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Kevin Graehl

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About Kevin Graehl

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  1. So next stage is making getting some alum boxes with built in heat sinks ordered and thermally conducting the boards to them.. 87 watts in from usb -c 20 volts... 75 watts makes it into battery. Ill lay some of the large caps down and maybe the inductor.. It fits in my pocket.. Thats all I wanted. I can make smaller ones that need less the 84 volts, DC cigarette lighter plug. With our without Volt heads up displays. I'm doing nothing special.. Its just been about ordering the right parts.. From alot of private messages, it seems like alot of you just want a car charger, Super easy . I'm not trying to make money off anything.. just looking to spread my obsession with killing the huge brick power supply from my backpack and have a portable charger i can fit in my pocket that will work anywhere.. I can make something half the size for a 54 volt charging bank such as the boosted board, or give you links to amazon 2 day shipping or aliexpress . Next project is to attempt to fit it all inside the EUC itself.. I'll definitely have to move some components around on the board and make a custom head sink for the high frequency chips that put off 15 watts of heat at full charge
  2. id really like to see a side photo before and after.. ANYBODY
  3. Lots of questions. . Just off the car,, its super simple and an amazon purchase away-- 30 bucks for a regulated one.. https://www.amazon.com/gp/product/B01GFVI6R6/ref=ppx_od_dt_b_detailpages00?ie=UTF8&psc=1 this will regulate the voltage .. You need to put it in a box of some type.. make it out of cardboard and put some vents for the air fan.. I'm going to source some tips and buy some bulk 10amp cigarette lighter tips and make you guys some for the 75 dollar out the door with shipping mark, with a proper enclosure . Below is the 4 amps, 20 volts in for usbc.. 84 volt step up.... and the multimeter is reading .75 amps @84 volts.. Efficiency is 87 watts in, 63 watts out =79% But a DC boost convertor has a bit more work to do if your pulling from a 12 volt source--- 13.8 when charging will be better with car running.. Ill hook it up to my power supply and run some tests.. I sourced a few smaller convertors from aliexpress and amazon.. testing them out right now... The usb-c was just a hard on I had to reduce the amount of brick power supplies I have laying around in the house For anyone who wants a lower voltage-- there are tiny options--- for bosch bikes/ skateboards.. a bunch of boosted board charging tips arrived for me to play with.. I need to go out and buy a boosted board battery to play around with. Kevingraehl@fb.com 415 341 2281 I you have any immediate questions..
  4. Ok usc-c prototype is working. Power in is a usb-c from MacBook/ Chromebook. Or from cigarette lighter 12volt car.. output is adjustable to charge anything from 14volts to 90 volts up to 200 watts off car or 90 watts off MacBook usbc (thunderbolt 3)..... To charge your boosted board, onewheel, solowheel, electric bike, or whatever you want. When I'm done and get some smaller boost circuits ordered, it will all fit in your shirt pocket. Just a 4" cord to fit your specific electric last mile device. Great for sleepovers where you forget your huge charger, or borrow someone's charger at Starbucks, or charge at work. USB-c is maxed out at 100 watts. Pretty nifty. Any suggestions? https://youtu.be/th8OX4M7-os