RAB

Farymann Charging

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I have a single cyl. Farymann diesel in my boat. In lieu of having a conventional alternator and regulator it has a "flywheel dynamo" with a voltage regulator.While motoring the other day at cruising rpm I checked the voltage and it read 15.9 to 16.1 volts.  I should note that I had never checked the voltage after running about an hour at this rpm.  The voltage at idle it was reading around 13.6 volts. My electrical system is very basic with one battery.  Since 16 volts seems a bit high I have done the following:

Checked voltage with multimeter  and verified the voltage at the battery was 16 volts.

Battery and cables are not at all warm to touch.

Checked electrolyte levels and were found to be OK

Cheeked electrolyte specific gravity and all cells were OK.

I have been searching for a new voltage regulator to install and see if that solves the problem but have been unsuccessful locating one.  The existing regulator has the following info: ZEM 343542  8504  12V  18A  

Any help with diagnosing the problem or locating a new regulator would be appreciated.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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I know nothing about farymans 

check mainesails website for charging voltage (compassmarine)

if your battery is happy, why change the regulator?  16 v may be a little high but magneto generators are pretty simple

agsin if you are not losing water and battery life is ok I’d keep sailing

p

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Moonduster - thanks for the manual reference.  Apparently it should be putting out 14.2 - 14.5 volts..  The search will continue for a new regulator.

In the mean time I will continue as is and monitor the battery.

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The Farymann itself is a fantastic little thingie. I abused mine for 30 years with not much maintenance, and it just worked perfectly all the time. ( Though I had some issues with the hydraulic propulsion that was fitted to it).

LeCanard

 

 

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Applying 16+ volts to your battery is like applying a continuous equalization charge and cannot be good for the battery. You should correct this if possible. I am no expert in this, but I will hopefully move the conversation forward and then Moonduster can chime in to correct me.

A Google search found this which is a surplus rectifier voltage regulator for a Ducati motocycle. It looks very similar and the number is the same except for the last four digits. http://www.surplusman.com/Detail.php?itemid=2369. This is a clue. 

The built in "dynamo" on your engine is like an alternator but it uses permanent magnets instead of the electromagnets of a modern alternator. This is old skool. A modern voltage regulator varies the voltage applied to the field coil to vary the magnetic field and thus control the output of the alternator. Your dynamo must use another method of controlling the voltage output. Your Zem is a combination rectifier (turns the AC current into DC using a diode bridge) and an electro mechanical regulator (coils and vibrating contacts control the voltage). Look under the hood of an old car and you will see this bolted to the inside of the fender. The mechanical components of the regulator get weak with use and the voltage wanders. Perhaps you can use a cheap generic auto "regulator" rated >= 18 amps intended as a replacement for old cars.  Its a cheap experiment. 

 

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On further search, these combo rectifier regulators are used on motorcycles and outboard motors. Probably because they embed the "generator" into the engine so they don't include the rectifier and bridge within the "generator" casing. Here is a youtube about replacing the vibrating shim that controls the voltage output. 

https://www.youtube.com/watch?v=0bN9sHL-hjs

 

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How much do you run the engine?  If you run it just enough to get in and out of the marina, it may not matter.  Check the electrolyte level in the battery often and top it up with distilled water, and save your money.

These permanent magnet alternators are regulated using a shunt regulator.  Essentially it's a variable load that wastes enough current to get the voltage down to the desired level.  While the original regulator could be electromechanical, you can use an electronic one.  You may be able to find an older-style shunt charge controller for solar panels that will work.  Finding one that has a sufficient current rating may be problematic.

Another alternative to consider, depending on your goals for the boat, would be to add a voltmeter and a manual switch that turns on a 5-10 amp load, then regulate the voltage by switching the load on and off as needed.

Here is the loading resistor you would need:

https://www.mouser.com/ProductDetail/ARCOL-Ohmite/HS100-2R-F?qs=sGAEpiMZZMtbXrIkmrvidNw3CpujCJIJOCvUg6rlzznafAjko4zl0A%3D%3D

They're like $11 each plus freight.

That will give you around 7 amps at 14 volts.  If that isn't enough, use two.  Any switch will work.

You can wire it in parallel to the wires from the generator to the regulator.  That way, it will burn AC and keep the rectifier cool, and it won't drain your battery if you forge to turn it off.

The voltmeter would still go on the battery side of things (between + and ground).

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Thanks to all who have taken the time to respond.  Phtt - I saw the regulator on e bay but unfortunately it was sold and they did not any additional.  I would have tried it.  Electronics is not my strong suit and if I can't come up with a replacement I'll have to explore other options.    2airishuman - Adding the resister and switch may be a good option if I can't find a workable regulator.  

Again, thank you for your replies.

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I am thinking my old Harley Sportster used the same style voltage regulator. You may find a few of those for sale if look in the right places. The permanent magnets in the clutch basket put out 50 volts from the two wire plug, then the regulator took that down to 14 v dc. Just pointing out some options, hope it works out for you

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Rab

i saw that the Ducati reg was already gone. I showed it because its a clue that a motorcycle reg will probably work. See what Monsters said about his sportster. Harley baggers like to hang a lot of farkles on their machines so the regulators will likely have the necessary amperage rating.  I saw prices around $50 to $100 so cheap and easy fix. 

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Ptjure and Monsters

I have tried a Ducati and Triumph dealer with no luck but did not consider Harley.  I'll give that a try.  

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Good find riley. I suspect you solved it. 

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Thanks Ryley.  I just took delivery of this item and it looks promising.  The connection symbols match and physical dimensions are identical.  One thing I was unable to get from the Mfg. was the amp rating of the unit but hopefully that should not be a problem.

I intend to install it today and see how it works.

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