How many amps does a 36 volt t-motor draw on high?

Johnny C · Post by **Johnny C** » Mon Dec 14, 2009 4:03 pm

A batteries specs always state that there is something like 210 reserve minutes at 25 amps. So if the t-motor is drawing 25 amps on high would that mean you have 3 1/2 hours of use at a constant high setting?

hydro · Post by **hydro** » Mon Dec 14, 2009 7:57 pm

John try this conversion table...

Trolling Motor Amp Hours
Calculate the Ampere draw based on the pound thrust of the motor:
(Pound Thrust / Motor Voltage x 12 = Ampere Draw)
Example:
- 55 Pound Thrust / 12 volt x 12 = 55 Amp Draw
- 55 Pound Thrust / 24 volt x 12 = 27.5 Amp Draw
- 55 Pound Thrust / 36 volt x 12 = 18.3 Amp Draw

101 #thrust / 36v x 12 = 33.66 amps

105 amp hour batteries / 33.66 amps = 3.12 hours run time on high

Johnny C · Post by **Johnny C** » Mon Dec 14, 2009 9:05 pm

Thanks Ken, I told a buddy the only guy I nknew who would know this was you. Is that drawing down all three batteries at that rate?

hydro · Post by **hydro** » Tue Dec 15, 2009 3:42 am

Thanks John

When Batteries are connected in series the voltages are additive and the amp hour capacity remains the same
12+12+12=36V at 105 amp hours

When connected in parallel the total battery voltage remains 12V
but the amp hour capacity is additive

105+105+105amp hours = 315 amp hours at 12V

Johnny C · Post by **Johnny C** » Tue Dec 15, 2009 6:32 am

Sent you a PM

Wally · Post by **Wally** » Tue Dec 15, 2009 6:45 am

Good job Johnny, Thanks Hydro

Oldschool · Post by **Oldschool** » Tue Dec 15, 2009 9:42 am

Good formula. Don't over look armature heating as the primary TM failure running at 100% thrust. Suggest divide the thrust value by 1/2 for factoring in amp hr use during fishing conditions. Also suggest using at least 2X the thrust need for boat control under normal fishing conditions when selecting a trolling motor.
Tom