Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Puzzle: Construct 12/24 volt dual system

Status
Not open for further replies.

afishyfella

New Member
Currently I have a boat where the outboard and electronics are wired to one 12 volt battery and the trolling motor is wired to a second 12 volt battery. I am wanting to purchase a new trolling motor that is 24 volts, however, I do not want to add another battery to make 3 batteries total in the back of the boat. I do not have a place anywhere else in the boat to add another battery. Space is at a premium and every bit of weight saved is fuel saved on my boat and on my truck.

Is there a way to build a circuit to utilize the existing two batteries where the trolling motor will receive 24 volts and the outboard and accessories will receive 12 volts. Also, the outboard will need to be able charge the starting battery at 12 volts when running. I'm aware of switches I can add to be able to switch between 12 and 24 volts, however having to go to the back of the boat to switch every time I move to a new spot will be a hassle. Yes folks, I know, I am wanting my cake and eat it too. But cake tastes good when made right. So, can this be baked or am I dreaming of pie in the sky? Thanks for your help in advance.

Sincerely,

afishyfella
 
What is the current requirement of the 12 volt electrical system?
 
The 12 volt outboard as he stated already buteman?
 
Hei, why don't you just use a power divider with two resistors of same size to feed the accessories?
 
cabelyn, 50% power loss as pure heat?
 
Wouldn't you just leave all the existing equipment connected as is, but, run new cables in series configuration between each battery so only the trolling motor is seeing 24v..
That way the alt can still charge the starting battery. A electronic isolator could be used to make sure the starting battery gets charged first, then the trolling motor battery gets topped up when the starting batt is full.

Depending on the draw from the trolling motor, a 12v to 24v inverter could be used if you don't want to use the starting battery to make the 24v.

If the 2 batteries drop the alternator voltage while charging reducing the charge potential, and the alternator has a reference wire, place a silicon diode in the reference wire to cause a voltage drop to make the alternator increase it's voltage. That way the reg regulates the voltage and when you add a load, the voltage drops, and the alternator can mitigate the voltage drop, to a point, under load.
 
Last edited:
From your post it sounds like you don't need to charge the trolling battery. If that's the case it's easy (see below) if you need to charge both it will be more difficult.
 

Attachments

  • bat.PNG
    bat.PNG
    58.2 KB · Views: 230
Sorry Sceadwain, not trying to be confrontational here, but if they are both charged from same source they are in parallel and are, in effect, a single battery. Which may mean they are, at present completely different circuits. I see this as meaning we need this information first.
 
Last edited:
afishyfella, how much current does the trolling motor draw? There should be a nameplate on the motor with this info. Or, perhaps, you have an ammeter and can measure the draw.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top