Probably Polarity


I need your assistance with my boat wiring.

I have changed trolling motor batteries in my boat and since, I have burned 2 twist plugs. My cables aren’t marked so is it possible I may have crossed them or is that something that would cause my dilemma.

What could be causing me to burn the plug? It has a 4 wire Marinco outlet.

Thank you


On a 12/24 marine electrical system, wiring the batteries is critical. Use a meter (not a test light) to determine if the polarity is correct and the battery cables are correctly connected.

The circuit protection in the positive leads at the battery should trip before you burn up the plug. If you don’t have fuses or breakers at the battery, now is a great time to add them.


Has Power. Won’t Start.


I have a 2004 Premier pontoon boat that will not start.

Premier Pontoon Boat

I have battery power as the motor will raise and lower, the radio will come on, etc.; however, the engine will not crank.

It worked well prior to putting it away for the winter.

What can I trouble shoot? Is there a fuse? How can I tell if the ignition switch is bad? Is there a neutral switch that can go bad? When I turn the key, nothing happens. BTW, I have a 50 horse Four Stroke Mercury.

Thanks in advance for any advice.


First check the in-line fuse on the engine near the starter solenoid (follow the battery cable into the engine from the battery to the starter solenoid). If the fuse is good, check for power at the key on the red or red/green wire.

This will solve your problem,


New BEP Digital VSR

One of the world’s top suppliers of marine electrical products, BEP Marine, is introducing a new digital voltage sensitive relay. It replaces the company’s well known VSR, which is hugely popular and is considered essential on any boat with more than one battery bank.

The DVSR, which functions as an automatic smart battery switch…

…allows charging of two independent battery banks from a single charging source. When the voltage on the start battery rises to a charged level, the DVSR engages allowing the 2nd battery to charge. When charging stops and voltage falls, the DVSR will disengage, isolating the two batteries from each other. Dual sensing functionality enables the sensing of two battery banks, allowing two way charging.

Here is an earlier post from our site explaining the VSR in detail.

According to BEP, their new DVSR offers a number of advantages over the older version. They include:

  • 80% lower stand-by current draw during normal operation when powered but disengaged
  • Zero stand-by current draw when remote sensing circuit utilized
  • Multi voltage – auto selects between 12V and 24V DC operation
  • Remote status LED output. Provides DVSR status indication at remote location
  • Remote sensing circuitry provides isolated control from secondary supply, and enhanced protection from voltage spikes when connected to ignition switch
  • Increased accuracy of voltage measurement through digital circuitry
  • Lowered cut in voltage from 13.7V to 13.4V (26.8V for 24V) to suit low output alternators, and high temperature environments

Boaters who want to upgrade to the new BEP DVSR will find it on our sister boat wiring site, EzAcDc later this summer.

Suspect Stereo


Last fall, I purchased a 2005 Playbuoy Pontoon boat with a factory equipped electric motor. The only thing that didn’t work at time of purchase is the tilt control for the outboard motor – at least that I knew of.Playbuoy Pontoon Boat

Ever since the purchase, I have not been able to keep a charge in the boat batteries. A couple of weeks ago, I purchased a new battery charger after measuring that I was not getting charging voltage to two of the four batteries. While wiring in the new charger, I observed arcing to the negative battery post on one of the two batteries serviced by the new charger, obviously indicative of some sort of electrical load, although the primary key switch was in the off position…all accessories off…etc.

I was able to charge the batteries to the point that both chargers shut off, and next time on the water, suddenly lost all electrical power to the electric outboard motor after only about thirty minutes of cruising time.

In consideration of the tilt control not working, and the wire arcing, is there a connection? Or might there be a short circuit that is a known problem for this model?



Hi Doyle,

I would use the process of elimination to find your excessive draw.

  • Buy an inexpensive meter that can measure DC current.
  • Install the meter in-line with the battery connection that is causing the arc and observe the current.
  • If everything is truly off, there should be no draw.
  • If there is a draw, try disconnecting devices at the fuse panel until the draw goes away.

My best guess is that the stereo is not powering down completely and the internal amplifier is drawing your battery down.

Good luck,


Power Distribution


Is there some sort of terminal used to send power to different parts of the boat – navigation lights, bilge pump, fishfinder, etc. from one of the boat batteries?

I know that I have to fuse them all, but what divides them?


Hi Red,

Your boat’s main power feed supplies either a marine electrical bus bar that feeds power to each individual circuit breaker or the main power lead can connect directly to the first breaker and then jumper to each additional breaker. The individual feeds or jumpers should be made from the same size wire as the panel feed.

The main power feed should have circuit protection as close as possible to the battery. The cable size should be large enough to maintain a 3% or less voltage drop to the panel feed.

Hope this helps,