Modern Vespa

Hi all,

Question that's been bugging me as I'm looking to add a speedo that needs DC power…

I'm running the Malossi vespower setup, and there's no electric start, and no battery.

Something tells me it's wired wrong but was done a long time ago, but it does work.

Without adding a battery and restoring some of stock wiring (battery, rectifier etc…) is it possible to draw power from somewhere and convert it to DC?

Or it's not possible with the PX lusso harness?

I see it's around 27volts out of the stator which I imagine is too much for the speedo to take…

Electrics isn't really my strong point, so would be good to hear from some pros…

Bike is just wired AC only like European bikes. All should be OK with current wiring.

You can add the speedo and use controlled AC power from the regulator and not the high 27V ac power you have coming out the stator.

Or you can buy a AC to DC converter to get DC power to the speedo. DC power works best and will not fluctuate like AC power with the revs of the motor.
https://www.denniskirk.com/koso-north-america/ac-dc-converter-bl000010.p214570.prd/214570.sku

The same item is out of stock at SIP.
https://www.sip-scootershop.com/en/product/voltage-regulator-koso_KOBL000010

Thanks Rowdyc!

Oh… that's fantastic…

Ignition key wire, ground wire and 2 wires to the speedo…

Talk about straight forward… lol

Koso FTW…!

You're welcome.
It's actually brown to an AC power wire, ground for that AC power wire in, red DC power to the speedo, and ground for that DC power wire. Still simple but no connection to the ignition wire.

Good luck!

Thanks! I made an order for the Koso converter.

My bad, just looking at the manual, I was assuming I would be taking AC power wire from the ignition wire from the keys (which I assume is from the regulator…)

Maybe I've interpreted it wrong…?

Where's best to siphon ac power from?

I will be doing that exact conversion soon on my own. I have a good idea of what I need but I will be checking other topics if I get stuck during the install. I have a Sprint Veloce that at one point it had battery, turn signals, ignition key, pilot light on the headset, oil injection and sometime between the 1970's and 2013 everything was deleted.

Now I want to install a SIP speedo and I will be doing a simple conversion. I never done it but I have a good background in electronics. My plan is to do the following:

1) AC to DC conversion to feed the battery
2) Battery will provide the power while the engine is running
3) I will install an on-off switch to feed the speedometer and to cut power to the battery once I am done riding
4) I also want to install 3 independent lines, one for a battery tender charger, a cigarette lighter plug and a USG type port.

Like I said, I have a very good mental picture of what needs to be done. You can PM me and I can share with you the progress.

You can pick the power from the voltage regulator.
I have a super simple set-up on my sprint, I have a 3 pole regulator and a 5 wire vespa stator PX style stator(red, green, white, black blue).

The KOSO schematic shows an ignition key as a part of the power circuit but I don't know if that suppose to be an ignition key that comes with it or assuming that you already have one.

That picture is confusing. The key is actually the accessory with a power wire and a ground wire. The speedo has the same wires...a red power wire and a black ground wire.

Yeah, like Scooterist said, grab the ac voltage from the regulator out wire. Since you're putting it in a P, the speedo computer box and the koso regulator will need mounting near the regulator side of the scooter. The speedo comes with a harness wire that can be ran from the speedo to the back of the scooter.

6 watts maximum output? wow!! that is very low and just enough to do the job. My guess is that the display is a very low consumption design.

I will be doing the AC to DC with voltage rectification(diodes and all of that) but I will likely outsource my stuff. The plan is to use a spare P series skinny battery that I accidentally ordered from not paying attention (it suppose to go to the PX).

The brand new stator that I just put is working great. I did some basic calculations and the 90watts stator should feed everything. My biggest concern is the drainage of power when the scooter is not being used and that is why I will be installing two on-off switches, one of them will be a conventional key.

Over the past years I had very bad luck with my scooters draining the batteries. Last week as a matter of fact the PX 150 battery was unable to start, I left the key in the middle position.
Installing the sip speedo is going to be my excuse to do the other two or three things that I wanted to do(charging my phone via USB , charging a GPS, and have the ciggarrete lighter as a valuable accessory for stuff like an electric air pump.

My biggest challenge is were to finalize the location of the main module. The headset that I have on my sprint is smaller and I don't think it would fit. I would like to scoop a glove box if I can and get a wiring extension to attach the module inside.

I'M WRONG. Had to go look at my crap after seeing the diagram above. You're right, the key in the picture is the power but in your case its the AC power from the regulator. Red wire in from power source and brown wire out to speedo. Works well and no more speedo flickering off and on.

Don't forget to get a resistor plug or it will still flicker...worst then AC power.

Ah bugger… didn't read the fine print…

I think I need 9v for my Speedo… I'm not using the SIP speedo… will give it a try regardless

Right, kinda got you…

But I'm currently using a BGM regulator, again I'm assuming I will be pulling power from the connector that says DC?

For your consideration, something like this setup to power your speedo only.
9v lithium battery, glued somewhere in the headset. Should last years:

The SIP speedo has a low battery signal for this setup. Maybe yours does as well.

That regulator has been around literally for decades, I have two of them but it has been rebranded many times. You will find it advertised everywhere mainly for small scooters, I had one on a P200 and recently on a Lambretta, they work like a champ. BGM is just putting their logo and pouring epoxy in it and calling it BGM.

As long as you can supply a reasonable amount of voltage to the battery(no more than 13.6 ish or so) you can use it. You are on the right path. I think I will be ordering my SIP speedo tomorrow and by the time I get it(On Monday) I should have the rest of the supplies that I need.

Never thought of that route, but again should work. I can hide it under the horncast…

Could I wire it to the ignition key switch? So the speedo turns on as I turn the key?

Yeah seen it in different places, same form, little silver box with the cooling fins, same yellow cables.

I doubt BGM have come up with anything original for a while…

But not sure how it should be wired properly to be honest… currently works, but had difficulty finding a wiring diagram that matches how I've had mine setup…

Went to test the regulator and measure to see the volts coming out of the DC terminal.

Seems like a sad 4v coming out, 3v at idle. Is that right? Or something I'm not doing right, like I'm actually suppose to be using and measure across the AC terminal.

(Old photo from 2 years ago when I was about to strip the paint and photo documented the parts/wiring)

Yes. Connect the positive directly to the speedo and negative through the key switch.

BTW are you sure your speedo doesn't have an internal rectifier?
If not, you could get a small 12vac to dc rectifier and connect it to the headlight + and - terminals(12vac). I think that's how it's usually done.

Don't think it has a rectifier, I think there's one the brand sells separately that goes with it.

Will connecting to the headlight make it even dimmer than it already is? Was thinking there must be somewhere I can pull power from without affecting the lights… but maybe there isn't?

Digital speedometers draw hardly any power.

This one has an internal rectifier/regulator:
https://beedspeed.com/products/vespa-speedometer-p125x-p150x-p200e-sip-koso-black-face-bezel

BTW bulbs get tired. If your bulb is older you'll see an improvement with a fresh one.

Maybe I should just get the good old sip speedo on your link… seems much simpler… but the components seem to be the same as what we've been talking about… looks like an ax/dc converter

I don't think it gets any simpler than this. Comes with splice connectors you connect to the lighting 12vac (no converters) in the headset.

There is no real internal rectifier/regulator in that speedo. It has something that regulates power so the components don't fry but nothing more. Plug that speedo into ac power, it will flicker and reset itself. When the revs are high enough and using a resistor plug, speedo works like a charm. Revs go down and that ac current goes down then speedo resets. DC rectifier or a battery is the best way to run one of those.
Not good to plug the speedo up to any power that's on a switch because of obvious reasons. The lights on some euro vespa was on the right handlebar switch and could turn off or on. Not offered on North American p series. Your bike may have that feature so wiring to lights may not be a good option. A good place to pull power is the wire leaving the regulator going to the headset before any switch. Pull the diagram and see which wire is best.

It's the black box that comes with it.

Spare CHT sensors too. That's awesome.

There's an installation video on SIP's product description page (last video). Gets revs from the headlight wire. Also awesome.

https://www.sip-scootershop.com/en/product/speedometer-rev-counter-sip-20_50000530?q=sip%20rev%20counter

The black box is the computer that runs everything. The first version of the speedo did not have a a good regulator in it and sometimes when using AC, during very high revs, it would fry the speedo. The small so call regulator inside stops that from happening but does nothing else.

Yes you can get the revs from the headlight wire but the power needs to come from something that is not connected to a switch that goes off and on.

Yeah I was assuming that black box was the converter if it's connected to the headlight, giving the speedo dev power.

The video doesn't go into much detail, but if that's the instruction to install…

Red and brown are both connected to the headlight wire with the supplied Scotch-lock connector (bike without a battery).

So managed to get the speedo from SIP today, threw it on the PX, looks great but couldn't make it work without a battery hooked up to the setup…

Ray8, unfortunately the speedo doesn't even power on with a 9v battery, unless I'm missing something. but it did worked with a 12v battery (something tells me it needs around 10v becos the instructions did mention to measure the headlight positive and look for 10.5-12.5v)

So back to square one. I hooked the speedo and ac converter (included with the speedo) according to the instructions and the video… so black box connected to the headlight, but voltage was around 7-8v… counter measures 800rpm (that was when it was powered with the 12v battery)

But disconnected the battery and there's no counter… switches off…

am I missing something?

I've taken away the horn and the starter safety switch… would that make a difference??

Some people have issues at idle when they don't have a battery. There's not enough voltage to turn speedometer on. Can't remember who it was here but my suggestion was to put in a small battery that could maintain voltage at idle. Did you try revving it up for say 10 seconds to see if it powers on?

The information provided about the 9 volt battery is wrong. Speedo needs around 12 volts to work properly. Also, the speedo having a typical regulator we are use to is wrong, too. The black box is the speedo computer and has something in it to make sure it does not fry from too much power but not a typical regulator. Removing the horn and safety switch does nothing unless the speedo wires are connected to those components and you don't so it doesn't matter.

A resistor spark plug is needed for the speedo to work correctly. Are you using a resistor spark plug or a regular spark plug?

With your setup and a resistor spark plug the speedo should work. Not well during low revs but it will work. I can't actually see the speedo connections in your picture above. I can only see the wires from the speedo. Are you using the red connectors that came with the speedo?

There maybe a problem with your setup if your scooter has a switch to turn the headlights off and on. If the lights are off the speedo will not work. I don't advise to put the speedo on a headlight with a switch and only should wire through the headlight if its an American P in which the lights are always on when the motor is running. Does your bike come with a switch that turns the headlights off and on? If so, is that switch off or on?

Once it is working, getting the AC to DC converter I mentioned above with make the speedo work well during low revs without a battery. A 12v battery only makes the speedo stay on during low revs. The AC to DC converter acts as the battery.

Me personally would setup the bike totally different. I would run the long harness, that came with the speedo, from the speedo to the back of the scoot and place the black box near the bikes regulator. This will allow easy access to the black box. Also makes it easier to setup the temp sensor from the back of scooter to the motor's spark plug. Hook up the black box to a 12v wire from the regulator and call it a day.

I just went through this on my 58 Allstate. The Koso DC converter works perfectly. I have pics in my thread of the hook ups. I have no battery and the speedo works fine at idle and doesn't turn on and off over and over again. Resistor plug is mandatory for the speedo.
The red splicers that come with it are less than ideal. Get some solder connectors and you'll have a much better connection.

Also like rowdy said, putting the black box in the seat cavity near the regulator is an easier place to put it.

Thanks guys! Starting to make a bit more sense why it's not working…

I have the resistor plug BR8es… should work if I'm not mistaken…

Yeah the headlight has a switch, but the headlight was on when testing the speedo…

Will pick up the ac dc converter tomorrow… want to double check, but where should I hook the koso converter to? I was initially planning to wire it to the headlight, but doesn't seem ideal.

You mention hook it to the regulator, but which terminal?

Splice the existing yellow wires?

Didn't rev the bike, but I imagine it would just flicker on and off with high and low revs… wouldn't be ideal when riding

His P has holes under the left cowl for electrical components. Most don't put a regulator under the seat cavity but under the left cowl. Easier to get to using the tool box door or removing the left cowl like on a P. Removing the seat and tank to get to electrical seems like a PITA. I understand why some do it in order to not drill a unseen hole in the side under the left cowl but battery bikes came with holes so I don't see it as a big deal. With smallframe there are few option for electrical so they go under the seat but not under the tank.

Thanks!

When through the thread, around page 13, I see the koso, but don't see how it was hooked up or with the rest of the speedo…

Positive you managed to get the speedo working without a battery, there is hope!!

Will make more solid connections if I can get it to power up on its own! Lol

I have the tank out now, I can take better pics this afternoon and send them to you

Do you have a picture of the regulator side of the scooter (left rear with cowl off)? Not sure what yellow wires you're referencing without a picture and a electric diagram. Will need to connect the wire with the connectors provided or some type of other connections. The red connectors that came with the unit worked well for me.

If you plan on using the temp sensor on the speedo you'll have to run the small wire provided from the Black box to motor spark plug. You do have options of where you want to place the black box. Some place it in the headset, some place it under the horncast and some place it at the back of scooter on the battery/regulator side. I didn't like mine in the headset so I ran the main large wire provided to the back and placed the black box near bike's regulator. Easier for me to get to. Don't know if you will have room in headset for black box and KOSO converter.

The koso converter goes to any 12 volt AC wire. Not idea to do when there is a switch on the bike to turn all the headset lights off. If keeping the black box in the headset, will need to find the hot wire from the regulator before it makes it to any switch. If placing black box near bike's regulator, you can connect it to any 12v AC wire. The KOSA has easy instruction for installation. Your setup will be different because you don't have the same regulator on your bike like FridayMat.

This is what the side looks like…

Apologies about the mess… this was before repaint, it's the clearest pic of that side though…

So I was referring to the yellow wires coming out of the regulator…

Yeah I can imagine my setup will be slightly different… not seen many people run the old Malossi vespower without the battery