Amp Hours??

[Member]

G'day All!

Looking for some advice on best deep cycle batteries for my 24v Minn-Kota Maxxum.  Do amp/hrs matter?  Any advice would be great.  For all intents and purposes I was looking at 2 deep cycle 100 A/H batteries, is this best way to go?

Thanks,

Colin

[Member]

For electric motors, amp/hours is everything.

IMHO 100 AH is probably about the smaller you should use.

[Member]

What you using the motor for, and what size is it? If your just wanting something to fish with after using an outboard to get there, probably a good size selection. If your wanting to fish electric only dams, or use it to troll for extensive periods, no go bigger.

I run a 24 volt 65 (smallest 24 volt you can get). I use it for electric powered dams.

I originally ran a pair of 100 amp hour batteries to power it. A Days fishing used to knock them right down to around 20 to 30% capacity. I was always worried about a headwind, or going that bit further than usual and getting stuck. In the end I killed them in less than 12 months, to much cycling to to low a level.
I run a pair of 160 amp hour units now, never drops below 50% even with a big days fishing.  Downside is its a lot of weight in the boat, you need to be careful where you mount the batteries both for balance on the water, and the affect on the balance of your trailer and the towing ride.

[Member]

Some useful info from the Minn Kota web site:

•Amp draw is the measurement of electrical current drawn from a storage battery (or battery), while the motor is being operated.
•Minn Kota’s published amp draw figures represent actual on-the-water conditions at full power (with all of the motor’s wiring, switches and circuitry in the electrical system as the test measurement is taken).
•Approximate length of running time when operating a motor at full power can be determined with a motor’s amp draw and the battery amp hour rating.
◦Example: A single 120 amp hour, 12-volt battery and a 12-volt trolling motor drawing 30 amps at the highest speed setting will run for about 3.4 hours.
•The formula for the calculation is as follows:
◦.85 A.H.R. = Hours of running time (A.H.R.= Battery Amp Hour Rating)
M.A.D. (M.A.D. = Motor Amp Draw)
•As the speed setting is reduced the motor amp draw is also reduced.
•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.

The maximum amp draw of your 80lb Minn Kota is 58 amps, so with a pair of 100Ah batteries running at full speed you could expect about 1 1/2 hours running.  With the maximizer fitted to this model you will get much more than that, as at less than full speed you draw much less power.  I try to keep my motors at less than 75% speed to extend battery life.  100Ah batteries should be the minimum you consider.

[Member]

Thankyou!

It's a 74lb Maxxum (cable steer) Going to put it on my 12 ft Tinny (possibly too big for it I am thinking) It will be used as the main form of propulsion ie Electric only lakes.  I am concerned with the weight issue given the boats size so it may be a case of downsizing the trolling motor to 54 or 48lb 12vlt system.  The only reason I bought the 74lb was that I got it for a steal. 

Thanks again for the clarification it confirmed what I intially thought (bigger is better when it comes to A/H's)  I guess now is to start researching and see whether this particular unit is too big for the size of my boat.

Cheers,
 
Colin

[Member]

You will definately need something on the transom on the lakes.  If you have to remove your petrol motor either make a fixed keel to hang off the back or run a transom mount electric as well.  Boats were not made to be pulled along by a motor in a straght line, and with cable steer it's going to get very tedious holding your foot on the pedal and fighting the zigging and zagging all day.

[Member]

Thanks Dale,

Good old Torque steer.........That could be seen as fun for the first 5 mins.....NOT!

Thanks again!

Colin