The Loud Zoomy Boi——21S4P——Red Ember 44——Build Thread

[Shadowfax]

The Loudest One - Build thread

Part 1 - why am I building this?

I finished my “dream board” 18s nazare with BN 5.5 straight cuts and am left without a project. The truth is I enjoy building esk8’s just as much as I enjoy riding them. Building campervans, espresso machines, I need something to DIY and tinker with at all times.

@Evwan sold me xcell RS tires and I had a 100D+ on hand, so naturally I started to think about what I could do with them, and building a ridiculously overpowered race board was the only clear answer.

@bboybowzer happened to have a RE44 deck, enclosure, and 3-link package he was kindly willing to sell me, so that put me off to the races.

@Skyart and I talked about going big on 21s, and we’re going for it together with brother builds. I think @zero_ads and @poastoast are joining the club too. This doesn’t mean you should. This is possibly a bad idea. We might blow up components. BTW this isn’t on the 100D+ - that red hot unobtanium is going up for sale.

Another thing to think about with 21s is that if you only charge cells to 4.1v you get 90% capacity, but the cells have a 3x longer lifespan. Just saying, you don’t have to go all the way to 88.2v. I’ll likely start out below 4.2v on the first few rides to get comfy.

I’ve placed orders for everything, and the parts are starting to roll in. I’ve got some exciting plans for this build, and I’m not ready to spoil all the surprises just yet.

The plan is to build a ~50mph “God Tier” esk8. This refers to the interpretation chart from the “ultimate esk8 calculator” (>1000 Newtons of force)

To get an idea of what this board will be capable of:

Build thread:

Part 1.5: parts arriving - it begins

I call this enclosure mounting tactic the @Linny method because I learned it from Linny’s build thread. If you use inserts, go with the stainless steel ones.

[ShutterShock]

putting those straight cut gears to use huh

[Shadowfax]

@ShutterShock

putting those straight cut gears to use huh

You’re on the right track but wrong side of the street detective Ryan. The 5.5’s are staying put on my Nazare.

[Egtscs]

Not going 100s for this build? I’m disappointed

[bboybowzer]

You forgot to reserve th 2nd post

[Shadowfax]

Bump for build thread updates posted in original post - teaser here:

[zero_ads]

1000N!? Damnnnnn

[Flyboy]

I am now sold on the Linny method

[frame]

this is a very long title

[SquishyCat]

What controller are you gonna use for this beast?

[monsterbuilder]

Bitchin. Can’t wait to see more progress updates.

[ShutterShock]

That’s pretty crazy ngl

[SquishyCat]

I smell a SKP Solo in your future

[rafaelinmissouri]

That deck is so gorgeous and this is so much power.

I’d like to simply hit copy and paste…

[glyphiks]

Can’t help but feel that you’re probably compensating for something

Not even 4wd. What is this weak sauce

[ShutterShock]

Not with 21s

[poastoast]

it only takes up to 18s

[SquishyCat]

Ah gotcha for some reason i was thinking 22s hah

[Shadowfax]

@SquishyCat

Ah gotcha for some reason i was thinking 22s hah

AFAIK only the Ubox 100v has a claimed rating at 22s, and that comes with a caveat that you must not have voltage spikes above 93v, and none of us really know what the safety line for voltage spikes is. I believe @poastoast has seen up to 8v spikes, and he’s on 20s? Poast, what kind regen do you run? anything you do to lessen spikes?

I believe 25% headroom is the generally accepted reliably safe headroom according to people on the VESC discord, but this is perhaps overly conservative, as there are a good number of people running 20s on hardware that doesn’t afford that 25% headroom.

When you push voltage and current higher, weird things starts to happen. My take is if you want anything above 20s, it’s a proceed with caution deal.

Credit to @jaykup - half of this post is just relaying info I have heard from him at one time or another.

[jaykup]

I still have a ways to go before I fully understand all this stuff, but the only thing I’d add to this is that voltage spikes don’t just happen from regen. There is a lot that goes on microsecond to microsecond that the VESC logs don’t capture.

Running these things under full load while scoping several areas of the ESC is really the only way to know for sure what the limits are. The DC bus voltage ripple may be within acceptable range, only for the mosfet gate ringing to exceed the 20v spec and kill the mosfets anyway. All this changes as the voltage and current levels change. PCB layout choices, proper component selection in things like the snubber circuit or any number of other factors can make the difference between a controller that works or dies at 22s using 100v components.