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Do I Need a Third Battery To Run Sonar With A 24-Volt System
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Snowman6479
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If you pull off the positive on the first battery in the series, you will be getting 12v off of it. No need to run a 3rd battery unless you really want to spend the extra money unless you really want to
Snowman, can you elaborate a little because I'm not sure which one would be considered (first) in series. And I need to know where to connect the two pairs of pos/neg leads to?
One pair of wires (pos/neg) powers the lights/bilge/live-well.
The other pair of (pos/neg) wires is for the fish finder.
The last pair is right off the evenrude outboard motor.
In the past, I'd connect all positives to the positive terminal and all negatives to the negative terminal on the single battery that came with the boat.
I recently bought the new trolling motor and an additional battery. I wired them together in series and connected the motor, which ran fine.
So now, I'm not knowing where to connect those other pairs (of pos/neg wires) to?
One pair of wires (pos/neg) powers the lights/bilge/live-well.
The other pair of (pos/neg) wires is for the fish finder.
The last pair is right off the evenrude outboard motor.
In the past, I'd connect all positives to the positive terminal and all negatives to the negative terminal on the single battery that came with the boat.
I recently bought the new trolling motor and an additional battery. I wired them together in series and connected the motor, which ran fine.
So now, I'm not knowing where to connect those other pairs (of pos/neg wires) to?
Zum
Well-known member
I take it that you have a 24volt trolling motor?
If you use just one of the batteries(in the 24V system),that will give you your 12 volts.
You can also just buy a small battery and use that.
If you use just one of the batteries(in the 24V system),that will give you your 12 volts.
You can also just buy a small battery and use that.
The sonar, lights and engine starter need to be run on 12 volts.
If you take a meter to your boat, you'd find that measuring from the negative of the first battery to the positive of the second (in other words, put your meter on the same posts the trolling motor leads are on), you'll have 24 volts. Now, if you put the meter on both the positive and negative of the same battery (doesn't matter which one), you'll have 12 volts, even though the jumper is still connected.
What these guys are saying is that if you put the other leads on the positive and negative of the 'same' battery, you'll still have 12 volts. That said, it's strongly preferable to put it on the first battery in the circuit (battery that trolling motor negative is attached to - think of the power starting there, then gaining 12 more volts as it runs through the second battery - definitely oversimplified, but you get the point). Reason for using that battery is that if somehow the negatives got crossed, and your sonar ended up tied with the trolling motor negative, it still would lead to the bottom battery, and wouldn't give your sonar 24 volts. Were you pulling the 12v off the second battery, crossing negatives would end up feeding 24 volts. Chances of negatives getting crossed are next to none (this is more used in cases with common negatives - such as a car - a shared negative is still workable, even with two voltages), but this is still good practice.
So, to answer your question, connect the sonar/light/engine negative lead to the same post that the TM negative is on, and the sonar/light/engine positive lead to the positive post of the 'same battery.'
Dawson
If you take a meter to your boat, you'd find that measuring from the negative of the first battery to the positive of the second (in other words, put your meter on the same posts the trolling motor leads are on), you'll have 24 volts. Now, if you put the meter on both the positive and negative of the same battery (doesn't matter which one), you'll have 12 volts, even though the jumper is still connected.
What these guys are saying is that if you put the other leads on the positive and negative of the 'same' battery, you'll still have 12 volts. That said, it's strongly preferable to put it on the first battery in the circuit (battery that trolling motor negative is attached to - think of the power starting there, then gaining 12 more volts as it runs through the second battery - definitely oversimplified, but you get the point). Reason for using that battery is that if somehow the negatives got crossed, and your sonar ended up tied with the trolling motor negative, it still would lead to the bottom battery, and wouldn't give your sonar 24 volts. Were you pulling the 12v off the second battery, crossing negatives would end up feeding 24 volts. Chances of negatives getting crossed are next to none (this is more used in cases with common negatives - such as a car - a shared negative is still workable, even with two voltages), but this is still good practice.
So, to answer your question, connect the sonar/light/engine negative lead to the same post that the TM negative is on, and the sonar/light/engine positive lead to the positive post of the 'same battery.'
Dawson
Snowman6479
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A lot of times, but not always, you run the risk of getting interference when hooking a FF up to a TM battery. You can try what the others have recommended about hooking the FF to the 1st battery, but I would just get the smallest riding lawn mower battery you can find and use that to power all the accessories. If you have a cranking battery on a gas engine, just use it. The small deer feeder batteries will power a gps/2d FF for several trips before needing a charge and are about the size/weight of a brick, can say how long a deer feeder battery would power lights and a FF if you are concerned about weight in the boat.
