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  #11  
Old 5th December 2021, 09:56 PM
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roberto roberto is offline
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MikkiJane are you up to doing my D3 one day ?
sounds like it would be rear wheel drive as best option
lets face it now its worth next to nothing what a car it would make
and my son would have a worlds first

Audezla Teslaudi MJezlaudi

i could start stripping bits off and mothball the shell
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  #12  
Old 6th December 2021, 12:46 AM
ainarssems ainarssems is offline
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For even more range, a couple more could be fitted under the boot floor. Of the 16 batteries in a Model S, I reckon 10-12 could be fitted in to an 8, giving a range of probably 200 miles.
200 miles range would be a stretch, definitely not real world range. See the breakdown below.

16 module 85 battery new is actually about 81kWh total capacity and 90 is about 85-86. 4kWh is reserved capacity when the left range indicates '0'. 90 is degrading faster at start but then slows down, by the year 2 or 3 they are about the same. By the year 5,100k miles they are all about 75-77kWh and with 4kWh reserved you get about 71-73kWh usable which is about 250-260 miles indicated on full charge. You do not charge it full because the fuller it gets the slower it charges and it's also not goog for battery to charge it full and you do not run it empty either. So in real life you use 20-80% which is 60% so would be 150 miles indicated range. It's possible to get indicated range if you do not use AC or heating and take it easy but in reality you get maybe 130 miles out of 150 in summer and 100 in winter.

Then add the fact that A8 will probably has higher air resistance and it will not be packaged and optimised as well as Tesla. If you keep the charging range 20-80% you will get maybe 70-100 miles usable range.
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Last edited by ainarssems; 6th December 2021 at 12:48 AM.
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  #13  
Old 6th December 2021, 07:35 AM
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roberto roberto is offline
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yeh i suppose its a case of doing one first which is a fair old task i imagine
ironing out the bad bits , fabrication work maybe

just shut up robert and buy a Tesla .. lol
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  #14  
Old 6th December 2021, 07:44 AM
MikkiJayne MikkiJayne is offline
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Originally Posted by ainarssems View Post
200 miles range would be a stretch, definitely not real world range. See the breakdown below.
<...>
Then add the fact that A8 will probably has higher air resistance and it will not be packaged and optimised as well as Tesla. If you keep the charging range 20-80% you will get maybe 70-100 miles usable range.
Thanks. Not a road-trip car then! Good for a daily though
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  #15  
Old 7th December 2021, 03:31 AM
tintin tintin is offline
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Originally Posted by ainarssems View Post
200 miles range would be a stretch, definitely not real world range. See the breakdown below.

16 module 85 battery new is actually about 81kWh total capacity and 90 is about 85-86. 4kWh is reserved capacity when the left range indicates '0'. 90 is degrading faster at start but then slows down, by the year 2 or 3 they are about the same. By the year 5,100k miles they are all about 75-77kWh and with 4kWh reserved you get about 71-73kWh usable which is about 250-260 miles indicated on full charge. You do not charge it full because the fuller it gets the slower it charges and it's also not good for battery to charge it full and you do not run it empty either. So in real life you use 20-80% which is 60% so would be 150 miles indicated range. It's possible to get indicated range if you do not use AC or heating and take it easy but in reality you get maybe 130 miles out of 150 in summer and 100 in winter.

Then add the fact that A8 will probably has higher air resistance and it will not be packaged and optimised as well as Tesla. If you keep the charging range 20-80% you will get maybe 70-100 miles usable range.
I'd broadly agree with Ainars logic, but not wholly with his conservative estimates , after the point above about 250/260 miles range once this has "stabilised" a bit. I'd say charging to 90% regularly is just fine (& to 100% occasionally, as long as you're then using it straight away - which you would do on a road trip). I don't get the maths about 60% though, and aircon/heating makes virtually no difference (maybe 5 to 10 miles, max...) to range, although winter certainly does.

So my number for the installed range in an '8 would be higher, and almost certainly in excess of 150 miles using an 85/90D battery.

However, if such an installation was in my S8, I'd still drive it like one (what would be the point otherwise, with all that instant power, and no auto gearbox lag ? ), so the range would probably end up closer to Ainars (upper-end) estimate anyway - S8s are meant to be driven, Model Ss less so
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Last edited by tintin; 7th December 2021 at 04:10 AM.
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  #16  
Old 10th December 2021, 10:50 PM
ainarssems ainarssems is offline
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Originally Posted by tintin View Post
I'd say charging to 90% regularly is just fine (& to 100% occasionally, as long as you're then using it straight away - which you would do on a road trip). I don't get the maths about 60% though, and aircon/heating makes virtually no difference (maybe 5 to 10 miles, max...) to range, although winter certainly does.

So my number for the installed range in an '8 would be higher, and almost certainly in excess of 150 miles using an 85/90D battery.

However, if such an installation was in my S8, I'd still drive it like one (what would be the point otherwise, with all that instant power, and no auto gearbox lag ? ), so the range would probably end up closer to Ainars (upper-end) estimate anyway - S8s are meant to be driven, Model Ss less so
The 60% I am talking about is the difference between 80% max charge and recharging when you are down to 20%. Maybe I am being paranoid a bit but Model S I bought is more than 10 times the cost of the cars I normally buy and only bought it because of free supercharging. While I still have more than 2 years unlimited mileage warranty on battery I want to take as good care of battery as I can, I would hate it if I needed to replace it shortly after warranty ran out. That being said in my calculations I could still spend 10k on car in 10 years and come out on top comparing to another £3k diesel spending £4k per year on fuel.

Lithium NCA (Nickel Cobalt Aluminium) batteries like the ones used in Model S does not like being charged too much and from the data I have gathered before buying Tesla and continued to after buying it it seems that most battery failures happen to the cars that are regularly charged close to 100%.
90% might be OK for occasional road trip but definitely not for regular occurrence. My opinion is 80% in summer, maybe 85% in winter.

The lower level does not seem to be that important for battery life but you do not want to run out end up in situation where you ran out of juice because you went to charger and it was either out of order or all chargers taken. I have definitely ben in both situations both with Model S and ID.4
LFP ( Lithium Iron Phosphate) like used in latest standard range cars does not mind being fully charged and does not slow charging speed as much as it gets fuller. But they have lower voltage 3.2V instead of 3.7V, lower energy density, and lower output but remain viable option as they use more common materials and are cheaper and it does not make that much of a difference in every day use. If you charge NCA 80kWh battery to 80% that's 64kWh and at the same time you could have 65kWh LFP battery and charge it to full. You might loose some performance and o 0-60 mph in 5s instead of 4s.

I have seen reviews people using cells from Model S for other things and testing them fully discharged. I have seen one guy fully draining single cell, connecting resistor to it do drain any residual power, storing it with resistor attached for a year. And the charging it up and it was still fine and had almost full capacity. So while it is not recommended to fully discharge battery and there are no guarantees if you do it regularly it does not seem to be much of the problem. My main concern fully discharging an older battery would be that some cells would get fully discharged while others still having plenty of charge. While the Tesla does good job matching cells and balancing them there is a possibility that some of them degrade a lot faster than others considering there is over 7000 of them and even 1 bad cell can bring the module down putting too much stress on other cells and then the whole battery. There are reports of cars just cutting out at 40% charge as BMS shuts down battery because one of modules gets below the voltage threshold. Of course they are getting replaced on warranty most of the time but something to keep in mind .

Now if I am getting to how much energy AC or heating is using I think I need to start it with baseline of what car is using driving along. So while you are driving along at 65-70mph at a steady speed on level surface the motors are using about 20kW and at 30mph about 8-10kW as witnessed by me plugging into powertrain CAN. By the way there are 6 or 7 CANs on Model S as to separate data traffic and prevent it from tripping over each other. Normally they do diagnostics over ethernet either local or over mobile network but there is an option to plug into each different CAN as well.

In September while it was quite warm and AC was being used the Thermal controller was showing 1.3-2kW usage so that's about 25% increase in power consumption driving around town, 10% highway.

With the cold weather now it goes up to 6kW for thermal controller so about 30% increase at 65mph or 50%+ increase in at town speeds.
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Last edited by ainarssems; 10th December 2021 at 10:53 PM.
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  #17  
Old 16th December 2021, 10:03 AM
ulfilias ulfilias is offline
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Originally Posted by MikkiJayne View Post

It is an eminently sensible option for the future, rather than replacing all combustion-engined vehicles with new EVs, but until parts are common enough to become commodity items, they are still going to be prohibitively expensive for 99% of motorists. A Tesla swap in to a D2 for example would be in the region of £15K just for parts, to get motor, control electronics, and enough batteries for a reasonable range. No one is going to spend that, but £5K and it becomes more realistic. Even to swap my Mum's Beetle Cabrio using Nissan Leaf bits is going to be in the order of £10K by the time it works, which is just silly. Yes, I have looked in to both extensively

We need more EVs on the road so that 1, the parts are produced in higher volumes and get cheaper, and 2, more of them end up crashed and broken for bits, and then we also need government subsidies or incentives to do the conversions in the first place. Only then will we see this becoming mainstream.
Loving the thought put in here. The 8s are big, but that low weight aluminium base helps in terms of weight and longevity and them being huge is a big bonus.

I'd be tempted to put a stack in the back of boot too. The back bit is so awkward for day to day use that loosing some space would still result in a decent size boot. My old S8 had an LPG tank there and it was no great loss!

I'm guessing as battery tech improves we'll get better range from smaller packs, along with high efficiency motors.
Tesla are WAY ahead of the pack on almost everything here, but there are still break throughs to be made!
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