I had a discussion with the guys from the Skatemetric youtube channel and I am starting to think that most dual 6374 builds are severely bottlenecked and just wasted money (don’t get triggered yet)…
There are a few comparisons between dual 6355 vs dual 6374 (or 5065), but all of them are basically useless since they use either different battery configurations or different kv motors, even different gearing, so they are always biased (and stupid).
The battery is the bottleneck usually, so you might have to go lipo or multiple li-ion packs in parallel.
Larger motors, even though they use more battery for doing the same task, might be more efficient for long distance cruising because of the heat dissipation. Lower heat also means lower resistance which makes it more efficient. Hot motors have high resistance and eat more battery than cool ones.
I thought about it again: larger motors can be more powerful (listed W). Torque does not mean everything, a more powerful motor will move a bigger mass more easily. That is IF ONLY the battery can keep up with it.
The question is what would be the difference between motor performance if they have the same specs all around, besides dimensions and power, while being constrained by the battery (which is the case for most boards).
A 12s4p samsung 30q battery can only supply 3.6V * 12 * 4 * 15A = 2592W at 43.2V.
6374 motors are rated for over 3000W, multiply that by two for a dual setup.
Result: you have a crazy bottleneck caused by the battery. I assume 90% of eboarders don’t have more than 50 cell batteries.
Makes you question if it’s worth getting a 6374 setup that will have the same actual power as a 5055 setup.
Can someone shine some light on me and tell me what the actual benefit of a 6374 setup is in a build like the one above?
I stated this calculation before also.
The thing is, that a lot of guys here wanna go bigger and bigger but for the most they can’t even reach out the max performance of there Motor as they restricted by the battery or the vesc.
Besides this I would say a 63xx is still a good choice. You get better breaks and better heat dissipation.
Edit: I would step up your calculation…
The 30q can handle 20a so 80a total
And I wouldn‘t take the nominal voltage here as you look for the max values
So now we here:
12 x 4,2 x 80 = 4032W
That would be 2000w for each motor in dual
Let’s be straight for a moment – a single 5065 is enough for an esk8. It will move you and keep you moving. Many commercial boards use it. I’ve done it before across town, no problems at all. But the performance is very underwhelming, to say the least. Especially if you’ve ridden anything else, ever.
single 5065 - adequate, but crappy
single 6355 - it works
single 6374 - minimum imho for a “good” build. perfectly fine
dual 5065 - now that’s much, much better omg
dual 6355 - I think I have rocket skates
dual 6374 - I think I have rocket skates, but they don’t get quite as hot and they’re heavier
dual 6384 - I think I have rocket skates, but they don’t get quite as hot and they’re even heavier
So my answer is “not really but maybe sometimes, depending”
For a normal polyurethane-wheeled street esk8, dual 6355 is plenty to give you that Nascar feeling and is lighter and fits on trucks better than dual 6374 or 6384.
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TL;DR: use dual 6355. saves weight. fits better. fast as balls.
I have dual 6355 on just 10s3p 25r and they are plenty for me. The dual 6374 is just becuase I wanted wider trucks for stability (becuase I still suck at higher speeds). The 74s just looks better on wide trucks
Hey so has anyone pulled much more than 1000w with a 6355 or 6374 190kv on 10s? Urethane wheels, around 15/36 gearing?
I’ve got a 12s2p a123 pack, and got ahold of a vtc4 10s4p, both on dual 6355 190kv with 50a batt max per vesc. Can’t seem to pull more than 70a from either setup. About 1kw per motor. Both these packs should be able to at least show me 120a.
I also tried dual 6374 on a r2 pack (30q 10s4p) with similar power numbers in vesc. This one’s 107mm wheels with I think 16/36.
Theoretically I should be able to pull more than 70a from the packs. Am I hitting the 42v bottleneck? I thought the 6374 would pull more out of the pack.
I watched that video too. Also notable, they mentioned that the thing is geared to 50 mph, so if you ran a single 6374 instead, and geared down to 25 mph max, you would actually have the same torque they achieve. In their case, traction is the main bottleneck, and they really should have picked larger contact patch wheels to manage that torque. Venom Cannibals would be awesome.
Assuming you gear to the same top speed, the only thing that matters for torque is max continuous current. 5045 200 kv motors are typically 30A max. 6374 200 kv is 80A max. So a single 6374 is capable of 33 percent more torque than dual 5045.
How much current do you need? Well, you can calculate the torque you need to accelerate up a given hill at a given weight, and convert that back to current based on Kt. I ran the numbers for my use case, and found that for my 12s setup, my gear ratio, body weight and terrain, I need about 60A capability. Dual 5045 would work barely, solo 6354 would work, hub motors would not, dual 6354 is way overkill.
Another interesting point from those videos, they mention the boosted lacks top end torque, but do very well down low. I think that is direct evidence that their bottleneck is battery current. Their dual 5045 setup can draw 65A from the batteries easily at low speeds/duty cycles, but closet to top speed, the a123 lifepo 12s1p setup they run, likely at a max battery current of around 40A, cannot supply enough current to fully utilize the capability of the motors.
I think a very sensible setup overall is dual 5045, and 12s3p vtc5a. Max motor current of 65A or so, and max battery current of 75A or so. Very well matched, and should be PLENTY torquey to hill climb most riders while still reaching 25 mph
Here’s the thing though - you get to say that you have dual 6374s. That’s enough to make jaws drop on boosted riders faces, which will make me happy enough to be worth it aside from the awesome torque.
I’ve just wrapped up on my first build The eLFF, with dual 6374 TB motors on a flexible loaded board at stock drop thru height. That torque kick is absolutely amazing. It’s like any good turbo car, no one ever wants to turn the boost down.
IMO dual 6355 coupled with a 12s5p are more than enough as far as power is concerned
That said I am thinking about switching to dual 6374 in the future.
Why may you ask?
I live in Greece and it can get hot during the summer, this combined with some serious hills I have to climb during my commute has led to overheating the motors above 80C and leaving me without brakes. I weigh 77kg +backpack (ca. 10kg).
Here is a typical ride, check the motor temperatures near the end.
So if you do not have overheating problems I see no reason to go for anything bigger.
If you are a heavy guy, live in a hot climate and have serious hills where you ride then bigger motors may be required.
I’ve ridden many setups of motors before, single 6374, dual 6374, single 6355, dual 6355, and dual 5055, and as from I experienced anything less than dual 6374 doesn’t really satisfy me, heck even dual 6374 on 10s are pretty meh.
And more motors = more boosted guys dropping their jaw, and it also makes it easier to do the “Hey I’m just cruising, and I see a bunch of people on the sidewalk. Time to impress them by passing them slowly and then full throttle to go flying”
It does also depend on the motor, let’s say you have a motor with 28 stator teeth compared to 14, it’ll have more torque off the line. Bigger motors do actually help at high speeds. The raptor 2 is also limited to 40 battery amps total in the firmware but it kicks like a mule even at high speeds.
Urethane just gripped board—-> dual 6355 it’s the perfect combo!
Pneumatics gripped board daily commute—-> dual 6355
Mtb with bindings—> 6374 and tons of amps and torque
dual 6355 - I think I have rocket skates
dual 6374 - I think I have rocket skates, but they don’t get quite as hot and they’re heavier
dual 6384 - I think I have rocket skates, but they don’t get quite as hot and they’re even heavier
