Ground Wire Size, does it matter??

[brokemerc]

I have a 20' 2008 center console. I'm in the process of installing a 24v trolling motor. I understand from previous posts that it's ok to ground the trolling batteries to the ground on the Main motor battery. It seems that all battery system wire is 6ga. I have a pre-made marine 2ga. wire that I was planning on using to ground the battery.. Would going to a larger dia. wire for the ground present any problem?? Just thought I'd ask first.. Thanks,, I always seem to resort back to this site for answers.. You guys are great..

 

[wellsc1]

Re: Ground Wire Size, does it matter??

2 ga. seems a bit large, but if you have it on hand it beats buying more 6 ga.

I hope you find lugs affordable compared to buying 6 ga. and lugs for it.

As long as your the same size or larger you're ok. Remember the current flowing through the positive wire has to flow through the negative wire also.

 

[brokemerc]

Re: Ground Wire Size, does it matter??

Thanks,, the 2ga wire I have is already made up with lugs on each end,, and is marked "Marine",, Don't ask me where it came from I found it in my garage.. Thanks again..

 

[SKEETR]

Re: Ground Wire Size, does it matter??

I understand from previous posts that it's ok to ground the trolling batteries to the ground on the Main motor battery. ..

Not sure what you mean by this but it doesn't sound good. Unless you are planning to incorporate your main battery into the 24v equation. Power to an accessory has to return to the batteries that supplied it.

 

[Silvertip]

Re: Ground Wire Size, does it matter??

You NEVER use the cranking battery for 24 volt trolling motor use unless you have a motor than can be pull-started. Sooner or later you will end up with a dead starting battery. Besides, do it wrong and you send 24 volts to motor electronics and end up with a real big surprise. There is another post in this forum about 24 volt wiring schemes. I suggest you look at it.

 

[bruceb58]

Re: Ground Wire Size, does it matter??

What is being connected to the 24V batteries for the trolling motor besides the motor themselves?

 

[brokemerc]

Re: Ground Wire Size, does it matter??

I have two 12 volt batteries hooked together to power the 24 volt trolling motor,, that is the only thing those batteries do. I was just looking to connect the ground wire from these batteries to the ground wire of the 12 volt engine battery. I had read another post where someone was told that it was ok,, guess I'm reconsidering it..

 

[brokemerc]

Re: Ground Wire Size, does it matter??

Just called the boat mfg and their Engineer told me that the trolling 24 volts does not get grounded to anything, it is just hooked in a big loop. Now I installed this same trolling motor in my last IO and know for a fact that I hooked a ground wire from the engine block to the negitive on the battery terminal, possibly I didn't need to. Hope it works.. Thanks.

 

[John_S]

Re: Ground Wire Size, does it matter??

It can float or you can ground them. If you get noise/interference or other problems, try the other.

http://forums.iboats.com/showthread.php?t=186986

 

[Knightgang]

Re: Ground Wire Size, does it matter??

There was another post about this, might have been you, but you never want to try a 24vdc system and a 12vdc system together. The 24v system will eventually backfeed into the 12v system and cause damage to you engines electrical components and anything else that is hooked to the 12v system. Keep them seperate and they are right, the 24v trolling motor system is a big loop, no need for external ground.

 

[brokemerc]

Re: Ground Wire Size, does it matter??

Makes that part easy THANKS.. One other question,, I have my trolling motor plug (3 wires) going into an on/off switch,, from the switch there is just 2 wires Pos/Neg to a 50 amp breaker and the pos/neg to the batteries. Ideas on hooking the three wires into the switch,, only two feed out of it to the breaker.. I think it's red/orange/black.. Hook red/orange together??

 

[bruceb58]

Re: Ground Wire Size, does it matter??

The 24v system will eventually backfeed into the 12v system and cause damage to you engines electrical components and anything else that is hooked to the 12v system. Keep them seperate and they are right, the 24v trolling motor system is a big loop, no need for external ground.

It is true that the ground is not needed if the trolling motor is the only thing on the 24V system.

It is NOT true that if you connect the two grounds that the 24V will eventually feed back into the 12V system. That's just BS and whoever is saying that does not understand basic electrical theory.

Take your computer as an example. Your power supply has +12V, -12V and +5V. They all share a common ground and the power from each supply does not interfere with the other. In fact, it is a requirement to have a common ground. If the OP ever has something on 24V interfacing with something on 12V, you have to have the grounds tied. If you don't, the ground potential between the two would actually float and you could create a lot of damage from over voltage.