[kbeck]

Always higher voltage. I've heard these can handle 72v so shoot for the sky if you can. There is a relationship between rotor field voltage and stator voltage on these. If you go 72v on the stator and 5v or more on the rotor, you can get more torque but keep the higher rpm range. Were you testing a 30amp esc on it? Because 30amps won't push that alternator very hard, especially only at 12v power supplies. My esc is the mystery cloud 200amp 2-7s lipo capable. They are $30-45 depending on where you buy them. I know the voltage still isn't very high, but it can get you at least 5hp out of it. Amp wise it is probably at the limit of the alternator. Rc speed controllers jump in price with anything higher in voltage, but price wise, idk if the one I got can be beat. I know there are 100-200amp 72v ebike controllers that can run sensorless but they are usually at least $200. I'd look at Kelly controllers as there isnt much else over 4hp for a decent price. Also I haven't tried it myself, but I heard if you short the field coil to itself, you can run the motor as an induction using and induction motor controller which Kelly controls also has which is only $150 for a 72v 200amp which should definitely be the limit for the alternators...but I wouldn't buy it myself because I'm not 100% sure if I can get it tuned in to work correctly, and if it wasn't as I hoped, it wouldn't be useful for any other motor I have. Now that I am talking about it though. I am seriously contemplating it because that is serious horsepower for cheap. Altogether total cost for someone to build this not including battery would be only $200 for a motor capable of 17hp max. That is insanely cheap. And shorting the field coil is less complication than powering the field separately. It's interesting stuff..must tell the wife I need to get one lol.

 

[ODaily]

How much does your 4 wheeler weigh when loaded? How fast do you want to travel, and how quickly or slowly do you want to accelerate up to speed?
What size battery pack will you use? From that you can calculate your power requirement.

I'm actually working in reverse of that. Seems silly, I know. Unless you think of this as a motor project only. I just need a testbed and while I could have used a waterpump, big fan, friction brake, etc..., the 4wheeler seems like a fun idea.

Good find on the sensorless controller article, interesting to read.

Thanks, man. Don't know if you noticed but there's several articles there. In the next one he revamps if from 350 watts to 1800 watts. Good read.

Were you testing a 30amp esc on it? Because 30amps won't push that alternator very hard, especially only at 12v power supplies.

120 amp. It's a HobbyKing WP-SC8

It's interesting stuff..must tell the wife I need to get one lol.

Good luck. Might wanna butter her up real good first!

 

[kbeck]

I found a good sonsorless motor controller.
http://www.cyclone-tw.com/motor.html
Go down to controllers, and then there is a 48v-72v 120amp controller for $145. If you don't mind doing at least 72v for certain, you can get the better one and run the motor up to 150amps with Bluetooth connectivity for phone screen speedometer,rpm,voltage,amp draw, etc. And programmability through your phone too. Of course that one is a decent bump in price $289. But if you want to go the other direction down to 4kw (36-72v) and have the Bluetooth control those are $99. Not bad at all for about 5hp output.

 

[ODaily]

Finally got a controller actually ordered. 36 volt 800 watt ebike controller from china / ebay. Looks like one seller is moving most of them, so that's the one I went with. Shipping is high, but ironically the cost plus shipping is almost exactly what I paid for the RC controller.

Now I just gotta wait for it to arrive, from Guangzhou, China.

 

[kbeck]

You plan on upgrading the controller with higher voltage caps and higher power fets? See how big the traces are on the board when you get it and see how much more current you can get it to handle.

 

[ODaily]

You plan on upgrading the controller with higher voltage caps and higher power fets?

Not right away, but the plan has always been to head for the release of the "magic smoke" in pursuit of "Just how much can I get out of this?".

 

[ODaily]

I HATE waiting for international shipping, but the controller finally showed up today.

So, of course, I took it apart first thing.

General impressions,

63 volt caps. There's some headroom there.

12 FETs total. YPI8323C, Google had nuthin on em.

Dual Shunt wires. Interesting

Lots and lots of wires. Some will be pointless. A haircut is in order.

Flat copper bar / strip has been used to reinforce the traces across the FETs similar to how I see modders upgrading them with copper wire. BUT, the traces are not reinforced from the power wires to the FETs. Kinda defeats the purpose, I think. Fixable though.

More spare space than I expected. Going to shove an extra cap in there.

Wires are thin and meager. Anything that carries a load will need replaced / upgraded.


In other news; I really gotta get on the stick now and source some more batteries. Gonna stay lead / acid for awhile longer, and don't want to buy new.

 

[MineAngerBR]

I see a thread with alternators, let me give my 2 cents (even with it being old already)...

Yup, alot like that. I see alot of finished or at least finished on the benchtop projects. I've seen a few go-karts and such. Not much on the process.

Here's the front of the conversion candidate. Its from a 2003 F-150 with 5.4L motor.

Here's the back of the donor.

OP's alternator is the same model that Austiwawa used on his project:

Messing with the armature current has gotten me thinking. I see people who talk about dropping the current at high RPM to increase the RPM. Apparently with a corresponding drop in low RPM torque.

This seems counter-intuitive to me, but unless people are faking videos, then I've seen it work.

Questions this has given me:

Is the increase in RPM only valid for a free-running no load application?

Is this a case of just finding a "correct" current that will provide both torque and RPM? Or, will these two goals require conflicting current levels?

If this does require adjustment to get the low end torque and the high end RPM, then what is it a function of? Do I need to reduce armature current according to RPM, motor load (measured by amps drawn?), or some other factor?

Would this be a linear relationship, or graph as some kind of curve?

Good questions, I think. But not for tonight. First I gotta get it running well and consistent, then I can start throwing variations at it.

The rotor is a fixed resistance becauseits basically wires. So cutting the voltage, changes I =V/R, and with less current = less magnetic flux, giving more RPM range but losing torque, both with and without loads on the motor.


And its unfortunate that OP didn't appeared anymore, but here follow some videos about the project that Austiwawa did, including installing hall sensors and swapping the wound rotor windings for a permanent magnet: