How to wire batteries and inverter?

[Phrancus]

Hold on, please take a lot of time to learn before you start connecting stuff. Especially on a boat with unmarked wiring with cables running over and under themselves and equipment it's easy to make costly mistakes.

As advised go to that blue sea and find that there are a few configurations that are a matter of choice with pros and cons.

No one can safely answer all questions in your post for you to follow up and be OK. There's to many potential differences to your ship. In fact, every ship is not completely the same even when the standards are adhered to and the same configuration concept is chosen. Boats are not mass-produced all the same products even if they seem to (and we would like to sometimes when it comes to this kind of stuff)

So I can give some concepts that you can investigate and start building your configuration. After you get the schematics right, then you can start building it up.


> One for each engine and one for the house...If this is correct?
Possible, pro: if one is empty, you can start the other engine. Should the running one charge the emtpy battery, you need some clever cabling or switching. Con: the switching or manual jump starting and a lot more one can think of.
Also: diesels require more starting power generally so customary to put two batteries parallel (same voltage, double amperage) for the engines and a separate one for the house. And sometimes another one for the bow/stern prop.
This can also get complicated when you also have 24V and 12V for different functions but you'll learn about that when you investigate mentioned website.


>Does the inverter pos and neg go to the same battery...I'll call it the house battery
Your choice. The inverter will power something and that will drain the connected battery. When that something is not on, the inverter will still draw some power. So when you forget to switch it off, you can't start if you connected to the starter battery.
So commonly: starter battery are for starting only (apart from critical infrastructure required to start safely like bilge blower in case of gas engines)
The rest is for house battery (or batteries). The house is charged after engine start so everything connected to that is powered too from that point on.
Automatic bilge pump may be a discussion: engines off, household drawn emtpy, boat starts to take water. What should happen?


>I have 2 red cables from the battery switch.
Only plus (red) needs to be switched so that's normal.

>I have 2 black cables from the engines...there also is a jumper cable from engine to engine (I believe grounded to each other)
Yes, sounds good. you'll see in those Bluesea schematics that all negatives are somehow connected. Note that there is a logic to the gauge of the various connections.

>Do I need to jump any of the engine batteries to the inverter/ house battery?
would not be my choice. Better from the house plus an extra switch to cut it off completely when nothing needs to be powered by it.

>I also have 2 black cables that go to the radio/receipts, gauges, and bilge pumps...where
>should these be wired too? house or engine batteries
That sounds like the negative (ground) for all devices throughout the boat so these should go to one or more bus bars to which all devices are gounded individually.
They should be accompanied by red cables that connect to some circuit breaker/switch unit and from there individually to each device, mostly through a switch on your dashboard.


>Note I have a new 3 bank battery charger that charges each battery
Sounds strange if you have two banks. But perhaps you have a controller that can organize the charging smartly. For example: first always charge starter battery bank first and then charge bow/stern prop battery and then house battery. Monitoring each all the time, alarm when below certain voltage and disconnect house battery untill charging power (shore or engine) is detected.

My advice: dive into the boat, follow each and every wire, mark it on both ends and preferably along the way sometimes too. Make a drawing, schematic. Using the same markings of course. And get someone over who knows how boats are wired. You'll save him/her a lot of time figuring out how your boat is set up - saving you money - and you'll learn a lot about your boat. Should you ever get some problem along the way, you'll know where to look and what your options are.

With a drawing with lots of detail people here can help you too filling in the blanks.

Any tips from anyone on how to create such a schematic on a computer are welcome (for me too, haven't found a good one that fits my thinking) but on paper is best for starting anyway: you'll find many more wires and connections with plugs in between than you expect.....

[KandJ72]

Have you been able to get the situation squared away? One thing I will add in here is that you stated you don't use the battery switches. I know on my system the starboard engine switch turns on all DC lights and gauges (except for Port). My bilges are wired into battery 1 all the time, there is only a fuse to disconnect them ( this is to prevent you from accidentally ever turning them off and having a major issue). There "should be" and auto switchover that cuts off the inverter as soon as shore power is connected.