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TRAMPA-FS SGD AWD mountainboard

IMG_20191228_152916

Components :

  • 1x TRAMPA HS11 deck
  • 2x TRAMPA VERTIGO trucks
  • 4x TRAMPA EXTERNAL STRAIGHT 10/59 SPUR GEAR DRIVE drivetrains
  • 4x 9 INCH MEGASTAR hubs
  • 4x 9 INCH PRIMO STRIKER tyres
  • 2x FSESC 6.6 DUAL controllers (I’ve used 5 of them, killed only one but it was my fault)
  • 2x METR PRO
  • 4x ESKATING.EU 6374 190kv motors
  • 1x MULTICOMP MC001291 250x200x130mm box
  • 2x HAMMOND 1590XXBK 145x131x39mm boxes (for ESCs)
  • 4x TURNIGY GRAPHENE PANTHER 6000mAh 6S 75C battery packs
  • 1x HK GT2B transmitter
  • 2x HK-GT2 waterproof receivers
  • 8AWG and 10AWG TURNIGY cable

Weight :

  • 23.7 kg (more than expected)

Settings :

  • Front and back dual ESCs are independents : 1 receiver for each ; two 6Ah 6S in series (12S for each) ;
  • VESC-Tool 1.19 official firmware ;
  • FOC ;
  • Battery max : 99A, min : -40A ;
  • Motor max : 62-67A, min : -40A ;
  • Custom positive ramping time : 0.10 sec ;
  • Throttle expo : +20% ;
  • Traction control : ON.

Testdrive :

  • First, I had a lot of bugs and troubleshooting while trying to set the ESCs with VESC-Tool for android (HUAWEI P30 PRO) : bad firmware unexpected warnings, can connection issues and slave ESC not found, bad FOC detection with motor dysfunction ; at the end I stopped wasting time and used latest software available for MacOS ;
  • I ran FOC detection with gear drive assembled because it takes to much time to disassemble, then I don’t know if motor max amp is correct because older ESKATING.EU 6374 190KV motor got 73-74 max amps in VESC-Tool ;
  • I only rode it once today ;
  • METR data for one of the two FSESC 6.6 DUAL :

  • CONS :
  • PROS :
    • I’m now the king of the forest, destroying dead tree branches, although it’s not easy to go on the hilly areas ;
    • Motor temperature is always low, what is a big advantage ! I didn’t exceeded 50°C during a 25 min ride where I usually reach 85°C in less than 15 min ;
    • Braking is the safest with this build ;
    • I was afraid turning would be a problem with 4WD 9 inch wheels, but actually turning radius is very good.

Conclusion :

  • A nice build when you already have a 2WD light build ;
  • REAL all terrain build ;
  • I NEED MORE POWER.

Some comment about the MEGASTAR hubs. They look really nice, but I expected them to turn more precisely.
@Trampa, please take a look at my goofy front left wheel, it turns very bad!! What do you think about that? I don’t think I can improve that with counter weight bolts. Faulty MEGASTAR hub?

16 Likes

Awesome looking build that many here would kill for, myself included.

So you think this is due to ESC configuration? A quad 6374 board with 6:1 gearing in lipo should have plenty of torque.

Edit: after looking at your logs I think your settings must be somewhat conservative. Your max battery current is well under what your battery is capable of and so is your motor currents.

6 Likes

Love your build! I would throw more amps like @ducktaperules said…Also if you are planning to change motors, I will think about lower kv…Big wheels will compensate speed loss, and torque will be much powerful…

1 Like

It is not the vesc settings.
If you look at the metr log the max motor current he gets is 85A for both motors and the battery current 36A.
So either punch the trigger more or track down why the motors are not drawing enough current.

2 Likes

Classy build, man. Love that cabling work. Neat!

Appreciate the close-up on the enclosure mounting too. I’ve been deliberating on a good way to approach that on mine.

2 Likes

Very nice build!

I had the same problem with all my wheels. I have Superstars, but the spokes are the same as in the megastars. They have crazy tolerances, try to measure the widths of the spoke’s “ring” around the bearings with a caliper. If the two spokes of one hub have large differences here, the hub and the wheel will wobble.
I had to contact Trampa to send me additional spokes, they kindly sent me a whole set of new spokes, so I could measure all and find good pairs. Having pairs with similar tolerances is the key here.

3 Likes

Thanks!

I’v chosen quite high kv motors because I feel that if I can give them enough amps then they give more torque and everything than lower kv motor that will saturate quicker.

I’ve had the same issue before with 2WD builds. When I follow VESC-Tool amp setting advices it feels so wrong. Solution was ACKMANIAC firmware, 100A battery/motor max and +20-30% throttle curve for everyone. Maybe it’s not “linear”, but linear is no fun.

I’m going to check that! That wheel turns so bad that rubber seal lip plunges into the carter at a side.

1 Like

It’s probably a bad spoke. Seams like some spokes warped during heat treatment and the CNC mill couldn’t centre the spoke. We are currently checking the entire stock for such tolerances and build new heat treatment moulds. We can send you a new spoke or pair of spokes.

5 Likes

His vesc has traction control enabled so must have CAN setup. This means his metr log is for 2 motors.

Therefore that 85A motor current is less than 45A per motor. These motors should be capable of almost double that, if not more.

Also 36A battery current means he will be pulling around 70A for the whole board which is well below the few hundred Amps this battery should be capable of providing.

ESC is running cool so it’s also got plenty more overhead for being driven harder.

3 Likes

Generally lower kv results in more torque, as there are more, thinner windings.

1 Like

Just crank up your motor current A LOT and have fun!!!

The values VESC tool recommends are for safe continous use. Yes, they will go into saturation, loose efficiency and heat up exponentially but as your board will never see full load for more than a few seconds there won’t be a problem.

I’m running my 6364 with 100A mc and they still stay cool most of the time. Your 6374 should easily handle 120A if your FSESC can…

4 Likes

I wouldn’t go that high motor current wise. A saturating stator can result in clogging and that can throw you off.
The best way to figure out max Amps:

  1. Tune down all motors to 5A, except one motor.
  2. Adjust that motor to a conservative Amp value (Wizard value). Battery Amps should match motor Amps.
  3. Now go full throttle from stand still. If you feel cogging, reduce the motor resistance value by 3 to 5%. Try again until you can hit full throttle from stand still without cogging.
  4. Now increase the motor amps until you get cogging on full accelaration from stand still.
  5. Decrease Amps a bit.
  6. Do the same for all four motors
2 Likes

What’s the theory behind this? Why are you making changes to the motor resistance, what difference does this make?

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Making sure cogging doesn’t result from wrong motor resistance values.

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Awesome build! What is the maximum offroad incline you can go up at slow speeds? Are 20° (40%) and beyond possible (perhaps also with mud plugger tires)?

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I don’t feel that in my experiments. I found 190kv motors to be the most powerfull in 6364-6374 range. My worst build was a 6S car ESCs build with Maytech 6374 130KV. I replaced the 130KV with 190KV (same brand same size), and got more “everything” (torque, speed, fun).

Thanks I’m going to try 100A, with official firmware.

Yes, I took a look at all spokes, I’ve got 8 :

  • 2 only are perfect (4.5 mm everywhere) ;
  • 4 are quite accurate (from 4.3 mm to 4.7 mm) ;
  • 2 are bad (from 4.1 mm to 4.9 mm).

It’s a shame to have CNC’ed hubs and quite inaccurate spokes. I prefer to wait the moment you are able to provide the new accurate ones.

Til that time, I matched the spokes where it’s thick with where it’s thick and where it’s thin with where it’s thin. It’s a bit better this way. Another issue with inaccurate spokes : I had to use a mallet to put one of them in place.

Nonetheless, I’m very happy with all other TRAMPA parts.

I have to test that ! :smiley: Unfortunately I bought the PRIMO STRIKER tyres a few weeks before 9 inch MUD PLUGGERS were available.

Well, I have 80kv and plenty of torque :smile: 80100 though

It’s just the theory, I don’t have any real world experience. But I would be really astonished if higher kv actually gives you more torque. I guess you are just feeling the increase in speed more than the torque.

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Gearing should do the rest thou

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They were 6374 motors. I would say all 80100 motors are plenty of torque no matter the kv.

Yet, this guy (Willozboard) uses 6374 90kv motors with BLDC and I wouldn’t say his mtbd is not torquey :sweat_smile:

3 Likes

It’s easy to resolve the issue. If you file down the spoke edge, so that it doesn’t touch the hub, the spoke will centre according to the 4mm holes. These holes are done in the same process as the bearing fitting and in consequence the bearing will centre. We can ship out some new spokes that have been checked for you.

1 Like