Motor Guide blowing fuses.

[Tony T.]

I have a 54lb thrust Motor Guide trolling motor hand operated on my Tracker boat, 3 weeks ago I was using it and on #5 max output setting the fuse blows leaving me with a dead trolling motor. The fuse was a older inline glass style fuse 30 amp and I was not able to pull it out, like it was corroded into the holder, I thought there's the problem. I replaced it with a inline blade style 30 amp fuse and the same thing happen today #5 max output setting fuse blows. Is a 30 amp the right fuse for a 54 lb thrust motor or do I need to go larger amp fuse ? I bought the boat used and the trolling motor came with it so I did not get a owners manual with the trolling motor.

Thanks for any info


Tony

 

[MH Hawker]

more than likely it should have a 50 amp fuse on a # 6 or # 8 wire depending on how long wire

 

[Silvertip]

Use a circuit breaker rather than a fuse.

 

[gm280]

Obviously the #5 (max) setting is drawing more then 30 amps. In fact I am surprised you are using a 30 amp fuse with a 54lb trolling motor. I would go up to 40 or 50 amps, but also a circuit breaker instead. Then you can simply reset the breaker and troll on. BUT, verify your wiring can handle the higher amperage or you will be heating up the wires and could possibly start a fire. Safety has to be first. JMHO!

 

[Harvey Manfrenjensenden]

My old 46# had a 12/24v wiring setup, and it had a 40amp fuse wired into each line coming from the batteries, so two 40 amp fuses in total for that motor, and yours is a 54lb thrust so I definitely think it should be greater than 30amp.

 

[Tony T.]

Obviously the #5 (max) setting is drawing more then 30 amps. In fact I am surprised you are using a 30 amp fuse with a 54lb trolling motor. I would go up to 40 or 50 amps, but also a circuit breaker instead. Then you can simply reset the breaker and troll on. BUT, verify your wiring can handle the higher amperage or you will be heating up the wires and could possibly start a fire. Safety has to be first. JMHO!

Ok thanks all of you guys for the advise so far. Like I said the trolling motor came with the boat and there was no owners manual,when the first fuse blew I checked it and that was what it had in it a 30 amp glass style fuse,so that's what I replaced it with, again no owner/service manual for fuse size reference. Buddy of mine that's a mechanic said the same as you guys try a larger fuse or use a circuit breaker and check to make sure your wire is no over heating. I was also hoping someone might have the same trolling motor on here and would know what the max draw amps is on the Motor Guide 54 lb. Trolling motor works fine until you set it on max #5 setting and it works there for a little bit then it blows the fuse, that buddy of mine being a smart azz said well just run it on setting #4 and you won't have to worry about it.


Tony

 

[Harvey Manfrenjensenden]

Ok thanks all of you guys for the advise so far. Like I said the trolling motor came with the boat and there was no owners manual,when the first fuse blew I checked it and that was what it had in it a 30 amp glass style fuse,so that's what I replaced it with, again no owner/service manual for fuse size reference. Buddy of mine that's a mechanic said the same as you guys try a larger fuse or use a circuit breaker and check to make sure your wire is no over heating. I was also hoping someone might have the same trolling motor on here and would know what the max draw amps is on the Motor Guide 54 lb. Trolling motor works fine until you set it on max #5 setting and it works there for a little bit then it blows the fuse, that buddy of mine being a smart azz said well just run it on setting #4 and you won't have to worry about it.


Tony

One more thing that I had heard a while back, and it seems to check out as a rough calculation is that your fuse size should be 0.75 of what your total # thrust is... so in this case 54lb thrust would roughly equal 40amp fuse.

I am by no means an electrician or anything like that, but from the bit of research that I've done this calculation works pretty well. Hopefully it helps for future calcs if you get another trolling motor or something, or someone else can come on here and tell you that I'm way off base

Heck, what do I know, I have a post on here trying to figure out my own trolling motor problems!!! hahaha

 

[gm280]

Harvey, I understand what you are saying, but it really doesn't work that way. The thrust output does not translate to current by any math equation that I ever heard of. There may be some correlation, but not a direct calculation. The only true way to know exactly what amount of current the trolling motor can draw it to either put a quality inline amp meter or measure the absolute resistance of the motor on the highest setting. Then using Ohm's law calculate it out. Of course the easier way is the current meter inline. Then you will know for certain without any guess work. If you want to know the mean average current draw, I am sure the trolling motor manufacture has some specs for that.

With all that stated, I would measure the current on the highest output while in the water (for a load on the motor) and then buy a resettable circuit breaker of a little more current capability and install it. Example, if you read current of 42 amps max, I would install a 50 amp breaker. JMHO!

 

[Harvey Manfrenjensenden]

Harvey, I understand what you are saying, but it really doesn't work that way. The thrust output does not translate to current by any math equation that I ever heard of. There may be some correlation, but not a direct calculation. The only true way to know exactly what amount of current the trolling motor can draw it to either put a quality inline amp meter or measure the absolute resistance of the motor on the highest setting. Then using Ohm's law calculate it out. Of course the easier way is the current meter inline. Then you will know for certain without any guess work. If you want to know the mean average current draw, I am sure the trolling motor manufacture has some specs for that.

With all that stated, I would measure the current on the highest output while in the water (for a load on the motor) and then buy a resettable circuit breaker of a little more current capability and install it. Example, if you read current of 42 amps max, I would install a 50 amp breaker. JMHO!

gm280 is 100% correct. I had heard that as a way to perform a "rough" calculation as I stated above, but in reviewing where I had read that, it was also for a 24v system. Forgive me, I screwed the pooch on that one. There is no replacement for an accurate measurement by any means whatsoever.

 

[Grandad]

I suggest that you download a manual here http://www.motorguide.com/support/literature for the model that you have. I took a quick look and I think your unit is expected to draw just under 50 amps, so I would agree with others that the fuse is too small. I notice one model lists #10 wire with a 50 amp circuit breaker with a caution to increase the wire size if longer than 6' from your battery. Another model is supplied with #6 wire. Don't cheap out on the size of wire. The concern is voltage drop caused by wire resistance. The motor can't provide full rated thrust if the voltage drops as current passes through the wire. Undersized wire tends to get warm and a lot of your battery's energy is wasted as heat. - Grandad

 

[Tony T.]

I got a small bag of goodies extra with the purchase of the boat and motor (changed out parts, some new parts,etc.). There also was the original owners manual for the boat and motor only but no owners manual for the MG 54lb trolling motor. Being the age of the boat, the 54lb trolling motor I'm sure was added later since probably the original troll motor quit working at some given point I'm assuming. I found in the bag of goodies a new 50 amp circuit breaker, probably the owner before me may have just stuck the 30 amp fuse in as a get by at the time until they could change out to the 50 amp circuit breaker, so I wired up the 50 amp circuit breaker with 10 gauge wire, the existing supply wire supplied to the battery compartment is factory 10 gauge, my deep cycle battery for the trolling motor is located roughly 3 to 4 ft apart from each other. I'll keep a eye on how this preforms especially checking the wiring to make sure it's not over heating I just wired it up yesterday and have not tried it on the lake yet.

Thanks for all your suggestions

Tony

 

[mjf55]

A little late, but I looked for a owners manual for the MG motor. Found one for an X3 model which covers 55 lbf models. Here is what they say:
--Install a manual reset circuit breaker in line with the trolling motor positive leads within 180 cm (72 in.) of the batteries.
----50‑amp manual reset circuit breaker MM5870
----60‑amp manual reset circuit breaker 8M0064076 (mynote - may be for the 70 lbf model in the manual)
--Do not extend the included 10‑gauge battery cables more than 1.8 m (6 ft) for a total of 3 m (10 ft). If longer battery cables are required, MotorGuide offers accessory 8 mm? (8‑gauge) battery cables.

So if your batter run is longer than 6 feet, move to a higher gauge wire.

Hope this helps.

 

[Tony T.]

A little late, but I looked for a owners manual for the MG motor. Found one for an X3 model which covers 55 lbf models. Here is what they say:
--Install a manual reset circuit breaker in line with the trolling motor positive leads within 180 cm (72 in.) of the batteries.
----50‑amp manual reset circuit breaker MM5870
----60‑amp manual reset circuit breaker 8M0064076 (mynote - may be for the 70 lbf model in the manual)
--Do not extend the included 10‑gauge battery cables more than 1.8 m (6 ft) for a total of 3 m (10 ft). If longer battery cables are required, MotorGuide offers accessory 8 mm? (8‑gauge) battery cables.

So if your batter run is longer than 6 feet, move to a higher gauge wire.

Hope this helps.

Thanks for the info, I believe I'm below the 6ft length on the 10 gauge , I'll keep a eye on the wire to make sure it's not over heating, if so I'll go to the 8 gauge.


Tony