage graph as soon as possible

[CruxisCore]

12,3v is still around 70% state of charge and does not by itself put the Battery in any kind of danger or damage. Of course, it is less leeway before the Battery is in dangerous levels for it's own durability. But it's true that the car will never be able to charge the Battery to full with the parameters they charge with now.

Also, I suppose AGM temperature compensation may not 100% apply to a regular wet sealed battery, since most here dont seem to have AGMs in their different kinda of Yaris'

[CruxisCore]

My 12v USB charger + voltage meter thingie just arrived today. I figured no point testing it in my Aygo X but ended up doing it anyways. It's kinda interesting how much it lives under load. When I turned power on from the ignition but not the engine, it started at 12,4V (but obviously already under load) and rather rapidly dropped even below 12V before I fired up the engine. With the engine running (this is a regular non-hybrid, so probably the usual alternator driven by the ICEs belt or so) it was at 13,8v. When I turned off the car just handful of seconds later again, it dropped to 12,7V. Keeping power on after turning engine off it rather rapidly kept dropping again until I just turned power off again.

Not actually sure if I can properly see the screen in the Yaris Cross cos the 12v socket isnt very visible to the driver, but it's not like I plan on staring at it all the time 😄 

I also wanted USB charging ports that wouldnt be connected to the infotainment as I dont want my lady's phone to try connecting to Android Auto if she is just charging it while we drive or whatnot. So now I have 3 USB ports at the front 😄

 

 

[TopGeek]

16 hours ago, Graham47 said:

@Dala

without external charging, it is not possible to keep the car battery in the best condition

That seems to be true. I fully charged my 12-volt Battery last weekend, went out locally several times and did one trip of 100km during the week. Yesterday, I was using ACC mode for about 5 minutes and a warning came up saying "Battery low. Switch off Power" or words to that effect. That doesn't seem reasonable to me.

I put it on charge overnight and it was fully charged by this morning ......but, for how long?

[Graham47]

2 minutes ago, TopGeek said:

Yesterday, I was using ACC mode for about 5 minutes and a warning came up saying "Battery low. Switch off Power" or words to that effect. That doesn't seem reasonable to me.

Of course it could be that the warning message is triggered, whatever the true SOC of the Battery, urging you to either switch off on turn on ready mode so that you don’t deplete the Battery further.  You don’t know what the SOC was when you got the message, you only assume it was very low.  After all, you had only just fully charged your Battery.

[TopGeek]

2 minutes ago, Graham47 said:

Of course it could be that the warning message is triggered, whatever the true SOC of the battery, urging you to either switch off on turn on ready mode so that you don’t deplete the battery further.  You don’t know what the SOC was when you got the message, you only assume it was very low.  After all, you had only just fully charged your battery.

Too many unknowns. I shall have to get one of those cigarette lighter monitors, although I doubt they are very accurate.

[Roy124]

29 minutes ago, TopGeek said:

Too many unknowns. I shall have to get one of those cigarette lighter monitors, although I doubt they are very accurate.

Why?

I have a BM6 and its readout is different my voltmeter by a couple of points.  In fact I have 3 voltmeter as sometimes the voltage will jump all over the place. 

There is no reason to suspect that the plug in sensor would be inaccurate.   However while it might be inaccurate by a point or two you will be looking for difference rather than absolute.

[Dala]

Today driving 10 minutes - the car Battery was maintained at 12.8V by the system
then I left the car in "READY MODE" for 1 hour - the car Battery was charged by the system to 14.08V the whole time

I have to correct my previous post :

the information about the possibility of charging with a longer ride will not be true

without external charging.....or running in READY MODE...... it is not possible to keep the car Battery in the best condition