[SteveB_UK]

Just collected my car from its end of warranty inspection, brake fluid change and MoT (UK annual safety test for cars three years old and over).

Very nice dealer experience. Couple of warranty issues fixed: sticking auto wiper button and water collecting in the boot lid and dripping into the boot when opened.

They also agreed to further investigation on my battery range, which is around 20% lower than when I go the car 12 months ago and 25% lower than the 900 mile i8 I was given as a loan car for the day.

Will be interesting to see how they investigate it as they have no official way of testing the battery capacity or so they say! And they expect Germany to tell them to fully charge and drain over a number of use cases to try and determine the range.

I wonder if anyone has tried to challenge the 80% battery warranty that's advertised? Likely not as few cars are three years old with 37500 miles on the clock.

[SteveB_UK]

Originally Posted by SteveB_UK

Just collected my car from its end of warranty inspection, brake fluid change and MoT (UK annual safety test for cars three years old and over).

Very nice dealer experience. Couple of warranty issues fixed: sticking auto wiper button and water collecting in the boot lid and dripping into the boot when opened.

They also agreed to further investigation on my battery range, which is around 20% lower than when I go the car 12 months ago and 25% lower than the 900 mile i8 I was given as a loan car for the day.

Will be interesting to see how they investigate it as they have no official way of testing the battery capacity or so they say! And they expect Germany to tell them to fully charge and drain over a number of use cases to try and determine the range.

I wonder if anyone has tried to challenge the 80% battery warranty that's advertised? Likely not as few cars are three years old with 37500 miles on the clock.

And the work was only £135. Very good value for main dealer on their range topping car!

[NGR]

Originally Posted by SteveB_UK

And the work was only £135. Very good value for main dealer on their range topping car!

Good to see some quality service, always worth highlighting as anyone in the area would hopefully be tempted to switch to them!

On the battery front, I'm surprised they have no way to measure capacity on such a key component especially as perceived capacity varies so much depending on terrain, temperature, driving style etc.
I have a few LiPo batteries for various hobby activities and every time I buy a new battery, I do a complete discharge followed by a charge. My charger actually tells me what has been put into the battery e.g. my new 8000Mah for my bike lights actually soaked up 8197Mah, a good indicator. In a few months I expect that be lower. Also, doing a discharge using the charger, it will tell me how much comes out of the battery making a good comparison.

The batteries are basically the same LiPo setup, just a lot more of them in the i8!


PS did you get the extended warranty?

[SteveB_UK]

Originally Posted by NGR

Good to see some quality service, always worth highlighting as anyone in the area would hopefully be tempted to switch to them!

On the battery front, I'm surprised they have no way to measure capacity on such a key component especially as perceived capacity varies so much depending on terrain, temperature, driving style etc.
I have a few LiPo batteries for various hobby activities and every time I buy a new battery, I do a complete discharge followed by a charge. My charger actually tells me what has been put into the battery e.g. my new 8000Mah for my bike lights actually soaked up 8197Mah, a good indicator. In a few months I expect that be lower. Also, doing a discharge using the charger, it will tell me how much comes out of the battery making a good comparison.

The batteries are basically the same LiPo setup, just a lot more of them in the i8!


PS did you get the extended warranty?

Thanks for the battery testing method info.

What they told me and what is the truth can be two different things. The more info they give, the easier it is for the customer to ask for data and challenge the warranty....

I don't think the car ever let's you completely discharge the battery in normal operation - I believe to protect the cells.

I fully charged it last night when I got home. Indicated range 11 miles. I drove on battery around my local town, so no faster than 30-35mph, for just 1.9 miles and when I returned home the range indicator said five miles and was on the half way marker.

In comparison earlier that evening in much the same temp the loan car was fully charged and driven to the dealer just on battery. Max speed was 50mph as the roads were busy. Plus a fair bit of stop start so similar amounts of acceleration/deceleration and the car managed 10 miles with 2 remaining on the range indicator and showing about and eight left.

Ref the warranty I'm definitely renewing. This is the sort of car that no warranty could equal financial suicide!!

[ChiTownM]

I did wonder about my battery as I also have a 2014 and feel that I am getting less range. But that is my butt dyno so to say based on my regular route.

Keep us informed.

[NGR]

Originally Posted by SteveB_UK

Thanks for the battery testing method info.

What they told me and what is the truth can be two different things. The more info they give, the easier it is for the customer to ask for data and challenge the warranty....

I don't think the car ever let's you completely discharge the battery in normal operation - I believe to protect the cells.

I fully charged it last night when I got home. Indicated range 11 miles. I drove on battery around my local town, so no faster than 30-35mph, for just 1.9 miles and when I returned home the range indicator said five miles and was on the half way marker.

In comparison earlier that evening in much the same temp the loan car was fully charged and driven to the dealer just on battery. Max speed was 50mph as the roads were busy. Plus a fair bit of stop start so similar amounts of acceleration/deceleration and the car managed 10 miles with 2 remaining on the range indicator and showing about and eight left.

Ref the warranty I'm definitely renewing. This is the sort of car that no warranty could equal financial suicide!!

I can see them wanting to not give much info away - these batteries are expensive so they'll want as few as possible to replace.

From various posts on this forum and my personal experience, a normal realistic range is usually 13-18 miles. Mine is a 2014 with 18000 miles on the clock, careful driving in current temperatures around freezing, mine estimates 14 miles on a full charge. In summer I've seen 18 but that's just the computer's estimate of course.

I'd say yours sounds like it is lacking, however whether it is <80% of original capacity is another question.

And, you're right, the car doesn't allow full discharge (it needs power for reversing, heating, cooling anyway) and I suspect it never goes to full charge (4.2V per cell) either in order to lengthen the lifespan of the battery.

Keep us informed of any progress re a replacement - I'm sure BMW are very keen to understand how the batteries perform long-term, I would expect them to do a capacity test at each visit to the dealer to gather a load of data but I'm pretty sure they don't (maybe they get it from telematics or a data dump when you go for a service?).

[Lorcan]

I was chatting to an i3 owner recently who told me it was bad news to charge over 90%, and to discharge below 10%. He said that if you could stay between those two figures the batteries would basically last forever. I don't know how much truth there is in that but he seemed to know what he was talking about!

[SteveB_UK]

Originally Posted by Lorcan

I was chatting to an i3 owner recently who told me it was bad news to charge over 90%, and to discharge below 10%. He said that if you could stay between those two figures the batteries would basically last forever. I don't know how much truth there is in that but he seemed to know what he was talking about!

I think the car does that for us as it only makes about 5 KW of the 7 KW available for use. So when "fully deprecated" there's potentially 2 KW available. And when "fully charged" only 5 of the 7 needs to be charged.

[Lorcan]

KW is a power rating, rather than battery capacity which is usually quoted in KW/h. There needs to be a time element as obviously you can run for longer at lower power.