Hi All,

I'm hoping some of you help me out.

I want to make a power box for my trolling motor. Using a weatherproof case, I want to put a battery, charger and a combo voltmeter/USB charger inside. On the outside would be power connections, the voltmeter display and an on-off-on switch. I want to use the switch to switch between charging mode and trolling mode. The idea being when I want to use it to power the trolling motor, I plug the motor into a power connection, set the switch to one of the "ons" and when I want to charge, I connect 110v to a separate connector and set the switch to the other "on" and let it charge.

The trolling motor is 50 AMP draw. So I think I need a relay and a circuit breaker. The charger is a 10 AMP draw, so i think I need a relay for that too. I made a wiring diagram (attached). I'm kindly asking for any input anyone is willing to provide.

My questions are:

Is my diagram accurate?
Am I doing this right?

Thanks!
Dane
Budd Lake, NJ

 

Hi All,

I'm hoping some of you help me out.

I want to make a power box for my trolling motor. Using a weatherproof case, I want to put a battery, charger and a combo voltmeter/USB charger inside. On the outside would be power connections, the voltmeter display and an on-off-on switch. I want to use the switch to switch between charging mode and trolling mode. The idea being when I want to use it to power the trolling motor, I plug the motor into a power connection, set the switch to one of the "ons" and when I want to charge, I connect 110v to a separate connector and set the switch to the other "on" and let it charge.

The trolling motor is 50 AMP draw. So I think I need a relay and a circuit breaker. The charger is a 10 AMP draw, so i think I need a relay for that too. I made a wiring diagram (attached). I'm kindly asking for any input anyone is willing to provide.

My questions are:

Is my diagram accurate?
Am I doing this right?

Thanks!
Dane
Budd Lake, NJ

Hi,

Another Jerseyian, I feel sorry for you
I am from (central) NJ also and I feel sorry for myself too

You will have to make a clearer drawing. It is unclear how you are powering the relay coils.

 

Looks like you maybe shorting wires. Do a clearer schematic and try again.

 

Thanks!!!

OK. I gave it another try. Still learning so I appreciate your help. The way I envision it, the 12V battery powers the relays. If I understand how a relay works, I am putting power through the switch onto the low amp coil of the relay. That will engage the coil and connect the same 12v battery to the circuit break then to the high amp trolling motor.

When I turn the switch the other way. the relay is engaged again, but this time it allows the charger to send power to the battery.

When the switch is in the off position nothing gets power.

Thanks Again!
Dane

 

What is the amperes for the trolling motor at stand still and full throttle?

 

42 Amp Max. Not sure of the other throttle settings. It has five speeds, so I'd guess a range between increasing by 8 Amps per speed.

 

Looks good enough to me if your looking for approval. You may want to measure the amperage on the motor from stand still and full throttle, because it may rise above 50 amps briefly.

 

Thanks!!!

OK. I gave it another try. Still learning so I appreciate your help. The way I envision it, the 12V battery powers the relays. If I understand how a relay works, I am putting power through the switch onto the low amp coil of the relay. That will engage the coil and connect the same 12v battery to the circuit break then to the high amp trolling motor.

When I turn the switch the other way. the relay is engaged again, but this time it allows the charger to send power to the battery.

When the switch is in the off position nothing gets power.

Thanks Again!
Dane

Hi,

That looks reasonable, as long as the "Charger" has polarity such that the positive battery terminal is on the right and the negative on the left, in this last drawing.

 

Thanks so much! I'm so excited to make thing. I saw a few on YouTube, but all the ones I saw were running the motor directly through the switch. To me that seemed like a bad idea to have that much amperage going through a little switch. Others were using the circuit breaker as the main switch but that seemed to defeat the purpose and thought that would affect the life and functionality of the circuit breaker.

I know enough about circuitry to get me in trouble but want to be better at it.

I'll post when I have it done.

Thanks again!
Dane

 

I see one big problem which is that there is no "off" option. Either the troll relay is on or the charger relay is on. And so the battery will run down when neither is being done. OR you can use a three position sw2itch wit a center-off position, one way to enable charge, the otherway to enable troll, and the middle switches it all off..

 

Yes MisterBill. That's exactly what I planned on doing. I think they are called "On-Off-On" switches. At least that is what they are calling them when I look for them. Thanks! Cheers!

 

Yes MisterBill. That's exactly what I planned on doing. I think they are called "On-Off-On" switches. At least that is what they are calling them when I look for them. Thanks! Cheers!

Oh one thing though.

Do you have the wiring right to the relay contacts? It looks like the switch still has to carry the full battery current.
The contacts probably have to go right to the battery, the switch just to the relay coils.
Sorry about that must have looked too quickly.
See attachment. New wires shown in light blue, old red wires cut in two places. Note the switch controls only the relay coils not the contacts. Also, is the volt meter connected the way you really want it to be? If you want to monitor charging voltage it's not connected right, but maybe you want to measure the voltage regardless what mode the circuit is in, charging or not charging.
Another thought would be, is it possible for you to charge while the circuit is supplying power to the motor? That might be a possibility.

The switch would then be on-off-on or SP3T.

 

Very seldom is mains power available for charging while actually using a trolling motor.
That is why we do not see mains powered induction motors used for the trolling motor application.
Most water-craft large enough to have "mains power" on-board are a bit too large for the typical trolling motor.

 

Very seldom is mains power available for charging while actually using a trolling motor.
That is why we do not see mains powered induction motors used for the trolling motor application.
Most water-craft large enough to have "mains power" on-board are a bit too large for the typical trolling motor.

Hi,

Oh if this is only going to be used for that purpose then I have to agree.

 

Hi,

Oh if this is only going to be used for that purpose then I have to agree.

The drawing in post #12 clearly shows a trolling motor wired into the system. Therefore my guess is it s for powering a trolling motor. The TS was very good about clearly stating the purpose of the project, and I appreciate that clarity.

 

Yes Mr. AI.... Thank you! That makes much more sense to me now.

Thanks MisterBill2,.

I probably should have clarified. This is to put a trolling motor on my fishing kayak. I have an Old Town Sportsman 120. I didn't opt for the pedal ($1000 add on) or trolling motor ($3000 add on battery not included). I love it, but after a long day on the lake in the sun, paddling back is a bit much and it always seems to be into a headwind LOL. I found a Lithium Ion Battery that is rated at 100Ah. I figure I can get close 2 hours at full speed and longer at lower speeds. I want to make a battery box using a pelican case to hold the battery, charger and waterproof connectors.

Thanks again for everyone's help.

Dane

 

OK, that project makes a lot of sense, But if your Pelican case is like my "Zero" box, there is no electrical insulation on the inside. So in that case it means extra attention towards insulating all of the electrical connections. I am guessing that the trolling motor has it's own control box, not sure if that box would be inside the Pelican case or closer to the motor for easier operation.

 

The drawing in post #12 clearly shows a trolling motor wired into the system. Therefore my guess is it s for powering a trolling motor. The TS was very good about clearly stating the purpose of the project, and I appreciate that clarity.

Yes, I know that, of course, but you never know who else might read this thread too, or a change of application for the original thread starter.

 

Yes Mr. AI.... Thank you! That makes much more sense to me now.

Thanks MisterBill2,.

I probably should have clarified. This is to put a trolling motor on my fishing kayak. I have an Old Town Sportsman 120. I didn't opt for the pedal ($1000 add on) or trolling motor ($3000 add on battery not included). I love it, but after a long day on the lake in the sun, paddling back is a bit much and it always seems to be into a headwind LOL. I found a Lithium Ion Battery that is rated at 100Ah. I figure I can get close 2 hours at full speed and longer at lower speeds. I want to make a battery box using a pelican case to hold the battery, charger and waterproof connectors.

Thanks again for everyone's help.

Dane

Just make sure you have a very nice long 120vac wire (1000 feet might do it) to run out to the boat from an electrical outlet on shore so you can charge the battery while you fish (just kidding here as per some other replies, ha ha).

 

Now there is a question about the charger, and if it can stay connected to the battery when it is not charging, and not cause any problems. If that is the case then the whole project becomes very simple: Keep both the charger and the connector for the trolling motor directly connected to the battery, with appropriate fuses, and no relay and no switches.
Certainly adequate precautions to avoid accidental shorted circuits will be required, but that was the case no matter what.

So the big challenge is discovering if the charger is OK to leave connected when it is not charging. That may possibly be determined by examining the charger's data sheet and user instructions, iif they are available.
If no information is available, then a suitable current meter can be used to verify that the charger does not draw any current from the battery while connected but not charging. The meter will need to be able to measure current in both directions, which is usually possible with many digital multimeters.