12 volt vs 24 volt staying power.

[whizkids]

I thought this had been discussed before but I was unable to find the post.
I have a 55 lb thrust 12 volt Minnkota Autopilot. Max amp draw is 50.

I run 2 Delco Voyager group 27 trolling batteries. 550 CCA . 2.7 hours @ 25 amps. according to what is on the label. I hook the batteries in parallel.

An 80 lb thrust 24 volt Minnkota has max amp draw of 56.

Question: Which trolling motor will run longer at 1 mph?

The 24 volt has 80 lbs of thrust at 56 amps. Does that mean it has 55 lbs of thrust ( same as the 12 volt) with 68.75% of the amps. (55lbs / 80 lbs of thrust) . Therefore the 24 volt would only need 38.5 amps to produce 55 lbs of thrust?

I had some trouble with wind this weekend. I want to determine if I can get better ( longer not faster) stamina from a 24 volt motor on the same batteries.

[Barnacle Bill]

I'm sure Canepole can explain this better than me. Bottom line is if it requires 50 amp @ 12V to run a motor, it will only take 25 amps to run the same power motor at 24V. So to answer your question, Yes, a 24V system will last much longer. (theoretically twice as long). Ohms law.

[Dickieboy]

The way I understand it is with the 24v the two 12v batteries must be tied in series. The total available amps is the average of the two batteries.

2*550/2=550 amps

The two 12v in parallel is the sum of the two available amps

2*550=1100 amps

With the amp draws you concluded the following would be the result.
24v
550ah/38.5a=14.28hrs

12v
1100ah/50a=22hrs

This is a simple analogy of volt/amp theory and other things affect these calculations related to the battery's ability to 'recover', state/condition of each battery and continous discharge.

Hope this helps.

[KScrappie1]

Whizkids, I run a 12 volt MG and I added a Kipawa prop. It gives me more power, better control and a little longer battery life per charge. You may want to check it out. Cost is around $32.00.

KScrappie1

[Moose1am]

Ill buy that puppy!

Good explaination mate.

You sold me with this. I still would like for cane pole to verifiy this but I feel that he will somehow. I have not read his reponse yet. I will probably find it in the next post LOL

The way I understand it is with the 24v the two 12v batteries must be tied in series. The total available amps is the average of the two batteries.

2*550/2=550 amps

The two 12v in parallel is the sum of the two available amps

2*550=1100 amps

With the amp draws you concluded the following would be the result.
24v
550ah/38.5a=14.28hrs

12v
1100ah/50a=22hrs

This is a simple analogy of volt/amp theory and other things affect these calculations related to the battery's ability to 'recover', state/condition of each battery and continous discharge.

Hope this helps.

[Barnacle Bill]

Whizkids, I run a 12 volt MG and I added a Kipawa prop. It gives me more power, better control and a little longer battery life per charge. You may want to check it out. Cost is around $32.00.

KScrappie1

I tried the Kipawa on a 42 lb MK and a 65 lb MK. I really couldn't tell that much difference.

[CatFan]

You can't compare amps at 24V to amps at 12V without some calculation. At 38.5A, the 24V TM uses 924Watts. (24V X 38.5A= 924W) The 12V system at 50A uses 600W, or essentially 2/3 the power. You have two batteries in both systems, so in the above situation, the 12V will last longer.
However, I don't think you can assume that the power consumed is linear to pounds of thrust for the 24V system, or that max amps is the current the motor draws at all times on high.
The advantage of a 24V system over a 12V system is in wire size and efficiency. To do the same work on a 12V system, you require twice the current as you do on a 24V system, which means all the wire from the battery to the motor, and inside the motor itself must be twice as big in cross section. Every connection causes more loss at higher current, meaning 24V will be more efficient. It's the same reason household power is thousands of volts until it gets to the pole near your house, and then is stepped down to 220/120 right before it comes into the house.

[deputyking]

Just to make sure that everyone knows that amps is not a measure of power. Power is measures in units called watts. Amps is the units of measure for current. Olms Law formula is Power = Current x Volts. This is why 50 amps at 12 volts is the same "power" as 25 amps at 24 volts. It sounds like that for something to pull 25 amps takes less power than something that takes 50 amps but this is not correct unless both have the same voltage. For those of you that remember when cars and tractors used 6 volts batteries and had large cables connecting the battery. When they changed the system over to 12 volts they did not have to used the large cables but could use smaller cables because the current (amps) were 1/2 what they were on the 6 volt system. The cars still needed the same amount of energy (power) to crank the engine but the amps were less because of the voltage increase. Look at the size of the wires along your highway feeding all the houses. They are smaller than the wires feeding your house. This is because they have less amps than your house wires because of the voltage difference. The voltage is reduced going to your house by the transformer on the pole and thereby increasing the current(amps) and thus needs bigger wire. Now that I have everyone confused, just remember that fishing should be fun and not so complicated. Enjoy (grin)

[Moose1am]

that discussion made me hungry. I think I am going to go eat some PIE lol

Power = Watts = P
I = amp and
E = Volts

P=IXE or PIE That is one formual that I do remember due to my fasination for food. Apple pie is my favorite followed by Cherry Pie.

Where is Cane Pole on this deal?


[QUOTE=deputyking]Just to make sure that everyone knows that amps is not a measure of power. Power is measures in units called watts. Amps is the units of measure for current. Olms Law formula is Power = Current x Volts. This is why 50 amps at 12 volts is the same "power" as 25 amps at 24 volts. It sounds like that for something to pull 25 amps takes less power than something that takes 50 amps but this is not correct unless both have the

[Dickieboy]

I agree with Deputyking, this is getting way too complicated. I did confirm my previous calculation on the battery usage. If you do not consider losses from the increased resistance in the wiring and connections the 12v system will run longer. Much more information is required to calculate these losses but since the difference between 12v and 24v is about 8 hours I doubt there would be a significant difference in the results. The calculations for power are correct but we are using thrust (ft/lbs) as the energy which can be converted into watts.