Gallium Nitride (GaN) Charger for Esk8

Hey guys, so I’m in touch with Transphorm through an OEM who makes chargers for laptops, and I’ve asked them the max power their GaN-fet might be able to handle. A week later that OEM they’re working with told me that they could potentially make a 9000W charger, and obviously, anything under gets easier and easier.

Gallium Nitride chargers for laptops are typically at least half as much in volume when compared to their Silicon Carbide counterparts (the vast majority of chargers out there today, including for esk8) due to their energy conversion efficiency. In laymen’s speaking, SiC are typically around 80% efficient and GaN are 95%. This means you get less heat, which allows for less heat-dissipation area, which allows for less volume. If you apply the same to our current heavy and bulky esk8 chargers, you’ll see where I’m going with this: either make existing chargers more portable; or even get faster chargers while having the same volume as our current ones.

Some of you may know that I’m also looking into getting quality battery packs made for DIY manufactured for less labour cost compared to manual assembly by having them made in fully automated battery pack factories, using A grade Moli P42a, and that cell supports 2C charging, which is about 40 minutes for a full charge from zero. Having fast chargers working with the packs in combo might make our lives much easier. Just imagine your 12s4p board gets 85% of its juice back in a short coffee break, the implementation of both these techs will do wonders for group rides.

As of right now, I asked them to develop 3 different wattage levels for different riders:

  • 250W 12s 5A charger that will come with a universal port adaptor, this will mainly target riders who own production boards that are made using cheap ass cells which can’t handle too much current. Even the very few who are using Moli or Samsung power cells have their charge port and BMS built cheaply, which makes even these “premium” production boards incapable of handling high current charging.
  • 600W 12s 12A charger that most of the DIY community can integrate easily into their builds
  • 1500W 12s 30A charger that is designed for 12s4p P42A fast charging.

It would be awesome if you guys let me know whether you are interested in these chargers, which one interests you the most, and if you want even faster chargers or chargers in 13s/16s/18s

They will work on both 110v and 220v, although technically a 110v 12A charger is safe enough to work at 15A when using a 220v network.

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we need an user adjustable one, from 3s to 20s, and at least 20a at max voltage

also, get on with ur battery pack progress first instead of starting new one

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So 1680W adjustable voltage adjustable amperage

Chill man, rome wasn’t built in a day. I’ve done as much as I could possibly do at this stage for the pack projects, it’s just a waiting game now. It’s not like I’m charging (or ever will be charging) for pre-ordering, so y’all really shouldn’t be more worried about the progress than I should.

If you really want the packs done maybe you could just come over here to Shenzhen and help me, eh? It’s literally right next to HK xD

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more like 1900~2000w adjustable when u factor in all the efficiency and headroom

people who built rome wasnt’ juggling 6 projects at once

i can’t even if i want to

I’d love a compact GaN charger. Here are a few things I’d like to see if you are designing one:

  • 10s, 12s, 18s and 20s are probably the most common voltages, but you could compile data from the “DIY Build” category to see the actual numbers.
  • Adjustable voltage and current pots. Ideally this would adjust from 10s/12s and 18s/20s so one or two chargers could work with a bunch of different boards. Also you’d be able to deliberately undercharge to extend cycle life if you battery was large enough that it covered your normal range anyway.
  • In the US, outlets are usually 120v 15a, so you’d just have to be careful that the input current draw (and inrush) isn’t going to trip a breaker at the ~1500w level.

Also I think the benefit of a GaN charger is that it’s so light weight you can carry it with you to charge along the route. I don’t think people want to lug around a heavy 1500w charger, but would rather have that at home, and then the size/weight doesn’t really matter.

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I have, GaN is efficient enough. After 85% charged you’re gonna be slow charging anyways.

That’s why I tossed the other 4 and is now working on these two tirelessly.

Was just kidding lol, I’ll get you some samples to test though since you’re one of the physically closer located & trusted forum members

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i wasn’t exactly thinking of just charging one board at a time

we at least need to see evidence to start believing

i appreciate u think that highly of me, but there are others who are experts in this esk8 scene than me. they should be the one u target first. im just a mere random dude building slow speed skateboard illegally in where i live

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Sounds cool, if you can get 12s10a smaller than a radium charger that would be pretty sick. Carrying the heavy charger all of carve this weekend took a toll on my shoulders lol

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I’m going with 12s to start because as far as I know that’s what most people go for. One of the goals of creating this thread was to see if there are enough people on alternative voltage systems that doing a different voltage/adjustable charger is worth it. Charger manufacturing is not exactly kids games, stocking microchips becomes exponetially harder the less chips you order at a time, the lowest volume each batch I can manufacture these in is 500, so if I make a 18s/20s charger and I sell like 12 in a month, that’s just not feasible in terms of capital flow.

That was one of my concerns. Seems like 1500W is the max I should go for then?

We’re on the same page here. I hate how you don’t need fast charge at home, therefore you can use a slower charger which is PORTABLE, and how you need fast charge outside but fast chargers are NOT portable. A GaN charger seems to solve this issue perfectly and that’s why I think it’s worth investing my time and energy into.

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I wouldn’t put that much amperage for most production boards. The typical 5.5mm jack is not known to carry that much without melting.

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That was one of the jacks I used for testing, it was solid.

I’ll compile a list of production boards that I’ve done testing with on the site when I have them for sale.

:arrow_up:

Came to say this.

Reduce the weight of our bag we carry. Also 10S, 12S, 18S with Amass XT30 plug on the end

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You sure that can handle 20 Amps+ ?

Some 5.5 x 2.1 can be solid. But many get rather hot at 4A. It depends on the specific jack and the plug. Over 4 - 5A I would avoid.

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Nope, but it should be good to 30A continuous, I THINK. (You should test it)

Amass seems to name their connectors according to their continuous rating, and then puts out nonsense “CYA” datasheets.

CYA = Cover Your Ass, aka “don’t sue me, I told you not to do it”

There’s a lot of variations with the particular jack, case in point:

The connector compendium also lists a version that is limited to 2A

I’d rather play it safe when you’re catering to the less educated masses than fly too close to the sun and get a bunch of angry emails from customers who had substandard jacks or shoddy soldering from some companies and melted their jack with your charger.

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yup, that’s why I’m gonna make this list

Still a risk though IMO, what if the manufacturer stealth changes a component for cost savings measures after you tested it? What if QC misses a poor solder joint on a run of boards? Neither of these would really be covered by a list of tested products, and they can happen quite often, especially stealth changes. Heck Wowgo once completely changed an entire battery pack in the lineup without anyone knowing for a few months.

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fair point. I’ll address this clearly.

At the end of the day, I’m just trying to provide better tech that improves the esk8 experience. A smaller charger that charges faster is definitely something that adds points to the user experience.

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