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Fabrication 101 Everyone has to start somewhere and for some, theOFN might be that somewhere.

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Old 01-19-2023, 10:45 PM
2Xtreme's Avatar
2Xtreme 2Xtreme is offline
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Join Date: Mar 2010
Posts: 196
Talk to me about Amp Hours

I?ve done a considerable amount of research regarding amp hour calculations, but I?m still stumped.
Hoping someone here can shed some light on this for me.

Using round numbers and assumptions:
If I have a trolling motor that draws 40 amps (max) on my kayak with a 100 Ah battery, I should expect approx. 2.5 hr of use out of the battery. (I know it's actually less, but for the sake of this question, let's go with that)

If I put that same motor and battery on my 10? pontoon with 2 people fishing from it, in my mind there is no way I can expect that same usage.

So, what am I missing, here?
Are amp draw ratings of components (trolling motor) based on zero load??

I guess my real question is- how can Ah be calculated by the manufacturers without knowing how much 'work' is going to be done by the component(s) a battery is powering?

Thanks in advance!
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Old 02-26-2023, 08:40 AM
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redidbull redidbull is offline
Join Date: Jul 2007
Posts: 57
Using your numbers. I believe that if the motor draws 40 amps when wide open that is what it will draw no matter what the load is. A small boat with 1 person will go faster and you will get physically farther than with a larger boat. The motor has no idea what it is pushing just that it is at max. Jim
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