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Patbarbeau 08-12-2008 08:45 PM

Battery switch
 
For most people here, this question might look very simple. I have searched for a while the different forums to see if I could find threads on this topic but with single-word search, it was difficult to get the result I am looking for... therefore, I need your help. Please do not hesitate to forward me to an existing thread if easier.

My new boat is equipped with the standard 2 batteries (crank & deep) with a switch and an electric panel. It appears that the switch only serves for the engine starter and engine area ventilator because everything else is directly plugged to the deep cycle battery. I can shut off all equipement from the panel (except engine starter, ventilator and bilge pump). The charger which can manage two batteries in a 3-cycle mode is also directly plugged to the batteries.

Is this standard or acceptable? If not what should I change?

SteveInMD 08-12-2008 09:11 PM

You should have an on / off switch for the house bank that turns off the entire panel. You should also have a 1 / 2 / all / off switch that allows you to start the engine with the cranking battery, or the house bank (in case you have trouble with your cranking battery). That's the setup I prefer anyway.

The bilge pump should be wired directly to the battery (with an inline fuse). Some people also like to wire the VHF this way too.

Patbarbeau 08-12-2008 09:31 PM

confirmation
 
Thanks Steve,

This is pretty much how my set up is since I can shut off the entire panel from the panel directly. Just to confirm my understanding:

1. It is normal then that the 1/2/both/off switch serves only to select the battery to ventilate and start the engine?

2. The wiring of the other appliances is completely independant of the 1/2/both/off switch (all wired to the house bank via panel and fuses)

3. radio and bilge pump bypass both the panel and the switch with in-line fuses

4. the charger is directly wired to the batteries

Thanks again so much for your help. Everything seems to be working fine but I am far from an expert with electricity:o

sailingdog 08-12-2008 10:03 PM

You really need to re-wire the boat IMHO. You need to have a main battery switch, usually a three or four position switch. The one I generally recommend is the Blue Sea Dual Circuit Plus models. They isolate the house bank from the starting bank and unless the battery switch is in the "COMBINE" position, starting the engine doesn't affect the electronics at all. It often comes in a kit with an ACR battery combiner, which allows you to charge both battery banks if either bank has a charging source attached.

The DCP switch has four posts... two for battery bank 1 and two for battery bank 2. Ideally, the house bank would be hooked up to post 1a and the main DC panel feed would be hooked up to 1b; and the start battery would be hooked up to 2a, and the starter and ignition system hooked up to 1b. Then there would be a lead from 1a to one side of the ACR, and a lead from 2a to the other side of the ACR. The alternator output and a shore-power AC fed battery charger would both be connected to the 1a post.

It would make some sense to have a bilge pump wired directly to the house bank batteries, but with a switch and fuse in line. The switch should be a three-position: Off, On, and AutoŚwith the auto position wired to a float switch.

It might also make sense to have the bilge blower connected to a separate switch and fuse, especially if the boat has a gasoline in-board engine. The switch should be an ignition proof model.
Quote:

Originally Posted by Patbarbeau (Post 353432)
For most people here, this question might look very simple. I have searched for a while the different forums to see if I could find threads on this topic but with single-word search, it was difficult to get the result I am looking for... therefore, I need your help. Please do not hesitate to forward me to an existing thread if easier.

My new boat is equipped with the standard 2 batteries (crank & deep) with a switch and an electric panel. It appears that the switch only serves for the engine starter and engine area ventilator because everything else is directly plugged to the deep cycle battery. I can shut off all equipement from the panel (except engine starter, ventilator and bilge pump). The charger which can manage two batteries in a 3-cycle mode is also directly plugged to the batteries.

Is this standard or acceptable? If not what should I change?


GBurton 08-12-2008 11:46 PM

This is a personal thing in my opinion. If the system makes sense to you and is up to code there is really no need to change it.
Draw yourself a schematic of the electrical wiring and then take a hard look at it and decide for yourself. You will get 10 different answers here...you should decide for yourself.

Quote:

Originally Posted by Patbarbeau (Post 353432)
For most people here, this question might look very simple. I have searched for a while the different forums to see if I could find threads on this topic but with single-word search, it was difficult to get the result I am looking for... therefore, I need your help. Please do not hesitate to forward me to an existing thread if easier.

My new boat is equipped with the standard 2 batteries (crank & deep) with a switch and an electric panel. It appears that the switch only serves for the engine starter and engine area ventilator because everything else is directly plugged to the deep cycle battery. I can shut off all equipement from the panel (except engine starter, ventilator and bilge pump). The charger which can manage two batteries in a 3-cycle mode is also directly plugged to the batteries.

Is this standard or acceptable? If not what should I change?


sailingdog 08-13-2008 07:09 AM

One good reason for a master electrical switch is in case of an electrical fire. The way your system is currently setup, there is no way to kill the power going to the panel easily and quickly. The master battery switch should be easily and readily accessible, and without having to reach over or near the rest of the boat's electrical system—so that in case of an electrical fire, you can kill the power flowing to the fire.

You should also have fuses on the main lines to the two batteries.

SteveInMD 08-13-2008 08:24 AM

As usual sailingdog gave you good advice and many more specifics than I did. I gave you a quick overview; there are many more details to work out.

Maybe someone else can confirm this, but I believe the American Boat and Yacht (ABYC) standard is that you must have a main disconnect. Only the bilge pump and possibly the radio may be direct wired. There are many more standards regarding fuse locations, wire gauges, connection methods, etc. I don't know if there is a Canadian equivalent or not.

It seems to my that you may want to have a marine electrician go through the boat wiring with you so he can check that the wiring meets at least his standards, if not a published standard. Also, I think you will learn about your boat during the process.

One more thing...adding a Link Xantrex battery monitor is a good investment for proper battery care. (Unless you spend mostly travel from one shore power connection to the next).

I'll try to answer your specific questions...

Thanks Steve,

This is pretty much how my set up is since I can shut off the entire panel from the panel directly. Just to confirm my understanding:

1. It is normal then that the 1/2/both/off switch serves only to select the battery to ventilate and start the engine?

- Yes. Having one large single house bank with an on / off switch and a 1/2/both/off switch for the engine start selections is a modern approach and the best arrangement I have seen. However, there are many more options.

You could have a 1/2/both/off switch for the house system if you have multiple house banks, but these days unless you are talking about a really big yacht, a single house bank is the way to go. Generally, the days have alternating days between two banks are over. It's much easier on the batteries to draw all house batteries down a small amount, rather than hit one bank hard one day and the other hard the next day.

I would label your house bank, Bank 1 and your cranking battery Bank 2. Your starting selector always is switched to Bank 2 under normal conditions. If your starting Bank has problems, you can switch to Bank 1 if needed.


2. The wiring of the other appliances is completely independant of the 1/2/both/off switch (all wired to the house bank via panel and fuses)

- Yes, but you need a main disconnect in my opinion.

3. radio and bilge pump bypass both the panel and the switch with in-line fuses

- Good.

4. the charger is directly wired to the batteries

- That's okay, but sailingdog's advice is better (adding an isolator). The starting battery could be charged via an echo charger. (Your charger may have a built in echo port, or you can add an external one.)

Thanks again so much for your help. Everything seems to be working fine but I am far from an expert with electricity

- A while back I took a few short courses on marine electrical systems. It was one of the best investments in my boat that I made.

sailingdog 08-13-2008 09:07 AM

I'm not a big fan of isolators, since most use a diode that induces a .7 V drop. I do like the battery combiners, which do not incur the .7 V penalty, but, if installed properly, keep the batteries isolated unless there is a charging source present.

SteveInMD 08-13-2008 09:30 AM

Yes, my mistake - thank you for the clarification.

SteveInMD 08-13-2008 10:08 AM

The system sailingdog recommends can accomplish the same goal as the method I suggested, and then some.


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