trolling motor power loss

[flatstick]

I have a MG tour 70LB thrust trolling motor that seems ot be losing power .

Started the end of last year and was out yesterday and on the water it does seems slower and I have to use more speed all the time.

My batteries are good , tested them 2 days after charge and they both ar 12.82 , optima blue tops .

Chnged the male and female TM plug at the beginning of last season as they were a a few years old .

Snipped off the pos and neg lead of the TM and tin with solder before inserting into new Marinco TM plug.

Installed a new circuit breaker last year where I can shut down power to the bow.

New lead installed between fuse for TM battery this year .

I have 6 gauge pos and neg lead from front of boat to the rear .

Never checked my speed until yesterday and it seemed to confirm what I feel that boat is moving slower than it used to and needing more throttle.

There were two guys and 19 gallons of gas in the boat hardly any tackle , no water in boat or livewell.

Into 5-mph wind speed was 1.5 mph, downwind speed was 1.7 mph.

I did hook up a MG tour 82 and hiting the pedle out of the water for a couple of seconds seems to be the same on high speed for both motors.

Do I buy an ammeter and see what the draw is on the lake at 100% to see if the connectors or 6 gauge wire needs to be replaced .

The wire was replaced 10 years ago if I remember correctly from bestboat wire.

Boat is a skeeter ZX195C with a 200 ox 66.

[CatFan]

What size are the Blue Tops?

[flatstick]

The batteries are Optima D34M

I had them as my last set and they have performed great for me wit hthe same TM.

Never have had any issues with enough power to get through the day even when it was windy .

[CatFan]

L

The batteries are Optima D34M

I had them as my last set and they have performed great for me wit hthe same TM.

Never have had any issues with enough power to get through the day even when it was windy .

Reason I asked is the full charge voltage is much different on the 34s than other Blue Tops. Your numbers are good for 34s, but would indicated failed batteries in the larger sizes.

I would figure out a way to measure voltage at the connector up front or inside the head of the TM. Measure both with the motor off and running on 100% briefly.

[flatstick]

Thought about removing the front panel where the female receptacle is so I can take out my meter to connect to the pos and neg connections to see what the voltage is.

[bobcoy]

It sounds like it's an older motor,maybe brushes?

[flatstick]

That is what I thought at first I hooked up a MG82 that has little use on it.

Ran the 82 lbs thrust at high speed for a few seconds out of water ( used the same new male Marinco plug ) it did not seem like there was any increase in speed ,with the same exact prop.

At that point I figured maybe a wire or connection is causing the problem.

Changed the wire from the fuse to the battery with a brand new one , two new connectors.

[bobcoy]

Speed without a load will not tell you much. In water will tell you more.

[tritond]

I second the "brushes" . There are 2 , 1 on each side of the spindle, and one is probably worn down and the other is not. I have had this to happen to a MG 72 in the past.

[flatstick]

This issue has been resolved .

Measured the voltage at the female receptacle without taking apart my front dash so to speak .

Voltage was 12.8 , interesting .

Cleaned up a few leads same thing.

Disconnected the trollbridge and hooked up a jumper between the two optima batteries and voltage went up to 25.6 bingo .

Hit the button and the motor has a lot more thrust now , like it should.

Replaced a couple connectors on the trollbridge hooked it back up , still ended up with 12.8 volts, even after engaging the motor for a few seconds .

So for some reason the trollbridge will not allow the batteries to form the 24 volts.

I double checked the wiring and it was all correct , even referred back to some pictures I had of the wiring from a few years ago.

I used that set up to charge both of my batteries from one charger and it worked well for years.

Glad it was a simple repair but now I have buy a dual bank charger .

Appreciate the common sense trouble shooting tips , always find useful information on this board.

Thank you to all !