Nissan 6 HP 4 cycles

[ariel417]

I just purchased a tohatsu 20" sailmaster. Fingers crossed! Ill report back when I have used it a few times. It seemed to be the best deal, and it will charge batteries while running. I see the 20" version of the sailmaster was not offered in the nissan badge. If they are the same engine, I wonder why it is available in one brand and not the other?

To those that already own this engine, how good is the charging system using basic necessities? Example, vhf, gps, led cabin lights, anchor light.

[pbryant]

> To those that already own this engine, how good is the charging system using basic necessities? Example, vhf, gps, led cabin lights, anchor light.

Beware: the output is unregulated half-wave (uni-polarity) AC. If you look at the output of a typical outboard generator on an oscilloscope, it's half wave pulses that peak around 18 volts. Unless that model is more sophisticated than most - the generator is intended to power incandescent running lights on a skiff that's underway at night - not sensitive electronics like radios and GPS receivers. Incandescent bulbs are rather insensitive to the non-uniform current, and their filaments stay hot when the voltage dips to zero for tens of milliseconds at a time (which is why they work as well on AC as DC current).

LED lights that are rated to handle 24 volts or more (most these days have regulators to allow dual 12/24 volt power) will probably tolerate the spiky voltage, but you won't like the flicker you'll get at low RPMs, without a battery to smooth the voltage. For powering ONLY LED lights (not electronics) you could use an electrolytic capacitor in place of a battery to stop the flickering, but to be effective at low RPMs, it would have to be huge.

While it can be used for short duration and occasional charging of a battery that is large enough to absorb and smooth out the pulses (multiply the generator's rated output current by 10 - you need a battery of at least that many amp hours), be VERY careful that no situation can ever exist where the battery becomes disconnected so it is no longer regulating the voltage spikes and the generator is powering sensitive electronic systems directly. If it ever does - you may have a very expensive smoke generator, or at least a mysterious source of failing electronics. Transistors don't like transient voltage spikes. Also, you will only get the rated output current when the engine is running at top RPM (in neutral) and making a sound that will likely drive you nuts.

I'd also suggest installing a fuse at the battery terminal rated for the full output current of the generator on the lead from the generator. The generator should have a fuse inside the engine, but if the wiring becomes shorted along the run downstream between that fuse and the battery, there's nothing to limit the battery output current.

If you want to verify what I'm saying and you don't have an oscilloscope: get an 8 ohm speaker you don't care about ruining, connect a 100 ohm 1 watt resistor in series with either speaker terminal (to limit the current), and then connect the generator output to the speaker through the series resistor. Start the engine and listen. If it's DC, the speaker cone will just move one way or the other once and not produce any sound. Instead, what you'll probably hear will sound like a playing card running through the pokes of a bicycle, with the pitch varying with engine RPM.

[maikelc]

Have the same motor in Louise Michel. Took out an old Gray Marine inboard that came with boat. What a nasty job that was. Haven't regretted it once. Have about a thousand hours on the engine, including an eight month trip to Bahamas -Norfolk to Miami, down the ICW, eight hours a day, day after day, that little motor ran like a top.
I have the charging system but haven't used it. Instead we use a 80W solar panel mounted on a raised stern pulpit, with a 15A contoller and two 90AH deep cycle batteries. Powers cabin lights [ some incandescent, some led], running lights when needed, VHF [not always on], GPS. Run laptop, battery chargers [AA, cordless drill etc] and FM radio via a small inverter. Anchor light is a rechargeable lantern hung on boom.
Doubt you'd be able to power all the items you list, about what I have, from engine charger without running it just to recharge batteries but you have to do the math...add up all the items times hours of use, figure in the formulas for inefficiencies, rate of discharge etc.