Best way to wire my boat with dual batteries

[fucawi]

Re: Best way to wire my boat with dual batteries

a 400/600 AH bank on a narrow boat can easily be discharged in a 24 hr period ..central heating ..fridge ..freezer ..TV ..electric kettle . washing machine most run via a 3 kw inverter ..big loads at 12v.(250A at 12v ) In this continuous discharge charge cylcle of 24hrs a failure to connect in the modern style does make a difference to battery life....two 90A alternators ,computer controlled , sort out the re charge in about 8 hrs of engine running.

 

[Silvertip]

Re: Best way to wire my boat with dual batteries

I dpm't dispute that. The issue is that of the boats being discussed in this forum, few have any of the items you just discussed, nor the electrical loading, nor the charging issues. The boats I refer to are aywhere from 5 - 8.5 foot beam and from 14 to about 24 in length. They would likely sink with all that power hungry stuff on board. I guess in my view, if one can afford a boat that has all this stuff in it, there is a strong likelyhood battery replacement will not be a major consideration -- but battery run-time would be. If this "modern" wiring is as critical as it seems, there has to be some data available to support that.

 

[fucawi]

Re: Best way to wire my boat with dual batteries

A good site to look at is http://www.smartgauge.co.uk ..go to the technical infor section ..... when you look at the diagrams you will see that it is now taken for granted that you will wire your batteries up in the correct way and diagrams like those below litter the world of boat wiring .

 

[bruceb58]

Re: Best way to wire my boat with dual batteries

Oh Prince of Darkness,

The OP's boat is a 17' boat with 2 batteries. :facepalm:

It's not a load bank and he is only doing heavy discharge off of 1 battery. What part about that do you not understand?

 

[fucawi]

Re: Best way to wire my boat with dual batteries

Good practice is good practice on any boat.

 

[ronsealdeath]

Re: Best way to wire my boat with dual batteries

Hi, this thread turned interesting!

In any case I got myself some 35mm2 cable (AWG2 I think?) and it was blinking fat! A lot fatter than the battery cables from the motor. I have wired up a large 105amp hrs auto battery as number 1 to crank with then a 75amp hrs leisure battery as number 2 to run a radio, bilge pump (wired in directly) and lights/horn etc.... So its really a small load with no fridges or TV. Although a small fridge would be useful, the weather here means you just need to leave things outside to chill them down nicely The massive battery for cranking ir overkill for my 50hp Merc but I couldn't resist it as it was dirt cheap and gives me peace of mind. Had a few batteries die on me before!

The lengths of cable weren't the same as I couldn't afford to go buying extra lengths of cable with copper prices the way they are. My batteries are cheapo jobs so its all a bit low budget anyway. I'm not concerned about matching the lengths up to save on battery life as I don't expect they will have a hard life on my 17ft fishing boat. I haven't tested it all yet but it should do the job.

Its interesting about the cable lengths and there is no harm in being a perfectionist. Its true to say though that if such a variable is really not important in this kind of application then its really not much point in most people shelling on extra money on cable.

Thanks again

Al