Marine Batteries - Danger or Electrocution?

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Rushmore12345

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So I have an extremely dumb question to ask.
I am currently building a mini boat from fluted plastic based on this video -
.

In this video, a 1.2HP engine is used. I am thinking about using an electric trolling motor instead as it creates less noise and is less expenisve.


I have chosen to go with the Rhino Cobold 18 lbs Trolling Motor and the Yuasa 12V AGM 22AH Waterproof Battery.

However

I am worried that if the boat capsizes (of which there is a high probability). There is a danger of electrocution. I can't find much info about this, but it seems most people suggest that it will only cause corrosion to the terminals and ultiamtely kill the battery. What is stopping the battery sending a current through the water?

Thanks and apologies for my ignorance.
 
Rushmore12345 said:
So I have an extremely dumb question to ask.
I am currently building a mini boat from fluted plastic based on this video -
.

In this video, a 1.2HP engine is used. I am thinking about using an electric trolling motor instead as it creates less noise and is less expenisve.


I have chosen to go with the Rhino Cobold 18 lbs Trolling Motor and the Yuasa 12V AGM 22AH Waterproof Battery.

However

I am worried that if the boat capsizes (of which there is a high probability). There is a danger of electrocution. I can't find much info about this, but it seems most people suggest that it will only cause corrosion to the terminals and ultiamtely kill the battery. What is stopping the battery sending a current through the water?

Thanks and apologies for my ignorance.
Click to expand...
You need volt, lots of them, to electrocute someone.

You could put one finger on one terminal and another on the other terminal and not feel a thing.
 
Most people are right; with 12VDC electrocution is highly unlikely. The reason is not trivial because what kills a human is the current through his/her body and not the voltage; while a 22Ah battery is able to abundantly provide the killing amperage, the resistance of a human body will not allow a 12V potential to produce such a current (at least in the 99.99% cases!).
The problem you pose is not trivial either; you should have your battery enclosed in a waterproof case and an EXTERNAL sensor that sends a signal to an INTERNAL device able to cut the power at the outgoing wires.

Daniel
 
Rushmore12345 said:
I have chosen to go with the Rhino Cobold 18 lbs Trolling Motor and the Yuasa 12V AGM 22AH Waterproof Battery.
Click to expand...

You need a bigger battery. Rhino don't quote current draw for the Cobold, but their other motors running at similar thrust consume 25-30A. The 22Ah battery will only last about 15 minutes before it's flat.
 
danielefua said:
Most people are right; with 12VDC electrocution is highly unlikely. The reason is not trivial because what kills a human is the current through his/her body and not the voltage; while a 22Ah battery is able to abundantly provide the killing amperage, the resistance of a human body will not allow a 12V potential to produce such a current (at least in the 99.99% cases!).
The problem you pose is not trivial either; you should have your battery enclosed in a waterproof case and an EXTERNAL sensor that sends a signal to an INTERNAL device able to cut the power at the outgoing wires.

Daniel
Click to expand...
Ahh thank you so much! This makes so much sense with the research I have done.
For anyone who finds this useful, will put my research here:

Although the physics are complicated, some experts use an analogy of a flowing river to explain the principles of electricity. In this analogy, voltage is equated with the steepness, or pitch, of the river, while amperage is equated with the volume of water in the river. An electrical current with high voltage but very low amperage can be seen as a very narrow, small river flowing nearly vertical, like a tiny trickle of a waterfall. It would have little potential to really hurt you. But a large river with lots of water (amperage) can drown you even if the speed of flow (voltage) is relatively slow. Of the two, amperage is what really creates the risk of death, which becomes clear when you understand just how little amperage is necessary to kill. Different amounts of amperage affect the human body in different ways. The following list explains some of the most common effects of electrical shock at various amperage levels.
To understand the amounts involved, a milliampere (mA) is one-thousandth of an ampere or amp. A standard household circuit that supplies your outlets and switches carries 15 or 20 amps (15,000 or 20,000 mA).
1 to 10 mA: Little or no electrical shock is felt.
10 to 20 mA: Painful shock, but muscle control is not lost.
20 to 75 mA: Serious shock, including a painful jolt and loss of muscle control; the victim cannot let go of wire or another source of shock.
75 to 100 mA: Ventricular fibrillation (uncoordinated twitching of ventricles) of the heart can occur.
100-200 mA: Ventricular fibrillation occurs, often resulting in death.
Over 200 mA: Severe burns and severe muscle contractions occur. Internal organs can be damaged. The heart can stop due to chest muscles applying pressure to the heart, but this clamping effect can prevent ventricular fibrillation, greatly improving the chances of survival if the victim is removed from the electrical circuit.
Regardless, investing in a A marine battery box would be a good idea.
A marine battery box is intended to keep a trolling motor battery enclosed and secured, prolonging the useful life of the battery and protecting it during transport and use. Exposure to fresh or saltwater can cause corrosion to the trolling motor batteries. To prolong the usable life of your trolling motor battery, a battery box power center can be used to protect the battery from corrosive elements such as water. A marine battery box prevents the battery terminals from making contact with other metal objects, which can cause short circuits and pose risks to the user. The battery box gives us the assurance that the battery connections are secure by keeping it sealed and exposed; thus, reducing the chances of the passengers getting shocked. Without the battery box, high powered batteries can generate dangerous voltage that may cause electrocution. Furthermore, when batteries are open, the electrolyte it produces is toxic and dangerous when it comes into contact with the skin and eyes.
 
Molteni said:
Correct, it's only AC (Alternating Current) that kills.
But a 12v DC system could still be unsafe, from acid spillage, short circuit etc
Click to expand...
Absolutely wrong. AC is more dangerous than DC because it causes the muscles to contract meaning that if you're gripping a live wire you won't be able to release it. With AC the muscles will pulsate and so there's a good chance of releasing. None of this applies at voltages as low as 12v. The voltage at which things become dangerous depends on the conductivity of the circuit ( mainly the dampness of the skin) but will be greater than about 50 volts.
 
reeac said:
Absolutely wrong. AC is more dangerous than DC because it causes the muscles to contract meaning that if you're gripping a live wire you won't be able to release it. With AC the muscles will pulsate and so there's a good chance of releasing. None of this applies at voltages as low as 12v. The voltage at which things become dangerous depends on the conductivity of the circuit ( mainly the dampness of the skin) but will be greater than about 50 volts.
Click to expand...

As an aside to anyone interested, and not relevant to the use case here, but 12 Volts can kill if it gets in the wrong place in the body. This is important to medical instruments used during some types of surgery. It's important to prevent currents of more than 10uA away from the heart. The resistance of the inside of your body beyond the skin is sufficiently low that currents greater than 10uA can be conducted even at low voltages. This can be lethal if it traverses the heart. There are strict standards on medical instruments that must be adhered to to limit any currents to less than the safe level, which means low voltages. It's all a bit theoretical as the risks were identified early from animal testing and the standards have been in place for decades, so there are no reported deaths.
 
Rushmore12345 said:
I have chosen to go with the Rhino Cobold 18 lbs Trolling Motor and the Yuasa 12V AGM 22AH Waterproof Battery.
However
I am worried that if the boat capsizes (of which there is a high probability). There is a danger of electrocution.
Click to expand...
You will NOT be electrocuted in the above scenario
 
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