Yamaha 15 hP 2001 Two Stroke - Charge Circuit

[smallribber]

One I suspect for Fenlander He knows about most Engines.

I just got my newly acquired Yam 15 HP SS 2 Stroke out of the boot of the car after picking it up second hand last Wednesday. As I said Cowl a bit scratched but immaculate under the cowl. I moved it from the car to the Shed on my converted golf cart that actually works incredibly well and the cart folds up when not in use.

Anyway

When looking her over and reading the book I am surprised that I seem to have a charge plug in the back. I was wondering if this was standard on these motors and if it is likely to be connected. If so I assume I should be able to use it to charge the little 12 v battery for my chart plotter.

I am waiting on my Outboard stand from Amazon to be delivered so will start it up then and see if there is any voltage at this plug when running.

Exciting times and something to fiddle with when the sodding weather warms up a bit

[jwalker]

Originally Posted by smallribber

One I suspect for Fenlander He knows about most Engines.

I just got my newly acquired Yam 15 HP SS 2 Stroke out of the boot of the car after picking it up second hand last Wednesday. As I said Cowl a bit scratched but immaculate under the cowl. I moved it from the car to the Shed on my converted golf cart that actually works incredibly well and the cart folds up when not in use.

Anyway

When looking her over and reading the book I am surprised that I seem to have a charge plug in the back. I was wondering if this was standard on these motors and if it is likely to be connected. If so I assume I should be able to use it to charge the little 12 v battery for my chart plotter.

I am waiting on my Outboard stand from Amazon to be delivered so will start it up then and see if there is any voltage at this plug when running.

Exciting times and something to fiddle with when the sodding weather warms up a bit

Doesn't you manual state that the output is 12v AC and not to connect it to the battery?

[smallribber]

Originally Posted by jwalker

Doesn't you manual state that the output is 12v AC and not to connect it to the battery?

Ah yes. So I will need to have a rectifier in the circuit somewhere. If it is 12v ac Is it just to power a light of some sort ?

[smallribber]

So somthing like this should do the trick ?

https://www.ebay.co.uk/itm/Universal...8AAOSwlE9dy66q

[Oldman2]

It may already have the rectifier, it was an optional extra, check the wiring from the coil.

[Oldman2]

power output and regulator.jpg Wired like this.

[smallribber]

Originally Posted by Oldman2

It may already have the rectifier, it was an optional extra, check the wiring from the coil.

If it does already have the rectifier then should I not get 12v DC at the plug. If this is the case why should I not connect to the battery or does it also need a regulator in the circuit somewhere

[smallribber]

Looks like I am in Luck. It has a Regulator/Rectifier already fitted.

So it looks like the P2 Plug is wired for 12V ac and the regulator is there with a Red take off not plugged into anything. If I check the voltage when running Between this red wire and earth and I get 14v Plus This is the wire I run to the Battery Positive with a earth wire to the block and to the Battery negative.


Quite why they give to a 12v AC plug baffles me.

[Oldman2]

The ac plug and the coil are factory standard fitted so you can operate at night with lights I think. But yes you are lucky, charge away.

[smallribber]

Interesting....... Some more help needed I think.

I have just started the engine on muffs so dont want to rev it too high and the upshot is that if I out a multi meter connected to the Red of the Regulator and then earth the black from the multimeter I get the following results:

1) At Idle on the engine I get about 4-5 Volts DC
2) If I advance the throttle to about a third I get about 8 - 9 Volts DC

I dont want to run it WOT on muffs out of gear as I dont think that would be a good idea.

Is this what I would expect. Is this usual. If it were flat out would I get enough volts to charge a 12V battery.

Thanks in advance

[Oldman2]

Try putting a load across the output, a battery and then see what you get voltage wise across the battery terminals, should with some revs be 14v ish.

[smallribber]

Originally Posted by Oldman2

Try putting a load across the output, a battery and then see what you get voltage wise across the battery terminals, should with some revs be 14v ish.

Yes and thanks I think it needs the battery connected... As an aside I am very pleased with this engine

[smallribber]

So I am going to make up a charge cable with one connector coming out of the engine and another short length coming out of my battery box. Each end will have a connector on the end. When I want to charge I will have a length of 2 core sheathed cable also with connectors on each end that I will connect between the two when needed.

I was wondering how much current I might end up with in this wire so that I can get an idea on size. I was thinking probably no more than 4 amps so wont need to be too think. I will get a fuse in the wire somewhere.

[smallribber]

So spent a Pleasant day making up some wire to have a 'removable' charge circuit to my 12 v gell battery that powers my chart plotter, Small bilge pump and phone charging etc.

This needs to be removable for when we pack down and will not always be used. Hence I made the following with bits and pieces I had:

1) Loom to fit inside the engine cowl with external plug. This will exit through a usefull Grommet Yamaha supplied

2) An extension cable with plugs at each end

3) A small loome inside the battery box which includes a 5 amp fuse in the positive.

Hopefully when the engine gets to the higher rev band I will get enough volts to charge the battery

[smallribber]

I 3D Printed a little end cap for the connector to cover it when not plugged in to keep any crud out. A 3D Printer (Cost about £150) is a great addition for making boating and other bits

[Poly]

Originally Posted by smallribber

If it does already have the rectifier then should I not get 12v DC at the plug. If this is the case why should I not connect to the battery or does it also need a regulator in the circuit somewhere

Originally Posted by smallribber

Interesting....... Some more help needed I think.

I have just started the engine on muffs so dont want to rev it too high and the upshot is that if I out a multi meter connected to the Red of the Regulator and then earth the black from the multimeter I get the following results:

1) At Idle on the engine I get about 4-5 Volts DC
2) If I advance the throttle to about a third I get about 8 - 9 Volts DC

I dont want to run it WOT on muffs out of gear as I dont think that would be a good idea.

Is this what I would expect. Is this usual. If it were flat out would I get enough volts to charge a 12V battery.

Thanks in advance

Unless the issue is not having a battery/load attached then I don't think you have a regulated supply there - it shouldn't change a lot with revs (although mine used to be far from stable) but it should be putting out >12V even at tick-over. However we can all speculate wildly on what you have, and whether its working but actually you can test it easily yourself...

[smallribber]

Well the Rectifier is indeed a regulator all it needed was a 'load' connected. Set it all up with my 12v gell battery connected and all was good charging at over 14 volts.

The removable charge wire also doubles as a wire for my small bilge pump so if I get water in the bottom of the boat (pain in the bum on a T38) I just unplug the wire from the engine at the cowl and plug into the Bilge pump and pump out the boat.

Quite pleased with how this little project has worked out.

https://www.youtube.com/watch?v=tErILE0DguM