BMWs 48volt Mild Hybrid review

[@leomux2004]

Despite this being the most common use currently of 48V architechture, 48V could replace 12V in every way, so not only the start/stop would be improved, but the entire car would, since you could run all the pumps electrically, power the active aero, the suspension, the clutches from the transmission and diff, and even air-conditioning and heating would be improved, and all of that without sapping any power from the engine.

[@themodfather9382]

The sole purpose of hybrids is to reduce cost. Adding all that crap will increase cost and complexity. Cost of repairs. It should be standardized by now, though. But most hybrids solve one problem and create another. The goal is to standardize a system, maybe a 48 volt system, with regen breaking, where you can break even on brake replacements alone.

[@jacocoetzee8603]

This is all cute but does it save on fuel?

[@leomux2004]

@@jacocoetzee8603 Yes, less parisitic losses means less energy wasted on turning the components, which means fuel saved.

[@jacocoetzee8603]

I I meant is, apart form this... What else is the hybrid good for in terms of fuel saving.

[@leomux2004]

@@jacocoetzee8603 Adding power to the engine without changing the engine itself, so it means that the engine don't need to work too hard to get the same power, also during braking the isg can regenerate the energy and use it to power other things from the car later. Not to mention that in turbocharged engines it can eliminate turbo lag and during braking, the turbine wheel spins the motor and regens energy that would otherwise be wasted. 48V can really transform a car, manufacturers just need to dare a little bit more and don't play too safe.

[@larinoriani]

Actually the mild hybrid technology does more than assist and improve the start/stop function, it adds some +/- 10 HP to the total power of the car, giving it a boost at WOT.

[@BMWofFW]

I mean yeah, just couldn’t fit that in a 60 second clip

[@larinoriani]

You’re welcome.

[@Shockload]

The horsepower boost is negligible, what's important is the instantaneous extra +200nm of torque

[@archimedesbird3439]

Is regenerative braking viable? With a larger electric motor and battery, it seems like it would be.

[@BMWofFW]

@@archimedesbird3439 I full electric cars yes, but for the 48v mild hybrid no, it’s a set regen for the small system

[@Shockload]

Mild 48v hybrids can absolutely do regenerative braking

[@kevinn1158]

BMW needs a Toyota type hybrid that runs on electric only at city speeds

[@BMWofFW]

@@kevinn1158 the PHEVs do exactly that…

[@kevinn1158]

@@BMWofFW They aren't selling the PHEV in NA as far as I know. They had the X3 PHEV in Canada but not for 2025.

[@cadethatdude85]

Nice use of tech.. when it brakes.. it’ll be expensive to repair I’m sure

[@BMWofFW]

just an alternator, and in terms of reliability i've seen 0 cars come in with 48V mild hybrid issues since i've started working here (now statistically i'm sure there HAVE to be some that go bad, but as of now i have yet to come across any... at least at our location and in our market)

[@cadethatdude85]

@@BMWofFW post the bill on the first one you get. I give it six months

[@BMWofFW]

I’ll let service know to hit me up once one comes in

[@larinoriani]

Bills are going to be $0.00 since most if not all the mild hybrids are still under warranty.

[@BMWofFW]

Still no 48V claim come in the dealership… called out to a few local ones and nothing there either…

[@Onhaey]

Being honest I don’t think anyone is interested in discussing that. Glad it helps you justify your purchase though

[@dunphyjp]

I drive electric

[@992seefouress]

Actually, I’m interested. Thanks for the explanation JP!

[@larinoriani]

@Onhaey He works for a BMW dealership, is not justifying any purchase. Lol

[@Trenchluv]

Lol I appreciate the information as there is not a lot out there that actually thoroughly explained the system. Bmw didn't even bother specifically noting that they're adding it to their models. Apparently virtually all models begun having them mid 2021 production year. And it's definitely nice to know how it works and some basic engineering behind it.

[@justinshaffer3419]

Start / Stop was the dumbest idea ever!!

[@dunphyjp]

You’re right, cutting CO2 emissions by millions of tons per year when idling is very stupid

[@shaw8e.]

​@@dunphyjp could do better .

[@robertmcgee4050]

When I lived in Germany, many years ago, I was told it was illegal to idle at stoplights. For those German residents, this is a very nice feature. For us, maybe it's nice too.

[@justinshaffer3419]

@@robertmcgee4050 Not when you are in 110 degree heat and it decides that it can shut off and make it very hot very quickly and it's annoying as hell.

[@mbradea]

@justinshaffer3419 what are you talking about, having engines running while stopped is the dumbest idea ever. Or for that matter while coasting after you get up to speed. BMW’s are one of the only cars that are made with Neutral as a first-class citizen and I drop into neutral after every acceleration in my non-MHEV 3-series, just as you would in a manual car. Wish it could turn off the engine altogether while costing though, which the Active Hybrid 3 did - and I’m hoping the new B58 MHEV’s do. Can anybody confirm this? And if so does it turn off the engine while coasting in in all driven modes? (ie: Sport Mode)