Installing a USB Socket on eBike 52V Battery

[portals]

I have decided that for longer rides I'd like USB charging on my ebike, no socket on my battery.

Battery is a 52V 17.5Ah LG 14S6P so it has plenty of juice.

Whilst I am reasonably competent with electronics and soldering I don't want to mess with the battery or controller or display to take a feed, I want this to be a complete ADD-ON solution that can be removed easily when I know it won't be required.

So this is what I've come up with, all comments welcome.

My battery cradle has female XT60 connector so I plan to add a splitter plug to this so I then have TWO female XT60s available, one for the controller and a spare for USB socket implementation. Second XT60 cable 52V (max 58.8V) goes to buck converter, buck 12V output goes to USB input. I will 3D print a small project box to protect it and probably velcro it to frame when using it, easily removed when I won't need it.

So I plan on buying:

Or is there an easier / cheaper way?

1 x XT60 Parallel Adapter Splitter

Pardon our interruption...

1 x XT60 Male / Female Connector 10CM Silicone Wire Cable 14 AWG

Pardon our interruption...

1 x DC-DC Step Down Buck Converter (15-72v) 24V 36V 48V 60V to 12V 5A 60W Output

DC-DC Step Down Buck Converter (15-72v) 24V 36V 48V 60V to 12V 5A 60W Output

15-72v to 12v 5A buck converter. Features: Dimensions: 58 x 40.5 x 22mm Weight: 88g Input voltage :DC 15-72V Output Voltage: DC 12V Output Current: 5A MAX Output Power:60W Output ripple: 40mV Item Material: Epoxy potting, seismic, moisture, dust, long term stable and reliable quality...

torquetech.co.uk

1 x 12V USB quick charging port
Ultimateaddons Dual USB Charger - Handlebar Mount

https://www.amazon.co.uk/Ultimateaddons-Handlebar-Hardwire-Charger-attachment/dp/B07SNDXYDT

Leaning towards this one as mount is narrow and not lot real estate left on my handlebars and it's pretty small, a lot of them are bulky.

 

[Wayners]

I'm going to run lights and charge phone off either a power bank or one of my power tool batteries with clip on USB adaptor. I have all that already.
I've also had fun with a tp4056 module. You could make your own power bank up with that and print case.
Re buck. They do get hot when lowering voltage.

I'm not helping with your question, although I'd want to add a short circuit protection to your add on. If you get trouble you don't want to brick the bike system.

 

[portals]

I have a few USB power banks that aren't too heavy but again it's something else to carry/lose and I want to travel light as possible.

Also have a few power tool batteries however they are heavy and again something else to carry and adding significantly to weight of backpack.

It seems a waste to have £500 battery that only gets used to power the bike, I will be getting an inverter shortly for when we go camping (with car not ebike), but that's for another day.

I'll need to have a think re best way to ensure I can't damage the battery or possibly the controller if the buck converter shorted out, if USB charger port shorted then buck should detect this. A Schottky diode (much smaller forward voltage drop), inline on the wire from battery XT60 cable to buck should protect everything?

Or a diode in parallel?

Any thoughts appreciated

 

[jimriley]

I bought a usb socket gubbins which has the voltage control within it. No need for a separate buck converter. I did have to fit a handlebar mount extension bar or whatever they are called. I have sit up and beg handlebars with bends, so no other way. There are several ebike dual usb on ebay, one with a switch.

 

[Bikes4two]

Schottky diode (much smaller forward voltage drop), inline on the wire from battery XT60 cable to buck should protect everything?

I'm liking your ideas - lots of minor permutations on your aproach including the idea of a combined USB charging port that can take upto an 80v DC input (example ebay link HERE).

An alternative to a Schottky diode might be an 'Ideal Diode' - even lower voltage drop but a bit more complicated to mount/box in but with a 3D printer that will be achievable.

 

[saneagle]

I'm liking your ideas - lots of minor permutations on your aproach including the idea of a combined USB charging port that can take upto an 80v DC input (example ebay link HERE).

An alternative to a Schottky diode might be an 'Ideal Diode' - even lower voltage drop but a bit more complicated to mount/box in but with a 3D printer that will be achievable.

You should use an isolated one. There are all sorts of different ones for you to choose from on Ebay and Amazon, but make sure it has enough smoothing.

DC-DC 28-120V to 5V 1A Isolated Step-Down Buck Converter Power Supply USB Module | eBay

Find many great new & used options and get the best deals for DC-DC 28-120V to 5V 1A Isolated Step-Down Buck Converter Power Supply USB Module at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[portals]

Thanks for all the replies and suggestions!

I bought a usb socket gubbins which has the voltage control within it. No need for a separate buck converter. I did have to fit a handlebar mount extension bar or whatever they are called. I have sit up and beg handlebars with bends, so no other way. There are several ebike dual usb on ebay, one with a switch.

Despite a lot of searching I never came across a USB socket with the buck electronics enclosed, very nice, thank you!

This one cost under £7 and looks like a candidate:
https://www.ebay.co.uk/itm/234581807101?hash=item369e2a4ffd:g:ABkAAOSwWf1inzBZ&amdata=enc:AQAIAAAA4IixLOLO+UxKoKdJ87b7t4Fxb5wyg1u8vPefckzaDOzVXe6Ma4zaFCUdMLqOhjmuSFMjbsncdwA2Vt5Axh0LPT8jqFBzLd1LYfMmcrotcvt64OuioJfqQkgxsvbV3v691gqPVJV/1JvFW+/fhVljy0Ia7j0kq3wv3wdpBuIiHWNYkPsDSJgBa1Qzns9MkesTl6OddvzGW5G3xXeORypwQ6lTuRFNJcw1buQZfeM8Vy4mA02ftQqYrTAhsqj+y5lhjPu/sxSD3/3NCBk3x7jgMZmbPEuY/xmATD6rQ holder KquysXO%7Ctkp%3ABFBMguOclZRi

It claims it provides protection against overload, overvoltage, overcurrent, overheat and short circuit - so no diode required but will probably put one in anyway..

Just need a way to fasten it, maybe a custom 3D printed holder similar to the KTLCD8 holder I printed after it snapped, or maybe glue velcro strip on to barrel then it's just a matter of plugging/unplugging the XT60 connector ;-)

 

[portals]

Found and going to try this USB kit for £7:

Pardon our interruption...

Will replace the crocodile clips with XT60 connector and adjust cable length, sorted!

 

[saneagle]

Found and going to try this USB kit for £7:

Pardon our interruption...

Will replace the crocodile clips with XT60 connector and adjust cable length, sorted!

Didn't you see what I wrote. I hope you don't want to plug in an expensive phone or GPS, but it's your choice!

 

[portals]

Didn't you see what I wrote. I hope you don't want to plug in an expensive phone or GPS, but it's your choice!

I get the idea of using an isolated buck with separate grounds however that means a small project box. more wiring and larger footprint etc.

Using the USB link above with a Schottky diode between XT60 and base USB connector will essentially give same protection - I don't want to over-engineer something as simple as a USB charge point this so that seems simplest solution?

It will not be required very often and given small current draw I'm not too worried.

Appreciate the comments, thanks

 

[lenny]

 

[AntonyC]

I like your first idea much better, the cheap one isn't water resistant, has unprotected wiring etc. Fuses can compromise as much as protect. Stuff that shorts often fuses itself - cable damage is more of a risk.

You need a blanking plug for the second XT60 socket when it's not in use. The wire from XT60 to buck converter needs to be well sheathed, secured to the bike and stagger the joints. Keep that short and extend the buck to USB wiring as needed, much safer. These are more weatherproof than printed boxes:

Pardon our interruption...

Phones have recessed sockets so non-isolated USB should be OK with these two lots of smoothing... no?

 

[portals]

Well I went with the less hassle second option as it's minimal work to install (soldering two wires), and no 3D printing etc. required

Parts arrived from ebay (approx £15 total), wired it up today and it's working great.

The big black plug socket is a little unnecessary size wise and was a little worried that the USB port that plugs in to it would get hot, it does get quite hot (it's taking 52V), but I've been monitoring it and it's not any hotter than my Samsung quick charger gets.

It claims to have over voltage, over current, over temperature and, short circuit protection and appears to quick charge the phone so we'll see.

I can remove the harness from the bike in about 15secs, just need to unplug the XT60 cable.

Going to get a small velcro pad to keep the usb socket stable on top of battery so as not to stress any wiring.

I'll report back after been using it for a while, seems like a cheap and easy solution to add 2 usb ports to your ebike without messing with any of the kit wiring.


Harness soldered up and shrink wrapped:



Mounted on bike:




I don't think it's waterproof so in the event of rain I will stash it in the controller bag out of the way,

 

[Bikes4two]

Nice one @portals - let us know how it all works out.

And a bit off topic, but I like the look of that particular frame bag - do you still have a link or other reference to point of purchase?

Thanks.

 

[portals]

Thanks.

I hunted high and low for a frame bag that size for months that wouldn't take the face off the bike, the one that came with kit was just too small for the 17.5/35A controller and all the spare cabling, this one is almost perfect and so far would recommend!

Link:

https://www.amazon.co.uk/dp/B07KCP18C8?psc=1&ref=ppx_yo2ov_dt_b_product_details

 

[portals]

 

[portals]

You can pack a lot in it, even with with pic below I still have maybe 1inch height of space the length of the bag at top so the USB charger socket fits in easily if you want to carry it all the time.