Electric Boat Motor Batteries


Tamer of Trouts
So I picked up a very lightly used Minn Kota Endura 44 yesterday for next to nothing. I figured it'd be nice to have around when I head up to a lake with the DB. Didn't come with a battery and I am not quite sure what size/brand/type of battery to get for it. Figure I probably need a true deep cycle marine battery (not dual purpose or starting). The battery that I looked at yesterday was a true deep cycle marine battery rated at 150 mins at 23 amps...anybody have any idea how long that would last? The motor has 5 forward settings and 3 reverse. I was hoping to find an owner's manual online somewhere but haven't had any luck as of yet.

Thanks, Josh
Hey Josh,
You’ve probably been on the MK site by now but either that or a good marine dealer should be able to hook you up. In any case, I’d recommend leaning toward a stronger battery plus good means to charge it…money well spent, otherwise your motor won’t perform nearly as good as it should. I had an MK 10, bought new in ’78, that worked fine on a standard car battery and a Sears 4 amp charger. Years later I picked up the 24 (I think) and it sucked noticeably more power out of the source since it had more power and multi speeds. The 44 should give you a good amount of work with enough juice behind it. Have fun!

Jim Wallace

Smells like low tide.
I have one with 1195 marine cranking amps, 945 cold cranking amps, and a reserve capacity of 178 minutes that is adequate for my Riptide 50 pound thrust. It is a Cabela's AGM (absorbed glass mat), group size 24, which is a "dual purpose," but works fine. This is the cheapest AGM of that rating that I could find anywhere. Its made in China.
Your standard "wet cell" marine deep cycle works just as well and costs considerably less (only 1/3 the cost of an AGM), but will probably only have half the life (# of recharges) of an AGM. So the cheaper route is probably more bang for the buck. AGMs are maintenance free and won't spill, though.
Hope that helps.

Jim Wallace

Smells like low tide.
lets see....the battery you mentioned...a 44 amp suck at full throttle will give you approx 80 minutes before the battery's charge is exhausted. At trolling speeds it should last a good half day, or nearly all day, especially if you take breaks and anchor up, or wind drift at times.
I have an endura 30 with 5 fwd and 5 rv for the pontoon. works great to point the motor once and then use an oar as a rudder to steer. Or in reverse you can use fins to steer and control speed to some extent. You should only drain a batter 1/2 way if you plan to keep it long term and always recharge as soon as you can. If you are going to drain it to exhaustion might as well get the cheapest deep cell or marine you can find cause it's only going to last a year or two. Better to get two and take care of them. :confused:

Jim Wallace

Smells like low tide.
Yup, only drain the battery halfway. When you notice it really dropping off in output, its time to shut it off and switch over to your OTHER battery. The meter on my charger reads 56% on a heavily discharged battery...I think taking it down to 50% would weaken it. I "killed" a battery once by discharging it too much. I didn't have a second battery, I stayed up river too late, and I had to fight the incoming tide and wind as it was getting dark, and paddling just wasn't getting the job done fast enough, so I squeezed every last bit of juice out of the battery, and it never held a full charge again. I used it for another year on lakes, and then it died completely.
Proper care and feeding of your battery will keep it healthy, without a doubt.:ray1:
Josh, Lots of choices out there, Way to many factors to take into account, weight, wind,
trolling or fast, weight of the battery, cost, life.
What ever you do, make sure you buy it from somewhere with a good warranty policy.
That way when it stops taking a charge, your covered.
P.S. The 44 Josh was referring to is pounds of thrust not amps.

Tony Kraft

der Fliegenfischer

My Father In-laws friend had this gel no maintenance battery that looked like a six pack for his 14' boat. We used it about 3 days, 8 hours a day and it didn't seem like it was losing it's charge. Do a search on Optima Sealed AGM, they are pricey, but very light.

David Loy

Senior Moment
I've used the Optima sealed (six pack) batteries for several years. They had a good rep when I bought them and I didn't want any possibility of spilling "juice" in my wood boat. I have 2, partly for balance (1 on each side near the bow) and for peace of mind. They were pricey but I like them. Don't recall amperage but bought the most I could.


Be the guide...
Optima's are great. Check Costco, at one point they carried them. When I went to buy one, they didn't have deep cycle, so I ended up getting 2 of the 'costco brand' deep cycles for less than a single optima. Been using them for several years now with no issues. It's always nice to have a spare and confidence that if your battery dies while your fighting your way back in the wind, you have backup power...
Think about other applications where draw/drain is a major factor .... motor homes/campers. I'd suggest you look at the T-105's which are pretty standard for this type of application. Secondly, and more importantly, you want a battery charger that's set up (has a setting) for deep cycle batteries. The 'regular ones' you buy are fine for a 'car battery,' but NOT recommended for deep cycles.


Edit: Go here and use the search function for more info that you'll ever want to know: http://www.rv.net/forum/

Jim Wallace

Smells like low tide.
I also have one of those Optima's, and it has been a very good battery...I have used the heck out of it for five years now, and its only now starting to hold a little less of a charge. I've gotten well over 125 discharges out of it (25 to 30 per year, at least). Mainly, the charge dissipates a little bit if the battery sits for over a week, so I just hook it up to the charger for a couple of hours before I use it to "top off" the charge and its still "good to go." I can stow it on its side underneath my canoe seat, and it only weighs about 43 lbs. I got mine on sale 5 years ago for "only" $145 plus tax, but I see they've gone up quite a bit in price. I'm sure it will be fine for at least another year or two as a backup, and for lake fishing at lower speeds with my Endura 30, especially if I don't over discharge it.

I always put the battery on the charger immediately upon returning home. Don't let 'em sit too long discharged.

The Cabela's AGM I mentioned is about 10 lbs heavier, but stores more juice and is capable of producing more power. I've only had it for 3 years, so i don't know how long it will last...still seems "good as new."

I know guys who really like those less expensive Costco "wet cell" deep cycles. My first battery was a regular "wet cell" type, and it worked fine. Definitely the cheaper way to go, with not much noticeable difference in on-the-water performance from the AGMs (which have the advantage in total number of cycles). The AGMS are good for about twice the # of cycles.

Thanks for the link, Fred.

Jeff, you are correct. Strangely enough, my Endura 30 draws about 30 amps with the throttle set at top speed, and my 50 lb thrust seems to draw somewhere near 50 amps at full throttle. I may be hallucinating, but I think I have observed some correlation here.:confused:
There is a new type of lead/acid battery coming out in the next year which uses lead impregnated foam rather than lead plates. This not only lightens the weight but allows the acid to interact with more lead surface since it can penetrate the foam. Also reduces the crystalization buildup which is what kills a lead battery. Also charges up in a fraction of the time. Less weight and lots more power = expensive, at least at first. Will see them in hybrids and electric cars at first and compared to the batteries targeted for those uses they are lighter, more durable and way cheaper meaning electric cars are coming soon. http://www.wired.com/cars/futuretransport/news/2007/07/batteries


Active Member
P.S. The 44 Josh was referring to is pounds of thrust not amps.
The best I could determine after asking a lot of questions, MinnKota included, is that pounds of thrust = amp draw at full speed. 44# = 44 amps.

("Jeff, you are correct. Strangely enough, my Endura 30 draws about 30 amps with the throttle set at top speed, and my 50 lb thrust seems to draw somewhere near 50 amps at full throttle. I may be hallucinating, but I think I have observed some correlation here.
Yesterday 02:41 AM ")

And again the "stranger" is right on.:cool: