Brushless alternators
 

In the past I've read many of the threads on this topic here, and my understanding is that most alternators are not very efficient, somewhere in the ballpark of 60% peak. To my knowledge, brushed motors generally have electromagnets on the rotor, and permanent magnets in the stator. Brushes are necessary because one needs to transfer electricity to the spinning rotor, and these brushes cause friction. Brushless motors by contrast have permanent motors in the rotor and electromagnets in the stator.

Right now I have most of the hybrid system removed from my Insight. The large brushless 3 phase AC motor is still in place, and I've been using that to generate 12v for the car rather than adding an alternator. My setup is as follows:

3 phase brushless motor, producing ~70-300v AC -> Schottky diode rectifier, efficiently converting 3 phase AC into 70-300v DC -> Meanwell power supply with its internal rectifier bypassed, producing 14v DC

My question is this: If brushless motors are generally more efficient, why aren't alternators brushless? Does it make them more expensive, or larger?

Brushless alternators are much larger and more expensive.
ACdelco had made brushless tractor trailer alternstors.
Unless you are putting lots of hours on your vehicle it's probably not going to be worth it.

I'm going to go with expense also, to explain why new vehicles still use the same old method to generate 12vdc.

Fortunately, when all (or vast majority) of cars utilize an electric motor, we can finally start realizing those efficiency gains.

I found one by delcoRemy, stated efficiency of 73% at 12v and capable of 430amps, 80% at 24v.

I don't want to get too off-topic, but I would love to see 24v replace 12v in cars.

Detroit (and US military) have talked about 48VDC systems for years!

There is a cs130 style 12v brushless alt on ebay for $350.

Nice.

Which vehicles have small altermotors which might be usable in a retrofit? Any of them belt driven?

The small 12v brushless alt appears to be a 100 amp CS130 style. It could fit tons of GM vehicles, the cs130 was used in GM cars and trucks, some dodge use the cs130 other trucks could use it with little modification.

It's a ACdelco so you can put any size and style of past and present of ACdelco 17mm pulley on it.
For years the CS130 was the cool upgrade for Ford, mopar, older GM, Jeep, tractors and stationery engine drive machines.

Also engine compartment temperatures are close to Currie temperatures of higher performance magnets to start with, so it’s easier to just use electro magnets for alternators that don’t see tons of hours.