To Power the Future, Carmakers Flip on 48-Volt Systems
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Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#2This article is kind of weird. The push for 48 volt is mostly about secondary systems that need a lot of power and doesn't have much to do with "mild electric" or whatever it is implying.
The 21 HP direct boost mentioned in the article is going to be for performance rather than running on electric, the vehicle comes with a 1 Kw-h battery (~5 minutes at full output).
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#3There is a TLDR for this article, but as far as I can tell it cannot be derived from the article itself.
Will someone please explain why 48-volt systems are newly desirable in cars?
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#4Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#5There is a TLDR for this article, but as far as I can tell it cannot be derived from the article itself. Will someone please explain why 48-volt systems are newly desirable in cars?
The higher voltage means lower amperage, which means smaller components and so on.
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#6There is a TLDR for this article, but as far as I can tell it cannot be derived from the article itself. Will someone please explain why 48-volt systems are newly desirable in cars?
You want a higher voltage to allow more power without huge cables due to high current. You want low voltage to avoid high-voltage safety issues which increase engineering, assembly, maintenance, and emergency costs.
The 48V system sits right at the boundary where you can deliver enough power for more auxilliary systems and some mild-hybrid techniques including frequent start/stop systems, brief acceleration boost, and regenerative braking. Yet, it's not high enough to require switching to a different electrical wiring safety paradigm.
This is similar to the reason power-over-ethernet runs at the voltage it does, or "low voltage" lighting exists for home applications where consumers are moving fixtures around and interacting with the wiring.
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#7> It is diesel's decline, executives and analysts say, that has finally set the stage for mass electrification. While diesel pollution problems became notorious with the Volkswagen test-cheating scandal, the subsequent shift to gasoline is bloating carbon dioxide (CO2) emissions, making the next round of European Union goals harder to meet.
> PSA Group, which had previously seen no need for 48V hybrids, now plans to introduce them "across the board" in response to diesel's faster-than-expected decline, the Peugeot maker's programs chief Patrice Lucas told Reuters.
> "What automakers are finding is they need more than just advanced combustion engines to reach the fleet average reductions," said Mary Gustanski, Delphi's engineering boss.
quoted from http://europe.autonews.com/article/20170923/ANE/170929892/vw...
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#8There is a TLDR for this article, but as far as I can tell it cannot be derived from the article itself. Will someone please explain why 48-volt systems are newly desirable in cars?
You want a higher voltage to allow more power without huge cables due to high current. You want low voltage to avoid high-voltage safety issues which increase engineering, assembly, maintenance, and emergency costs. The 48V system sits right at the boundary where you can deliver enough power for more auxilliary systems and some mild-hybrid techniques including frequent start/stop systems, brief acceleration boost, an…
Thanks. I had always understood PoE's relatively high voltage as helping deal with the attenuation from long runs of thin copper wire.
I couldn't find a succinct explanation in the article why cars would benefit from this spot in between merely sending information (digital levels like 1.8, 2.2, 3.3, 5.0, etc.) and using electricity to do "real" work (120V, 240V, 480V, etc.). As I understand your answer, yes, they'd like to use it for work, but not so much as to stray into the range of orange wires. I got the second part of that from the article, but the first part was very hard to extract from it.
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#9Some RV makers (both commercial [0] and DIY [1]) are already on 48V systems for their house batteries. Advantages: lighter wiring, can use a higher-voltage alternator that needs less heat dissipation. Note that the system in the Sprinter van is able to run the air conditioner at 100% duty for 8 hours, then allow the alternator to recharge the battery while continuing to run the A/C unit. Which is really impressive (and should be, for the $200k their RVs cost)
Re: To Power the Future, Carmakers Flip on 48-Volt Systems
#10It's too bad that automakers didn't make this change a long time ago.
One thing the article didn't mention is that power losses in a wire are a function of the square of the current. So, let's say one needs to deliver 48 watts to a load. In a 48 V system, that's 1 A of current. Using 12 V, that's 4 A of current.
Power loss is 16x greater at 12 V for same diameter of wire, loss = (4 A * 4 A) * resistance of wire.[1] Therefore, wires are made thicker in 12 V systems to avoid this. That's a lot of extra weight in a car.
Before the nitpickers chime in, I know the above is simplified. But it also clearly explains why long distance power transmission lines run at such high voltages, 230 KV or higher.