Trolling Battery ?

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I know this has been covered but I was unable to find it. Bought a terrova with Ipilot last year (12v) and it eats up my single battery pretty fast. I'm pretty sure I need to get a second battery and wire them in PARALLEL to increase trolling time. Can somebody confirm how to connect the two batteries together.

Also, i have a one bank on-board charger.....will this charge both batteries if they are connected together?

Thanks..

[remington 300]

brokeline, theres a post on this very subject in the boats/motor threads,

www.hotspotoutdoors.com/forum/ubbthreads...ost2798075nline,

as far as a single bank charging both batteries it will ,but it will take twice as long,

mike,

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Thanks Rem......perfect. Project for tomorrow and off to Red Wing on Tue!!

[goose89]

as far as a single bank charging both batteries it will ,but it will take twice as long,

mike,

True, but not really best over the long haul. If you've got 2 batteries of different age / condition, you're apt to ruin the one quicker than need be. The charger just see's them as one big battery, and one of them could easily get "cooked" (overcharged) waiting for the 2nd battery to get charged. Can be done, but not without possible consequences. Just food for thought.....I'd still feel okay doing it for awhile if I needed save up some $$ to do it right. Good luck....You'll love the extended run-time you get with the "bigger tank" (two batteries).

[harvey lee]

I would go with a 2 bank charger simply because it will cut down considerably on the recharge time. NO overcharging of a battery if it is in poorer shape.

[goose89]

I would go with a 2 bank charger simply because it will cut down considerably on the recharge time. NO overcharging of a battery if it is in poorer shape.

+1

[hanson]

I love spending other people's money.

Battery life is a big issue with a 12v trolling motor. Once you jump to a 24v trolling motor with 2 batteries, it really is a game changer. Since you are thinking of adding a 2nd battery for longer life, may I suggest jumping to a 24volt motor as well. And you'll want a charger that charges each battery (bank) separately. So 2 batteries in the boat = 2 bank charger.

Sorry.

[adamr]

WHen your questioning how to wire the batterys think of it as if you were jump starting a vehivle and hooking up the jumper cables.

[BobT]

I love spending other people's money.

Battery life is a big issue with a 12v trolling motor. Once you jump to a 24v trolling motor with 2 batteries, it really is a game changer. Since you are thinking of adding a 2nd battery for longer life, may I suggest jumping to a 24volt motor as well. And you'll want a charger that charges each battery (bank) separately. So 2 batteries in the boat = 2 bank charger.

Sorry.

Not doubting you personally but I would be inclined to dispute this until I either proved it to myself or found the math to back it up with an explanation. Assuming you had two motors that draw equal power (one at 12v and the other at 24v) the batteries will last about the same amount of time. For example, do you have information that indicates a 50pd trolling motor at 12v is less efficient than a 50pd motor at 24v? That would explain it.

[fishnowworknever]

A 24v trolling motor will draw less amperage than a 12v. That is what matters, not so much the voltage.

I've been researching this for the past week or so since I need a 24v system.

They say a 12v will draw 1.1 - 1.2 amps / lb of thrust and a 24v system will draw .83 - .89 amps / lb of thrust

[tcwin]

I would go with a 2 bank charger simply because it will cut down considerably on the recharge time. NO overcharging of a battery if it is in poorer shape.

Just curious - when you have the batteries hooked up in parallel; how do you not charge both at the same time?

Do you remove the connecting cables when you charge the batteries?

Thanks for insight - I currently run 2 batteries in parallel for my 12v motor and charge with one bank charger. I will certainly change if it makes a difference.

[BobT]

A 24v trolling motor will draw less amperage than a 12v. That is what matters, not so much the voltage.

I've been researching this for the past week or so since I need a 24v system.

They say a 12v will draw 1.1 - 1.2 amps / lb of thrust and a 24v system will draw .83 - .89 amps / lb of thrust

I don’t believe this is correct. What matters is power. Another term for power is watts. Watts is the product of Volts x Amps. By your numbers the 12v motor will consume approximately 1.15A x 12V = 13.8W per pound of thrust and the 24v motor will consume .86A x 24V = 20.64W of power per pound of thrust. By this math your 24V motor will consume almost 1.5 times as much power as the 12v motor. The 12v motor would run 1.5 times longer.

1. I do believe a 24 volt motor is probably a bit more efficient than a 12v motor. For this reason I believe a 24v motor will give a little longer run time BUT I also believe the difference is minimal at best. The numbers you preset don't support this at all. Doesn't even make sense electrically.

2. Going by your numbers the 12v motor is 1.5 times more efficient than a 24v motor. I don’t believe this at all.

I agree with Hanson that the 24v motor is very likely more efficient than the 12v motor. Where I differ is that I don’t believe the difference is significant enough to mention. Horsepower is horsepower. All esle being equal, two motors rated for the same power will consume the same power under the same load regardless of voltage used. Some differences might come from torque characteristics but I would expect them to be minimal.

[BobT]

Just curious - when you have the batteries hooked up in parallel; how do you not charge both at the same time?

Do you remove the connecting cables when you charge the batteries?

Thanks for insight - I currently run 2 batteries in parallel for my 12v motor and charge with one bank charger. I will certainly change if it makes a difference.

Your two-bank charger will be connected to each battery as normal.

[fishnowworknever]

I see where you're going with that BobT, but...

What matters is amps drawn from the batteries over a certain amount of time.

Power does not consume, amperage does.

Deep cell batteries are measured in amp hours.

An amp-hour is one amp for one hour, 10 amps for 1/10 of an hour etc

Let's just say that both motors (12v and 24v) draw 1 amp / lb of thrust.

12*1=12w

24*1=24w You're getting more power from this system.

Now go back to the original formula.

12*1.5= 13.8W

24*.86 = 20.64W

You're getting more power with less amps drawn in the 24v system.

Now back to the amp hours for the battery

It is amps x hours. If you're pulling 1.5 amps, and you use it for 20 minutes, then the amp-hours used would be 1.5 (amps) x .333 (hours), or .49AH used.

Now the 24v system .83 (amps) x .333 (hours)= .28AH used

Less AH(amp hours) used = longer running with more power available.

[fishnowworknever]

Ok maybe the part about power not consuming is not correctly stated...but I think I got most of it right..

[BobT]

I see where you're going with that BobT, but...

What matters is amps drawn from the batteries over a certain amount of time.

Power does not consume, amperage does.

Deep cell batteries are measured in amp hours.

An amp-hour is one amp for one hour, 10 amps for 1/10 of an hour etc

Let's just say that both motors (12v and 24v) draw 1 amp / lb of thrust.

12*1=12w

24*1=24w You're getting more power from this system.

Now go back to the original formula.

12*1.5= 13.8W

24*.86 = 20.64W

You're getting more power with less amps drawn in the 24v system.

Now back to the amp hours for the battery

It is amps x hours. If you're pulling 1.5 amps, and you use it for 20 minutes, then the amp-hours used would be 1.5 (amps) x .333 (hours), or .49AH used.

Now the 24v system .83 (amps) x .333 (hours)= .28AH used

Less AH(amp hours) used = longer running with more power available.

I won't take this any further from here on.

What you're failing to recognize is that the total capacity in the 24v system is half that of the 12v system. In a 12v system you are connecting two batteries in parallel. When power supplies are paralleled, the current capacity is added together while the voltage remains constant. In the 24v system you are connecting the batteries in series. This doubles the voltage but the total current capacity remains unchanged.

[fishnowworknever]

And this is as far as I'll take it.

I do understand that you get more capacity with 2 12v batteries in parallel. But you still get more power from the 24v while using less amperage than the 12v system.

It's not an easy argument either way that's for sure.

[Nick Kuhn]

Doesn't matter, you still get the same total power capacity. What does matter is the efficiency of the motors at the speed you are operating them. But good luck getting Minnkota to send you a power efficiency curve for both motors.

[low277]

The math says that that given a specific load the power used in the two systems will be the same. The voltage and amperage will be different, but the power consumed will be the same.

The voltage and amperage are inversely proportional.

12 volts x 2 amps = 24 watts

24 volts x 1 amp = 24 watts

There could possibly be a slight advantage in starting torque of the higher voltage system and voltage drop would be less of an issue. Remember when you are starting with only 12 or 24 volts it doesn't take a very long cable to effect voltage at higher loads.

" your mileage may vary"

[slipperybob]

Something about electricity.

Double the voltage and uses half the amount of ampherage....

[Esox_Magnum]

Don't know all the math but I know my 24 volt Terrova will last a day or more longer than my friends 12 volt Terrova... Normaly a long day and his is done, mines never been less than 2/3 after the same amount of time, I run a bigger/heavier boat than he does to....

[bottom-bouncer]

Don't know all the math but I know my 24 volt Terrova will last a day or more longer than my friends 12 volt Terrova... Normaly a long day and his is done, mines never been less than 2/3 after the same amount of time, I run a bigger/heavier boat than he does to....

+1 doesnt matter what the math says 24v will outlast 12v by a long shot.