1996 270 DA battery wiring, & inverter addition

[Dave M.]

My boat had the inverter already installed when I bought the boat, so I have so surmise what it looked like before the inverter was installed. I believe the inverter was installed the same year the boat was first purchased, and may have been done by the dealer in Portland, OR.

Anyway, here is what I think the battery, battery switch, and some of the breaker wiring would have looked like before the inverter addition. Not everything is shown. For example, the fuse for the stereo memory is not shown,and the fact that the ground return is at the engine block is not shown. I also don't have a Windlass in my boat. But I do have a breaker with the same wiring that goes to the helm breaker panel.

Notice in this configuration the alternator is not hard wired to any battery. Some have stated that if you turn the battery selector switch, if will fry the alternator, probably by open-circuiting the output and the sense lead.

Here is what it looks like with the additional house batteries, the diode isolator, and the inverter added, plus the alternator rewired. Now the alternator does not go through the battery selector switch, and I know of no reason one cannot change switch positions with the engine running.

With the original configuration you could only charge the battery that was selected on the selector, and the sense line read that battery voltage to control the alternator output. With this configuration, you always charge both batteries with the alternator, regardless of the position of the battery selector switch. Also, the alternator is wired to read the voltage of the house battery. It is assumed that when you have spent the day on water, you will mostly have used house battery while the engine was not running, and it is the one that will need to be recharged.

Also notice that the bilge pumps and Mercathode have been moved from Battery 1 to Battery 2, as battery 2 has twice the capacity as battery one.

Another difference is that now the second output of the originally supplies converter is not used to charge battery set 2. It is not connected to anything. Now battery set 2 is charged by the Heart Interface Inverter, which is a significantly higher output and more capable charger.

This mid-90's wiring puts a lot of wire terminals at the battery post, where they may suffer from poor contact due to corrosion if not properly maintained. In the more recent boats, the leads hot from the batteries have been picked off at the battery selector switch input terminal. Same point electrically, but physically removed from the battery post. This makes a cleaner battery installation, without all the extra wires hanging off it.

This thread belongs in the electrical section.

 

[MLauman]

This mid-90's wiring puts a lot of wire terminals at the battery post, where they may suffer from poor contact due to corrosion if not properly maintained. In the more recent boats, the leads hot from the batteries have been picked off at the battery selector switch input terminal. Same point electrically, but physically removed from the battery post. This makes a cleaner battery installation, without all the extra wires hanging off it.

My boat was wired from the factory basically as your first diagram indicates. There were many connections directly to the battery posts which was messy and as you indcated susceptible to corrosion and damage. I relocated most of that to a new buss in the bilge electrical box and now all I have on each battery is the main cable.

I made one other change that some might frown on - I moved my bilge pump, mercathode and stereo memory to a buss that feeds off the FEED terminal on the switch (not Batt1 or Batt2). While I understand the intentions behind the direct connection, I don't think they apply in all cases. First, I never turn my switch to off when I leave the boat (in the water). Second, I like knowing that I can choose which battery (or both) is powering my bilge pump. Third, when I turn the switch to Off for maintenance, etc I know that there is nothing powered on.

 

[Dave M.]

I relocated most of that to a new buss in the bilge electrical box and now all I have on each battery is the main cable.

Not a bad idea at all. Mine needs cleaned up some. In particular, when they ran the alternator output and sense wires to the battery, they put them across the floor, over the stringer, where I always get my feet tangled up in them. Clean up needed in the bilge!

Normally only electrical workers know the difference between buss and bus, one is for electricity, one is for people. :smt017

I made one other change that some might frown on - I moved my bilge pump, mercathode and stereo memory to a buss that feeds off the FEED terminal on the switch (not Batt1 or Batt2). While I understand the intentions behind the direct connection, I don't think they apply in all cases. First, I never turn my switch to off when I leave the boat (in the water). Second, I like knowing that I can choose which battery (or both) is powering my bilge pump. Third, when I turn the switch to Off for maintenance, etc I know that there is nothing powered on.

I will have to give some thought to doing that too. When my boat is in my garage, as it is most of the time, there is no reason to power anything.

I have been tracing out my wiring more accurately lately. I have a problem where when I bring up the rpms on my engine above 1000 or so, so that the alternator starts putting out amps, my helm voltmeter goes down, not up. :smt013 I don't think the battery is really doing that. I think I have alternator current flowing in reverse to the voltage sense circuit somewhere, across an impedance that probably should not be there. I have not found it yet.