More Yamaha outboard nonsense

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Lucas shops

[/ QUOTE ] Lucas shops ....... history I'm afraid.

I have reservations about a relay or similar to disconnect the battery from the outboard charging circuit. "They" say that it will damage the rectifier.
We know it does if you do it to a proper alternator but maybe it will do the same with an outboard. Personally I doubt it but I am not going to try it 'cos my engine has a built in 3 phase Evinrude rectifier which would cost many arms and legs to replace.

The output from an small outboards charging circuit really is no problem unless perhaps you have a very small battery. It was never any bother when I only had a 45Ah leisure battery, in fact I had to take that home periodically to charge it until I got the Solar panel. A 5 watt panel did not need a controller either even though it was connected 24/7.
 
The plot definitely thickens... I re-united my engine with the boat today, and as soon as I connected the charging plug the engine cut out. Having checked that the charge regulator wasn't shorting I tried connecting a 25w bulb to the charge line and this stopped the engine without ever illuminating.

While the obvious is that the AC output is so meagre that any draw causes a voltage drop which stops the ignition system working, I wonder if there is any possible fault in a rectifier which might show up in this way?

Wishful thinking I am sure - my money is on the minimum generation theory.

Looks like you get what you pay for.
 
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and as soon as I connected the charging plug the engine cut out.

[/ QUOTE ] Very puzzling and clearly not right. You should be able to power a 25 watt bulb, a 60watt bulb for that matter, with no problems but I dont know what the specs are for a charging coil on your engine

As I said earlier it is really only small Johnsons and Evinrudes that I know much about BUT I would not expect there to be any connection between the charging circuit and the ignition circuit. I'd expect the charging coil to be a separate unit feeding out to the rectifier with no connection with anything else.

Sounds as though there might be some mix up with the wiring.
 
Regulators

sailboatamelia said:
The "alternator" on the Yamaha 9.9 is actually made up of a couple of coils under the flywheel that generate AC into a rectifier assembly when a magnet in the flywheel passes by. A pretty blunt instrument indeed. You would have to get into the motor's guts to find a way to reduce the charge voltage.

The problem is that I can't merely reduce the maximum output voltage, as that will also cut output at lower RPM's. What happens is that when the batteries are getting near full charge, the voltage starts creeping upwards, and can reach 16 or 17 volts, which is hard on the house battery.

I have to constantly monitor charging voltage and when it gets above 14.7 volts, I have to turn on the cabin lights, etc. to get the voltage lower. That's really not satisfactory. As I mentioned, my owners manual recommends buying an optional regulator from my Yamaha dealer for just this situation, but no dealer globally seems to be aware of it's existence.

The cables from the engine to the battery are used for both supplying power to the starter, and then to provide charging to the batteries. I need to limit the charge voltage to 14.7 volts, and whatever rectifier/regulator is built into the motor doesn't do that.

I tried asking Yamaha, since they vaguely mention the existence of such an animal in the literature that came with the motor. After going in circles between the company, and the numerous dealers they referred me to, nobody has a clue. I have found some regulators designed for solar panels, but they don't take into account supplying heavy (100 amps!) current back to the starter motor.

Thus is my predicament when it comes to safely charging the house (other than using a separate on-deck generator, or going totally solar).
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There are many ways of solving the problem but firstly I'd like to say that regulators for solar panels are quite different from regulators for wind turbines (usually). For the solar panel the normal method is to have an electronic switch that disconnects the panel when the battery is fully charged. If this type of regulator was used on a wind turbine the machine would race when the battery was charged as there would be no load to slow down the blades. Usually a wind generator regulator is a high power resistor into which the surplus energy can be dumped. When the battery is full a transistorised switch sends the surplus power through the resistor. A similar method was used on British motorcycles in the 1970s however the switch and resistor were not needed. Instead a large Zener diode was used to dissipate the surplus energy. It was mounted on a heatsink between the front forks. In short, either the humungous Lucas zener diode would do the job OK or alternatively a wind turbine regulator. The solar regulator might be a bad choice because switching inductive loads causes voltage spikes. Avoid "fast recovery" diodes as these are liable to cause radio interference. Good luck!
 
sailboatamelia said:
Here's one for the more mathematically/electrically inclined.

I have a Yamaha 9.9hp 4-stroke electric start as our main engine. I want to be able to continue to charge the starter battery as needed and then via an A/B switch, trickle charge the house batteries.

The Yamaha ignition system is AC with a rectifier, not an alternator. There is no regulator. The battery leads from then engine outputs 13 amps DC at 13.5 volts, thus producing 175 watts. This being the case, I want to make sure I don't over-cook the house battery bank with 13a when only a 2a float charge is required.

As silly as it may sound, I'm toying with the idea of simply connecting a 150 watt, 240v inverter to the 13 amp 13.5v engine output to run my 240v shore-power battery trickle charger. In essence, I would be using the 240v inverter as a regulator between the engine and the batteries.

My shore power charger 240v mains supply specs:
Charging at:
2a draws 0.16a off the mains,
4a draws 0.26a
8a draws 0.51a
16a draws 1.04a

As long as I set it to only a 2a charge, a 150w inverter should be more than enough. Indeed, an 8a charge would only require 122 watts.

My question is; while motoring, would I be able to do a 2a trickle charge from the 240v mains charger (which requires 38.4 watts) using a 150w 12v inverter which supplies the 240v?

I'm sure I'm missing something obvious here, or my math is wrong, but if it works, it would enable a more stable charging environment for the house batteries.

The mains charger automatically adjusts its output to maintain the proper charge and gives a nice digital readout of amps, volts and percentage of charge. Also it would be nice to leave everything connected when we simply want to re-plug into shore power again.
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Sorry can I start by asking you a question ..the battery you want to charge is a normal 12v lead acid battery...not a dry one.. if so it should be easy and only cost you a few £... in components. The idea of converting up to 240v and back is very inefficient
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you have low voltages and need low voltages... I just need to figure out how to send you a diagram via this forum TrevorB new member and an Electronics engineer,
 
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