Wiring 24volt system

Hi All,

I wanted to see if any of you all see anything wrong with this configuration. I currently have two batteries connected to a switch as indicated with one of them being a Start/Deep Combo. I wanted to add another Deep cycle for my 24vt trolling motor. I have a Minn Kota power center that I was going to put in the bow while leaving the other two batteries in the stern. To me it makes sense, I can operate the boat on 12v and then have the 24v system ready for trolling. Looks like the system is seperate.

Re: Wiring 24volt system

Not only are you flirting with disaster, your system will not work as you show it. Remember, you have two independent electrical systems here. One is 12 volts with its own ground (the one on the starting battery) and the other is 24 volts with ground as you show it for the trolling motor. That ground and the starting battery ground would need to be tied together to create a complete circuit for the engine. Unfortunately, that's the disaster part. Don't do it. With the switch connected as you show it, you are feeding 24 volts (if you had a ground) to the engine so any engine electronics would turn to toast. Lastly, even though you don't have the starting and troller batteries grounded together, current will find a way from the engine to a ground -- any ground and that current will melt wire. Do not use this system. If you don't believe me that you are feeding 24 volts to the big motor, follow the 24 volt wire from the troller to the switch. You suddenly say that's 12 volts when it was previously 24 volts. The switch makes no conversion.

Re: Wiring 24volt system

I agree with Silvertip,

You have 24 volts going to the 12 volt system. thats never a good thing.
You need to have them seperated.

Also I think what you are trying to do is charge the 24 volt side with the alt.
You need a isolater, and then i still dont think you can do it. Unless you had a 24 volt alt that had a step down for the 12 volt side.

Re: Wiring 24volt system

Yes, the wiring diagram is not correct and you will be feeding 24V to 12V circuit as ST said.

But, if you connect 24V jumper wire the other way and pull your 24V off where the 24V jumper wire used to be, that will fix your problem. I had my old boat wired like this and my new boat also, works fine.

Re: Wiring 24volt system

You gotta seperate them. No way a 12 and a 24 volt system can be ont he same switch. Also, you cannot allow the 24v system to be wired to the engine for the purpose of charging. It will fry everything. Use the 12v for the engine only. Seperate the system and either make sure your 24v system batteries are charged before you leave out and/or use solar chargers or some totally seperate charging system for them. Not sure what that might be, or if the solar chargers have 12v or 24v or just put a 12v on each ??????

Re: Wiring 24volt system

I am so glad I asked, you guys saved me a huge headache. I will keep them separate and just buy another battery. Thanks again for your replies!!!!!

Re: Wiring 24volt system

That is why we are here. To save each other as many headaches as we can... Good luck...

Re: Wiring 24volt system

You don't need another battery! You have three. Eliminate the switch entirely. Connect two batteries in series for 24 volts for the troller. Leave the starting battery for the engine and some accessories. Add a two or three output on-board charger and plug in at the dock to charge the batteries. Carry jumper cables or a jump start box for emergency start if you feel you need that protection.

Re: Wiring 24volt system

I don't know what you guys are talking about because there is no way he is getting 24V to his motor. He has it wired correctly. I do not see a problem.

Silvertip said:

If you don't believe me that you are feeding 24 volts to the big motor, follow the 24 volt wire from the troller to the switch. You suddenly say that's 12 volts when it was previously 24 volts. The switch makes no conversion.

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The battery on the left side of the diagram is completely out of the picture. So what if its positive terminal is connected to the ground of the other battery. The ground of the left hand battery does not go to the Outboard's ground! This is totally fine.

The only way you would get 24V at the outboard is if you removed the ground going from #2 trolling battery to the start battery and then put a ground from the #1 trolling battery to the start motor. As long as that never happens, not a problem.

Re: Wiring 24volt system

First -- I will take 20 lashes with a wet noodle for my mistake. Second -- depending on the alternator output of this motor, trying to charge three batteries from the motor is a losing proposition. Third -- I stand by my statement that this setup is flirting with disaster. Any connection (on purpose or accidentally) to the isolated troller battery ground can put 24 volts on the motor and accessories. Will it happen -- maybe/maybe not. Is it worth the trouble -- in my view no!

Re: Wiring 24volt system

I like his idea of being able to parallel up one of his trolling motor batteries for an emergency start. I agree, his alternator won't be able to adequately charge all of these but I believe his intention is not to do that. The scenario would be, switch to both...start engine...switch back to the start battery.

As long as cables are labeled properly, there should not be a problem. To be safer, he can bring the ground and the output from battery #1 instead of battery #2. I totally agree that there could be a problem with cables inadvertantly put on wrong terminals but you will have this problem with bringing in a 4th battery as well. There is always a way that things can get screwed up.

Re: Wiring 24volt system

bruceb58 said:

I don't know what you guys are talking about because there is no way he is getting 24V to his motor.

The only way you would get 24V at the outboard is if you removed the ground going from #2 trolling battery to the start battery and then put a ground from the #1 trolling battery to the start motor. As long as that never happens, not a problem.

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Silvertip said:

I stand by my statement that this setup is flirting with disaster. Any connection (on purpose or accidentally) to the isolated troller battery ground can put 24 volts on the motor and accessories.

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Yes, I jumped the gun too in saying that there would be 24V at the switch as there won't be 24V. BUT,,, I'm sticking with my recommendation of flipping the jumper wire and pulling 24V off where the jumper wire was before. I wouldn't connect the battery switch to the trolling motor's 24V + connection, because as ST said, it's flirting with disaster. Connecting the battery switch in the middle of the 24V bank will have less of a chance of smoking something. As it's wired right now, if the 24V - lead were to ground out for any reason, you would get 24V to the battery switch. All the stars would have to align for disaster to strike (switch on bank #2 when 24V hit ground) but I wouldn't tempt fate.

Something else to think of, you should have have a breaker on each batteries + terminal in the 24V bank if you are going to run the batteries far apart. It's a given you will need a breaker on the +24V terminal to protect the TM (and wiring), but should also have one in the middle of the bank to protect the long wire(s) going to the bow of the boat, in case it shorts out.

BTW, there is a way to charge both TM batteries from the alternator if you use a Marinco 4 pin 24V socket/receptacle. If you take a 4-pin Marinco TM plug and reconfigure it so the batteries are paralleled (instead of connected in series) you can plug in the "charging plug" while running long distances to help top off both of the TM batteries instead of just one. Marinco makes a red "charging" plug which you are supposed to wire to a battery charger, but I'm not sure if this plug is parallel jumpered. I just took a spare TM plug and parallel jumpered it, instead of buying the red charging plug. If I'm running 20-30 miles I plug in the "charging plug" to charge both of the TM batteries a bit, instead of just one. I have a 100 amp alternator, so the batteries don't get discharged too bad if I run a 1-2 hours a day, depends on the TM usage though. I'm not saying this will keep the batteries completely charged, but it will put some charge back on the TM batteries while running long distances. Could be the difference of the TM batteries being dead at the end of day 1 or the end of day 2, depends on the output of your alternator.

http://www.marinco.com/product/chargingtrolling-system-package

Re: Wiring 24volt system

fishrdan said:

As it's wired right now, if the 24V - lead were to ground out for any reason, you would get 24V to the battery switch. All the stars would have to align for disaster to strike (switch on bank #2 when 24V hit ground) but I wouldn't tempt fate.

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From the drawing the OP drew up tells me the guy has some brains in his head. Personally, I wouldn't hesitate hooking up the switch to one of the TM batteries(preferably the bottom one in the chain) and trust myself to be careful. I think the OP would do similarly.

Jeez...all you guys with the "me too" responses.

Re: Wiring 24volt system

bruceb58 said:

Jeez...all you guys with the "me too" responses.

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Niiiice....




I never said not to double duty the TM battery, heck I've been doing that for years. I just said to wire the batteries different to be safe, as careful as one might be, mistakes can and do happen. Sending 24V through your 12V system could be a costly mistake. (Hope that wasn't a "me too" response)

Re: Wiring 24volt system

bruceb58 said:

From the drawing the OP drew up tells me the guy has some brains in his head. Personally, I wouldn't hesitate hooking up the switch to one of the TM batteries(preferably the bottom one in the chain) and trust myself to be careful. I think the OP would do similarly.

PHP:

Jeez...all you guys with the "me too" responses

.

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I agree
+1
Read my mind
Took the words out of my mouth
Second that
Ditto

Re: Wiring 24volt system

fishrdan said:

I never said not to double duty the TM battery, heck I've been doing that for years. I just said to wire the batteries different to be safe, as careful as one might be, mistakes can and do happen. Sending 24V through your 12V system could be a costly mistake. (Hope that wasn't a "me too" response)

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What was this?

fishrdan said:

Yes, the wiring diagram is not correct and you will be feeding 24V to 12V circuit as ST said.

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Of course you can make mistakes with any system. Like I said, the guy seems to know what he is doing. He can wire it either way and it will work fine.