New Z19 TM swap wire size/breaker question

[bishoptf]

I am about to pick up a new z19 and going to rig it myself. The one thing that I think is odd is that the TM wiring is all 6awg with a 50a breaker. I was a little concerned about the 50a rating but that sounds about right for 6awg wiring. I also looked at the bigger boats and they all list 6awg and 50a breaker. Do they upgrade the wiring if you select an ultrex etc? Just need to know if I really need to upgrade to 4 awg and bigger breaker, I am leaning towards a garmin force and they list the higher speeds pulling over 50a. I think I've read that some use a 60a breaker but that seems higher than what I think 6awg is normally rated for which I believe is 55a.

Just thought I would ask...

[M-D]

You can pair a 60A breaker with 6AWG.

[xxstang90]

The garmin force calls for a 60amp breaker in their manual. Their wire chart for 10-20ft says 6 AWG minimum, 4 AWG optimal. I think in english that translates to 4AWG with 60amp breaker if you go with the force. No idea what Nitro installs in the boat but wouldn't surprise me if they go the bare minimum route.

[bishoptf]

The garmin force calls for a 60amp breaker in their manual. Their wire chart for 10-20ft says 6 AWG minimum, 4 AWG optimal. I think in english that translates to 4AWG with 60amp breaker if you go with the force. No idea what Nitro installs in the boat but wouldn't surprise me if they go the bare minimum route.

Yeah I know a lot of folks think Nitro's are not the best built boat and while I agree that some of the stuff is budget minded and I wish it was better, overall I think its a pretty nice boat. I've talked to some Trolling motor places and they say 6awg and 60a breaker is pretty common. I tried to look up some of the other boat mfg but at least nitro lists what they are using etc on the website, most of the others do not even list it. Honestly I bet the 50a breaker would be just fine but I may swap it out also. Would be interesting to know what other boat manufacturers are using.

[FrancoCialone]

My 24v, 80lb. Fortrex uses 56 amps at full speed, so I use 6 gauge wire with a 60 amp breaker near the batteries. I think your wire gauge is fine but your manual will tell you what breaker is required.

[MTW]

6 awg 105deg c is rated for 94 amps bundled conductors. the force needs a 60a breaker. if youre going to run lithiums the higher voltage on the 36v setting will keep the drop just below 3% at 25 feet with 6awg. at the 24v setting youre looking at right around 5% drop.

[xxstang90]

Yeah I know a lot of folks think Nitro's are not the best built boat and while I agree that some of the stuff is budget minded and I wish it was better, overall I think its a pretty nice boat. I've talked to some Trolling motor places and they say 6awg and 60a breaker is pretty common. I tried to look up some of the other boat mfg but at least nitro lists what they are using etc on the website, most of the others do not even list it. Honestly I bet the 50a breaker would be just fine but I may swap it out also. Would be interesting to know what other boat manufacturers are using.

Apologies, not bashing Nitro boats. Congrats and enjoy your new boat! I think most manufactures whether it be ford, chevy, nitro, skeeter, phoenix, etc are going to use the bare minimum they are allowed to in hopes to reduce costs. If the boat already has the 6awg wire and 50 amp breaker installed when you receive it I would certainly go ahead and use that and just change the breaker out to a 60amp. If you're receiving the boat with no wire/breaker installed I would spend the extra money to use 4awg on the install.

[bishoptf]

Apologies, not bashing Nitro boats. Congrats and enjoy your new boat! I think most manufactures whether it be ford, chevy, nitro, skeeter, phoenix, etc are going to use the bare minimum they are allowed to in hopes to reduce costs. If the boat already has the 6awg wire and 50 amp breaker installed when you receive it I would certainly go ahead and use that and just change the breaker out to a 60amp. If you're receiving the boat with no wire/breaker installed I would spend the extra money to use 4awg on the install.

Yeah no problem, the plan currently is if they are using a 50a breaker and are using 6awg wire I will just replace it with a 60a breaker and call it a day. I do not have the boat yet so I cannot verify but that is what they have listed in the literature so I assume it's accurate but will find out soon enough. The boat currently has a maxxum 24v TM on it that I am going to replace but agree, if it wasn't rigged and I was going to pull wire I would probably use 4awg but talked to several TM places and all of them say that they use 6awg when they rig a boat.

[basscat21]

Yeah no problem, the plan currently is if they are using a 50a breaker and are using 6awg wire I will just replace it with a 60a breaker and call it a day. I do not have the boat yet so I cannot verify but that is what they have listed in the literature so I assume it's accurate but will find out soon enough. The boat currently has a maxxum 24v TM on it that I am going to replace but agree, if it wasn't rigged and I was going to pull wire I would probably use 4awg but talked to several TM places and all of them say that they use 6awg when they rig a boat.

These are pretty nice....

[msupc]

6 awg 105deg c is rated for 94 amps bundled conductors. the force needs a 60a breaker. if youre going to run lithiums the higher voltage on the 36v setting will keep the drop just below 3% at 25 feet with 6awg. at the 24v setting youre looking at right around 5% drop.

I believe your calculations may be off due to wire length. Wire length should account for the full circuit (batteries to TM & TM to batteries), so a 25' run is actually 50'. With that, voltage drop with 6awg at 50', 39v, and 56a would be 6% or so. Of course this is only with the motor wide-open, which will be a small fraction of the time if ever for some folks.

[bishoptf]

These are pretty nice....

For me it will be a Blue Sea breaker, just think they make quality stuff - https://www.bluesea.com/products/718...face_Mount_60A

[MTW]

I believe your calculations may be off due to wire length. Wire length should account for the full circuit (batteries to TM & TM to batteries), so a 25' run is actually 50'. With that, voltage drop with 6awg at 50', 39v, and 56a would be 6% or so. Of course this is only with the motor wide-open, which will be a small fraction of the time if ever for some folks.

i use an electrical calculator and it doubles it automatically depending on phase count, but i did use 14.6v per battery. ie 43.8v and 29.2.

[MTW]

manually. vd=56x(2x25)x.395/1000=1.106v

1.106/43.8x100=2.53% for 100% charged lfp 3 battery system.

[msupc]

manually. vd=56x(2x25)x.395/1000=1.106v

1.106/43.8x100=2.53% for 100% charged lfp 3 battery system.

To begin with, lithium batteries, from my experience, have a resting voltage around 13.3v. This yields 39.9v for a 36v system when using three (3) lithium batteries in series. Depending on the load applied, the voltage will drop from 13.3v to 12.5v or so (I have seen as low as 12.4v on a 24v Ultrex with 6awg). My most recent measurements and experience are as follows:

- Three (3) 50aH Ionic batteries in series
- Ultrex Quest 36v trolling motor
- 2AWG Ancor Tinned Copper Marine Grade wire - approximately 25' run one way

Capture.PNG

At full rip (setting 10) the Ionic iPhone app shows 59a draw and 12.5v/battery. This can be confirmed with the formula for voltage drop, which is VD=2*L*R*I. To utilize this formula, we must know the impedance of the 2AWG Ancor wire, which according to Ancor's Primary Wire Battery Cable Chart is .16 ohms @ 1000'. Impedance @ 1' would be .00016 ohms.

VD: 2*25*.00016*59 = .472v
13.3v - .472v = 12.828v

While the calculation above doesn't align directly with real-world results, it is close enough for discussion purposes understanding that other variables are at play (terminations, fused connections, etc.).

With all that being said, a more effective way to address bishoptf's concern might be "Use a breaker that complies with the specified amperage rating from the manufacturer of the trolling motor". The Garmin Force specifies a 60a breaker, so there is your answer. Any less, and you run the risk of tripping the breaker.

Additionally, there is concern regarding the factory 6AWG trolling motor wire. You can modify the voltage drop formula to determine wire selection (or adequacy), which would be R=(VDx1000)/2*L*I. For this, we need to specify the desired maximum voltage drop, and we will use 3%. To input this into the formula we need actual voltage after drop = .03*39.9 = 1.197v.

(1.197*1000)/(2*25*59) = .4 ohms per 1000'

Ancor Marine Grade Primary Wire & Battery Cable @ 6awg is rated at .4 ohms/1000', therefore this should work. There again are other variables at play (battery type, terminations, fused connections, additional wire not accounted for, etc.) that will negatively impact this best-case scenario equation. I would advise erring on the side of caution and upgrading to 4AWG or even 2AWG (which is what I did), but that would apply more for a new install or if the decision had already been made to pull new wires.

As an aside, it is easy to get buried in the details when considering this, as this discussion is centered around the trolling motor being on its highest speed. This happens infrequently for most, but in the event of an emergency (big motor down), you want to rest assured that the trolling motor will serve you without fail.

In summation, use a 60a breaker and the existing 6AWG should be adequate. For new installs or re-rigging, I would advise using the same 60a breaker and consider 4AWG or even 2AWG marine grade tinned copper wire.

[MTW]

To begin with, lithium batteries, from my experience, have a resting voltage around 13.3v. This yields 39.9v for a 36v system when using three (3) lithium batteries in series. Depending on the load applied, the voltage will drop from 13.3v to 12.5v or so (I have seen as low as 12.4v on a 24v Ultrex with 6awg). My most recent measurements and experience are as follows:

- Three (3) 50aH Ionic batteries in series
- Ultrex Quest 36v trolling motor
- 2AWG Ancor Tinned Copper Marine Grade wire - approximately 25' run one way

Capture.PNG

At full rip (setting 10) the Ionic iPhone app shows 59a draw and 12.5v/battery. This can be confirmed with the formula for voltage drop, which is VD=2*L*R*I. To utilize this formula, we must know the impedance of the 2AWG Ancor wire, which according to Ancor's Primary Wire Battery Cable Chart is .16 ohms @ 1000'. Impedance @ 1' would be .00016 ohms.

VD: 2*25*.00016*59 = .472v
13.3v - .472v = 12.828v

While the calculation above doesn't align directly with real-world results, it is close enough for discussion purposes understanding that other variables are at play (terminations, fused connections, etc.).

With all that being said, a more effective way to address bishoptf's concern might be "Use a breaker that complies with the specified amperage rating from the manufacturer of the trolling motor". The Garmin Force specifies a 60a breaker, so there is your answer. Any less, and you run the risk of tripping the breaker.

Additionally, there is concern regarding the factory 6AWG trolling motor wire. You can modify the voltage drop formula to determine wire selection (or adequacy), which would be R=(VDx1000)/2*L*I. For this, we need to specify the desired maximum voltage drop, and we will use 3%. To input this into the formula we need actual voltage after drop = .03*39.9 = 1.197v.

(1.197*1000)/(2*25*59) = .4 ohms per 1000'

Ancor Marine Grade Primary Wire & Battery Cable @ 6awg is rated at .4 ohms/1000', therefore this should work. There again are other variables at play (battery type, terminations, fused connections, additional wire not accounted for, etc.) that will negatively impact this best-case scenario equation. I would advise erring on the side of caution and upgrading to 4AWG or even 2AWG (which is what I did), but that would apply more for a new install or if the decision had already been made to pull new wires.

As an aside, it is easy to get buried in the details when considering this, as this discussion is centered around the trolling motor being on its highest speed. This happens infrequently for most, but in the event of an emergency (big motor down), you want to rest assured that the trolling motor will serve you without fail.

In summation, use a 60a breaker and the existing 6AWG should be adequate. For new installs or re-rigging, I would advise using the same 60a breaker and consider 4AWG or even 2AWG marine grade tinned copper wire.

lol almost the exact same numbers. even at a level 2 drain its still good. i design data centers for a living so no need to try to impress me lol.

but i agree, if it were mine id probably pull new conductors.

[msupc]

lol almost the exact same numbers. even at a level 2 drain its still good. i design data centers for a living so no need to try to impress me lol.

but i agree, if it were mine id probably pull new conductors.

The goal of my response/post was to provide the OP with a complete set of information to base their decision on, not to impress anyone. All too often I see posts on BBC that appear to be quickly written and incomplete in the sense of providing enough information to allow not only the OP to make their own decision, but in the future might provide an answer to someone else who has a similar question.

[MTW]

The goal of my response/post was to provide the OP with a complete set of information to base their decision on, not to impress anyone. All too often I see posts on BBC that appear to be quickly written and incomplete in the sense of providing enough information to allow not only the OP to make their own decision, but in the future might provide an answer to someone else who has a similar question.

thats cool. thanks for explaining.

[bishoptf]

I will keep this in mind but from the charts I have seen it all depends on the distance once I actually have the boat in hand I will do some measurements and see where we land. I know this in anecdotal but I talked to several trolling motor shops and each one said they use 6awg with a 60a breaker. Not saying thats right and for longer runs and keeping under 3% you should go with larger gauge wire. I too will be running lithium's for TM batteries, what I am not convinced is does a larger than 3% drop make any difference to the trolling motor. Maybe it runs a little faster but overall I think its not going to matter.

Again thanks for all the information, will make some measurements when I get the boat but being a 19ft boat my guess is 6awg is going to be fine for my situation.

[CJ1]

t but being a 19ft boat my guess is 6awg is going to be fine for my situation.[/QUOTE]

I would believe this also. IF you plan on running the troller at 100% then upsize the wire but as was stated most don't. I have been getting by with 40 amp breakers and 8 gauge wire for years on a 54 amp draw troller. I know this so I don't run it on 10 much but it gets quite a bit of river travel on 9 as I normally can't run the big engine. Not worth it to me to change everything out. I have all the supplies as I do electrical work but why when it works just fine for what I am doing. CJ

[lpugh]

For me it will be a Blue Sea breaker, just think they make quality stuff - https://www.bluesea.com/products/718...face_Mount_60A

They dont make their own stuff. They relabel other quality products, for instance their breakers are made by BUSS, the best there is, same for everything else they.