Gary Northrop Loc: Richland WA

I have an Ulterra 24Volt, 80lb thrust motor on my boat, and
I'm curious about how many hours it would continually run
at the 3 power setting. I do a lot of trolling, and I'm always
worried about running out of power. (I have new MinnKota-
recommended batteries.)

Thanks!

Tom Wasz

That's not very fast but a lot depends on what kind of boat you have and the wind speed and wave height. It will be a trial and error

Robert J Samples Loc: Round Rock, Texas

CALCULATING MOTOR RUN TIMEA common question people have when trying to select a motor is “How long will this motor run out on the water?” To answer this question, it's necessary to know two things: a battery's amperage hour rating and a motor's amperage draw. Keep in mind that trolling motor run-time is not an exact science but the following parameters will help you approximate your potential run time.Amperage Hour Rating: Marine batteries are rated on a metric called “amperage hours”, which is an indication of how long a battery can supply a consistent amperage. The larger the rating, the more power the battery can hold, and the longer it will be able to power a motor at a given speed. For example, a 100 amperage hour battery is one that would be able to supply 25 amps of power for 4 hours (25 amps * 4 hours = 100 amp hours) before running out of energy. Alternatively, the same battery could also supply 10 amps of power for 10 hours (10 amps * 10 hours = 100 amp hours) before running dry You can think of the amperage hour rating as being similar to a gas tank in a car – the larger it is, the more energy/fuel it can store, and the longer it can power a motor.Motor Amperage Draw: The second factor we need to compute estimated run time is motor amperage draw. A motor's amperage draw rating refers to how much amperage (or current) a motor draws at a given speed. A motor's exact amperage draw rating isn't always easy to find, but should be available from the manufacturer or, if it's a motor we stock, from a TrollingMotors.net representative.In order to approximate how long a certain motor will run on the water, you simply take the battery's amp hour rating and divide it by the amperage draw. For example, for a motor that pulls 20 amps at medium speed using a 100 amp hour battery, the run time would be:100 amp hour rated battery / 20 amp draw = 5 hour run timeMost manufacturers will only list a motor's maximum amperage draw at top speed, so you may need to estimate other amperage draws at various speeds using the max speed amperage draw as a baseline. For a general idea of approximate amperage draws by motor size, please see the chart below. Please note that these are approximations only and results will vary based on exact motor figures, batteries used and water conditions.
Calculating Trolling motor run time Considering Weather ConditionsIt's important to note that water and weather conditions can significantly affect battery performance. A motor drawing 20 amps to move a boat at medium speed in calm conditions may need 30 amps to move the same boat in strong wind or waves. If you plan on using your motor frequently in windy or stormy conditions, you'll want to factor this into your calculations.Extending Battery LifeThere are a few things you can do to get the most run time possible from your battery & motor combination.Use Variable Speed Motors: Using a variable speed motor (vs. a fixed speed motor) generally results in significantly longer run times. Variable motors are more expensive – generally about $100 more than a comparable fixed-speed model – but are more energy efficient, especially at slower speeds. They are also much more convenient as they allow you to dial in the speed to the exact setting you want vs. having to select from pre-set speeds. For more details, see these notes on fixed vs. variable speed motors. Buy a Larger Motor: Larger 24v and 36v multi-battery trolling motors are able to provide the same thrust as smaller motors with less amperage draw, which results in longer run times. If you need seriously long run time for your smaller boat, it may make sense to buy a 24v or 36v motor.Don't Fully Deplete Your Battery: It's never good for a battery to be run completely bone dry. Doing this on a regular basis will almost certainly reduce the lifespan of your battery. If possible, try to recharge your battery(s) before they are completely empty. Using a battery life indicator – a handheld unit or one built into the motor – will help you monitor battery life as well as reduce the chances of unexpectedly running our of power miles from shore.Remember The Off-Season: It's really bad for batteries to be left uncharged for months at a time, and will contribute to shorter battery life and reduced performance. During the off-season, it's a good idea to use a battery tender or battery trickle charger which keep a small amount of current running through your batteries. Alternatively, you can also re-charge your batteries every month or so to ensure they retain a charge and don't sit empty. Both options will significantly increase the life of your batteries. Just Sayin....RJS

Jeremy Loc: America

Ohms Law

Voltage x Amperage = Wattage

Most batteries have an Amp Hour Rating

A 100 AH ( Amp Hours ) battery should provide 10 Amps for 10 Hours and then need charging. 12.6 VDC Lead acid or Lithium Battery Should be 12v x 10a = 120 watts. Your Trolling motor is rated for its wattage at a certain throttle ( potentiometer ) setting. I would have your main gas motor set up with isolator if possible and then Shore Power cord is 120vac that plugs in when boat is in port ( shore ) or at home.

OHMS LAW is utilized in all electrical configurations. Try to keep voltage up above 11 VDC.

Whenever any 12 vdc battery gets below 12 they should be getting charged. At 11 VDC the battery will be getting damaged if you keep it under load ( turned on ).

woodguru Loc: El Dorado Ca

I'm curious how fast you are trolling at 3, In strong wind with the motor working really hard, often up into 8/9 using the spot lock, 3/4 hours of use was still showing three bars on the battery minder gauge.

My guess it this thing would last all day without any problem.

woodguru Loc: El Dorado Ca

So by that same logic you shouldn't let your 24v pair go below 22v? I'm curious how the battery minder on a Minn Kota is registering, when it's down to the last bar is it still running at 24v or better, or does it fall below recommended output when it's closer to dead?

Jeremy Loc: America

When voltage drops in all circuits the amperage WILL increase due to OHMS law. Therefore the components will get hot. Electrical components are rated. WGuru...if you put a parallel voltmeter on the 24vdc leads you will see what dc voltage is. Your owners manual may have the information your asking.

keep on fishing

hook em and EAT em



Hopefully that will answer your questions.

Time for some football. I will not be close to the computers for quite awhile today.

CatchinWallies Loc: Gillette, WY

I have the same electric motor and use it on a 20’ glass boat. RJS has the math figure it out, but, I can use mine easily for 8+ hrs as long as I’m not pushing much wind and only have two men fishing. If it’s windy it will knock it down to 4-5 hrs. That’s why I use a battery life indicator gauge, not very expensive, easy to install and works great. Even has a app. you can download and check from your phone.

Tom Wasz

I have a Minn Kota Ultrex 24 V on my 18 ft Skeeter Musky boat and with 2 people and a hefty wind I'm in trouble in 4 to 5 hours almost dead w no power and good batteries. We were at 8 and 9 Musky fishing in Lake Okaboji for 2 days because of the wind when this happened

woodguru Loc: El Dorado Ca

Shoulda turned and gone with the wind...just sayin

woodguru Loc: El Dorado Ca

Is yours the 80lb?
Someone was saying the Ultrex uses more power than the Terrova, because of the deployment? Doesn't seem like that should really make any difference.

CatchinWallies Loc: Gillette, WY

Yes, mine is exactly the same everything. Deployment and recovery doesn’t take anymore juice than keeping the prop turning underwater.
If you buy the metered gauge you’ll never have to worry. 😊

Gary Northrop Loc: Richland WA

Thanks, Everyone!