Older Evinrude12/24V Trolling Motor Question

[Central FL Mike]

My trolling motor is probably a '90 or a '91, mod # BHL4TS. When switched to 24V I know it draws from both batteries and I presume the draw is equal between the two batteries. Does it also draw from both batteries when switched to 12V? Could I use a single 24V battery for the trolling motor and use the extra battery for accessories? The batteries were in the boat when I bought it used and I think they are nearing the end of their service life. When I replace them I am considering adding an onboard charger. What would some recommend for my 2 trolling and 1 starter battery setup? Any insight or suggestions would be appreciated.

 

[Silvertip]

Re: Older Evinrude12/24V Trolling Motor Question

See the post above for the Motorguide Brute 750. For 24V operation, your motor draws from two 12V batteries connected in series. On 12V, one of the batteries is switched out of the circuit. The schematic shown in the previous post is for that style of system. If your boat has a separate 12/24V panel then there are a couple of different schemes to consider. The key thing to look for is how many wires/terminals are there on the trolling motor plug. There will be 2, 3, or 4. Each requires a separate wiring scheme. Single voltage motors (12 OR 24V) have two wires. since there is only one voltage to consider. Keep in mind the plug may have three terminals but only two of them are used so count the wires. Dual voltage motors (12 AND 24) will have either 3 or 4 contact plugs. Let us know what you have and whether or not you have a separate 12/24 switch panel on the boat as well as one on the motor. I'll post a schematic for you.

 

[Central FL Mike]

Re: Older Evinrude12/24V Trolling Motor Question

Thanks for the reply Silvertip. I just replaced my old trolling motor plug so I know there are three wires. However, at the batteries, there is a positive (+) and a negative (-) lead for each battery; two pairs of wires. I don't know if that has any bearing on anything. There is no 12/24 switch on the boat, only on the trolling motor itself.

 

[Silvertip]

Re: Older Evinrude12/24V Trolling Motor Question

You said you replaced the "old" trolling motor plug. Does that mean you had a trolling motor before, and was it a 12/24, 12V only, or 24V only style motor? There are a couple of wiring schemes for 12/24V motors so we need to determine what you had before, so we can make it work for what you have now?

 

[Central FL Mike]

Re: Older Evinrude12/24V Trolling Motor Question

Sorry for the confusion. The old plug was worn so I replaced it. That's how I know it has three wires. Everything else is still the same. 12/24V trolling motor with the switch on the motor itself.

 

[Silvertip]

Re: Older Evinrude12/24V Trolling Motor Question

I guess I'm not getting my point across so I'll try again. If you have two pairs of wires (+ and -) from each battery, how are they connected at the receptacle? If you look at the diagram I provided for the Brute 750 you will see there are only three wires running to the receptacle. If you have four wires to the receptacle (which is apparently a three prong plug) you can see why I need more information on how the batteries are wired. To answer your question about charging, you would need either a two or three bank charger. Two banks are needed to charge the trolling motor batteries. If you want to charge the starting battery you need a third bank. However, two and three bank chargers typically have all outputs at the same charge rate which the starting battery rarely needs. Three bank chargers also get spendy so why not use a two bank and add an inexpensive "battery maintainer" for the start battery. Schumacher makes a small water proof unit for about $25.00. Any brand name two-bank charger with isolated outputs will work for the trolling motor battery.

 

[Silvertip]

Re: Older Evinrude12/24V Trolling Motor Question

I forgot to answer the 12/24 question. On 24V the motor draws from both batteries which are connected in series. When switched to 12V, the 24 (red) line is broken and the orange (12V) line feeds 12V from one battery to the motor.

 

[Central FL Mike]

Re: Older Evinrude12/24V Trolling Motor Question

Thank you for your help Silvertip. I dont know anything about the wiring between the batteries located in the stern and the trolling motor up front. All wiring is under the deck with the exception of the leads protruding from the bilge that go on the posts of the batteries. There is a red and black lead for each battery. How these wires are connected to each other under the deck is a mystery to me. There is a 3 prong plug in the bow where the trolling motor plugs in. I know there are 3 wires to the receptacle because I recently replaced the female receptacle on the boat and the male plug on the trolling motor. I used a standard MotorGuide or MinnKota locking plug. How I got from 4 leads at the stern to 3 wires at the bow is unknown. Since I'm electrically illiterate, I presumed that it was standard wiring. Maybe its not. BTW the boat is a 1992 19ft Osborn bay flats center console with a 1993 150HP Johnson V6 outboard.

*** Afterthought ***
I purchased this boat from a friend of mine that I used to fish with. He used it bout 3 months prior to me buying it and he said the bilge pump and the livewell pump worked. When I bought the boat, the batteries were dead and I couldn't run the bilge or livewell pump. I removed the batteries one by one and charged them. I may have re-connected the wires out of sequence. I wonder if they are tied into the bilge and livewell pumps somewhere and thats why they don't work now. That may explain why you don't recognize the wiring in this particular boat. Possible?

 

[Silvertip]

Re: Older Evinrude12/24V Trolling Motor Question

I could provide more information than you probably want to digest so l'll keep working with you using a step by step process but I need you to get your hands dirty. 1) Disconnect the wires from both trolling motor batteries. 2) Remove the screws that secure the trolling motor receptacle and pull it out of the panel as far as it will go. 3) Check to see if there are two black and two red wires in that bunch of wires. If not, what exactly do you have. 4) Does the receptacle have red, orange, and black wires coming out of it? That's your job for now.

 

[Central FL Mike]

Re: Older Evinrude12/24V Trolling Motor Question

I'll check when it's daylight tomorrow. When I replaced the plug there were only 3 wires that I disconnected and re-connected to the new receptacle. 1 orange, 1 red and 1 black. I only pulled the wires out a far as I needed to replace the receptacle, I didn't look to see if there was a splice or anything down the wire. I'll let you know what I find out. I really appreciate the help.

 

[Silvertip]

Re: Older Evinrude12/24V Trolling Motor Question

One more question: Where the two black and two red wires leaving the batteries all the same size wire? They should be pretty heavy gauge -- probably 6 gauge.

 

[Central FL Mike]

Re: Older Evinrude12/24V Trolling Motor Question

Silvertip, I apologize for the delay. The holidays and a bout with the flu kept me away from the boat for a while. Yes, the wires leaving the batteries are the same size and appear to be about a 6 gauge wire. I checked the receptacle and there is 1 red wire, 1 orange wire and 1 black wire. I ran my hand down the length of the wires and I did not find a splice anywhere. I don't have full access to the bilge so the wires could be attached to the stringers or coiled up somewhere in the center of the boat. I have no idea how it changes from 4 wires at the battery to three wires at the plug.