WheelchairDriver

Looks like a trianglar piece (plywood?) with castor wheels & a seat bolted on. Entirely doable with all the power & speed limits of the original scooter. It doesn't look very compact for transport. Twice the weight of the biggest piece of my TravelScoot but much less cost. I don't think I'd pay $50 for "plans".
Depending on an individuals transportation needs & construction abilities might be a clever choice.

Doesn't look unreasonable, but it certainly feels to me like a violation of the "Instructable's" website spirit if not their terms of service (I haven't looked to see just what their rules are)

The site doesn't have any significant amount of 'instructions' - just a pitch to sell 'plans'... The idea of Instructables as I've always seen it is to spread ideas on doing Open Source hardware - meaning instructions on how to do a project, not just an offer to sell it...

(No objection to the idea of selling stuff, including plans - just don't think it is the right place to do it....)

ART

If you know what you're doing, you won't need his instructions. I'm sure BM could reverse engineer it easily.

He uses aluminium to create the triangle, and then something with more grip on top of that.

If you could start with something that already has a variable enough throttle, all you need is a way to make it more stable. It's rather noisy, though, and it's possible to find cheaper ones if you know where to look.

I read through the article. He made one out of aluminum which the auther didn't recommend. Said most were built on a base of 3/4" plywood. Any carpender could cut one out. The castor wheels need to pivot to allow for steering. The only challenge I see is locating a variable speed control.

Google Search: Razor E300 variable speed controller:
www.ebay.com/itm/Razor-E300-Variable-Sp ... 1232755657 $57.99
www.electricscooterparts.com/razore300.html $21.95
www.monsterscooterparts.com/thumb-throt ... ver-1.html $14.99
I'm not saying that this is a complete list by any means but there are lots of choices & the variable speed control is readily available as KITS!

In reading the ads for the E 300 it states 45 minutes of driving time with 8 hours or longer charge times. Replacement battery sets (24V) are available inexpensively. I'm thinking that the variable speed controller might extend range... or battery interchange or upgrade to Li.

A TON of reviews on Amazon. Complaints:
Short battery life (per use) probably due to heavier user.
Battery failure at 6-12 months probably due to small SLA batteries used to the extreem. Nobody here should be surprised at this. Battery needs to be shut off when not in use... apparently still has draw when "on".
Thermal circuit breaker cut out.
Occasionally motor failures. Occasional on/off switch failure.
Occasional drive chain or rear wheel ajuster failures.
Poor product support & poor parts availability after short warantee.
Never the less, used within these limitations, this clever adaptation probably has it's uses.

Perhaps a better base unit like the e-zip 450 would give better service.