Agree.Originally Posted by oldboot
Only done some backyard car mechanics but for a 12 Volt system 14.6 - 15.2 is charging well.
Your battery , let it rest for 15 minutes then check it, Ideally should read between 12.3 - 13.
Charging does depend on a regulator, this 'regulates' the rate of charging, not sure about boats any further than this.
Your regulator might be on the way out. 14 odd is usual for a v4'yammy. My 94 v4 115 just started charging 17.3 at revs and reg replaced at back to 14 volts.
The limp alarm may well be heat. What checks have you done? The ya
Oil injection is very reliable. Cheers
Boat: Seafarer Vagabond
Live: Great South East....love Moreton Bay fishing
old forgotten about thread...
all resolved now
it turned out to be a temperature alarm, just barely able to set it off then and went back into normal range almost immediately
got sorted by a good clean out (heads off and water galleries cleaned out)
Mobsta mate...has this motor ever had a battery connecte to it in the past?
If not it is pobaly not fitted with a rectifier.
If it has been fitted with a battery and it has now been run without a battery connected the rectifier is probably stuffed.
In these small motots it is not an alternator, it is magneto.....there is a very big difference.
A magneto will generate huge volatges when run unloaded like hundreds of volts..this will snot the diodes or regulator.
so exactly what is the situation and what is there.
cheers
Its the details, those little details, that make the difference.
Magnetos fire spark plugs they don't charge batteries.
You can run outboards without a battery just don't disconnect a battery while the outboard is running.
Not sure with a outboard alternator but some of the new vehicle ones will not output unless they can feel a voltage from a battery.
Be warned a deep cycle depending on type may never fully charge and is not what your outboard was designed to charge.
Oh goodo then.
More controversy.
I might even learn something here
I intend on living for-ever....so far so good
RUBBISH
A magneto is any type of electricity generating device where a rotating permanent magnet is spun past a stationary coil to generate electricity.
They can take many similar forms.......your outboard ( unless it is a large one) will have a magneto that usually has two coils, one high voltage coil to generate spark and another low voltage coil that may be used to generate a charging current The tacho usually takes pulses from the charging coil.....engine goes and tacho does not the charging system may be stuffed
A magneto has no means of active regulation within its self, magnetos are also relativly high impedance devices ( they have significant internal resistance)..as such run without a load they can generate much higher voltages than their normal operating voltage.
Any regulation is either electronic and external to the magneto, or it is accomplished by playing the internal resistance against a designed load.
You can varify this by looking at any decent outboard motor manual, althout it may not have all the detail.
Many early airoplanes had wind driven magnetos to run the radio and lights.....
An alternator is a device where a electricaly energised windings are spun past a stationary field or fields to produce electricity......the output voltage is regulated by varying the field current.......this is what produces electricity for most of our homes and what you have in your car.......mostly only very large outboard motors have true alternators.
Now here is the important difference and one that costs outboard owners $$$$ every year.
If you run an outboard motor with a working charging circuit, without a battery or at least a sufficient load you have a very real probability ( not posibility, not risk, near certain probability) that the diodes in the rectifier or the semiconductors in the regulator will be blown due to over voltage.....This is a very common occurance.
An alternator on the other hand, ( in automotive we use non self exciting alternators), if you can get the motor started, an alternator will not properly function without the battery it needs to make the field.....even if the alternator can self excite from residual magnetism it is unlikly to generate high voltages, and has a pretty damn good chance of comming out of the whole thing unscathed...people have driven cars hunderds of Km with torch batteries or other small or near dead batteries powering only the coil, with the remainder of the electrics disconnected.....and just stick a good battery in and away.
Not a god idea to run you car alternator with no battery, but it is not near certain death for the alternator.
If you have to or want to run your outboard without a battery and there is a complete and working charging system.....you are best advised to disconnect the MAGNETO wires from the rectifier or regulator.......most usually these are the yellow wires comming from under the flywheel....many outboard manuals will detain how to do this
Now back to the deep cycle battery and the non working charging circuit.......as I have detailed before....with our uotboard charging systems, they are designed arround a battery of a certain size....there is quite a bit of latitude, but if you go silly either way you can have a problem.
I doubt that the battery being deep cycle in its self will be a problem, but if you have a very large battery connected to a small charging system..... it wont reach charging voltage and wont charge it.
If the battery is way too small, the battery will not provide sufficient load and it will overcharge.
The above two points are particularly true of charging systems that have only a rectifier.....those with a regulator will suffer less on bothe counts.
even if the small charging system reached sufficient voltage to put in some charge..simple maths will tell you it aint going to do much to fully charge a big battery.
6 amps into a 120 AH battery and you be taking 10 to 12 hours and then some high RPM running the fully charge from half flat
cheers
Remember too that these magneto charging systems, are very inefficient and produce very small amounts of charge compered to what we are used to from an alternator in a car, truck or tractor.
Its the details, those little details, that make the difference.
Well I disagree oldboot.
Oh, come on now.
You can do better then that Fed.
So apparently.... A magneto is any type of electricity generating device where a rotating permanent magnet is spun past a stationary coil to generate electricity.
And apparently an alternator is a device where a electricaly energised windings are spun past a stationary field or fields to produce electricity......the output voltage is regulated by varying the field current.......this is what produces electricity for most of our homes and what you have in your car.......mostly only very large outboard motors have true alternators.
Besides the way one of the above doesn't really correspond to my learnings and the other is very vague and not the whole story but I'm not going to butt in here for a bit.
So what is your full definition of a magneto, an alternator, a generator and a dynamo Old Boot?
I love working my brain by bringing back all the old stuff I've learnt. It's going to stop me from getting alzheimer's I reckon and more fun then doing a crossword
I intend on living for-ever....so far so good
Come on Finga - just put those of us who dont really know and would like to know (like me who has always thought a Magneto charges a battery in a boat using regulated current - hence why when my regulator blew my Yammy was charging at a battery frying 17.3v - but doesnt charge with much amperage unlike a decent alternator).
I know you are having fun poking at stick at OB (and that is fun..no offence OB but it is) but I would like to know... I can search the net all day but I wont know the reality until an electrician who knows boats tells me.
Cheers
Boat: Seafarer Vagabond
Live: Great South East....love Moreton Bay fishing
Mate I'm not going to argue the magneto vs alternator point, I couldn't be bothered.Oh, come on now.
You can do better then that Fed.
As far as I'm concerned the common usage of the words is,... magnetos make the sparks & alternators charge the batteries.
It's like calling a fuse a circuit breaker, well fuses do break circuits you know. LOL!
So is a pair of pliers sometimes
I intend on living for-ever....so far so good
Come on chaps this is 1st year electrical theory.
As for common use..who's common use.
There are a great many situations where the ignorant common use by those who don't want to know the difference causes a failure in understanding, failures that cost people.
There are a great many cases where the common use term is plain wrong and gives and exactly wrong idea of the way an item works.
There are a lot of terms that have become generalised, particularly in trade areas where they no longer mean anything becuase those specific items are no longer encountered.
For instance it would be almost unknown for a houshold or industrial sparkie to have anything to do with an electrical generating device that was not an alternator and most likley only one specific type (medium sized and self exciting).
So to them, it matters little what you call it....call it a spinning round thing...and apart from the stupid looks from others it will make little difference.
A generator could be anything that makes electricity from motion, an alternator obvioulsy makes alternating current.....The word "Dynamo" is hardly used these days and anybody using the word magneto in relation to grid connected electric's is using it from ignorance.
BUT..for those who want to know.
In automotive, motorcycle and marine electrics the terms used are clear in their meaning, and refeer to specific types of components.
A Dynamo, again is a word hardly used these days and mostly will only be seen in books prior to the 70's...."I had a 'dynamo' on my push bike"..... many vintage car manuals refeered to the generator as a Dynamo......forget it hardly used these days.
NOW
In auto electrics and thus small craft marine electric's.
A "Generator" is a device that directly produces a DC output, as found in cars prior to the 70's..most usually it is a device that rotates a comutated (changing) spinning field winding past a stationary winding to produce a rough DC output.....output voltage is regulated by varying field current....a generator does not have a rectifier following the windings.
By the 70's most vehicles came fitted with "Alternators", these devices operate by rotating a spinning constant ( more or less) field winding past stationary winding/s and produce Alternating Current which is then rectified to produce DC, the output voltage is regulated by varying the field current.
Importantly alternators produce a pretty clean and symetrical sinewave.....in practice automotive alternators are 3 phase devices producing 3 sincronised but phase seperated sinewave outputs...when rectified and added together this produces a pretty danm smooth, clean DC output.
In general "alternators" are physically smaller, lighter, far more efficient and work well over a wider range of RPM than "generators"
As used with engines a "Magneto" is a very specific thing and differs greatly in both use and construction to the above.
Most importantly it is a permanent magnet device.
Mostly the permanent magnets are part of the flywheel of the motor and the windings are fitted behind the flywheel.
Quite often the charging and the ignition windings have common portions or are continuations of each other, although some times the windings are phisically and electricaly seperate parts of the same device and working by the same principle.
NOW here is where some people fail to understand......you will not get a good, hot, clean reliably timed ignition spark from a magneto winding alone....most magneto ignitions have some sort of interupter circuit (a set of points in some cases) to both correctly time the ignition and to intensify the spark voltage.......the magneto coil in this case opertaes similar to a coil in a car using the back EMF to produce a high voltage.
Many of the modern ( ish) outboards use some sort of seperate electronic ignition module to make and time the spark, the ignition magneto coil simply being a source of supply, there may actually be a more or less conventional coil involved.
The magneto charging circuit as mentioned before operates by the same principles as the ignition circuit, but it is run on a constant basis with no breaker points device.
The important things to understand and why we must darw attention to the difference is that "Magneto charging circuits" have some very specific limitations and effects.
It must be understood that a "Magneto" is one of the oldest, crudest, and least efficeint electricity generating devices we have.
It has no means within it self to regulate its output, the output voltage and its ability to deliver current varies with RPM. It may do very little in the way of charging at low RPM.
Depending on how the windings and magnets are arranged, the AC output from a magneto can be quite dirty, in that it may not be a nice smooth sine wave, even after rectification it will not produce the nice smooth DC that an 3 phase automotive alternator will.
The " Magneto" has an inherantly high internal resistance, so as current draw is increased voltage tends to drop.
This internal resistance also therefore impacts on voltage regulation.
So as load decreases voltage increases....with no load the voltage increases by a large amounts.
As RPM increases, voltage increases.....this is the combination that blows regulator and diode packs when motors are run with out load or a battery.
another limitation is how regulation is achieved.
Many of the smaller motors only have a diode pack......something resembling redulation is achieved by selecting battery size and playing that aginst the internal resistance....the battery is big enough to load the coil down and cop the charge but not so big that the voltage drops to the point that little or no charging occurs......sound crude..hell yeh, but it works as long as you use a battery close to the right size.
Most small motors that have small charging systems and are not electric start, do not come fitted with the rectifier pack, for two reasons...one, price and future accessory sale, and two...if the motor is started without a battery connected the diode pack will almost certainly blow
In the case of regulated systems, the regulator has to be loss bassed...the regulator disipates all excess electrical energy..this means that the size of the regulators and the magnetos is limited.
If the battery is fully charged and there is no accessory load, the regulator has to be able to disipate the full output of the magneto.
This differs to automotive generators and alternators that regulate by varying a relativly small field current....thus they do not generate excess power to start with.
Because of the above, magneto charging circuits are generally very low power in comparison to alternators.....20 pluss amps is a large magneto charging circuit..some outboads may be as small as 3 or 4 amps, some respectable sized outboards may come with quite small charging outputs....my 60 evenrude came with the big 18 amp circuit but it may have been fitted with as small as 6 amps.
A 40 amp alternator in a car is pretty small, many modern cars have 80, 100, 120 amp alternators.
Remember an alternaotor preforms consistently over a wide rev range.
It is these differences that trap people time and time again.
This is why it is important to call the generating systems by their correct names, because the names come with expectations.
A magneto charging system is a crude, pissy little, badly behaved charging system that may cost you $300 if your battery is disconnected with the motor running..
An alternator charging system is expected to be much higher output and far better behaved.
I hope this makes sence to those who want to know.
cheers
Its the details, those little details, that make the difference.
Hedging your bets are you?A magneto charging system is a crude, pissy little, badly behaved charging system that may cost you $300 if your battery is disconnected with the motor running..
Someone stick a fork in him I think he's done.
Posting Permissions
