Split Decision | 4WD IDEA Split Angle Build

[Dinnye]

I see your point that you were the first to use BRP tires on an esk8 and made reliable hubs for them. However your design already pretty much exists in the context of gokarts and maybe other motorsports as is, so you didn’t “invent” BRP hubs, you just were the first to adapt an existing design to fit BRP tires.

A BRP hub in it’s simplest form, which is basically your design, can be replicated in CAD in well under 5 minutes by anyone mildly competent in a CAD software who also happens to own a pair of calipers and buys a single piece of BRP tire and has seen a couple pictures of wheel hubs. Simplicity is not always a bad thing, it can mean a reliable product, that’s easy to manufacture. Which yours totally is.

However I don’t agree that noone else should make reliable well designed hubs for them. I am a fan of a free market - my opinion is that if someone can bring some actual improvement to a product, they shouldn’t hold back unless the original product is a never before seen novelty idea - if it is, give some time for appreciation of the original design, then a couple years later go ahead and bring the improvement if the original creator didn’t, just don’t outright copy. Even if it were considered a novelty product which it isn’t, that appreciation period should be over by now because you were selling it for at least a couple years at this point. And this project is very far from an outright copy. A healthy free market brings innovation and is good for every customer. Is it harder for the businesses? Absolutely. That’s why everyone involved should be continuously innovating, to stay on top, and that’s why it’s hard to be a business.

And that’s not even mentioning that as far as I understand this is just a one batch group buy basically to bring down production costs, not an attempt to continuously sell this product.

[Ac53n]

Now, can we get back to what this topic is really for?

Recently, i’ve realized that i can actually afford to make the enclosure slightly deeper, i’ll have the clearance. However, this would become problematic in turns due to scraping the enclosure edges. So? I made the center deeper, and the edges shallower, after making a parametric enclosure system in my CAD software. This means i can now design enclosures of pretty much any sizing and depth in minutes, meaning if you want to make a custom enclosure for an IDEA deck - i can do it for you ridiculously easy, and send you the files for you to make your own molds.

With the new enclosure depth selected, i needed to redesign the battery structure to be optimized for this enclosure sizing (and stay optimized, should i ever need to revise the enclosure shape) So? I present, the parametrically optimized 5P battery structure for my custom IDEA enclosure.

It is pretty much as mathematically ideal as i can get it, and includes a ton of neat features i have yet to see in any battery build. Non-symetric P group layout, provisions for supporting the folded nickel tabs, integrated cell holding and spacing/isolation, an integral cutout for mounting a zbms underneath, and wire routing channels for the BMS wiring on the bottom, and CAN/UART cables over topside without needing to waste space. Now, to me? This looks great, but i’d like some input from any battery builders as to the feasibility of this, given the rather unique construction (I don’t build batteries myself, as i don’t have the time). One idea i’ve had is mechanically connecting all the P groups lengthwise physically, since i’m already designing custom cell holders - However, i have no idea if this is strictly necessary.

The next step will be purchasing a set of dualities (little delayed here, my car got broken into so my budget for the next month is a little tight), and designing some custom drop brackets to optimize their axle height to this setup. I’m currently thinking 25/15 on the duality plates, with brackets in a +10/-5 layout to end up with a 35/10, with the option to easily drop to a 25/10 for faster track layouts, or if i want to run more lean angle. I am hoping i can get this board together for esk8con, as i’ve already paid to race lol.

[poastoast]

[glyphiks]

But you’ve already made the mold!?

[Ac53n]

That i have. Tis a small price to pay, i’ve already re-printed two of the new sections lol. In the grand scheme of things, another 30 bucks on filament is really not gonna kill me. If anything’s gonna bankrupt me, it’s my new car i finally got

[Dinnye]

@Ac53n

but i’d like some input from any battery builders as to the feasibility of this, given the rather unique construction (I don’t build batteries myself, as i don’t have the time).

It looks pretty but not gonna be an easy build I’m afraid Balance wires require a very unconventional approach, and at the very least slight design changes in your cell holders. First of all, how much extra length do you have for the battery length wise, assuming the groups are right against each other and assuming the ESCs and truck mounting brackets would still fit?

[Ac53n]

I’ve got about 22mm of clearance between VESC’s and battery nickel tabs as is on each side, and that’s with some gaps accounted for between the P groups. As i’ll be making the new brackets custom, i can modify them as needed lol. As for the balance wires, while they’re routed on the underside, i’m working on the assumption that i’m able to snake each individual one up to the topside to connect to the nickel tab in between the cells.

[SquishyCat]

[Dinnye]

Welp wrote up quite a bit but just had a look at the ZBMS pictures and this is how the balance wires exit… I honestly don’t know how you can route them out well.

TLDR of what I wrote up but is no longer 100% relevant is based around the two ‘rules’ that you should avoid two things: pinch / compress wires (so proper spacing between modules of the cable comes up there), and super tight bend radius (aim for 2mm at least if possible, and even more doesn’t hurt although isn’t necessary).

[Ac53n]

Oh for that, i’m gonna disassemble the bms board and solder the bms wiring straight onto the pcb. It’s not ideal, but it’s the only realistic way of making something this slim There should be enough space to have the wires route off the board parallel that way, instead of vertically up.

[Dinnye]

How many amps do you plan to charge at? Pretty sure you’d need to use the heatsink it comes with unless you plan to charge at like 3 amps max or something way too slow. Chances are that might not be possible after your surgery. edit: and that’s not even thinking about the fact that maybe the heat distribution of the heatsink is required for balancing to not overheat either

Also better make sure those joints are super secure then, you definitely don’t want them to break off
Definitely add strain relief! Has to be heat resistant, maybe some neutral cure silicone as much as I hate it…

[tuckjohn]

@Dinnye

I honestly don’t know how you can route them out well.

@Ac53n

Oh for that, i’m gonna disassemble the bms board and solder the bms wiring straight onto the pcb.

Took the intustive thought right out of my head

[Ac53n]

I’m not planning on charging very quickly at all haha. But figuring out a better heatsink is a pretty good idea, i think i can integrate a copper plate into the battery structure to better handle that. Good shout there haha. As for strain relief, i’m definitely going to be mechanically adhering the wires to the bms board after the 90 degree bend - I’m no EE but i know solder joints don’t like being flexed lol.

[Ac53n]

Back to this now that i haven’t gotten any other response from moe.

@Ac53n

Another update on the custom BRP hubs. Preliminary quote is in and it looks like i am not going to just hit my target of <$200/set, but completely smash it. So, whoever wants in, the pricing is guaranteed to be below $200 delivered within the states for four of them. Final pricing dependent on how many parties i can get interested upfront. Could be significantly lower depending on how many sets i can get sold.

So, please fill out the below poll to indicate interest! (Please dont select an option unless you are fairly certain, as I’m fronting the cost of the run myself)

• Absolutely, I’m willing to pre-order right now
• Absolutely, but i need to wait a bit
• Possibly in the future
• Absolutely not

8voters

• Votes are public.

Vote now!Results

Pricing looks like i can knock it down to $180/set of four hubs for anyone stateside, may have to tack on an extra 10 bucks for shipping and packaging but we’ll see. If i can get like, one more person interested i’ll knock the price down to 170 a set of four. This would be for just the hubs and the bolts needed to mount them up, bearings and spacers not included.

HOWEVER, if you would like bearings or spacers, i can offer them. NSK bearings in either 10 or 12mm ID, a full set of 8 with your hubs for $20, and i can add in 10mm ID spacers for an extra $5 if you don’t already have them. I unfortunately do not have a supplier for 12mm ID spacers, so i’d suggest sourcing from MBS if you need those.

[Egtscs]

@Ac53n

i’d suggest sourcing from MBS if you need those.

For anyone.
If you’re just buying spacers, send MBS an email first and they’ll help you work out shipping, otherwise the shipping on spacers alone is pretty bad.

[Ac53n]

Okay, we have smashed my initial estimate of 10 sets, so i’m now upping the upfront order quantity to 15 or 20 sets dependent on how much cash i have after my next paycheck Hopefully that’s enough for everyone here, if there’s a ton of interest by end of next week i might have to bump it again, but i’m going to hope not as that’s quite a lot of cash to front for this order. I am hoping i can have these hubs back out to you guys for esk8con 2025, but i can’t make any guarantees unfortunately as overseas manufacturing timelines get pretty interesting around CNY.

Now that it’s settled for sure, the final pricing will be $180/set of four hubs shipped anywhere within the states, or $100/set of two. They will come with the required hardware to mount them to your wheels, and potentially hardware to mount up pulleys or otherwise to the MBS/SR125 interface.

As per the above, bearings are an extra $20 for a full set of 8 for your hubs, and spacers are $5 if you’re on 10mm axles. Please vote on the following poll below so i know roughly how many of the bearings to order.

• One set of 10mm NSK bearings (8 bearings total)
• One set of 12mm NSK bearings (8 bearings total)
• One set of 10mm ID spacers (4 spacers total)

[Ac53n]

It’s been brought to my attention that there may be some different models of BRP wheel hubs, which may affect compatibility, particularly with sizes outside of those offered by SRB. So, to ensure i can guarantee compatibility and proper functionality with as many wheel options as possible, i’m going to offer a prototype program.

If you can provide proof of ownership of a set of BRP wheels outside of the standard 150x75 (6x3) that i already have, I’ll ship you a 3d printed prototype hub for you to test install and check fitment with, on my own dime(within the states), (Or, if you own a 3d printer, I’ll provide you an STL file for you to print your own) While i cant offer any further discounts for this program, it does give you the ability to test how the new hubs will fit your board setups and/or provide feedback. I also would request that you test fitment with as many different drivetrain setups as you have available.

As always, thanks for following the project and supporting it!

[Snowhiter]

I’m in and sorry, for i am that one and only trouble bringer to this otherwise superb item . . .

Proof incoming