Voltage rectifier?

rarms · 27 October 2011, 16:30

I have a mariner marathon / tohatsu 25hp engine

Would like it to charge a battery so I need to fit a voltage rectifier.

Question is, do I have to buy. Tohatsu one, or can I buy a generic one for say a motorbike off of eBay? Would there be any issues with that? It is just four diodes to turn the ac into dc I think so it shouldn't matter? Wanted to get advice though first!

uncle al · 27 October 2011, 16:35

why not buy the proper kit? and make life easier for your self!

rarms · 27 October 2011, 16:38

Because, it seems to be a box with four wires coming out of it.

Tohatsu want $300

eBay from China want £5

For the sake of wiring four wires, I wouldn't mind putting that money to something else.

That said, it seems too easy so I thought I would ask the experts

rarms · 27 October 2011, 16:41

For instance:

New Motorcycle Voltage Regulator rectifier for S125 | eBay

Four wires, Green with the ring on it must be earth, red will be in theory DC +ve. Leaving the two yellows for the yellow and white feed from my coil.

It really seems so simple there must be a catch?????

donald463 · 27 October 2011, 20:30

Ebay item has 5 wires in picture. Don't understand extra wire. An electrician with multimetre should be able to work out correct connections. For 5$ i'd buy one and play about but !!!

Courageous · 27 October 2011, 20:39

Donald don't wish to patronise but the 5th wire is the earth. I would go for the ebay item every time

donald463 · 27 October 2011, 21:41

No offence taken but,
I see 3 yellow, 1 red, 1green.= 5 wires
I expect a rectifier to have 2 wires for AC input, and 1 positive(red), and one negative/earth/chassis (green) for DC output.
Why three yellow wires?

Courageous · 28 October 2011, 05:26

Since some vehicles are positive earth I'm assuming that the negative output is not tied to earth. I could be "Wong" though

Courageous · 28 October 2011, 05:32

Oh dear, there are 6 wire ones as well...... Look what you started Donald!

5 wire rectifiers

I'm off back to bed now.

rarms · 28 October 2011, 05:43

Quote:

Originally Posted by Courageous

Since some vehicles are positive earth I'm assuming that the negative output is not tied to earth. I could be "Wong" though

This is kind of the conclusion I came too. Will let you know when it arrives from china!

rarms · 28 October 2011, 05:58

New Motorcycle Voltage Regulator Rectifier ZJ-125 | eBay

Just bought that one, and that has two yellow, one red, one black, and one green. So it would appear that the earth (presumably green) is different to the negative (presumably black). Hopefully it will be that simple. Still have a load of nice bullet connectors left over too from my jet rib restoration.

Just to wait 20days for postage now!

ashbypower · 28 October 2011, 08:45

Quote:

Originally Posted by Courageous

Since some vehicles are positive earth I'm assuming that the negative output is not tied to earth. I could be "Wong" though

Tied to Earth, on a vehicle with Rubber Tyres. Mmmm rather a long EARTH bonding lead on that i would guess!!

Peter_C · 28 October 2011, 08:52

I used a motorcycle rectifier/voltage regulator on my outboard to charge an AGM battery. So far so good. My older 1993 Evinrude 40hp uses a 3 wire so that is what I bought. Typically there is a red, which is the power output. The black is clearly ground too. Last but not least the green is often for a tach.

GaryC · 28 October 2011, 09:40

Quote:

Originally Posted by ashbypower

Tied to Earth, on a vehicle with Rubber Tyres. Mmmm rather a long EARTH bonding lead on that i would guess!!

I thought that it was called "Chassis" on a car but has the same effect as an earth (although they are not connected.

Courageous · 28 October 2011, 10:46

Quite right Gary, I'm assuming Brian was joking. It's often referred to as "earth return". Doesn't really matter though does it?

ashbypower · 28 October 2011, 12:31

Quote:

Originally Posted by Courageous

Quite right Gary, I'm assuming Brian was joking. It's often referred to as "earth return". Doesn't really matter though does it?

Indeed hence the

Courageous · 28 October 2011, 15:46

Thanx for clarifying Brian - darne'd smilies, they get me every time!

rarms · 12 November 2011, 18:30

Right, it arrived today.

Put some bullet connectors on it, and plugged it in to the feeds on my engine. Yellow to yellow, White from the stator coil to pink on the rectifier. Black from stator to engine earth. And then red to be wired to the battery. I put a sheathed female bullet on the green, and for the moment it is not connected to anything.

Turned the engine on the pull cord, and sure enough generated a dc voltage (1.5v) on my multimeter across red and earth. Looking good, and next weekend the engine will go back on the boat and then I will find out if it actually works!

Courageous · 12 November 2011, 19:41

Well done rarms