How many Amps is my Trolling motor?

kcamacho

Cadet
Joined
Mar 15, 2009
Messages
10
Hey there guys,
I just purchased a bass pro shops Prowler 55/40 Trolling motor.
My question is how can i find out how many amps my motor pulls. I need to purchase batteries and am trying to figure how many i need. If anyone can help that would be great. Thanks
 

Chris1956

Supreme Mariner
Joined
Mar 25, 2004
Messages
27,036
Re: How many Amps is my Trolling motor?

I would think the motor's owners manual would recommend a certain minimum battery size. You could also look on the company's website for that info or email them.

You could also figure it out using Ohm's law and an accurate ohmmeter.
 

Wee Hooker

Chief Petty Officer
Joined
Sep 11, 2005
Messages
615
Re: How many Amps is my Trolling motor?

You might try asking BPS but who knows if you get a straight answer. I JUST asked Minn Kota Customer service the same question for my two ( 55# and 40#) rip tide motors . (i.e.. How much thrust and draw @ speed 1, speed2/ etc) . After three attempts and some inaccurate info from a clearly "non technical" CS rep, I gave up.
That said, the general rule of thumb for a 12V trolling motor (without chopper/maximier/etc) is roughtly 0.9-1A draw for every # thrust produced. That equates to a max of 50 amps or so for your motor. ( This assumes of course that you have wire gauge and battery reserve to provide that kind of amperage. ) You should also note that the 5 speeds on these motors isn't neecessarily divided evenly/predictably (i.e. 11,22,33,44& 55) .


p.s. Have you tried the motor? I've been eyeing that exact motor as a replacement for my MK RT40. Seems like allot of bang for $200 (current sale price).
 

kinggabbo

Petty Officer 2nd Class
Joined
Nov 18, 2008
Messages
107
Re: How many Amps is my Trolling motor?

I have the BPS 55lbs 42 in shaft foot controlled motor that just came out. I think it pulls 46-47 amps. I can't remember for sure. It is in the manual. I would assume your motor would pull a similar number of amps.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: How many Amps is my Trolling motor?

You can use any 12 volt deep cycle battery of any size. The capacity of the battery determines how long it will last so knowing the current draw of the motor is the least of your worries. Your motor will draw, as indicated, somewhere between 40 & 50 Amps at it's maximum speed. What it draws at slow speeds is not of importance. Look for a group 27 deep cycle battery with the highest reserve minutes you can find. On that size battery it will be in the 110 - 120 minute range at a 23 amp draw. So your 50 amp motor would kill the battery in roughly one hour if run wide open. Or another way to look at it is you could use a battery half that size and run your motor at half speed and it would still kill the battery in one hour or 1/2 hour at full speed. That is why max current is used, not slow speed. If you a die hard fisherman and are out for very long periods, you should step up to a group 31 deep cycle. It all depends on how much room you have. when it comes to batteries, larger capacity is always better.
 

kcamacho

Cadet
Joined
Mar 15, 2009
Messages
10
Thanks for all your replies.

Thanks for all your replies.

Thanks boys. What if I use 2 6v deep cycle golf cart batteries run in parallel? They say they have 232amp capacity. I ask because a friend of mine works at a place that sells them. I believe they are interstate workhorse batteries. So if I have 464 amps available on the batteries and my motor draws say 50 amps how do I figure how long I can run the motor for? Sorry guys this is my first trolling motor so I am not familiar with them.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: How many Amps is my Trolling motor?

You need to run them in series to get 12 volts. Parallel doubles the a/h capacity but voltage stays at 6 volts. Series keeps the A/H rating but doubles the voltage.
 

kcamacho

Cadet
Joined
Mar 15, 2009
Messages
10
Re: How many Amps is my Trolling motor?

Sorry I was mixed up there. So if I run them in series I won't get more amp hours? I thought I would get double the amp hours also. So 2 232amp 6v batteries in series would get me about 4 hrs and a little of run time per charge.
 

Splat

Lieutenant
Joined
Jul 20, 2008
Messages
1,366
Re: How many Amps is my Trolling motor?

Sorry I was mixed up there. So if I run them in series I won't get more amp hours? I thought I would get double the amp hours also. So 2 232amp 6v batteries in series would get me about 4 hrs and a little of run time per charge.

Correct, however 6v Golf cary batteries have stupid good reserve amps. So the A/hr rating will still be greater with a 6v battery compared to a 12v one.

BIll
 

Wee Hooker

Chief Petty Officer
Joined
Sep 11, 2005
Messages
615
Re: How many Amps is my Trolling motor?

Also bear in mind that allot of your run time will likely be at considerably less than full throtle. i.e. If you were running in 3 of 5 speeds, your likely to get twice that kind of time or better. If your using the motor to position vs power the boat, maybe 3-4x that.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: How many Amps is my Trolling motor?

Deep cycle batteries have a specification on the label that reads "Reserve Capacity: xxx minutes @ xx Amps. Those numbers are what you are interested in. Normally deep cycle reserve capacity is specified at a 23 amp draw. I don't know what the equivalent spec is for the golf car batteries you are considering but the same concept applies. 23 amps is roughly half of the maximum current draw of your motor so whatever "minutes" are specified you would cut that number in half for run time at maximum speed since you are drawing twice as much current (46 amps instead of 23). So you cut the time in half. Regardless which battery you settle on, never run it totally dead. That is not good for any battery including a deep cycle or golf car battery..
 

Wee Hooker

Chief Petty Officer
Joined
Sep 11, 2005
Messages
615
Re: How many Amps is my Trolling motor?

Thanks for the correction Silvertip. That's what I was trying to getting at but it came out backwards (after a extra long day in the office and two glasses of wine.....)
I'll shut up now!
 
Top