06-19-2010, 04:13 PM
[quote Jim_T]I have a 40# Minn-Kota Endura (no maximizer) and have been using a borrowed 85amp hour battery which has yet to run out of power for the type of fishing I do (motor point to point then fish extended periods). However, it weighs almost as much as my entire boat.
Looking at the Minn Kota FAQ's on their site they talk about the speed coils taking up the extra power when on lower settings just as cpierce describes above. However, on the same page they also discuss amp draw of the motor at different speeds saying "A motor drawing 30 amps at high speed may only draw 5 amps at the slowest speed. The same motor that will theoretically run about 3.4 hours at high speed will run for over 20 hours at the slowest speed.". Am I to assume this extra power goes to the coils and there is no advantage to running the motor at slower speeds?
You do save power at slower speeds which do go through the resistance coils, but not as much as with an electronic PWM control.
I'm interested in getting a smaller battery such as a wheelchair battery to reduce the weight (and strain on my back). If the constant draw theory above is correct, how do I determine the draw of my motor so I can estimate the amp hour rating of the battery I need to buy.
You can estimate based on the battery you already use. A 10 amp charger would require around 8.5 hrs to charge a completely discharged 85 ah battery. So if it charges in 4.25 hrs, you are only using 50% of your battery capacity. You can get the idea from this.
Also, I'm starting to do some multi-day trips where I don't have access to charge the battery. The external PWM sounds like it might be a nice addition for these events. Where can I get one and how difficult is it to hook up.
There is no simple plug and play PWM anymore, like every troll company offered years ago. If you know a little about electric are interested in tinkering, you can use a speed control from a scooter motor which is available from internet purchase.
Jim[/quote]
Hope this helps.
Pon
[signature]
Looking at the Minn Kota FAQ's on their site they talk about the speed coils taking up the extra power when on lower settings just as cpierce describes above. However, on the same page they also discuss amp draw of the motor at different speeds saying "A motor drawing 30 amps at high speed may only draw 5 amps at the slowest speed. The same motor that will theoretically run about 3.4 hours at high speed will run for over 20 hours at the slowest speed.". Am I to assume this extra power goes to the coils and there is no advantage to running the motor at slower speeds?
You do save power at slower speeds which do go through the resistance coils, but not as much as with an electronic PWM control.
I'm interested in getting a smaller battery such as a wheelchair battery to reduce the weight (and strain on my back). If the constant draw theory above is correct, how do I determine the draw of my motor so I can estimate the amp hour rating of the battery I need to buy.
You can estimate based on the battery you already use. A 10 amp charger would require around 8.5 hrs to charge a completely discharged 85 ah battery. So if it charges in 4.25 hrs, you are only using 50% of your battery capacity. You can get the idea from this.
Also, I'm starting to do some multi-day trips where I don't have access to charge the battery. The external PWM sounds like it might be a nice addition for these events. Where can I get one and how difficult is it to hook up.
There is no simple plug and play PWM anymore, like every troll company offered years ago. If you know a little about electric are interested in tinkering, you can use a speed control from a scooter motor which is available from internet purchase.
Jim[/quote]
Hope this helps.
Pon
[signature]