Mild hybrid and 48v battery lifetime

[sorin1987]

Hi, I am looking to buy my next car, a BMW 5 series and it seems that most 520i after 2020 are mild hybrids, meaning they have a 48v battery that helps with the start stop function. The car is 3 years old and has 26k miles, but I am worried about the 48v battery. Does anyone have any idea what the life expectancy on these batteries is like? I read they are quite costly to replace and I am thinking manufacturers wouldn't use this technology if the battery would need replacing every 2-3 years.
I do about 300-400 miles a month, in case that matters for the battery life.
Any opinions and experiences would help me making a decision.
Thank you!

[fouroaks]

I'm unsure which battery BMW use in their cars but Mahle say 20,000 cycles before performance drops below 80%.

https://www.mahle-powertrain.com/en/experience/48v...

[sorin1987]

I couldn't find the battery manufacturer but it is likely a Bosch.

[PJM54]

Hi I do similar miles pa (3.5-5K) and have 22 reg mild hybrid 440i X Gran Coupe. I have ongoing issues with very low battery messages. In garage 3 times and answer "do more miles" ! I believe there is an issue with mild hybrid vehicle battery's and Dealerships will not change due to cost !

[Baldchap]

I seem to recall Toyota recently reported never having hybrid failure due to battery degradation. Teslas are out there with over 1.2 million miles on their fourth battery packs.

Battery degradation isn't the problem some would have us believe.

Edited by Baldchap on Tuesday 30th January 20:40

[NelsonM3]

PJM54 said:

Hi I do similar miles pa (3.5-5K) and have 22 reg mild hybrid 440i X Gran Coupe. I have ongoing issues with very low battery messages. In garage 3 times and answer "do more miles" ! I believe there is an issue with mild hybrid vehicle battery's and Dealerships will not change due to cost !

It’s your miles.

[kambites]

sorin1987 said:

I couldn't find the battery manufacturer but it is likely a Bosch.

Bosch don't make Lithium Ion batteries do they? I thought they tended to use Varta cells and charge management electronics in their products?

[littleredrooster]

Baldchap said:

I seem to recall Toyota recently reported never having hybrid failure due to battery degradation. Teslas are out there with over 1.2 million miles on their fourth battery packs.

Battery degradation isn't the problem some would have us believe.

I think the actual quote from Toyota was that they had never had to replace a battery under warranty.

Toyota use Ni-Mh batteries, not Li-Ion for exactly this reason. Lower energy density but far longer life...I have a vested interest, as in 2018 I bought a Prius to be my 'forever' car and it needs to last until 2038. The MX-5 does not need to be quite so durable.

[Whataguy]

littleredrooster said:

Toyota use Ni-Mh batteries, not Li-Ion for exactly this reason. Lower energy density but far longer life...

They used to, the latest 5th generation Toyota hybrids use Li-Ion for better performance.

I’m not expecting any issues though, the car keeps the battery pack in the ideal 20-80% charge range for maximum life.