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angusmf
angusmf Reader
9/22/20 3:25 p.m.

What the hay! Berkeley and all that old timer stuff? Originally tried to post this at DIYElectriccarforumpostsnet.com but they black-hole everything on me, then maybe it appears a month or two later? Anyway hopefully there's ppl here that will dig this, or just want to say hi to an old troublemaker. Life continues to evolve and I voluntarily have tools in my hands again.

My fiance (convinced ME to buy a crashed basket case Jake Ryan--I mean 944) and I are converting a "bumper kart" (to electric) using a combo of golf cart and older EV stuff picked up from offerup:

  • D&D (couldn't afford AD&D--haha...) ES 15-6 Series Wound
  • Alltrax AXE 48V 500A -- 72V is probably in the future if I know me... (Actually looking like the future could be 156V, and sooner than I thought)
  • 42 poorly matched SPIM08HPs and 4 of those 40V batteries with the A123-ANR26650M1A cells in them, which are worse.

Not promising we won't try out some different sprockets, but the intention is purely to do (Aussie-style) burnouts with it at car shows (and maybe the street in front of my house!!!)

We used one of those 40V batteries (haven't yet mentioned the charger made from a computer PSU and DC/DC from amazon...) to do some bench testing, but they're in rough shape. Fiance wants to tear them down and do some salvage so we can build a real pack or two that will hold up to what we're planning. At the very least, we need to be able to spin the tires (going to run "duallies" in the back for double the rubber--wound up with a lot of front tires and wheels!) long enough to be able to pop them. Hoping to have enough juice left over for some lights and noisemakers, though. We have about 10 (so far) of the LED lights you get for free at Harbor Freight to make a flashing light bar. Maybe an open loop battery cooling system to run a steam whistle? Run an air compressor from the axle for train horns?

(Trying to add front brakes also. Bought a set for a "Chinese ATV", haven't yet enlisted anyone to TIG some brackets onto the spindles. Oh and...independent L and R in the front. devil)

We've done a couple videos on it so far--making a motor mount plate using a 4" hole saw and the initial bolting up and wiring. After a little drama with the reversing switch, it all tested ok. That'll be in the third video I guess? (Editing sucks my soul)

Anyway, here's a link if anyone has 15 minutes to kill: Motor assembly pt 1 of 2

-Angus

 

Stefan (Forum Supporter)
Stefan (Forum Supporter) MegaDork
9/22/20 4:07 p.m.

Welcome back!

ultraclyde (Forum Supporter)
ultraclyde (Forum Supporter) UltimaDork
9/22/20 4:10 p.m.

I heartily approve of this!

angusmf
angusmf Reader
9/22/20 6:15 p.m.

In reply to Stefan (Forum Supporter) :

Lol, thanks!

GIRTHQUAKE
GIRTHQUAKE Dork
9/23/20 10:36 a.m.

Man, where the heck can I live that EV stuff comes up for sale on Offerup?

This'll be neat to see, not just because I have a Lightningrods "Big Block" kit I should stop stalling and start working with.

angusmf
angusmf Reader
9/23/20 5:20 p.m.

In reply to GIRTHQUAKE :

First, all the batteries have come from ebay so far. Haven't found much out here for that. Phoenix is a pretty big town, and we're close to LA, so there's a lot out there...but I think I mostly lucked out and was persistent about buying cheap crap. I shouldn't have called this "EV" equipment in reality since hopefully nobody considers a Bug with a DC motor, probably lead-acid batteries and a top speed of 'lol' to be an EV anymore. This stuff is more like for the souped-up golf cart craze that passed through a while back.

So here's the latest! Finally got tired of editing videos for YT that nobody but (hopefully) my grandma watches and got back to making metal chips. Got the motor sorta test-fitted, and used my "sqaure" -- a bit of computer case with a lip on one side -- to line it up with the axle in one at least one plane. Unfortunately the main plate is warped and the output shaft points at the ground a little. Lots of options to correct it, but hopefully someone smarter or more experienced will nudge me at the best solution (for my budget of basically zero.) Happy Humperdink Day everyone! Humperdink, Humperdink, Humperdink!

 

 

EDIT!!!

Couldn't resist hooking everything up and seeing the axle spin. Here's a photo:

angusmf
angusmf Reader
9/24/20 6:56 p.m.

Here's a new build video to go with that last update:

 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
9/24/20 9:50 p.m.

Welcome back!

GIRTHQUAKE
GIRTHQUAKE Dork
9/25/20 4:33 p.m.

What's that motor from? Specs?

angusmf
angusmf Reader
9/25/20 7:28 p.m.

In reply to GIRTHQUAKE :

It was made by D&D motor systems and is sold by a bunch of online EV shops. That one is an ES 15-6. I got it used locally. It was attached to an aircooled VW bell housing adapter with a coupler that was probably made from a clutch disc. The guy said it came out of a converted VW Baja. D&D's website (https://ddmotorsystems.com) lists that motor for small EVs, go-karts, etc. I haven't seen a real spec sheet, unfortunately. The resellers all say 9hp @ 72V continuous and 25 (or 30 in one case) peak. That would be like 10-second bursts or so.I only have a 48V controller set to soft ramp and tired 40V batteries at the moment. Doubtful it could currently do a burnout even if it was assembled, but we'll try to find out soon!

If anybody cares: Series-wound (like this one) and permanent magnet DC motors have particularly good torque at low speed--a decent choice for a cheap toy burnout machine. AC and brushless motors (which is AC on the inside with tricks on the outside to work with DC supply) not so much. They excel at other things, so it would cost more to build with parts like those. We also have an (old) conversion kit for a 914, but it's AC. With many times the price and double the max voltage of our DC motor, that's supposed to be enough to get the 914 up to around 90 mph. I'll have to ask somebody that has one of those conversions running to see if it'll do a burnout.

angusmf
angusmf Reader
9/30/20 2:12 p.m.
AngryCorvair (Forum Supporter) said:

Welcome back!

Hey P! Can I beg some free brake engineering? I bought a set of Chinese disc brakes for an ATV or who knows what off ebay. Complete with discs, two calipers, a tee thing, and one sorta handlebar-style master cylinder. So like I said privately, I looked this up, so I sorta know what will happen when I do this, just not sure I know what the practical effect will feel like. I want to buy a second master and have a left brake and right brake, which will double my ratio of master to piston...right? So like, in general...is that a lot?? Assuming these parts were sized to work correctly together in the first place, will I just have a firmer brake, or will it be unusable? Not sure how to measure the bore of the master cyl without making a real mess. Also, is there such a thing as a "magic valve" where if you pulled hard enough you can operate the second caliper?

Patrick (Forum Supporter)
Patrick (Forum Supporter) MegaDork
9/30/20 2:32 p.m.

angusmf?

 

solfly
solfly Dork
10/1/20 4:29 a.m.

In my experience a master cyl that is too big makes for a very firm pedal and a feel like it's almost pushing back.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
10/1/20 9:45 p.m.

I'm going to answer you tomorrow. Right now it's almost 11 PM and I just found this question as I was going to bed.

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
10/2/20 9:49 a.m.

Angus, when you say add a second MC, I assume you'll want to control it separately, ie left hand applies left brake and right hand applies right brake?

 

angusmf
angusmf Reader
10/5/20 10:12 a.m.
AngryCorvair (Forum Supporter) said:

Angus, when you say add a second MC, I assume you'll want to control it separately, ie left hand applies left brake and right hand applies right brake?

 

Exactamente. If it was the other way around, that would just be unfair.

---edit---

 Also, the MC bore has to be less than 20mm since that's the diameter of the outside of the thing. Maybe 17mm. The (single) caliper pistons are like 27mm.

And here's a pic of the gnarly spacer I had to add to the rear!

 

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
10/5/20 2:08 p.m.

So, from the hand lever down to the caliper, it goes like this:

  • your hand puts a mechanical force into the lever;
  • the lever multiplies that force and applies it to the MC piston;
  • the MC piston converts that force to a hydraulic pressure;
  • the tubes and hoses carry that pressure to the caliper;
  • the caliper piston converts that hydraulic pressure back into a mechanical force.

and we can stop there for the moment because as Hetfield once said, nothing else matters. The difference between one MC feeding one caliper versus one MC feeding two calipers is only in how far the MC piston would have to travel down its bore to move the volume of fluid required to make that amount of pressure.

the challenging part is determining how much travel is appropriate, and how much force it should take to achieve it. For example, at the driver's end of the system, a huge MC piston feeding a tiny caliper piston will not take very much travel. and at the caliper end, that tiny caliper piston will result in a small clamping force. And in the other extreme, a tiny MC will not move enough volume of fluid to adequately pressurize a huge caliper.

yeah, I know, I didn't give you a direct answer. I *think*, which is all I can do without data, that you'll be OK feeding only one caliper with each MC.

 

angusmf
angusmf Reader
10/16/20 9:01 a.m.

It moves! Did some very very preliminary testing yesterday with the controller limited to half-current and a 40V battery instead of the 48V it was made for. Made it to the fiance's shop and back before the rear wheels fell off! Everything is zip-ties at this point. Battery, throttle, throttle linkage...and still need to make a chain guard. My car dad seems really worried about the safety of this rig. YT video coming whenever I can be effing arsed to do a bunch of editing again, but here's some instagrammetry for now.

 

 
 
 
 
 
 
 
 
 
 
 
 
 

Thanks @_northmountainauto_for the walk-in alignment on the #liltrashster the #electricburnoutkart !!!

A post shared by Angus Freeman (@angusmf) on

 

angusmf
angusmf Reader
10/18/20 1:51 p.m.

Turned up the controller to 100% and it's fast now. Like, "Gonna need my helmet before we add any more batteries" fast. This controller will handle 60V, we're at 40. The motor will take 72V (ok, probably more) once we have the scratch for another controller.  We've been worried about how to safely weld brake caliper brackets to our spindles for front brakes. But now I'm thinking maybe just go straight to rolling burnouts. Also was REALLY temped to load it on the trailer and see if they would let me run it at the autox yesterday.

angusmf
angusmf Reader
10/18/20 2:02 p.m.

Current:

Throttle:

This probably isn't going to cut it as a chain guard:

AngryCorvair (Forum Supporter)
AngryCorvair (Forum Supporter) MegaDork
10/18/20 4:21 p.m.

I like the chain guard

EDIT: but in no way am I saying it's enough

Purple Frog (Forum Supporter)
Purple Frog (Forum Supporter) Reader
10/18/20 8:23 p.m.

Man you really need a for real chain guard.  The kind of torque you are playing with... that license plate will just be more shrapnel for the doctors to dig out.   Just saying.

YMMV

GIRTHQUAKE
GIRTHQUAKE Dork
10/18/20 10:19 p.m.
angusmf said:

Turned up the controller to 100% and it's fast now. Like, "Gonna need my helmet before we add any more batteries" fast. This controller will handle 60V, we're at 40. The motor will take 72V (ok, probably more) once we have the scratch for another controller.  We've been worried about how to safely weld brake caliper brackets to our spindles for front brakes. But now I'm thinking maybe just go straight to rolling burnouts. Also was REALLY temped to load it on the trailer and see if they would let me run it at the autox yesterday.

That motor will absolutely take more, but eventually it'll just turn to carbon dust and an arc flash

angusmf
angusmf Reader
10/19/20 11:14 a.m.
Purple Frog (Forum Supporter) said:

Man you really need a for real chain guard.  The kind of torque you are playing with... that license plate will just be more shrapnel for the doctors to dig out.   Just saying.

YMMV

I fully agree with you. The license plate guard would be ok for a bicycle and was a fun exercise in banging metal. For the real thing we've got some weld tabs, 1/8-or-so steel sheet and plenty of time to practice welding. The cool thing about the license plates is how malleable they've turned out to be. I can probably hammer them back relatively flat and use them for something else along with a couple other virgin ones still in the scrap pile. It's probably time for me to read up on motorcycle chain being used in various motorsports.

GIRTHQUAKE said:

That motor will absolutely take more, but eventually it'll just turn to carbon dust and an arc flash

Right. It's rated for 72V max, so there's probably a bit of margin. If our pack comes out to 74, or even 80 volts, I wouldn't expect the pile of carbon dust, but OTOH, can't find a data sheet or any other docs for the motor (and haven't called or emailed D&D.) 72V controllers are actually rated up to 90V, so what I'm saying is, we may find out someday if 90V turns this particular motor to dust.

angusmf
angusmf Reader
10/31/20 11:39 a.m.

Made most of a new chain guard, haven't quite tested it out yet. We're looking for a bike flag and place to run the kart around (maybe a zombie housing division) today.

 

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