"Monster Board" High power 4X4 board with ATV tires

Hi Matt,

Why are u still using castle esc when focbox and vesc 6 are available and are much better? Your gearing is really high too. I think you need a bigger sprocket on the wheel if you are looking to take this beast off road. Can you please post a picture of the complete board.

Thanks Matt, love your project!
 
I see no need to change ESCs when these work great. Also, not sure why you say the Focbox is better...... The peak amps on that controller is 120. I have pulled over 300 amps from Castle ESCs reliably.......

The sprocket size is based on the fact that the board uses a two stage reduction, belt drive 5 to 1 reduction from the motor to the jackshaft and chain drive 3.2 to 1 from the jackshaft to the axle. That gives a ratio of 16 to 1 from the motor to the axle.

Matt
 
Long time since I have updated you.......

We did some coasting testing (downhill) and found it unsteerable because of the solid (live) axles. I loosened the hubs on the axles to allow the wheels to spin independently from each other and it is a blast to ride! So, the axles need differentials. After much research I found a company that makes reasonably priced differentials using the same 1 inch diameter axles I am using. I found two of these differentials on ebay and took the plunge. In order to use these differentials, I have to modify the diff housings, modify the axles and sprockets, and drastically modify the trucks I have already made....... Sheesh, this conversion is a big undertaking. I am about 3/4 done with the differential conversion. I will post pictures soon.

Matt
 
It's been a while since I looked at this thread. VERY nice! I really wish I had a TIG welder and machining tools like you do.

When I saw those pictures of the board jacked up on your couch and with both trucks turned so hard, my first thought was that the axles had to be driven independently. A fixed axle would create issues with turning radius. Why not drive all wheels from their own independent motors? It's not like you lack the room on those giant trucks. With some minor added circuitry, you could even account for steering angle so that the outer tire gets more throttle than the inner tire in a turn.

Regarding Castle ESC's, you mentioned getting 300 amps out of them before. I assume that was for a couple of seconds and that you are referring to phase amps right? With such a tiny heat sink, it is surprising that 160 amps is even possible without them getting quite hot. I've only ever owned a single Castle 160 and I burned it out on a small scooter I was going to use it on. After that I went back to real EV grade controllers. If the 160 could handle halls, do regen, handle an analog throttle and a few other things that you commonly get in EV grade controllers, they could be a real contender in my mind. After burning out that one ESC...I've just stayed away from them.

This build is pretty amazing. I love all the custom work! My guess is that the turning angle will be a problem as it tips over the board so far which makes staying planted on the deck rather difficult. My guess is that you will try to straighten that up a fair bit so that the deck doesn't tilt so much. I look forward to seeing this project getting powered.

Any idea how fast you want it to go? 48 volts ought to get you 40mph easily...depending on the gearing and motor Kv.
 
What an awesome build !!!
I want this, I need this, I will never have this hah hah.

But can I ask a question as the noob I am.
Why not use 4 hub motor wheels ?

You can get them in high torgue snd the same size.
Any reason I dont know?
 
Hey Guys,

Ok, some info;

The Castle ESCs are reliable ONCE YOU KNOW HOW TO SET THEM UP! That is key. I agree it is easy to blow them. But, that is if they are setup and programed incorrectly. I have gotten good at setting them up to survive. :D

The reason I am not using 4 motors is cost, complexity, packaging space, and weight. The differentials are $1,000 cheaper than adding two more motors. Oh, also, I have enough parts lying for two drive units, not four. :mrgreen:

As for hub motors...... That is a great question. I never even considered it. I am so used to using my own reduction units that I never really considered anything else. On, one problem with using 4 hub motors is using 4 large hub motor controllers. That would take up far too much real estate on the deck. Not a bad idea, though.

Matt
 
Well there is that phaserunner BAC controller from ebikes.ca (Dimensions [L x W x H, mm] 99 x 40 x 34 mm) weight 250 gr.
Even if you get 4 of those phaserunners you won't be making as much peak power as you do with your own drive unit and dual astro/hv160 setup. But iirc maybe peak of 5 kw from phaserunner. So few seconds of 20 kw. Should still be plenty even for a monster board. Four of those and 4 hubmotors would give you a silent ride.
 
One other thing I love about mid drive type systems is flexibility. I can alter gear ratios, mounting positions, etc. Besides, 4 hub motors would be extremely heavy.
 
Yes. It has taken huge time to convert the trucks to use differentials. I am nearly done making all of the parts for the conversion and the first converted truck assembly is nearly completed. I should have pictures very soon.
 
Yes I do! The front axle truck assembly is completed and installed! The rear axle and truck assembly is about halfway finished. For some reason I've been unable to get the pictures compressed and uploaded. I have a new camera a new laptop and new photo software. So, I've been messing around with that and I've been busy with my YouTube channel. Anyway, I promise I'll get pictures up very soon!
 
Subscribed, this is an epic build. Really want to see how this handles. My first EV was a mountain board -so much fun but I found the small wheels and bumps made it hard to have fun on anything but smooth ground . I thought about going to 12" bike wheels but didn't have the time to customise everything. This could be insanely good if it handles OK.
 
I did the remaining welding on the second axle assembly (rear truck) today. Tomorrow I am doing the modifications to the rear differential. After that, the remaining work required is;

Mount steering dampers to front and rear trucks

Do final fabrication and installation of the second drive unit for the other truck

Do all wiring

It is coming along!
 
The delay on this build it's due to adding differentials to both axles. I found genetic steel great differentials online. Having each of them required the following modifications;

Shortening the diff housings to fit the axles (trucks)
Shortening on axle (grinding a new keyway too)
Lengthening the other side axle with a sleeve
Making a box section in each truck to house the diff
Modifying the sprocket
Making new drive unit mount plates

Remember, I had to do all of this work twice! It was a monstrous undertaking.

Here is a picture of the differential in the front truck.

Matt
 
Wow, that is huge. Will it even fit in the trunk of common hatch backs?
 
It fits in my Tesla. But, most cars would struggle swallowing this beast.

I have it designed so each axle assembly is removed with only two bolts. So, 5 minutes of disassembly will break it into 3 large components. That makes it much more portable.
 
Great upgrades!
It will take huge skill (and balls) to ride that thing at it's full potential... :shock:
Would love to see the ride video's 8)
 
No kidding.

Honestly, it should run well at speed or as a slow rock crawler. It has crazy articulation!

Oh, it will have 400 pounds of pulling force. This thing should be able to tow a car!

Matt
 
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