Beta testers wanted: USB eBike charger

SamIsHere

New Member
Joined
Feb 12, 2026
Messages
4
Reaction score
3
Hi everyone

I’m building a compact USB-C eBike charger that lets you charge your eBike battery from a standard USB-C PD wall adapter (the same kind phones and laptops use).
I’m looking for a small group of test users to try it in real-world conditions and give feedback before I finalize the design.

What is it?

This is an attempt to make a slim and lightweight charging solution so that you can charge anywhere you are. The final size is going to be around 70x70x30 mm which is smaller than you phone.

You can use any USB-C adapter. It is able to use any phone adapter (~65W) to the strongest and newest bricks that are capable of 240W.

You can charge any battery pack up to 60 V. The output connector is an XT60, and I will provide adapter cables to the most popular battery connectors (ST3, XLR, Anderson, DC barrel jack).

At the end of the post I attached a few AI renders of how the charger will look like, just so that you get a general feeling.

What I'm testing

- Compatibility across common USB-C PD adapters and cables

- Real-world charging behavior (heat, stability)

- Usability: connector placement, cable strain relief, enclosure, indicators, etc.

Who I'm looking for

- You have a battery that charges via XT60, ST3, XLR, Anderson, DC barrel jack,...

- You can do a few test charge session and share notes/photos/comments

What you get

- I will send out the test prototypes without profit, this means that you cover only the material costs + shipping. Estimated material costs are around 50 €. I ship from Slovenia, EU.

- Your feedback will shape the final product and i'll credit the testers if you want.

- I expect to have the test prototypes ready within 6 months, if I fail you get your money back.

How it works

Before I ship the charger I will program it to your battery voltage. After that the charger is plug-and-play, no config, no app.

You use any USB-C wall adapter to power it and it will charge the connected battery to the programmed voltage.

Interested?

Reply here or DM me with:
  1. Your battery info (voltage 36V/48V, charging connector picture or type if you know it)
  2. Your location (for shipping estimate)
  3. Any questions you might have.

Charger in use.webp


Charger USB-C XT60 side.webp


Charger USB-C side.webp
 
⚡ EMTB Pro Go Pro — Living Intelligence Reports, exclusive discounts & ad-free Up to 25% off Peaty's, PEMBREE, Magicshine & more · Ad-free browsing · Pro badge See the deals →
Virtually all the major brands have dedicated CAN protocols sent on the charging circuit before the battery will begin to charge. Have you sorted this out as there will be few here on this site that have custom batteries that don't need CAN activation ?
 
You want people to pay for an untested, battery related product? Product testing for battery chargers should be in a controlled, safe environment, not a living room. You are asking people to pay money to test your product.
Good luck…………..
I second this.
This thing did not go through certification.
So if my house burns down, the insurance can reject me for gross neglect.
 
Take out a patent like everyone else does. Then secure investors so you can get your device certified.
 
I will gladly test your device. I will need 10,000 USD up front for the initial testing period of one month. Upon the first failure of device, the testing period will automatically end. The price of subsequent testing can be negotiated at later date. Also required will be the public disclosure of your name, address, and contact information, including phone number and email address.
 
Last edited:
Hi Sam. You are not going to be able to interface with the factory EMTB batteries. Nearly all EMTB batteries have a communication link to charge them. And even if you replicate this. What are the warranty implications of using a 3rd party charger ?

So a USB to 240VAC inverter, that we can plug our factory chargers into, would be better. I currently use a 12V to 240V inverter in my car, or my EcoFlow, when I don't have powerpoint access to charge my bike.

Secondly. There is zero guarantee that if someone sends you money, they will receive anything. So as you are asking us to help you. Anyone looking at this offer must insist the product is shipped, delivered and tested first, before you are reimbursed.

Thirdly : As stated above. Your device must be certified before anyone should consider using it.

Fourthly : This could just be a scam.

Best of Luck to anyone getting involved. Don't say you weren't warned.
 
Fourthly : This could just be a scam.
Those images look dodgy to me. Very artificially posed. Three black output wires that seem to blend into one. The USB port on the larger image doesn't correspond in size, shape or placement to the one on the first image, and the screw heads are blurred. AI generated?
 
AI is getting better and better every month but still ain't perfect.

IMG_1107.webp
 
AI generated?

I don't think the images do his pitch any harm as he did say he used AI for the images. His post has not been edited. But there are too many other issues, that remain unanswered, IMO.

There have been many a genuine entrepreneur who have raised money, but failed to produce a legitimate, useable product. This would be my main concern. But yes. Scam is also an option.
 
Hi everyone

I’m building a compact USB-C eBike charger that lets you charge your eBike battery from a standard USB-C PD wall adapter (the same kind phones and laptops use).
I’m looking for a small group of test users to try it in real-world conditions and give feedback before I finalize the design.

What is it?

This is an attempt to make a slim and lightweight charging solution so that you can charge anywhere you are. The final size is going to be around 70x70x30 mm which is smaller than you phone.

You can use any USB-C adapter. It is able to use any phone adapter (~65W) to the strongest and newest bricks that are capable of 240W.

You can charge any battery pack up to 60 V. The output connector is an XT60, and I will provide adapter cables to the most popular battery connectors (ST3, XLR, Anderson, DC barrel jack).

At the end of the post I attached a few AI renders of how the charger will look like, just so that you get a general feeling.

What I'm testing

- Compatibility across common USB-C PD adapters and cables

- Real-world charging behavior (heat, stability)

- Usability: connector placement, cable strain relief, enclosure, indicators, etc.

Who I'm looking for

- You have a battery that charges via XT60, ST3, XLR, Anderson, DC barrel jack,...

- You can do a few test charge session and share notes/photos/comments

What you get

- I will send out the test prototypes without profit, this means that you cover only the material costs + shipping. Estimated material costs are around 50 €. I ship from Slovenia, EU.

- Your feedback will shape the final product and i'll credit the testers if you want.

- I expect to have the test prototypes ready within 6 months, if I fail you get your money back.

How it works

Before I ship the charger I will program it to your battery voltage. After that the charger is plug-and-play, no config, no app.

You use any USB-C wall adapter to power it and it will charge the connected battery to the programmed voltage.

Interested?

Reply here or DM me with:
  1. Your battery info (voltage 36V/48V, charging connector picture or type if you know it)
  2. Your location (for shipping estimate)
  3. Any questions you might have.

View attachment 177641

View attachment 177642

View attachment 177643
Which batteries actually work with this device? It doesnt look like it will connect to any of the popular emtb batteries?
 
Aside from some of the comments above, I‘m not sure what the real-world benefit of this is.

I still need a wall socket or other source. Then a USB-C charger plus this box and the cabling to the bike/battery - all of that vs. the charger that came with the bike. Is that delta enough? All of the other possible ‚travel lighter’ scenarios (sponging from others, sharing with laptop) appear to only offer a small advantage, perhaps with the caveat of slower charging?

What am I missing?
 
Who I'm looking for

- You have a battery that charges via XT60, ST3, XLR, Anderson, DC barrel jack,...

It doesnt look like it will connect to any of the popular emtb batteries?

Yeah. I made the same comment as Rob. He lists the connectors in the post. None of which are used by the modern factory EMTBs.
 
Last edited:
Which batteries actually work with this device?
You are using the wrong tense in your question Rob! The device does not actually currently exist, which is why there are only AI generated images of what it might look like when/if it's built.

The title of the thread is "Beta testers wanted" which is highly misleading, especially for those with a low attention span 😁 who don't pick up on all the points of detail. It gives the impression that a device has been built and already undergone initial functional testing by the OP, whereas in fact (if you attend to all the points of detail) the initial prototypes won't be ready for an estimated 6 months.

I don't want to criticise the idea of the device itself (others have already done this), but I do think the OP should seriously rethink how he wishes to frame his proposition. Good luck with that!
 
AI is getting better and better every month but still ain't perfect.
It makes some freaky mistakes sometimes .. I was watching this video and noticed an anomaly ..

1771515914048.webp

Either that or I now know why some people find these things way easier than me, must be a bitch buying shorts and trousers.
 
You are using the wrong tense in your question Rob! The device does not actually currently exist, which is why there are only AI generated images of what it might look like when/if it's built.

The title of the thread is "Beta testers wanted" which is highly misleading, especially for those with a low attention span 😁 who don't pick up on all the points of detail. It gives the impression that a device has been built and already undergone initial functional testing by the OP, whereas in fact (if you attend to all the points of detail) the initial prototypes won't be ready for an estimated 6 months.

I don't want to criticise the idea of the device itself (others have already done this), but I do think the OP should seriously rethink how he wishes to frame his proposition. Good luck with that!
I actually tried a product similar to his a while ago but it wasnt USB-C

It was a right pain in the arse to remember all the bits you needed to take with you. Unless you're doing on some kind of minamalist adventure where you only have pockets to carry stuff Im not even sure theres a valid use case for this product.
 
has anyone charged a 5000 mah battery with a USB c wall charger? I have it takes about 8 hours.
So to charge my 840wah or ……227,000 mah ebike battery would take 363 hours……
That’s just the off the top of my head maths…..
When you have an idea. Dont just throw it up on a forum. Invest months and dollars.
Forums will not be friendly to dangerous, possibly fraudulent requests.
 
I guess the ideal scenario is that bikes come with a bi-directional USB-C port, so you can plug in your phone or whatever, but if you end up out and about somewhere without your charger, you could at least top up the battery a bit with a USB-C cable.

Like if you de-toured and ended up staying over at a mates, you could at least charge it back up over night.

Taking some weird box and cables is going to be similar to taking your charger and cable.
 
has anyone charged a 5000 mah battery with a USB c wall charger? I have it takes about 8 hours.
So to charge my 840wah or ……227,000 mah ebike battery would take 363 hours……
That’s just the off the top of my head maths…..
When you have an idea. Dont just throw it up on a forum. Invest months and dollars.
Forums will not be friendly to dangerous, possibly fraudulent requests.
That will depend on your USB C charger. Reasonable spec ones would be :

1771517865416.webp


So in theory, you could charge an 800wh battery with the EPR charger in just over 3 hours, except you'd probably melt the cable - so you'd be stuck to a 100w charger and at least 8 hours.
 
That will depend on your USB C charger. Reasonable spec ones would be :

View attachment 177698

So in theory, you could charge an 800wh battery with the EPR charger in just over 3 hours, except you'd probably melt the cable - so you'd be stuck to a 100w charger and at least 8 hours.
ok sure I agree
but charging in 8 hours would break the laws of physics.
12 hours minimum, plus a TON of heat to deal with.
 
AI is getting better and better every month but still ain't perfect.

While AI is getting smarter and smarter, it seems that humans are getting stupider and stupider. And other humans are becoming sneakier and more devious.
 
While AI is getting smarter and smarter, it seems that humans are getting stupider and stupider. And other humans are becoming sneakier and more devious.
Welcome to the twentieth century.
 
Most manufactures of EMTB batteries monitor battery conditions when charging to prevent battery damage. They automatically alter the charging rate etc to current conditions like temperature. They wrote software to the main processor in the bike to insure safety and reliability in battery charging. My guess is, one of those safeties is to prevent 3rd party charging devices from charging their battery or worse, burning someone’s house down.

I think the last business venture I would want to dip my toes into is charging LI batteries by multiple manufacturers. Seems like a VERY risky business venture.
 
Keep reading
    Browse all

    Similar Threads

    Community Stats

    Since 2018
    671K
    Messages
    41,219
    Members
    Join 30,000+ Riders, it's free!
    Back
    Top