electrics im confused

[bayC]

Hello everyone. Having enjoyed the Broads for many years I have purchased my first Boat so please go easy on me. I have a question about boat electrics. The previous owners have done all sorts of electrical works to the boat, so is no longer stock, but I cannot quite figure out what Is going on. The boat has two batteries. Is one for engine start up? and the second for powering lights and sockets etc? at 12V?

Firstly, it has had a shore power socket installed on the back of the boat which I assume feeds power straight to the sockets installed onboard? So the sockets will now be 240V? and I can plug various items in. When I look inside the cabin I find the following fuse box (see fuse box pic right). The question is: I assume for the house battery (or whatever it is called) will not be charged directly from the on shore hook up, there may be a battery charger installed somewhere so the shore power will recharge the battery? If this is the case why would the fuse be turned off? How can I find out?



My second question is why would you install this? (See zig picture left) Although when I inspected it no wires are plugged in?

Thank you in advance for any help

 

[cpedw]

It's impossible to know without a close inspection but your guesses describe widespread practuce.
It may be that the Off circuit breaker is used to switch the charger on and off. It may be off because the previous owner was installing a new charger, the Zig, but did not finish.
You need to look closely where all the wires go. A multimeter will help.

 

[halcyon]

Hello everyone. Having enjoyed the Broads for many years I have purchased my first Boat so please go easy on me. I have a question about boat electrics. The previous owners have done all sorts of electrical works to the boat, so is no longer stock, but I cannot quite figure out what Is going on. The boat has two batteries. Is one for engine start up? and the second for powering lights and sockets etc? at 12V?

Firstly, it has had a shore power socket installed on the back of the boat which I assume feeds power straight to the sockets installed onboard? So the sockets will now be 240V? and I can plug various items in. When I look inside the cabin I find the following fuse box (see fuse box pic right). The question is: I assume for the house battery (or whatever it is called) will not be charged directly from the on shore hook up, there may be a battery charger installed somewhere so the shore power will recharge the battery? If this is the case why would the fuse be turned off? How can I find out?

View attachment 121651View attachment 121653

My second question is why would you install this? (See zig picture left) Although when I inspected it no wires are plugged in?

Thank you in advance for any help

The Zig unit is for a caravan, normally they have a simple charger built in controlled by the charger switch.

As said you need a multimeter to test, or get a local marine electrician in as playing with mains can be dangerous.

Brian

 

[William_H]

Congratulations on purchase of the boat. You are obviously starting on a voyage of discovery of the boat electrics. Curiosity will finally get you an understanding of what is going on. (and questions on this forum)
I presume because you mention engine start that it is an inboard engine with only electric start available. While it is not so uncommon to just parallel batteries to increase capacity it is far better to provide one battery for engine start only and the other for domestic use which is isoolated fromn engine start battery so if you do run the domestic battery down you cans still start the engine. You may find one battery is different to the other. So battery specifically designed for engine start and usually physically smaller than the other domestic battery. The problem is that you need to parallel both batteries when the engine is running to charge the domestic battery. A simple solution is just have switch. You have to remember to switch it on when engine running and off when engine stops. or there is such a thing a avoltage sensing relay which automatically does this for you .
Another common arrangement for 2 batteries is to have 2 identical batteries designed both for engine start and storage. You choose to use one battery for engine start and domestic use and leave the other one disconnected so isolated for engine start if the first is flattened. This system has a special switch with positions for no 1 battery no 2 battery, both and off. Many people are lazy and set the switch to both for start and run and leave it at that until they finish. It charges both batteries. It also uses both batteries for an enthusiastic start. However as a battery gets old it will not start the engine. If that is the case you go to both and get the engine started with both batteries. If you always start on both you will not be aware that one is dead until the other also dies and you are stuck. Also of course if you run lights fridge etc with switch in "both" you can flatten both batteries. So you lose your "jump start" ability.
If you have this system the 4 position switch will be the give away.
Re the 240v system and possible battery charger, you need to look for a charger first. See if it is permanently connected to the shore power system. ol'will

 

[PaulRainbow]

I agree with post #3, get someone in to look at it all. Not only is 240 dangerous, you really need to know how things are connected, how they work and how to operate them, or you can end up with lots of strange issues, flat batteries etc etc.

Are you saying that the Zig unit has no wires going to it ? If so, it may have been fitted originally and has been replaced by the consumer unit in the picture on the right, with a separate battery charger somewhere. As for the breaker being set to "off", who knows why, try turning it on and see what happens, but keep a close eye on the batteries in case it was turned off due to a fault somewhere.