Usb pd 3.1

[Ianhill]

Seems usb c pd has got to the point it could be used as a charging standard for most small use cases.

48v 5a max 53.65v programable in steps of 100mv with 3a and 5a current outputs meaning it could chsrge the average 650wh pack from empty in under 3 hours.

While being extremely compact and of the highest efficency possible to date with gan fets.

Ive used the 20v 65w version to power an rc charger for light weight tasks and extremely pleased how well it works next up would be take it a step further and make the ultimate travel battery charge quickly anywhere there a 3 pin with plug and play cabability.

Im on the look out for development boards to test ideally i need a compact 12s bms with monitoring leds to complete the picture.

 

[SamIsHere]

Did you ever manage to make USB-C charging for your eBike?

 

[Ianhill]

So i never used it for an ebike i stopped riding past few years local police killed the vibe but i did implement it into my steering wheel and pedals for the ps5 just purely as a psu.

Have you got any ideas or needs for usb power delivery im more than happy to try help.

 

[SamIsHere]

I already made an adapter that allows me to charge my DIY battery pack using any USB-C charger up to 240W. What I am struggling at the moment is figuring out how to make this adapter usable for as many ebike models as possible. I am relatively new to the eBike space and all of the experience I have is from DIY, not from commercial products.

When you had the idea to make USB-C charging for you eBike what kind of a connector did you plan to use to connect to the battery?

 

[Ianhill]

I was going to stick with usb c to simplify an see how it performed, i take it your using a buck boost maybe to be able to use and usb c ?

My plan was to go direct from usb trigger board to bms 20v 5a is becoming widely available with gan fets and like you mentioned newer standards allow for 48v 240w i believe or a 12s pack.

Slow charge over night ( in a safe location out of house been well aware fires happen) could give around 2kw or so with 9 hours rest time would allow for a decent range bike

Ill have a poke about and see what new trigger boards exist if you have any links pop them up as its still of interest to me as id like to make a portable speaker from a sony karaoke unit.

Have to excuse me a bit I've become rusty over the years no longer ear to the ground in the same way.

 

[Ianhill]

Looks like things have come along a fair bit as when i started this thread 5 years ago 240w was just on paper there was no charger or trigger board available.

But looks like your in luck as standards change in the past year or so a usb 3.1 pd psu has become available (KFD 240W USB C PD3.1 Charger)

48v/5a trigger board
chargerlab power-z sink240

And usb 3.1 pd epr rated cables from silkland.

Greatscott has a video too explaining the fixed voltage outputs and using AVS to regulate voltage and current to become a direct battery charger to increase overall system efficency with no losses from a external buck boost/ charge controller setup.

 

[Ianhill]

So to use this set up on multiple differing ebike voltages would be difficult, from what i can tell the controller uses a switch on gpio pins to initiate different voltages but to engage AVS (adjustable voltage supply) the chip uses i2c commands i believe that need to be input from a script on a esp32 or simular and the vendor says AVS is not working on the ad so could take some serious technical back and for to even get it to work if at all.

To be able to swap from battery to battery it would have to be within 28v to 48v i think set by the usb 3.1 standard and have the ability to have multiple script profiles to swap between and thats were negligence and complacency could charge a battery with wrong setting hoping the bms catches it and shutsdown the battery charge.

So for me id only ever uses it for the max setting of 48v 12s or just one profile for 36v etc and hope it never loses memory etc plus the usb psu has 240w through a usb connector that screams rtx5090 power connector, ive had a barrel connector melt on me with age so i see any heavy use with water and dirt would soon end the ability to charge likely when needed the most.

So can this setup charge an ebike ? Yes
Is it really practical ? No

Whats the pros ? Its compact and efficent with gan fets and using I2C it could save on a charge controller all together for low power esp 32.

Whats the cons ? Extremely cheap alternatives that are a little larger and more powerful too with a variety of connection methods outside of expensive 48v/5a compatable usb leads that tend not to be that flexible and in turn quite fragile.

I'm i still interested yes .

 

[SamIsHere]

I am happy to hear this.
I am planning to have the first prototypes for testing ready somewhere within 6 months, depending on how much interest there will be from people.

i take it your using a buck boost maybe to be able to use and usb c ?

Yes, I have a USB-C trigger IC that negotiates the highest voltage the used USB-C charger can source, and then I have a buck-boost DCDC converter to charge the battery in CC/CV fashion.

What kind of a connector do you have on your eBike battery?
Do you have a DIY bike or a commercial one?

 

[Ianhill]

Ive got a ebox dragster last year i used for an event other than that I've been using pedal bikes in urban areas my legs are plenty for all i need.

I did like to cruise the mountians on differing rides but the police are on a rampage mission to crush any offroading diy ebikes etc so my road licence would be the one that gets the points or ban and i cannot afford to lose it.

Connection wise theres loads of choices, Rc hobby offers alot of high power connectors but at 48v 240w even an xt60 would be overkill but it does mean theres the ability to age and wear and still work fine while usb i dont see it working well offroad without concealment.

The most important part is to ensure the charge cable is silicone based with a high strand count so its flexibility is good that way it's easy to roll up store in a bag take on a ride with charger.

The handshake between charger is the problem diy ebike chargers in this regard just work they rely on the bms being the safe guard alone theres zero communication between them simplifying.

I used a chargery c10325 been in the cupboard a while now but adjustable voltage and current 24s 25amp or 1500w output fitted in a backpack.

 

[SamIsHere]

Ok, thanks for letting me know this.

I am thinking of using an XT30 connector on the output of my charger. I think that should be good enough since the maximum charging current will probably never exceed 15A.

Here is a sketch of how I imagined this charger to work. The user uses any USB-C wall adapter they have, they connect it to my charger which has an XT30 output and then they connect this to their bike battery. I am still unsure what are the most common connector types on ebike batteries. Do you have an idea?

 

[Ianhill]

Most lower power diy ebike batterys use a rip off of a xlr barrel jack connector for charging but as for commercial grade ebike batterys the chargers handshake the battery bms so pushing voltage at them wont charge until its seen a command of some sort.

 

[SamIsHere]

Yes, I realized that aswell. I am planning to make the charger compatible with those battery packs that have simple connectors (ST3, XLR, XT60, Anderson, Barrel jack). Maybe sometime in the future I will have enought time to revere-engineer the handshake for proprietary chargers.