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post #13 of Old 07-07-2008
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Just re-read your original post and thought I'd reply a bit more in depth.

Originally Posted by artbyjody View Post
If there was one gripe I did have when I finally started using my new Barberis, was that there was no easy access to the battery switch. It was under the nav table and impossible to see which mode it was selected to without getting on my hands and knees and hoping I do not bang my head on the table after I was done.
A good idea.

So, it was obvious to me that the first item in the electrical upgrade process would be a new switch. Blue Sea Systems sells a battery switch that is three positions but includes a automatic combiner / surge suppressor. The automatic part means that one doesn't have to switch to "combined" mode on the selector if the starter battery is low - it automatically switches over house banks to the starting circuits.

Actually the automatic part of this setup is the ACR, which is an Automatic Charging Relay, which combines the batteries when charging level voltages are sensed on either battery bank. The Dual Circuit Plus battery switch isolates the starting battery bank and engine starting loads from the house bank and house DC panel loads, and acts to protect the electronics from the voltage dropout and surge that can occur when starting the engine.

Installation is not difficult but can be a challenge for someone not quite sure where or what the wires currently on their Guest or Perko battery switches are. So, I figured I would share my tips on how I tackled the problem.

1. Turn off all power on both AC / DC side. This means pull out your shore power cable, and if possible disconnect leads from your batteries.

2. Undo the holding screws for your current switch so that you can pull out the original to actually handle it. Do not start disconnecting the cables on the back.

3. Your switch most likely will have three terminals on the back. You will want to label each wire with the position number that corresponds to the terminal / switch position. In this document I label the "off" terminal as #0, swith position #1 as #1, and the third as #2. I also drew a circle and annotated where the wire originated at. I used painters tape and a marker to annotate each.

This step is the most important because there is no one to one matching to the Blue Sea selector terminals. Once properly labeled then do one terminal at a time and remove the retaining nuts and cables from each terminal.
Most of the 1/2/Both/Off selector switches only have three posts. The problem you'll run into is that the new switch has four posts... and the wires on the common post need to be separated into the house side and starting side connections so that the new DCP switch does what it is supposed to.

Pause and reflect:

You now will have the opportunity to place the switch in a new location or into the old position. Note, that you may have to improvise a mounting solution if you do not drill a new hole. The Blue Sea selector was smaller in circumference than the Guest one I replaced. I opted for drilling a new spot myself, moving the selector to a slightly more accessible spot. A Light now goes where the old one was.
I would highly recommend putting the battery switch someplace that is readily accessible, since it may be necessary to turn it off quickly in an emergency. The severity of electrical fires can often be reduced by cutting power to them—if you can't reach the switch, you can't cut the power.

But before going all gung ho. Ask yourself, will the current cables reach the new spot? You may have to extend the current ones for the new location will mean a trip to the store to get matching gauge wire for the project. It will be cheaper in most cases to just keep it where it is...and once installed you may find you never touch the selector switch ever again.
If you're not using this switch fairly regularly, chances are you're not on the boat all that often or you're living on it. One is bad, the other is good.

Possible additional items you will need prior to starting the actual re-wiring:
  • Large Bus Bar (4 terminals minimum) for tying in the ground (I advise this strongly). Most boats simply tie everything to the negative lead of the associated battery. The bus bar will allow for a common ground for all systems. ($60-90)
  • Small Bus bar for connecting "always live" circuits such as bilge pumps, memory for stereo, etc...($26-50)
  • Additional battery cables to handle the new configuration of wiring. I used automotive battery cables myself as the marine versions were 2X the price.
The Blue Sea Switch has four poles. the right side is grouped as #1 consisting of top and bottom terminals. In my installation this was for the starting / motor aspect. Side #2 consists also of top and bottom terminals and this is your housing side.
You will probably also want to have a proper battery terminal crimper, which is not a cheap tool... about $130 or so. You'll probably also a proper wire crimper and adhesive-lined heat shrink terminals.
Attaching the Charger Circuits:

Odds are you have a charging system when connected to shore power to keep the batteries charged. On your old system, you probably had one attached to the #0 (for house battery) and a second one attached to #1 (for starting battery).

The charging cable attached to #0 on the old one will go to the top terminal #2 of the Blue Sea Switch. This is the house side.

The charging cable attached to #1 on the old one will go to the top terminal of #1 of the Blue Sea Switch. This is the starting side.
If you have a decent charger, you should only need one. The ACR will take care of combining the two banks when the charger is active.

BTW, jody's instructions below assume the #1 bank is the starting bank and the #2 bank is the house bank.

Attaching the house circuits
Connect up your house circuit wires (that run to your circuit panels) to the top terminal on #2 side of the Blue Sea System switch. In cases where you have more wires than will fit, you can use a bus bar, and run one lead from the terminal post to the bus bar. Remember to also install a protective cover over the bus per ABYC as it is a live circuit.

Attaching the Alternator:

The Alternator wire will go to the bottom post of #2.

Attaching the Starter:

Starter wire goes to top post of #1.

Before adding the Battery Cables:

Now is time to install the Automatic Charging Relay (ACR). Note that you want a decent location for this as the wires have to run underneath it. Also beware you need to install fuseable links inline, although I will admit I did not as of yet. They are not included with the system.

Mount the ACR in a suitable location - near the battery switch if possible - but enough distance that you can bend battery cables. Connect the Start Battery POSITIVE to the B terminal of the ACR.

Now connect the house battery terminal to your Selector by adding it to the bottom post of #2. Take another battery cable and attach it to the same post and run it to post A on the ACR. There is no need to run a separate cable from the house banks as the terminal post on the selector will do the same function just fine. You will also connect up any of the battery / metering sensing wires for the house battery to this post.

Now take a battery cable and from the POSITIVE terminal on the starter battery - connect it bottom post of #1. If you have a battery / metering sensing wire for battery gauge - attach here as well.

NOTE: The battery sensing wire can also be placed alternatively on the top posts for #1 or #2 sides of the Selector. Doing so will mean that the selector has to be ON to have the gauges read battery levels. That is how I have it arranged versus using the bottom posts.

Now install the negative terminal post. Please, make sure you get the large size one, its pricey all things considered but required. Attach all the battery, house circuit, and any other negative / grounding cables and secure them.

Now install the starting circuit wire the the appropriate terminal on the ACR, ground, led...

Double check the tightening of posts and nuts. Go back over how you installed it correct any issues you may find. Install any protective covers, secure battery etc.. The system should now be set-up.

To verify your system install. With the Selector OFF - turn on shore power, and turn on your battery charger if it is not hardwired with a circuit breaker. Using a voltage meter - measure the voltage output at the top terminals of both #1 and #2 of the battery switch. You should read 13.5 volts or so.

If you can turn off your battery charger do so. Now turn selector to ON. repeat the same.

Test starting the motor and go through your DC circuits and verify proper operation.

Hope this write-up helps someone else tackle this upgrade. It really is not difficult - just takes some patience and maybe a few runs to the store to get various cables and the likes...


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Telstar 28
New England

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