Modern Vespa

(updated, its actually ~13.2 volts idle and ~14.1 volts motor running)

Update: see thread; ended up running a new wire from the battery. This went through a relay that used the old USB circuit as a positive trigger for a relay. This ensured the 12V socket was fully off when the ignition was off and had available 12V at up to 10amp power availabe.


Is it safe to tap into the headlights circuit to provide power to a phone charger? Are there recommendations on how to go about tapping into it?

The headlight circuit is linked to the ignition key and is only active when the motor is running. This makes it an ideal source both for greater available power and significantly reduced risk of parasitic draw draining the battery.

The existing wiring for the original glove-box USB only puts out a maximum of 14 Watts of power (14.1V at 1 amp). My phone-app reports only ~11 Watts maximum (14.1v at .806 amp real) actually makes it to my phone. This was fine for my old phone; but is just barely enough to trickle charge the new phone. The new phone requires around 25 Watts to stay charged while in active use (Navigation, music, ride-info, etc). This is not ideal for longer trips when I want to have the phone active while riding and not drain the battery to nothing.

The older halogen (Xenon?) headlights are reported to be using 55 Watts of power which means 12V at about 4.5 Amp. The OSRAM 67210CW LED bulbs I have installed now use just 14 Watts of power (14V at 1 Amp). That leaves a little more than 41 Watts (14V at ~3 Amp) available for accessories. That fits well within what the 36 Watts (14V at 2.6 amp) that newer USB power plugs can provide. The service manual says the headlights (on fuse 4) are a 15 Amp circuit that goes through a relay to power the headlights. Thats 15 Amp limit total but the combined USB + LED headlights would only add up to about 5 amps maximum.

So this brings it to the question at the start. Is it safe and is there a good way to tap into the headlights circuit? The power-source for the USB must be linked to the ignition to prevent parasitic draw on the battery because I don't trust myself to remember to unplug things when parking the bike. There is the unused circuit for the electric heated leg cover, but this seems unreliable and is linked to a button on the dashboard; not ideal and problematic to use.

12V socket. I used a Dremel to carefully make the old rectangle USB abrade away just enough plastic to make the square old USB cut out round to fit this.
https://www.amazon.com/dp/B09P8G6GKR

The USB 12V plug; the little voltage LED is surprisingly useful on the bike.
https://www.amazon.com/dp/B0946VSWKH?

Run a new wire, direct from the battery and inline fused near that connection, to a relay whose coil is energised by the headlight coming on. That way you're not stressing anything else, and can run as much power as the stator can deliver - about 12A for the 500. Ideal for heated gear (gloves, grips, vests, whatever) as well.

Update: I bought the parts, I'm going to install this and report back with photos.

I found a basic 4 pole relay that if wired up as suggested would mean I don't have to mess with the headlight wires. I do however have to find a good path for the wire to the battery and suitable wires.

https://www.amazon.com/dp/B08D8TSMFV

From the diagram of the product.

The positive red wire circuit from the existing USB can be used as the "positive trigger source". That would make sure the relay is only energized and closed when the key is inserted and turned on.

The high amp red wire positive would come from the battery and from there connect to the positive side of the 12V socket.

The "Device ground" would connect to the negative terminal of the 12V socket.

"Common Ground" would be the former USB socket ground.

Is that correct?

You could also have used a voltage sensing relay. It's connected directly the battery and will "turn on" when the battery is charging. "Turn off" when the battery is not being charged. I have an old one that turns on at 13,7 V and off at 12,5. The better ones have adjustable voltages.

Wow! Thats amazing, I had no idea such a solution existed.

New plan to try this out. I bought this one from Amazon to test this method first due to being much easier to wire up. I'll report back here on how it works

Lithium battery reported as 13.2 at the terminals
Voltage when ignition on but motor stopped: 12.9v ~ 13.1v
Voltage when motor running: 14.0v ~ 14.3v

The manual for this one reports cut-in at 13.3 but comments and reviews report 13.2. So if thing works at the limits set in the manual then it might still be okay if the cut-in is indeed 13.3v otherwise if its lower at 13.2 then it might be "on" while ignition is off and battery is idle. Will test and report back; its a slim margin so a traditional relay might be safer.

This is the only one that says "works with Lithium" which the others do not.
https://www.amazon.com/gp/product/B0B38YQH3Y/

Two other alternatives, these things are a bit more expensive than traditional relays. The reviews are all largely positive but it should be noted that some of the diagrams are incorrect so use your volt-meter to verify and test.

https://www.amazon.com/Isolator-kemimoto-Solenoid-Compatible-Vehicles/dp/B0928GLXQX

https://www.amazon.com/Dual-Battery-Isolator-Waterproof-Compatible/dp/B0CCRQXQNM

https://www.amazon.com/Isolator-Waterproof-Sensitive-Automotive-Mata1/dp/B0BQYH23TC/

https://www.amazon.com/gp/product/B0B38YQH3Y/

Maybe this solution can help, I used it to power my satnav on my bike.

https://www.advrider.com/motorcycle-electrics-why-use-relays/

Mine came from my uncle who used it in his little fishing boat. Back home commercial fishing boats are required to keep separate battery for starting the engine. This would connect the start and winch batteries together for charging when cruising. I just remembered that it was in my CRF when I sold it .

Hello Modern Vespa Mp3 Group.
Following up on the thread for a new power source to keep my phone charged.

I need a peer review of the circuit wiring plan to make sure I do not create a very expensive electrical problem on the bike.
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To prevent battery drain I'm including a relay.
https://www.amazon.com/dp/B08D8TSMFV

I need a peer review of the circuit plan so I do not create a really expensive problem on my bike.
The old USB plug is keyed to the ignition key so will be used to trigger the relay. 12v at 1 Amp

The new 12V plug is like the same socket type in your car and can handle 12V at 3+ Amp.

To prevent parasitic drain on the battery, the goal is to use the old pre-existing USB plug circuit as the "Positive Trigger" for the relay.
In the diagram below.

-----------------------------------------------------------
In the diagram below.

Red line
Connected directly from the battery, through the relay RED input to the BLUE output and into the RED side of the 12V plug.

Green-Red line
Old USB circuit keyed to ignition. The red wire from the old USB will connect to the white wire "Positive Trigger" side of the relay.

Black lines
Common Ground back to the battery. Old USB black wire, Common Ground from Relay, and black wire from the new plug all connect together and back into the black terminal on the battery.

assuming on your mp3 the headlight only works once the engine has been started (like on a vespa gts) ...

could maybe wire your relay trigger to either the trigger of the headlight relay or the power that is switched by the headlight relay so that your higher drain usb is only active after the engine is started.

Maybe, but at this point I'd rather not tap into it. After much reflection and thinking, its allot more wiring and power to be messing with. The legacy USB circuit is already in the right location, linked to the ignition, the USB-plug itself is no longer there so may as well use it as the positive trigger.

That's probably best - it means whatever you have plugged in (GPS, phone, whatever) can be on whenever the ignition is switched on, not just when the engine's running. If you're waiting at a railroad crossing or whatever, this could be fairly important.

I'd hope that your gps or phone has enough battery to handle stopping the engine at a rail crossing 😀

On my gts if i start the engine then hit the kill switch leaving the ignition on then the headlight still works ...

But yeah it's something to think about.

Hi JIMC and SteelBytes

How does the circuit diagram in the post look with the red, black, and "Positive Trigger" look? My understanding of circuits and automotive systems isn't very good so it would be great to have a more knowledgeable mechanic's peer review.

Am I about to destroy my Mp3's electrics the way its wired or is it okay? The device should have plenty of power, but its nice to keep it topped up. In regards to the train crossing... in some parts of the US a freight train can be 5 miles (~8km) long. When the train gets stuck it can block many crossing leading to long detours around the stuck train. Also when stuck in traffic I might switch off my engine to prevent it overheating while idling. Yes there should be laws against trains that long, and there used to be, but thats a different topic and web-forum.

Some (my Garmin Zumo for example) will turn off after 15 seconds if external power is removed - unless you spot this and hit 'cancel'. I never liked that. You could add a relay that only lets power through if the voltage is above 13V. I've never done it, but it is one of those things I'd like to have got around to. But now our LX has a LFP battery there's no real point.

So I put a cable directly on the battery going under the seat, I have a 2 conductor connector that can be attached to a battery minder or to a 12V outlet in case I need it.

As far as my GPS on my 530 I tapped into the back of the switched 12V connector for the heated gloves located under the handlebar plastic. Works perfectly and has way more amperage than needed. My Garmin Zumo XT will shut down if I stop, but pick right back up where it left off when I start up and remove traveling, after having to agree.
That's my setup

I am confused, note: this is normal state of mind for me. Why are you trying to get 12v to the usb port and then convert that back to 5v to charge a phone? Why not just put a buck converter like this one and put the usb port back?

https://www.amazon.com/Female-Converter-Power-Adapter-Module/dp/B0CMT4PM7J/ref=sr_1_2?keywords=Prettyia+8-60V+to+5V+Dual+USB+DC-DC+Waterproof+Power+Module+Voltage+Converter+Power+Supply+Buck+Charger+Adapter+Inverters&qid=1705955519&sr=8-2

Couple of wires to the battery, one in-line fuse and up to 6amps 30 watts when ever you want it. Plenty to charge most phones. Been using one for years on my ebike never had a lick of trouble with it.

Hi Fruitcake
I want it keyed to the ignition so its completely powered-off when the ignition is off so there is no chance of parasitic battery drain.

The 12V is just a standard type plug like you have in the car, often referred to as "cigaret" plug. This allows me to swap out different USB connectors or charger systems without having to redo the wiring.

The motorcycle 12 volt to USB 5 volt conversion isn't really the goal or benefit. The goal is the significantly increased available amperage and higher wattage rating to keep the newer phones topped up. The 12V to 5V conversion only happens when I insert a USB charger plug, otherwise its 12V available to accessories that use the same automotive plug type.

Flexibility is better. I can also power my portable air-pump to the socket in the glovebox for convenience if I need to. I have an old Garmin automotive GPS that only has the 12V plug to get traffic and other info. While an older technology its useful for navigation in areas with bad cellular coverage.

If it was strictly about simplicity I could just get an SAE-Plug to USB adapter and use the under seat cables. But that wouldn't get me where I want to go for flexibility, convenience, significantly increased charging capacity and have it linked to the ignition key.

By documenting everything in this thread (diagrams, power calculations, etc) then future owners can follow along and make their own modifications for the same benefits.

I use a buck converter and the quiescent (standby/no load) current is 10mA, and it can handle 3A. so if you left it connected all the time without starting the engine you would have up to 2 months without flattening the average mp3 battery.

Is the 5vdc enough to trigger the relay?
You may need a 5vdc relay

Hi Garthhh
Its coming in at 12-13 volts at 1amp over the old USB circuit for the "Positive Trigger" of the relay. The old 5V 1 amp USB plug itself is long gone so its just the old wires that used to feed it being re-soldered and connected up as the relay triggers.

Success!

I created the circuit in the earlier post to specification and the relay works exactly as expected. The 12V "cigarette socket" allows me to put in a phone charger, plug in my air-pump, or power my old Garmin GPS Nav (with traffic).

I used "Fish Tape" to pull the power wire through existing wire paths and openings in the Mp3. This was much easier than removing and re-installing all the body plastic panels and the wire followed existing paths.

Power output
* Old: ~11 Watts maximum (13.1v at .806 amp real)
* New: ~35 Watts at (14.1v at 2.5 amps real)

Shopping list for anyone who wants to try this.

12V Car Cigarette Socket. These are fragile, the first socket broke when I over-torqued the retaining nut. The second one worked fine. These have an in-line 10A mini fuze on the red wire which I removed then re-installed at the battery connection. This way if the fuze blows I don't have to remove the windshield and plastic, just access the fuze near the battery for easier fix.
https://www.amazon.com/gp/product/B09P8G6GKR/

* Fish Tape to pull wires (or equivalent a stiff steel wire)
https://www.homedepot.com/p/Klein-Tools-25-ft-Fish-Tape-1-4-in-W-Steel-Blade-56335/312651190

* 18-20 AWG Gauge threaded copper wire, about 3 feet. This is used to bridge connections or extend existing wires. Need 2 colors, Black and Red.

* 12 AWG or better 2 conductor wire for the run between the battery and the relay behind the dashboard. This is the main wire, the other 3 feet black and red is used for splicing or fixing where needed. Joined wires make routing the wire through the frame much easier.
https://www.amazon.com/dp/B0C5R99ZVY

* Automotive Relay
https://www.amazon.com/gp/product/B08D8TSMFV/

* The old Mp3 USB plug gets cut away entirely. Make sure to preserve the socket connection, you are going to use this as a "Positive Trigger" in the circuit to prevent parasitic energy draw

* Lots of Zip ties of varying lengths for securing wires to the frame and to help join wires together to take potential stress off solder joints.

* Lots of "Wire Nuts" sized for 18 AWG and 10 AWG for connections.
https://www.amazon.com/Listed-Cable-Matters-180-Pack-Connectors/dp/B0CFGCKNVZ/

* Soldering Iron and solder
https://www.amazon.com/gp/product/B074W3W55T/r

* Heat Shrink Tubing to cover solder joints wherever possible
https://www.amazon.com/dp/B084GDLSCK

* Electrical Tape (2 colors red and black) to help secure connections, weather protect joints, and to temporarily secure wires to the fish-tape to pull through.

The easiest solution to provide a high amp USB source is to use one of Optimate's O-108 or O-118 series. It provides a 3.3Amp USB source, turns off automatically without the need to provide a relay and related wiring, and will not suck the battery dry. Another bonus is that it has a built in timer that allows you to charge a USB device for up to 1 hour after engine shutoff or until battery voltage drops to 12.4V whichever comes first.

Available in versions with USB A (O-108) or USB C (O 118), or with connection to a exisiting SAE style trickle charger connection or direct connection to the battery.

On my MP3, the charger lead is underneath the saddle so I use the O-100 dongle for a clean compact solution

https://optimate1.com/prod/usb/?wcmlc=USD

HealTech Thunderbox (Not from Australia I guess ) is another voltage sensing relay.

I'm an electronics guy myself and I'm not sure why everyone is over complicating this with relays. Here is a picture of the connector I attached to the battery. I plug in a battery tender when not riding and a 12V connector if I need 12V or 5V with an adapter.

I'll make another comment about where my GPS is powered from.[/img]

This connector right under the plastic in the middle of the steering column has switched 12V that I use for my Garmin. It's for heated gloves.
Red/Green is switched, Red/Black is direct to battery. Black is ground.

Here is how my Garmin is mounted. The quick release mount is wired to the switched 12 V

I like your use of proper connectors.

Which proper connectors? Those SAE ones are IMNVHO are dangerous, as there's no way to tell which polarity is which. I use Anderson pole connectors instead - there's absolutely no way they can be confused.

Suppose you have a 'ciggie lighter' plug wired to an SAE connector. Do you use it to provide 12V from the plug (gps etc) or do you use it for charging the battery via the ciggie socket? Each use would require a different polarity on the SAE connector, and heaven forfend you get it the wrong way round. Something will give up its smoke...

Proper connectors as in quality crimp conductors with separate crimp for conductor and insulation, with waterproof option. Made from oil tolerant plastic.
You can tell not only polarity, but also function of each wire, by the colours on the insulation.
The other extremity would be wires twisted together and taped with packing tape.
I've used Anderson Power Pole connectors. IMHO they are somewhere between. No crimping on the insulation and plastic crumbles apart when it comes into contact with some chemicals. And the resistance increases a lot with age.

Edit. Forgot to mention the sizing options and the way Anderson Power Poles crimp a "barrel" around the conductors while "quality" connectors have ends that are forced in between the conductors.

So just to be clear, I'm using that connector for 2 things under the seat.

1. as a connection to my battery tender.
2. to connected to the 12V adapter in case I need to connect 12V to anything that uses that plug, for instance a tire pump, or to plug in an adapter for USB 5V. So I can charge some camera batteries traveling down the road.

My GPS is hard wired into the back of the pictured connector on the switched 5V soldered properly and using heat shrink. Leaving the functionality of the plug intact.

I'm sure the connector you are using is fantastic, but I'm not too worried about how I set up my power needs.

This thread turned out great There is all kinds of information, solutions, and methods to install a better USB plug or 12V socket. Anyone who wants to make such an upgrade now has a wealth of information to draw on The Mp3 community is very good and seeing everyone sharing ideas, methods, opinions to solve the USB question was/is awesome.

Why go so complicated with relays, sockets, wiring etc?

My Mp3 is for recreation and touring so I only ride it maybe 2 or 3 times a month even in good weather. I do use it for touring in the back country where the nearest help is a long ways away so keeping the battery strong is a priority.

There is no power-outlet near where I park and extension cords aren't an option so without a battery-tender option a parasitic draw is a risk I cannot take. With how infrequently the bike is ridden, a dead or weak battery is possible if I forget to remove a USB charger or unplug something.

The lithium battery is great for bikes that sit long periods, but its voltage when not in use is uncomfortably close to the "activate" voltage of the suggested "voltage sensing relays" so I'd rather not risk it. Maybe its fine, but I already had a solution that did not risk this so went with the safe bet.

The 12V socket in the glove box looks like its from factory, I think it looks nice . I did not want to alter existing wiring any more than necessary and sacrificing the factory USB was low risk and worked perfectly for the relay.

I did consider tapping into the wiring for the heated grips (I have those installed) but it didn't seem like a good option. My phone/gps mount is not on the handlebars and I didn't want to risk damaging my heated grips by messing with the wiring there. Also the movement between the handlebars and the stationary phone/gps mount might have been a problem with abrading insulation or something in the future.

The 12V socket in the glove box lets me plug in all kinds of compatible devices and any variation of USB plug / charger with just an insert. I can plug in my air pump when I'm adjusting front tire pressure (I air up for highway and air down for uneven terrain or bad farm roads). If I change phones or want to mount my GPS there is already a compatible plug.

My phone / GPS mount is attached to the dashboard. I did consider attaching it to the handlebars but then it would be swinging around when I steer around corners. I like the GPS unit / phone to be stable mounted so its attached via screws and braces to the underside of the glovebox plastic.

Lastly, have ADHD . so I'm very likely to forget to unplug something, especially if its under the seat. While its super easy to just use the SAE plug or the 12V socket under the seat, its also high risk for me because I'm liable to forget its there and run the battery down between rides.