Wing Nuts and Charging Cranking Battery

[KellyJoe]

I have read a bit lately here that wing nuts aren't preferred on batteries and I don't know if I disagree or not.

My question is this. What would the difference be between a standard hex nut on top of a lockwasher vs. a wingnut with the same or more surface area on top of the same lockwasher cinched down w/ a pair of pliers? Not trying to start a fuss really. Just curious because when I bought the boat, the mechanic purposely took off the hexes and put on wingnuts as described above saying that it would be okay as long as the lockwasher stays and they're tightened enough not to back off.

Second question. My boat sits in the basement more often than I'd like and occasionally I'll charge the cranking battery the night before for peace of mind. I have always disconnected the battery before charging but was wondering, is it necessary to disconnect it? '04 Johnson 150

[RUSTY63]

My opinion, the wing nuts will come loose, I have seen them tightened with pliers and they still come loose, the hex nuts will not come loose.

I prefer nylon lock nuts with star washers.

It is not necessary to disconnect the battery when charging.

[KellyJoe]

Thank you much. I knew it would be quick. Disconnecting the battery is the only reason I left 'em on. Nylocks it is then.

[SEAHORSE]

What does your '04 owners manual say about battery wing nuts?

Johnson and Evinrude have been harping about using hex nuts (stainless steel, of course) and lockwashers for 20 years now.

[KellyJoe]

I would definitely have to look that up. I haven't seen it in there but that doesn't mean it's not. I am fanatical about checking the tightness of them every time I open the back hatch but now that I'm clear on the battery charging, I'll for sure go to the star washers and nylocks. Thanks for the resposes and harping enough here to prod me into asking in the first place.

[SEAHORSE]

Also make sure your batteries are protected inside a battery box or they have the rubber "boots" over the terminals to keep metal objects from causing a short should they fall on the battery. The lead terminals and the battery cable ends should both be shined up with a abrasive pad or wire brush before installing, for a good contact. Don't just bolt up a dull copper fitting to a gray battery post, you want both to shine so they happily let electrons run wild when they are fastened securely. A happy electron is a good electron!

[RUSTY63]

All Electrons should have rubbers......That way there are no stray Electrons running around that you don't know about....

This post made me laugh....Thanks Seahorse.

[Nauti Buoy]

I would also suggest you apply OMC Anti-Corrosion Spray, or similar product, to the battery terminal connections.

[centerc]

If thw wing nut backed off would that cause harm to the engine? or would you just have to retighten them?

[AB]

If a wing nut backs off, the intermittent conection created can send voltage spikes through the system. The hi-dollar computers on these motors now days don't like voltage spikes very well...

[jimh]

In a 12-volt system large currents can flow, particularly during starting. In addition, the starting motor has a winding which creates very strong magnetic fields. If the circuit opens at this point, as may happen if there is a loose connection at the battery due to a wing nut, there can be high voltage transients generated, much greater than the 12-volts from the battery. I explain:

When the motor is cranking there are strong magnetic currents created. If the motor winding circuit is opened suddenly and the battery is removed, the energy stored in the magnetic field of the motor begins to collapse. A changing magnetic field cutting through a coil induces a voltage into the coil. The voltage is proportional to the rate of change of the magnetic field. In this case the field is collapsing nearly instantaneously. This effect is called a back-EMF. If the battery is connected, it tends to absorb and limit the voltage rise of the back-EMF. But, if the battery is not connected, the circuit impedance is much higher and the voltage generated can be very high, often many times the 12-volts that generated it originally. This high-voltage spike can cause other devices still connected to be damaged.

I had read about this effect for many years, but I was somewhat skeptical. One day I was working on some ancient (c.1940) relay logic systems which used 24-volt relays. I had my finger in contact with a relay coil when the voltage was cut to the coil and the field collapsed. I got such a shock I yanked my hand out of there at 100-MPH and wiggled in pain. Ever since then I have been completely convinced about the potential for low-voltage circuits to develop high-voltage transients.

[rudetech1]

It really doesn't matter if we like wing nuts or not, the owners manual says not to use them!! You'll really find out why when you overtorque the wing nuts and the ears break off and you are left with nothing!! This happens especially with the "stamped" type wing nuts. Why not use what the owners manual says and be done with it, then you won't have to listen to me preach about my pet peeves!!