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30 December 2014, 15:51
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#1
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Outboard voltage
Hi Can any one help me with this
Outboard is
Ex rnli mariner 2 stroke 40hp
I have noticed on the newly installed volt meter that the voltage is going up with rpm to 16 volts!
I assume it's the same as a car and should Limit to 13.8v
Am I right in thinking the rectifier is knackered ?
I have just put in another one 2nd hand from eBay and that is exactly the same
Any help much appreciated
Thanks Stuart
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30 December 2014, 16:07
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#2
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Outboard voltage
Just found this on the net
"I've just fitted an identical one to my Mariner 15. This engine has a stator (like the al;ternator on a car) under the flywheel which puts out alternating current (AC) and if you want to charge a battery you need to convert it to Direct Current (DC) That is what the rectifier is for - you now should have DC power flowing out of the rectifier with the red lead being positive to the battery + terminal and returning from the negative terminal through the engine casing to earth (ground). You should check this with a voltmeter between the red cable and the engine case and you will find an output voltage of between 10 V at idle to about 18V at full revs - you may need to fit a voltage regulator to limit this top voltage to 14 V or 15V so as not to damage 12V instrumentation run off the battery such as VHF radiio, fishfinder etc."
I am now thinking it is only a rectifier with no regulator!
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30 December 2014, 18:41
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#3
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RIBnet admin team
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,069
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take a pic of the rectifier unit and post it-I should be able to tell you what you've got.
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30 December 2014, 18:54
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#4
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Member
Country: UK - England
Town: Littlehampton, W Sx
Length: no boat
MMSI: 235101591
Join Date: Jan 2012
Posts: 732
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I have protected each piece of electronics with a 7812 voltage regulator (about 50p each) but there is a thread on here somewhere about using a motorbike regulator...
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"Can ye model it? For if ye can, ye understand it, and if ye canna, ye dinna!" - Lord kelvin
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30 December 2014, 19:16
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#5
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Quote:
Originally Posted by Nos4r2
take a pic of the rectifier unit and post it-I should be able to tell you what you've got.
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These seem quite common on older outboards Stanley de4204
I cannot find any spec for this on the net I think now it is only a rectifier
Thanks
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30 December 2014, 19:20
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#6
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Quote:
Originally Posted by HughN
I have protected each piece of electronics with a 7812 voltage regulator (about 50p each) but there is a thread on here somewhere about using a motorbike regulator...
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Hi thanks just looked on eBay biggest was only rated at 1.5 amp
What did you use on your radio?
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30 December 2014, 19:40
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#7
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Member
Country: UK - England
Town: Littlehampton, W Sx
Length: no boat
MMSI: 235101591
Join Date: Jan 2012
Posts: 732
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There are a couple of other versions. I used a 78S12 which is 2A, but I should probably have gone for the 78T12 (3A).
They do get quite warm at times; a nice bit of metal nearby was a convenient heatsink... ...don't blame me if they burst into flames.
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"Can ye model it? For if ye can, ye understand it, and if ye canna, ye dinna!" - Lord kelvin
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30 December 2014, 19:56
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#8
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Quote:
Originally Posted by HughN
There are a couple of other versions. I used a 78S12 which is 2A, but I should probably have gone for the 78T12 (3A).
They do get quite warm at times; a nice bit of metal nearby was a convenient heatsink... ...don't blame me if they burst into flames.
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Thanks
Out of interest if you are still running your mariner 30 do you know what voltage it was kicking out to the battery ?
The rectifiers I have are the part used on the older mariner 30's
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30 December 2014, 22:14
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#9
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Member
Country: USA
Town: NorCal
Boat name: SHARKY
Make: AB
Length: 4m +
Engine: Honda BF75 & BF5
Join Date: Dec 2009
Posts: 2,108
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I put a motorcycle regulator/rectifier into my outboard to control voltage. It is not really important on brand as they will function if it is compatible with the boats current electric system. In other words it could be from a PWC, snowmobile, motorcycle, garden tractor, etc. Rectifier alone will smoke an AGM or gel battery very quickly, as the voltage goes too high.
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31 December 2014, 06:18
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#10
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Member
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
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I assume you have a battery installed? If not, that's your problem. Loading the output will pull the voltage down a substantial amount.
jky
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31 December 2014, 09:29
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#11
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Hi yes lead acid car battery fitted next step is to try some load on the circuit and see what happens
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31 December 2014, 11:44
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#12
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Member
Country: UK - England
Town: Littlehampton, W Sx
Length: no boat
MMSI: 235101591
Join Date: Jan 2012
Posts: 732
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Quote:
Originally Posted by popeyethesailor
Thanks
Out of interest if you are still running your mariner 30 do you know what voltage it was kicking out to the battery ?
The rectifiers I have are the part used on the older mariner 30's
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I'm now running the Yamaha version of the same engine. At some point I'm going to put an oscilloscope on the various wires and seem what is happening - my tacho has stopped working and needs troubleshooting.
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"Can ye model it? For if ye can, ye understand it, and if ye canna, ye dinna!" - Lord kelvin
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31 December 2014, 17:31
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#13
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Member
Country: UK - England
Town: Leicester
Length: 5m +
Engine: 135hp Mercury
Join Date: Sep 2013
Posts: 1,431
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13.8 on a car is indicative of a faulty alternator.
This from another forum:
"Correct proceedure is ......
take vehicle for a short drive with everything turned off and on return without stopping engine and with everything turned off raise the engine speed to 2-3000 rpm and check the battery volts .. should climb to 14.4v as a minimum.
If not 14.4v the voltage regulator is faulty ...a voltage reg that only reaches 13.6v will give you about 6 months battery life."
ETA. I've checked this on our own cars & that's also what I get.
I've not tried the boat & must remember to try it & see what I get - but that won't be for a while.
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31 December 2014, 18:25
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#14
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RIBnet admin team
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,069
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Quote:
Originally Posted by popeyethesailor
I think now it is only a rectifier
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It is only a rectifier. It is worth putting a rec/reg unit on-it's less likely to fry any electronics if you suffer a battery switch failure while running.
Give Electrex a call.
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31 December 2014, 18:45
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#15
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Member
Country: UK - England
Town: St Neots ( Cambs)
Boat name: Red Oktober
Make: Avon SR4
Length: 4m +
Engine: 40hp
Join Date: Aug 2013
Posts: 116
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Quote:
Originally Posted by Nos4r2
It is only a rectifier. It is worth putting a rec/reg unit on-it's less likely to fry any electronics if you suffer a battery switch failure while running.
Give Electrex a call.
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Hi thanks I have sent them a email they will prob come back with there universal one being suitable,
Out of interest where did you find out the spec of the Stanley unit?
I spent hours trying to get info on it on the net with no joy
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31 December 2014, 19:07
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#16
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RIBnet admin team
Country: UK - England
Town: The wilds of Wiltshire
Boat name: Dominator
Make: SR5.4
Length: 7m +
Engine: Yam 85
MMSI: 235055163
Join Date: Jul 2005
Posts: 13,069
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I recognise it
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02 January 2015, 16:28
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#17
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Member
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 5,596
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Since you're bugring about with your system, it might be worth noting that if you measure the output from a rectified but not regulated source it will be bumpy DC you are reading on your meter. Your meter will, therefore, not display a correct voltage unless you switch it to the AC range. Once you connect your system to a battery, you can consider it to be smooth DC (but it will still have a bump to it.).
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JW.
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03 January 2015, 06:29
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#18
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Member
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
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Quote:
Originally Posted by jwalker
Since you're bugring about with your system, it might be worth noting that if you measure the output from a rectified but not regulated source it will be bumpy DC you are reading on your meter. Your meter will, therefore, not display a correct voltage unless you switch it to the AC range.
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Won't read correct then either. The output will be pulsed DC, but the AC meter will read half the peak value, smoothed to RMS of the waveform; somewhere around 40% or so. It is useful if you know what you're looking for (much like a car "test light" that comes on when connected to anything over about 9V.)
jky
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03 January 2015, 13:13
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#19
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Member
Country: UK - Scotland
Make: HumberOceanOffshore
Length: 8m +
Engine: Volvo KAD300/DPX
Join Date: Oct 2002
Posts: 5,596
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Quote:
Originally Posted by jyasaki
Won't read correct then either. The output will be pulsed DC, but the AC meter will read half the peak value, smoothed to RMS of the waveform; somewhere around 40% or so. It is useful if you know what you're looking for (much like a car "test light" that comes on when connected to anything over about 9V.)
jky
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Well that's how we measure AC! As an example, our UK mains is nominal 230v AC but the peak voltage is around 330v. Your figures are out too but I take the point you are trying to make.
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JW.
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04 January 2015, 19:14
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#20
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Member
Country: USA
Town: Oakland CA
Length: 3m +
Join Date: Feb 2005
Posts: 6,653
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To clarify: Most meters on AC will center the waveform for reference, then read RMS (rather than peak.) Which is why you can get an accurate AC reading of an AC component riding on a DC voltage.
Since you're talking about a rectified AC stream, the reference point (normally zero volts when reading AC) will be something less than half the peak voltage value (due to the area under the curve on either side), and the reading will be based on that.
The RMS factor is based on a pure sinewave waveform, so any deviation from a sinewave will read wrong. The resulting "AC" waveform in your case will be rounded pulses further apart than sinewaves on top, and closer to a squarewave on the bottom. Throws everything all wonky.
jky
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