Saving Old Seagulls

Has anyone set up a regulator to keep from overcharging their batteries. I was thinking of buying an old auto regulator and wiring it up to the to the alternator. I don't have a state of charge meter on my battery now, but even if I did I would be unlikely to be watching it the entire time I was motoring.

Keith

It wont work as car regulators work by controlling the field current in the alternator which then controls the output. The Seagull alternator has a perment magnet in the flywheel for the field so cant be controlled. Maybe a really old regulator off a car with a dynamo, but that would be a collectors item 50 or so years old and have vibrating contacts and be a maintenance nightmare.

There are two possibilities that should work nicely though.

1. Solar panel regulators, they usually shunt excess current once the battery has reached its float voltage

2. lawn tractor regulators - I understand some lawn tractors also use a PM alternator.

Personally I'd go for the solar panel regulator but only if you find you are over charging excessively. As long as you are using converntional flooded cell lead acid batteries, gentle over-charging is not harmfull so long as you keep the cells topped up with distilled water so the plates always remain covered. On a boat where the batteries are frequently partially drained then not recharged till the next day, slight overcharging will be positively benificial.

If however you are usiing AGM or gel cells, YOU MUST USE A REGULATOR designed for them as they do not tolerate overcharging and require a different float voltage to a normal battery.

Most battery metrers are cr@p. All an ammeter will tell you is you are or are not using more than you are putting in. good foor a nice warm fuzzy feeling but not much else. You need a voltmeter that reads between 10 and 15 volts with a precision of 0.01 V. (any decent digital voltmeter will work fine) Even so its only an approximate indicator and you need to refer to the graph for the correct battery temperature to estimate the state of charge.

A microprocessor controlled battery manegement system could do this for you automatically and also keep track of the current in and out and give you very belivable guesses as to how much charge you've got, but would be insane over-kill for a seagull powered vessel and stupidly expensive.

P.S. the voltage measured on a meter out of a Seagull alternator off load is totally meaningless as its unsmoothed and rectified from AC which means the voltage you measured is nothing like what it can charge a battery to. Put an battery on it and see what it does.

I agree with most of what Ian has said but:-

The old car dynamo regulators also controlled the field current but by an elecromechanical device rather than by "eletronics" The control box that housed the regualtor also housed the cut out that connected and disconnected the dynamo from the battery as the volts rose above or fell below its setting. There was also winding on its coil that made it current sesitive as well. Later ones also had a third device in the box that was current controlling. So all in all no more suitable than an alternator regulator.

A solar panel, or wind generator, regulator is a good suggestion but you would have to ensure that it is rated to take the full output from the engine.

Before you do anything monitor the battery volts while you are charging with a decent voltmeter or multimeter. You need at least 13.8 for there to be any effective charging and unless it rises significantly above 14.4 for longish periods there is no need to consider a regulator. Thats for a conventional wet lead acid battery. I guess with a saturated mat type you need to a bit stricter about overcharging. I dont know about gel types.

My guess is that if you have a conventional battery you will not need a regulator. I don't with a "more sophisticated" outboard

With the max output of 4 amps, on a good day with the motor going flat out, it will take a long time to over charge a typical car battery!

How about installing a simple voltmeter with a press button switch to activate it, looking every now and again and if you are worried you have too many amps in the system, unplug it!

If you keep it as simple as you can it will be less likely to go wrong.

I have never heard of anyone complaining they have too much output from a Seagull alternator!

Never heard of anyone having to install a regulator on any small outboard... Let's be honest, if you ran it for 10 hours non stop you would only put 40 amphours into a battery. a 60 amp car battery, if flat will need somethig like 80 plus amphours to charge it!

(You always have to put more in by 25% than you get out!) Even on a good day!


Regards,
john
SOS

Just a few comments about regulators. Firstly car alternators and dynamos regulate their power by adjusting the field current. Permanent magnet machines cannot do this. As to wind generator regulators and solar panel regulators, usually these are completely different animals. Solar regulators usually just switch-off the panel when the battery is full. If this was done to a wind turbine it would overspeed and the blades might come off. Small wind turbines are regulated by dumping the surplus power into some kind of heating element.

As to small flywheel generators there are many techniques used to control the output. The simplest method is used by some mopeds. These have a single phase winding that produces alternating current. As the engine revs increase the voltage also increases and if unchecked itwould blow the bulbs. To prevent this happening a small choke is fitted in the line. As the revs and voltage increase, the frequency of the power increases and this causes the impedance of the choke to rise. It' s not a perfect system but it works.

The 6 volt system used by old British motorcycles was arcane. The headlamp shell would contain an ammeter and the rider could adjust the power with a switch that switched-in extra windings for riding at night. Later on a simpler 12 volt system was used byTriumph Motorcycles. This used an AC permanent magnet alternator, a bridge rectifier and a large Zener diode mounted on a heatsink between the front forks. The original metal rectifiers were unreliable so Silicon rectifiers were fitted at the first service. The 14.5 volt Zener simply dumped surplus energy when the battery was full.

Nowadays the electronics hobbyist is spoiled for choice with things such as the Simple Switcher range of regulators. It is however important to watch out for radio interference. One fiasco that I heard about was the sailor who threw away his wind generator because it caused radio interference. Possibly Fast-Recovery rectifiers had been used in the machine but capacitors are not very expensive!

I agree with our host John.

Keep things simple.
Absolutely no need to over complicate and already tried and trusted system. It worked back then, it will work today well enough for charging a fairly typical wet lead-acid type battery.
An "off the shelf" battery of around 60-80 amp hours should more than suffice the running of a few simple electrical systems on board.
A bilge pump, a radio, some nav-lights and so on shouldn't suck too much juice from a car battery, although i might look into fitting a leisure type battery often found in caravans etc as they have a much deeper charge cycle to them, better suited for a marine application.
Just my two pence worth.


Jon

Actually a leisure style battery is not suitable for boating. A marine deep cycle battery is designed and constructed to absorb the banging and slewing that is part and parcel of the boating adventure (even using a Seagull).

2 types of battery, on many boats. The 50ft yachts I sail have a single cranking battery purely for engine starting, and a seperate domestic battery bank (4 batteries) to power the domestics. These are deep cycle which can take a deeper discharge, and require a longer slower charge to bring them back up. Car batteries are cranking batteries, as everything runs off the alternator.

The cranking battery can be linked into the domestic bank in a flat situation to start the engine on the boats I sail.

As for the seagull alternator, its not much more than a trickle charger to maintain the battery on a smallish vessel. As mentioned before, perhaps some nav lights and a VHF etc.