Off-Grid Boat: DIY Electric Boat Motor Assembly - Ep. 9

[@modularhippo]

Join me in building a powerful off-grid electric boat motor-step into the future of sustainable boating!

[@ElectronTinkerer]

I guess the contactor is a safety measure that allows you to make sure that the motor doesn't spin even in an event of the controller malfunctioning. And you can also avoid standby consumption of the controller.

[@modularhippo]

Thanks Keyem, makes sense. Seen allot of setups where this is not used so a bit confused as to why this has not become standard. Sound like an obvious safety feature that should be a given for a setup like this. Thanks for taking time to elaborate.

[@petch41]

Electronics up, water down. Gravity is not your friend with leaks in that setup :)

[@modularhippo]

Hi Petch - Thank you for comment. Please expand, are you saying that I should not mount the motor controllers below the pumps and reservoirs in case of a leak?

[@petch41]

@@modularhippo Just a general observation :) The most lightly place for a leak is the unions at the end of pipes. If your reservoir and pumps are above your electronics any leaks will flow down. If your pumps and reservoir are at the bottom then the only place they can drip is to the floor.

[@modularhippo]

@@petch41 Makes perfect sense, big thanks:) For this setup I will keep the controllers where they are mounted based on length of cables I use but with your advise I will definitely have them covered with something as and when I start topping system up with water:) - It is great advise as I did not think that far!:) Thank you for taking time to flag it:)

[@emreesen1468]

I totally agree. water systems down electrical is higher than water systems just to be sure when you are installing to the boat

[@clivestainlesssteelwomble7665]

It also helps in keeping things working if water gets into your hull bilges elsewhere ... Keep battery's and controllers higher up unless they are water tight. It can save you money as well .. See how Windelo's organise their electric motor bays ..

[@Lagittaja]

5:20 keyem4504 already said it but it's basically a safety. Think of it like your car key, the switch has off run and start positions. What you show is basically how you will have off vs run. No reason to always have power going to your motor controller. As for the part itself, a contactor is a relay that is meant to handle higher currents than a relay. Critical thing is whether it's rated for AC or DC. Difference is the physical design and material choices. AC voltage goes high low high, constantly crossing 0V. That means the current also goes up and down. This makes disconnecting AC easy because eventually the voltage and current will fall to zero so no arcing. DC on the other hand is always high so there will be arcing and the contacts need to be able to handle that.

[@modularhippo]

Morning Lagittaja. Thank you for expanding. Just so I get this right. I turn the on/off switch for the motor controller and this will open the circuit to provide the 18w to the DC contactor to kick into action and open current. If something goes wrong with controller then contactor lose the 18w and acts like a kill switch (no power to controller and therefor no power to motor) adding extra layer of security (with trade of using an extra 18w). Getting there slowly😅

[@Lagittaja]

@@modularhippoI will type relay instead of contactor as relay is easier to type. You turn a key switch or you flip a switch, that provides power to relay coil only. Battery positive goes through relay contact and then to motor controller input. When relay coil is energized, the relay changes state, for example closing the contacts (normally open).

[@Lagittaja]

Relays typically have the following labeling on the various terminals. A1 and A2 is basically the coil of the relay. A2 is negative or neutral. A1 you provide voltage which energizes the coil, making the relay contact change state (for example off to on) Typically relays have multiple contact pairs and as such are labeled xy where x tells you which relay contact it is and y tells what type it is. The most common types are normally open (3 and 4) or normally closed (1 and 2) Therefore a relay might have contact pairs labeled 13/14 and 21/22. Contactor contact pairs are typically labeled just 1/2 3/4 5/6 and they will separately say next to the numbers is the type NC or NO. In your case, I assume the wiring would be Battery positive to switch > switch to contactor A1 terminal. Battery negative to contactor A2 terminal. Battery positive to contactor 1 terminal Contactor 2 terminal to motor controller input.

[@modularhippo]

@@Lagittaja Thanks Lagittaja!!:) Starting to get a better idea now:) Legend!

[@Lagittaja]

@@modularhippo I forgot to add that the labeling I described is for the electrical industry. Automotive stuff has their own thing, for example 85/86 is the relay coil. Check DIN 72552. What the marine stuff uses for labels, I have no clue. But the basic principle of operation is the same.