12v in series for a 24v system

[UPSman54]

Simple question – when hooking up 2 12v batteries in series does the jumper cable have to be on the batteries or can the jumper be placed on a bus bar as I believe it was on this system?

My situation:
I’m in my mid-60’s been disabled since 1999 and decided to buy a mini pontoon boat someone on the lake was selling for me and my 100lb lab to putter around the lake with.

The 14ft pontoon is powered by transom mounted dual Minn Kota Neptune EP96 24v system. The boat is all electric – the 2 motors are the only power. They’re older looking motors and on the engine it claims 96lbs of thrust. Having 2 of these I’m thinking they should have some decent power. Would they?

The previous owner had a friend who didn’t know what he was doing mess with the battery switch and melted the 4 wires to one of the batteries (see pics). That’s right, 4 wires to each battery for a total of 8 wires going to the battery switch (which appears to be a relic hard to find any info on it – see pics) with 4 coming out of the switch to a bus bar.

The pictures also show that on the bus bar is where the jumper cable is – my basic understanding the connecting a positive and negative from different batteries – turning the two 12v batteries to a 24v system. The bus bar posts seem to be set up pos/neg/pos/neg.

Also at the bus bar is where the Guest 2613 (with no A) 3 bank charger which I think is a 5/5/3 and the two engine control boxes are connected – these are connected to the pos and neg posts on the outside - with the jumper being on the 2 middle posts.

The previous owner assured me everything worked as it is set up until friend did something to the battery switch. Plus I saw the boat operating on the lake a handful of times so I know it worked as well as the charger.

My question is could I just eliminate the battery switch and take the remaining 4 wires (12 gauge – 5ft long) and just have 2 from each battery go directly to the bus bar and keep the jumper cable on the bus bar? Or, must the + and – battery connection be at the battery? Would it be safe? The bus bar is located under the bench seat at the back of the boat where I would sit.

I just bought two new Interstate group 27 marine batteries and don’t want to chance hooking them up and cooking one of them or, sit on a seat with the bus bar bolted under my seat and get 24v cooking me – haha.

Any guidance or answers would be appreciated.

Andy

[jawjatek]

Just looking at that kludge makes me want to whip out my cutters and go to town, but without at least a diagram of what all is connected I can only offer generic advice. It seems some 12V stuff is also connected (lights? accessories?), and I don't know what function the switch was providing. I'd say take it to a pro, or find someone who has electrical skills to help you suss it all out.

[John Jackson]

On the 24 volt stuff, I personally would never go buss bar. I want the fewest connections possible, less to go wrong or short out by dropping a wrench across is. You can run all the 12V stuff off a buss bar.

[wmitch2]

First, is there a third battery that runs all your 12v lighting and accessories ? If not, then this whole mess is so you can run a 24v trolling motor and a 12v lights and accessories system. I've never seen it done like this before tho. AND I wouldn't do it this way either. If it were ME, I'd remove ALL of the TM wires, add in a third battery for lights and acc., then run the TM batteries in series using a jumper on the batteries. then hook them to the TM's. and everything else to the new third battery.

[Jonestrollingmotor]

Andy, I've never seen the rig you have, but when you say 96# of thrust and dual system, I'm guessing you have two 48# 24V motors.if this is true, all the switches you have are to make a series connection from the 4 wires (two per motor) that you have. However, you'll also have some type of duel box that will have the imput wires with a control board in each box and probably controls for each box. From the pictures I can't tell which wires are going where. I'm pretty sure I could figure it out, however I think the best for you would be to take it to a competent trolling motor repair shop. I'm sure the junction busses were needed when the boat was made.
John

[billnorman1]

You need to find a competent wiring specialist to fix your problems or you will be hating your nautical experiences. The photographs show wiring insulation deformed from overheating and believe me, it will only get worse. Personally, I'd cut many of those wires quite a ways back, and junk the junction box, it has had and probably will continue to burn the wiring. With that much thrust, and the length of time that your motor will be operating in a high current mode, spade connections are an inferior method of making contact. You will be much better off with a large stud terminal strip, terminal lugs, and nuts and washers holding the wires together.

You were wise posting this issue, I think you were on course to be towed in or sitting on a box of sparks.

[dmac279]

[UPSman54]

Wow I can't believe I received so many response so quickly - thanks so much. Let me see if I can clear things up a bit more by providing a wiring diagram.

This is the setup I'm thinking should work. It's basically the same as it was minus the battery switch and with the jumper wire on the battery instead of the bus bar. I'm thinking it's called a bus bar but could be some other name I"m not familiar with - it's in the third picture I uploaded originally. The bus bar has 4 posts to it and is mounted under the bottom of the bench seat so there isn't any way to drop something on it. The way it's set up in the diagram the left 2 posts are for the 12v stuff and the right 2 posts are the 24v for the motor and charger.

The third battery has no electronics to it yet but I drew it in the diagram as it will be used for future 12v electronics as well to test the 3rd bank of the charger. My first concern is firing up the motors and the charger to ensure they're working properly.

Does this setup make sense? Again thanks a bunch for all the information it's greatly appreciated.

Andy

PS: Would 12 gauge wiring be good from the battery to the bus bar. The length is 5 feet but doesn't need to be that long.

[Idaho Sandman]

What in the holy hell... most of those wires need replaced as they have overheated and melted the outer sheath. Isolate the troller to the 24v system then isolate the 12v accessories to the single 12v batt on a fused bus. Those pics make my wiring ocd kick in hard.

[jawjatek]

NO! In your diagram, the charger is connected wrong - the 2 sets of charging leads should go directly to the +/- terminals of each TM battery, not to the 24V bar terminals. The charger may be smoked, because you have two outputs directly connected to each other, and to 24V - not good! I would remove these leads and the charger entirely, and get everything running before wiring in the charger.

I see no circuit breakers in your diagram. You must have breakers for both the 24V and 12V hots, located very close to the battery terminals, and sized for the wire gauge used. As Sandman said, all that smoked wire needs to go. If there were breakers in the first place, the wires would not have smoked.

I am unfamiliar with that brand of charger, or if it is safe to connect to two batteries wired in series, i.e., does not have common ground between the three outputs, and is safe to charge 2 batteries in series. Is it?

I have no idea what function the switch block in the pictures performed, and it is not shown in your drawing. I presume you are getting rid of it - I would.

I still recommend getting someone knowledgeable to look at the wiring first hand, and NOT the guy who did it last time. It is as screwed up as a soup sandwich.

[Ann-Marie]

I agree with George, using 2 banks of a charger in series to charge a 24 volt battery is bad for the batteries (will over charge one while the other comes up to charge) and could be bad for the charger.
Using 2 banks of a charger in parallel to charge a 24 volt battery is a disaster waiting to happen.
Each of your 3 batteries should be connected directly to a charger output, bypassing that kludge block completely.

[UPSman54]

Thanks again for all the fast replies. All the damaged wires will be discarded and yes there are fuses everywhere I just didn't draw them in. It appears not knowing the function of the unknown battery switch puts a monkey in the wrench. I will take the advice of forgetting the charger first off and connect everything to the batteries and go from there. Thanks again!

[wmitch2]

NO! In your diagram, the charger is connected wrong - the 2 sets of charging leads should go directly to the +/- terminals of each TM battery, not to the 24V bar terminals. The charger may be smoked, because you have two outputs directly connected to each other, and to 24V - not good! I would remove these leads and the charger entirely, and get everything running before wiring in the charger.

I see no circuit breakers in your diagram. You must have breakers for both the 24V and 12V hots, located very close to the battery terminals, and sized for the wire gauge used. As Sandman said, all that smoked wire needs to go. If there were breakers in the first place, the wires would not have smoked.

I am unfamiliar with that brand of charger, or if it is safe to connect to two batteries wired in series, i.e., does not have common ground between the three outputs, and is safe to charge 2 batteries in series. Is it?

I have no idea what function the switch block in the pictures performed, and it is not shown in your drawing. I presume you are getting rid of it - I would.

I still recommend getting someone knowledgeable to look at the wiring first hand, and NOT the guy who did it last time. It is as screwed up as a soup sandwich.

This ^^^
Also, what do the TM's ground to ? They should be grounded by a wire from each directly to the neg post on battery 2 and the Pos on the Positive post. DON"T tie these together, run each with a wire to the batteries. I'd get rid of the control box, remote, and that bus bar all together and simplify you whole system and make it work less and give you more in the end. You'll need to have a set of leads from the 3-bank charger to each battery. to charge all 3 batteries correctly.

[Spidergrub]

I'd separate the 12v stuff for sure. Chargers have to go to each battery individually.

Put the jumper between the batteries and then run wires from the 24v battery set to each of the control boxes individually.

The current wiring is a fire hazard

[UPSman54]

Everyone is responding that they must be attached directly to the battery. My batteries are located on the back of the boat (new pic) - so if a wrench or something would happen to fall upon it there would be more of a chance to mess something up if everything was connected to the battery instead on the underside of the bench seat. But I get it if that's where it needs to be. Another reply was to get rid of everything - the controller is the only means of driving the boat as there is no means to steer it or change gears and such without the controller.

I'm beginning to think that perhaps I should join the 21st century and get a new electric engine, charger and whatever else I need.

Thanks again for all the replies.

[wmitch2]

This ^^^
Also, what do the TM's ground to ? They should be grounded by a wire from each directly to the neg post on battery 2 and the Pos on the Positive post. DON"T tie these together, run each with a wire to the batteries. I'd get rid of the control box, remote, and that bus bar all together and simplify you whole system and make it work less and give you more in the end. You'll need to have a set of leads from the 3-bank charger to each battery. to charge all 3 batteries correctly.

Should read, Neg to neg post on battery 2 and Pos to Pos post on battery 1

[wmitch2]

Everyone is responding that they must be attached directly to the battery. My batteries are located on the back of the boat (new pic) - so if a wrench or something would happen to fall upon it there would be more of a chance to mess something up if everything was connected to the battery instead on the underside of the bench seat. But I get it if that's where it needs to be. Another reply was to get rid of everything - the controller is the only means of driving the boat as there is no means to steer it or change gears and such without the controller.

I'm beginning to think that perhaps I should join the 21st century and get a new electric engine, charger and whatever else I need.

Thanks again for all the replies.

HOLY CRAP !!! What a nightmare !!! Not understanding the whole controller set up. Can you post a pic of the helm ? If it were MINE, I'd start a whole new set up !! I'd be afraid that would/is going to leave you stranded some day.

[Jonestrollingmotor]

If I'm remembering correct about the Neptune series they are hard mounted to the boat and the boat is steered by a rudder instead of turning the trolling motor. The control boxes are placed in a dry area with wires going from them to the motors. You will then have two wires coming from each control box for positive and negative connections to the trolling motors. These wires will be battery 1 negative and battery 2 positive with a jumper from battery 1 positive to battery 2 negative. There will then be a controller for speed control that will mount at the helm. Your Guest charger will simply connect with bank one positive and neg to battery 1 and bank 2 positive and negative to battery 2.
John

[lpugh]

Don't take this wrong as I only want to help you with this, but you are in over your head. Take it to a pro and avoid a lot of grief

[UPSman54]

Sorry about the delay in responses - a few months ago my neighbors house burnt down and I suffered collateral damage. So I'm attempting multi tasking with a diseased/disabled brain that can only concentrate on one thing at a time. Insurance company is finally getting serious and has kept me captive as we finalize the dollar amount.


Jonestrollingmotor is close to the descriptor of what I"m dealing with. But instead of a rudder my boat has a bracket mechanism that allows both motors to be turned by the steering wheel. Yes, the controllers are mounted in a dry place - under the bench seat along with the Guest controller. So if I were to keep the charger and controllers in their spot and simply run the wires as you described out to the batteries - will it be alright to have all the wiring there at the batteries on the back of the boat in the weather? Should I protect the batteries and the wiring somehow from the weather?

Your descriptors have me close to what was originally on the boat without the battery selector and bus bar. My question about all the wiring being on the batteries out in the open is about the only thing I need to figure out before I give it a trial. The thing is since most of the electronics are on the underside of the bench seat - I've removed it and have it in the garage on a workbench. I've done this because the boat is tiny and I'm not and trying to work in the confined space was very difficult. Once I find out about the batteries and wiring being in the open like that I'm about to give it a go and put the seat back in and see what happens. If all fails I'm going to upgrade the engine and electronics if need be.

This is a small pontoon - only 72 inches wide - and the reason I bought it. With the narrow width I'm able to access another part of the lake I live on through a culvert type of span under a road where the arched 71 inches barely allows the boat to get through when the water isn't too high. Having this access gives me the reason of getting this boat motorized to access the spots most others can't to fish. On the lake everyone has access to it's pretty much just a cruising/partying type of boating. Having a pontoon allows me a stable platform to not rock back and forth with movement of me or my lab dog. Being 65 this year I don't need the boat to wobble and knock me into the water. I do enough wobbling on my own.

I added some other pictures of the boat that were requested. The switches to the right of the steering wheel are for electonics not yet hooked up. One is for a unneeded bilge pump and the other is for lighting and such.

Thanks again for all the response. I think I'm close to giving it a go thanks to you.

Andy