36V 101 lb thrust minn kota maxxim

[St_Croix_Banks]

Need some help. My 101 Maxxim has very low thrust. I think all 3 batteries are in decent shape and properly hooked up. When I dial it up----it goes from high thrust to low----almost like its in a pattern. The highest setting is no where near 101 lbs. It really lacks power. Someone told me there is a electronic board that controls speed that could have gone bad. It took the head cover off and there are only gears. Could this "board" be in the foot pedal?

Any other ideas on what might be going on?

[katoguy]

That doesn't sound like a control board issue. Usually when a board goes out of these (yes, in the pedal) either the motor is completely dead or it is stuck on high (no speed variation). I would suspect either water intrusion into the lower unit or low voltage.

I don't recommend going into the lower unit. That is what authorized service centers are for. Especially if the motor is still under warranty. If it is not, you could take off the prop and pull a thru-bolt to see if there is any moisture on it.

Make sure you have 36+ volts to the trolling motor. Take this reading with a multimeter. You should also test it while the motor is running underload (motor in the water and running). This is when you will get a voltage drop if you have an issue in your wiring. (You could get a reading of 36-volts sitting in your garage, but it may drop off significantly under load. That could be a battery issue, corroded plug connection, bad wiring, fuse/breaker issue, etc...).

The 101# motor will usually operate on 24-volts, but you would be closer to 50# thrust with 24-v rather than 101# with a full 36-v.

[PerchJerker]

Get your batteries load tested. What you've got going on is a classic example of a bad battery --- the battery reads 12+ volts (ie. fully charged), but there's no amps left in it therefore no power to your trolling motor. You've probably got 1 or 2 bad batteries causing your problem. I'd for sure look at the batteries before I looked at the trolling motor itself. Good luck getting it figured out!

[SpecialK]

Get your batteries load tested. What you've got going on is a classic example of a bad battery --- the battery reads 12+ volts (ie. fully charged), but there's no amps left in it therefore no power to your trolling motor. You've probably got 1 or 2 bad batteries causing your problem. I'd for sure look at the batteries before I looked at the trolling motor itself. Good luck getting it figured out!

+1 I would replace all three batteries if 1 or 2 are bad as well.

[PerchJerker]

+1 I would replace all three batteries if 1 or 2 are bad as well.

Good point. Better to replace them all than have a mix of old and new.

[CAMAN]

Exactly! The one or two good batteries will eventually fail sooner than later and take out the new batteries before you notice it has gone bad. When replacing batteries in series or parallel always! always!! always!!! replace them all.

[St_Croix_Banks]

I'll run a load test on all 3 tonight---I assume need to disconnect each battery completely and test them separately, right?

[Esox_Magnum]

Charge them fully then unhook and load test each on it's own.

[St_Croix_Banks]

OK guys--I think I've got it licked. As I was disconnecting each battery to test them, I noticed my connection from BAT 1 to BAT 2 was positive to positive. It should be BAT 1 NEG to BAT 2 POS, correct? Otherwise the batteries would be tied together parallel instead of series, right? So in effect my 36v system was running off of 24v or 12v. That would explain the low, fluctuating speed. At any rate, after making this change, the motor seems to be running great (in my garage). All 3 batteries tested right on 12v. I have an analog voltmeter, not digital, but it was pretty much nuts on 12v. I sure hope that was the issue. I need to be ready for Croix opener this weekend.

[St_Croix_Banks]

Charge them fully then unhook and load test each on it's own.

I'm going to test them tomorrow again just in case. Thanks.

[CAMAN]

Yup that would do it! Glad you were able to figure it out.

[PerchJerker]

Sounds like you got it --- bad batteries or bad wiring, they'll both cause the same problems, like not enough volts to the motor

Just a quick note ---- if you're going to load test your batteries you need to take them to an auto parts store or some place like that to have them load tested. Testing the voltage to see if they're 12 volts is not the same as load testing. Load testing puts a load on the battery, like starting your motor or running your trolling motor, and measures if (or how well) your battery handles the load.

[St_Croix_Banks]

Sounds like you got it --- bad batteries or bad wiring, they'll both cause the same problems, like not enough volts to the motor

Just a quick note ---- if you're going to load test your batteries you need to take them to an auto parts store or some place like that to have them load tested. Testing the voltage to see if they're 12 volts is not the same as load testing. Load testing puts a load on the battery, like starting your motor or running your trolling motor, and measures if (or how well) your battery handles the load.

Thanks PJ. I didn't know that.

[SpecialK]

Good job on figuring out the problem! I love it when a plan comes together.