T8 Efficiency questions

[benjo132]

Hi,

I have had my T8 R Design for about 2 weeks now and in general I love it. I have been disappointed with the battery range but I am starting to get an improvement and am searching for tips on how to improve it further.

I do have several questions though that I cannot find answers on in the forums or in the manual so I am hoping that you guys can help. These are:

1. What the heck is the pre-conditioning?! Before delivery I was expecting this to allow me to set the temperature in the car before a journey, such as warm it up on a cold morning / cool it down with the ac in summer by using the VOC app. The app does not allow a temperature to be set though so I don't really know what it does. The most information I found was that it prepares the battery for optimum use but after using it for this purpose the ICE kicked in on a 1 mile journey on the flat in 15 degrees - not sure why?

2. I understand that the difference between using D and B is that B mode uses engine braking to recover energy for the battery. I was originally driving in this mode all the time to recover and use as much energy as possible. Does this help at all?

3. If the battery is over 33% where does the car store the recovered energy, does it have a separate area to the battery or does it use the same battery and therefore the car can charge the battery above 33%?

4. If on the motorway and I select charge it will charge to 33% relatively quickly - can you get it to charge anymore by using b mode or anything else?

5. I have read that pure mode won't always use the battery if it needs ac etc, but I do find the ICE coming on in 20% degree outside temperature on flat roads with little acceleration, does anyone now why or how to stop this?

6. Charging - I generally charge at home on 13a and it takes about 2-3 hours. If I lower this it will take longer to charge but will it affect the cost? We only have 1 rate for our electricity so charging late at night wont save me anything.

Any other tips on getting the most out of the battery would be appreciated. I generally only do short journeys so im hoping to get as much out of it as possible.

Thanks for any help,

Ben

[Philip Fisher]

There are a lot of questions here but I will have a go with some of them.

1. Someone else can answer this, I think that there was a thread explaining it somewhere.

2. I don't understand B mode properly either.

3. The recovered energy is stored in the rest of the battery. The 33% just locks a third of the battery to not be used. If you select save when the battery is full it should save the whole battery for later.

4. You can get it to charge all the way up to 100% by selecting charge from the main screen, or by selecting power mode or 4x4 mode.

5. I find that too. Can't understand why. Someone said it was to charge the 12v battery, but the 12v battery is connected to the 400v battery to charge so I don't understand either. If you accidently knock it back from B to the manual gear selector in pure mode it will automatically start the engine and leave it running for 20-30seconds.

6. Charge speed shouldn't significantly alter the cost. Lower charge current will generally make the batteries last longer though.

Any other tips for max electric range? - Drive with a feather light foot!

[Philip Fisher]

Oh and welcome to the forums by the way!

[aab203]

The pre-conditioning question is answered by Lexman8 here:

Originally Posted by Lexman8

It's standard on the hybrid T8 and optional on all other versions.

You get it by specifying the Auxiliary Heater option. When the external air temperature is below a certain threshold, a small, fuel-fired heater (rated at 5kW) pre-heats the water in the car's cooling system and, together with an electric pump and the climate system's fans, allows heating of the engine block and passenger cabin for up to 40 minutes before starting the engine. You can set a timer (up to 8 actually) to turn it on or you do it via the VoC app on your phone. It can also be used without pre-conditioning to speed up heating of the engine and cabin when the engine is started. I suspect this is particularly useful on the D5 as diesels tend to take longer to heat up.

In a similar way, if the cabin temperature is high, eg on a sunny day, switching on pre-conditioning will blow external air through the car to help cool the cabin. I don't know if this ventilation feature is available without the auxiliary heater being fitted. Someone else may advise?
_

[Rojah]

Ben,

I think that Philip has answered most of your questions.

I hope the following will help you too, as I have probably over 300,000 hybrid miles in the last 9 years or so, and now have over 20,000 miles on my T8.

A full charge shows 18 miles on the display (19 if I am lucky and it's over 25C - rare in Lancashire). This does increase to 20 miles if in "Pure" mode. I have never had the quoted (by the press) 25 miles - ever, and my previous Plug in Prius had a similar 20% range deficit. That's life.

If charging from home, get an economy 7 tariff (Sainsburys is just over 6p per kWh). I run a timer from an extension lead, quite safe as the charge only draws about 10A, and my garage is rcd protected. This will save money, especially if you run dish washers and washing machines at off peak too!).

I have the following driving tips for a plug in.

B mode is best for generating battery charge when going downhill without using continual braking.

Try to Coast to a stop in D mode if you can, rather than braking and using regeneration, regeneration is not as efficient in terms of distance travelled.

Try to save hybrid battery for urban/ in town use. The petrol engine is much more efficient in mpg terms at 50-60 mph than at 30-40 mph. Judicious use of the "hold" facility helps here.

In Pure mode, there is slightly more acceleration power available when setting off from a standstill.

When the hybrid battery indicator is getting low, below about 15%, putting the car into "Pure" mode seems to increase the range by 1 or two miles.

A new "theory" of mine, undergoing testing at the moment, is that driving up long, steep hills when the petrol engine is working hard, and there's less than 33% charge in the battery, then putting it in charge mode is a quick way of getting a few more "electric" miles on one's journey. My journey takes me over Belmont Moor, which is quite steep in places.

Anyway, the stats don't lie. Car had its first service at 19,000 miles, and the last 1,700 miles has averaged 68.6mpg equivalent. Worst journey 39mpg (forgot to plug in at work), and regular 26 mile daily commute is giving between 100 and 140mpg, but this is summer, it's much less efficient in winter!

I hope that's helpful, the car has been a delight so far, and utterly reliable, no gremlins other than operator error or fat finger syndrome. BTW Spotify doesn't work, looks like system's down, but just as easy to stream through phone and Bluetooth.

Regards

Rojah

[Lexman8]

Originally Posted by aab203

The pre-conditioning question is answered by Lexman8 here:

Here's some extra info.

The 'comfort' temperature for the cabin during pre-conditioning is pre-set; you cannot change it. I've read it's 22c but don't take that as fact.

You cannot use the main drive batteries to power the aircon during pre-con. I'm pretty sure it would deplete them too quickly. So during pre-con you get ventilation but not aircon.

As well as the D5, the T8 should really benefit from the auxiliary heater by not having to start the ICE to raise the cabin temperature.

[benjo132]

Thanks for all of the replies and information on this, sorry for not responding earlier but I was out of the country.

Just on 2 points:

1. If driving in hybrid / pure mode and you get to a decent hill (i have also noticed the battery drop fast on hills) how do you get the ICE to kick in quickly and in the most efficient way? Flooring the accelerator to take the revs out of the electric zone seems a bit excessive as does selecting AWD or Power mode. I guess activating hold on the battery would work but is a little cumbersome (this definitely needs its own steering wheel button!).

2. Philip said "4. You can get it to charge all the way up to 100% by selecting charge from the main screen, or by selecting power mode or 4x4 mode." I haven't managed this, has anyone else managed to charge it all the way up? Having said that I've not had a really longer motorway journey yet (about 40 miles max.)

I am definitely managing to increase the electric range though and the overall mpg is creeping up.

One other point on economy 7, i read that if you are on this tariff you pay more for you daytime rate is that correct? With 3 young kids there is generally someone in the house all day so if this is true it may lower any potential savings?

Thanks,

Ben

P.S. I do love the car, just one tech issue with Lane assist, adaptive cruise control and speed camera recognition not working on the way to Manchester airport so I guess it was a camera issue. What's the quickest way to reset this? I tried to quickly turn off the engine and restart when in traffic but this didn't work. I wondered if it was because it didn't properly turn off (radio still on as this only turns off when you open the door)?