Lithium Battery Pack Design for Boosted's Electric Skateboard

I&#x27;d be concerned about buying a $1,300 battery-powered skateboard without the ability to replace the battery.<p>I&#x27;m not exactly sure how much it costs them to produce the battery, but it looks like single cells of similar LiFePO4 batteries are about $20&#x2F;ea. With 12 of them, that&#x27;s $240. Add maybe $50 for the BMS and $10 for the enclosure, and the whole battery pack is maybe $300?<p>It&#x27;d be a shame to have to replace an entire $1,300 skateboard after a few years when your battery capacity is reduced, when all you needed was a $300 battery pack. Hopefully &quot;non-swappable&quot; means something besides &quot;non-replaceable&quot;.

I&#x27;m imagining:<p>BMS PCB has high current input rings and a blade connector for balancing (like removable laptop batteries).<p>Bottom of case has screw lugs going up through high current input rings in PCB. Battery has ring terminals that are crimped &amp; soldered to high current wires. The battery is in a protective casing that holds mating balance connector and injection molded features keep the high current ring lugs in place.<p>Battery drops into board, high current rings go over lugs and balance connector engages.<p>Rigid plastic goes over the top of all this (bottom when in riding position) with silicone seal around the perimeter. High current lugs go through the cover. Special ratcheting thumb screws tighten down the cover using the battery lugs as a mechanical connection while also pressing the ring connectors into the BMS PCB. Conductive grease on the PCB helps keep out water.<p>Battery would be 100% rigid, no dangling wires. Installation is two lugs, drops in, can be done by hand. Battery should come with a protective pouch or have integrated flip-over cover so it can be dropped in a messenger bag etc.<p>Solves I think all the issues, including avoiding costly or underperforming connectors, environmental sealing, ease of use, and the expensive BMS does not need to be attached.<p>I emailed them something to this effect, since they asked for input, though it sounds like they&#x27;ve purchased battery packs already.<p>Plus they may have considered this, it sounds good but I know production high current battery stuff is really tricky, I&#x27;ve looked at the area quite a bit.

It sounds like their decision was justified, but it&#x27;s too bad they settled on a non-removable battery pack. It would be nice to carry a spare battery with you if you were planning a longer ride.

I hadn&#x27;t heard of this, but it is very interesting to me. I couldn&#x27;t skate to save my life, but for my capstone course, in our brainstorming sessions I had the idea of doing an all terrain electric powered board on wheels.<p>My initial intent was actually for carrying stuff for me. The idea came one of the many days that I was carrying a huge laundry bag to the laundry store a couple of blocks away. If only I had something I could just place the bag on top of with wheels. Then I thought it could also carry my backpack to school everyday, groceries, etc. Maybe I could tie a surfboard-like leash to it, and it would have a sensor attached that upon pulling it would know which direction to follow me on. The possibilities for my laziness are endless! Anyways, we ended up going with another idea, probably for the best, since the kinda board I was thinking off was probably out of the scope and time we had for the course.<p>Looking forward to how this goes. Best of luck to all involved.

I wonder why they used cylindrical battery cells. It looks like the battery pack on this skateboard could have been a lot smaller if they had used rectangular cells.<p><a href="http://batteryuniversity.com/learn/article/types_of_battery_cells" rel="nofollow">http:&#x2F;&#x2F;batteryuniversity.com&#x2F;learn&#x2F;article&#x2F;types_of_battery_...</a>

Having ridden an electric skateboard a fair amount, I am excited for Boosted&#x27;s play. They seem to have good solutions to two of my main gripes, which are weight (crucial for turning on the spot) and weight distribution (most boards have the battery pack in the middle where it gets in the way if you want to climb a curb). The battery pack still looks bulky, though.<p>One thing I am missing is the ability to disengage the electric motor from the wheels - as it is, you can&#x27;t just free roll on the board if you want to save power or the battery is depleted; the motor is engaged to the wheels at all times. I guess it is a difficult problem since no boards seem to be able to do this.<p>(By the way, I used to ride five-six kilometers through downtown Copenhagen to work, charge at the office and do the same trip back at the end of the day.)

Obligatory xkcd: <a href="http://xkcd.com/139/" rel="nofollow">http:&#x2F;&#x2F;xkcd.com&#x2F;139&#x2F;</a>

Is the board waterproof with this design? If it rains, can I still use it? Most electric boards I&#x27;ve found are not water proof and it&#x27;s going to suck dragging a 15 pound lode stone when it starts raining.

I&#x27;m really curious to evaluate the following:<p>Instead of a remote control with buttons to control the speed&#x2F;braking of the board...<p>What if it had a pressure pad on top so that it would accelerate when you put more weight on the front [1], and brake when you put weight on the rear. How would that control scheme compare (after getting used to it)?<p>[1] - The opposite arrangement wouldn&#x27;t work, because it would create a feedback loop that&#x27;d drop you out of control. As you put more weight back, it accelerates, shifting your weight more back, accelerating even harder.

A123 cells. 70A continuous, 120A burst, will stay at 3.4V until really tired. The bottom, with the array of holes, and the dead on power delivery numbers both give it away.<p>B456 now.

The batteries sound impressive. But I think statement<p>&quot;...the battery needs to deliver thousands of watts of electrical power&quot;<p>should read &quot;hundreds of watts&quot; -- the watt has a unit of J(oules)&#x2F;s. Thousands of watts then refers to thousands of Joules per second. They later clarify actual power output as being a sustained 230W (or 384W for a 10sec burst).

I need to spend as much time writing articles about the tech behind GridSpy as Boosted boards write about their tech.<p>Not only is it fascinating, it&#x27;s great branding and marketing collateral. I wasn&#x27;t sure I wanted a boosted board when they ran their KickStarter but I sure am ready to buy now.

That was an awesome write-up. Incidentally, these guys have designed the ultimate BattleBot battery pack. Send the enclosure specs to a Ti shop to get a Titanium holder made and we&#x27;re talking serious durability. Almost perfect sweet spot of power capacity too.

Very sexy build photos!! I asked on their post, but I&#x27;ll ask here too: &quot;How about LiFePO4 batteries instead?&quot; They&#x27;re slightly lower energy density, but much safer that LiPoly. It&#x27;s the type of batteries we preferred for big robots...

I love the effort that they are putting into the battery, but wouldn&#x27;t it be better to cut costs and bring the price down to compete with zboard?<p><a href="http://www.zboardshop.com/" rel="nofollow">http:&#x2F;&#x2F;www.zboardshop.com&#x2F;</a>

Unrelated to the battery issue: how does the rider control the throttle and braking?

This is pretty sweet. Remote is Bluetooth Low Energy?<p>Would be amazing to control with the Myo. :D<p>(<a href="https://www.thalmic.com/en/myo/" rel="nofollow">https:&#x2F;&#x2F;www.thalmic.com&#x2F;en&#x2F;myo&#x2F;</a>)

I&#x27;m surprised &amp; impressed by the power goals. That board, at &quot;thousands of watts&quot;, delivers at least 3hp peak. I&#x27;ve ridden old heavy motorcycles with less.

If RC Monster trucks can have replaceable battery packs, I imagine board vibration more than moisture has to be pretty severe to warrant permanent connections.

I think I read about this in Snow Crash.

The &quot;power&quot; claims for AA and 9V don&#x27;t seem right. A 9V has the same current draw as as AA?

Electric bikes have been using lifepo4 for years now.<p>My pack is nearly 5 years old.

Let&#x27;s hope they don&#x27;t run over any &quot;large metallic objects.&quot;