I replaced both batteries in a 2 battery system in my boat last night. I took the positive and negative leads off 1 battery at a time. I hooked all the leads from each terminal together so I could put them back exactly as they came off. When I installed the new batteries I have power to the console but not to the motor. I have a Perko switch that has 4 choices, battery 1, both batteries, battery 2, and off. The basic wiring is a positive lead to each battery from the switch. The negative side has a lead from one battery to the other and then one from this battery to the switch. Since neither battery works for the motor I think the problem must be the negative side. All the wires seem to be ok but I’m wondering if the negative going to the switch could be cracked inside. Any guidance would be appreciated as I’m going to try and find the problem tonight. How can I check these wires since the connection is in the switch? Does the Perko come apart, without too much trouble, to get to the end of the cable there?
Help!
There should be no negative wires going to the switch.
Negative side:
The two neg terminals on the battery should be connected.
The engine neg should go to one battery negative.
A smaller gauge neg wire to supply a ground to the helm should go to one of the battery neg
Positive side:
Battery #1 pos to switch #1 terminal
Battery #2 pos to switch #2 terminal
Engine pos to switch common
A smaller gauge pos wire to supply power to the helm should go to the switch common
Take the cover off your motor and check the voltage on the leads going to the starter motor.
If you only used wingnuts on the terminals of the battery, it’s harder than you think to get them tight enough for a good connection. Some times you can get them tight enough with a pair on channel locks and sometimes you can’t even then. The more things you are trying to power off the batteries the harder it is to get a good connection. Hex nuts are better but not always necessary.
Also don’t depend on a brand new battery to have a good enough charge to start the motor. Make sure the battery is fully charged before you start chasing connection ghosts.
Leo, thanks for the thoughts. It is wingnuts and they were only hand tightened. I’m betting that is the problem I needed pliers to take the old ones off and it’s hard for me to get my old hands to really crank on those wing nuts. I’ll definitely put some pliers to those nuts in the morning and let you know.
Mr Hardware
Dont know what motor you are running, i do know evinrude etec warns against wing nuts due to voltage spikes and finicky electronics. I think most battery manufacturers are starting to send hex nuts with there batteries
Leo, thanks for the thoughts. It is wingnuts and they were only hand tightened. I’m betting that is the problem I needed pliers to take the old ones off and it’s hard for me to get my old hands to really crank on those wing nuts. I’ll definitely put some pliers to those nuts in the morning and let you know.
Mr Hardware
You’re welcome. That’s likely it.
Hex nuts are definitely the better way to go. Chickenhawk is correct a lot of new marine cranking batteries come with the hex nuts nowadays.
I took everything back off and cleaned it again and reinstalled the terminals with the hex nuts that came with the battery. I took the Perko switch off the back wall and cleaned all the connections on it. I even tested the switch while I had it out to make sure it was working. It was fine. I put the meter on the negative at the battery and the negative on the starter and the circuit was open. All the ends on the cables are old but look good. No corrosion anywhere. Still nothing. I will let you know what it was when I get it back from the doctor.
Mr Hardware
Do you have an inline circuit breaker going to your control wiring? I have one on my boat and it tripped last time I changed batteries. It will show same symptoms you have, power going to everything else, just not to the motor.
I put the meter on the negative at the battery and the negative on the starter and the circuit was open.
Mr Hardware
Good tip on the Circuit Breaker. Also look for an inline fuse holder that has been pulled out of view.
Some boats have a junction point between the motor wires and wires going to the batteries. It could be something as simple as a block screwed to the transom under the deck with two “terminal” screws on it. If it gets corroded enough it will cause an open circuit. That’s what is on my Scout and I know those connections are something to watch. It’s hard to see and I would have never noticed it unless someone told me to look for it. When mine finally craps out I plan on straight wiring it and eliminating the connection.
The Dr called to tell me that the negative wire from the motor to the battery was nicked under the floor out of sight. He thinks it probably was nicked during initial rigging, it was small, and started corroding after several years. The boat and motor are 2001. He thinks when I moved the wires to get the batteries out and the new ones in I probably moved it enough to finally separate at the corrosion. He tole me he would keep the wire to show me. It is ready to go now. I will pick it up tomorrow. Thanks for all the advice and suggestions. I knew I had put everything back exactly as it was.
Mr Hardware