Danonboat Posted January 25, 2009 Posted January 25, 2009 I picked up a 12/24v evinrude trolling motor today. Very nice shape . It came with the manual and it says it must run off of two batteries. I have a small boat and want to run my electronics off of one of those two batteries. Is this possible? Or do I need a third battery to run 12v accessories. Why would they give you a switch for 12 or 24 v when either way you have to use 2 batteries?? Thanks Dan Quote
Super User Way2slow Posted January 25, 2009 Super User Posted January 25, 2009 No, you can do it with two batteries. You will connect the the TM negative to the negative of one battery. Then you will need a battery interconnect cable and connect the positive of that battery to the negative of the other battery. The TM positve will connect to the positive of the second battery. When connecting you electronics, you will just connect them to the negative and positive on one battery as is it was the only battery in the boat. Just be sure you connect them to only the one battery. A 12 volt battery is always a 12v battery doesn't matter if there are six in series for a 72 volt system, as long as you go across just one, it will still be 12 volts. The 12/24 switch is for speed control. You use the 12v setting for 5 lowest speeds and 24v for five faster speeds. Just occured to me, since your boat is not wired for a 12/24 motor you will need to add a third cable. You will need two positive cables and one negative cable going to the TM. One positive will be the one I described in the 24V hook up and that one will go to the 24 lead on your motor. The second positive cable will go connect between the two batteries on the interconnect cable and go to the 12V lead on the TM. Now when you connect your electronics I would suggest connecting their negative cable to the interconnect cable also and the electronics positive to the positive cable you used for your 24 TM connection. Trust me, it will still only be 12 Volts. What this will do is make sure you are using one battery to run the TM on 12V when using the 12volt mode and your electronics on the other battery. That way one battery is not doing all the 12 volt work. Quote
Danonboat Posted January 25, 2009 Author Posted January 25, 2009 That is great to hear. Thanks for the quick response. I don't know what a battery interconnect is but i'm sure a google search can help me. Thanks again Quote
Super User Way2slow Posted January 25, 2009 Super User Posted January 25, 2009 It's nothing but a cable short cable with eyelets on each end that will fit on the studs. You can get them with with regular cable ends like a car and use the lead post if you want. You can make one but I would recommend at least #8 wire. If you buy one, it will probably be #2 or #6. Quote
Super User Way2slow Posted January 25, 2009 Super User Posted January 25, 2009 May I also add, you might want to look at getting a 40 - 50 amp breaker and installing it on the battery and then connect the negative TM cable They make special breakers for this and can be gotten from BPS or Cabela's. That way it will protect you if you happen to get a short in either the 12 or the 24 volt cable Quote
Super User Wayne P. Posted January 25, 2009 Super User Posted January 25, 2009 The OMC manual that I have shows a positive and negative wire from each battery going to a 4 conductor receptacle and then a jumper is used in a 4 conductor plug to get the 12V and 24V to the three wires going to the motor. There is no jumper at the batteries. My last fiberglass bass boat was wired that way. If you would like a 3 wire diagram, I have one from a motor guide manual that shows the jumper at the batteries and motor wiring for a 12/24V 3 conductor plug set-up. purdum43@aol.com Quote
Super User Way2slow Posted January 25, 2009 Super User Posted January 25, 2009 Most boats wired for 12/24 will be wired with four wires going to the front. They do this so they can use a toggle switch marked RUN/CHARGE to switch them from series to parallel and use the TM receptical in the boat to plug your 12 battery charger in and charge both batteries from the front. The only way he would need four wires is if the TM has four power leads and required four, which is something I've never seen but I will say I haven't seen them all. Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.