Battery location

[pandos]

I have three batteries, two for the house under a port side bunk in the aft cabin and a starter battery under the starboard bunk.

Between the starter wiring, and the windlass, the 12B switch , there is heavy cabling running all over the place.

Is there an advantage/reason to keeping the batteries spread out.?

I really do not like the fact that they are under bunks and the fact that the cabling is all over the place so I am considering putting them all together in a cabinet nearer the engine, with the 12B switch, the charger, solar controllers, etc all fitted nearby. Easily accessible easy to keep an eye on and tidy.

This would allow me to put really good storage drawers in the aft cabin and perhaps I might keep the boat tidy.

 

[Neeves]

Batteries are often located to balance other weight, say the engine, chain and windlass, mast and boom but with a view to keeping weight low down and as centrally as possible. It would be common for the builder to define where the best location is with this in mind. Our batteries are under the sofa, which is fairly central and all our circuit breakers are located adjacent. We have three long runs, to the engines (its a cat so we have 2) and to the windlass, the batteries are just behind the mast and the windlass is just in front of the mast (with the chain under the windlass).

It is quite possible that your batteries were moved by a previous owner and the first thing I would check would be other yachts of the same model and define where their batteries are located.

But you cannot escape the fact the cable runs, for the big items, alternator, windlass etc will be long runs as the engines are usually afte and the windlass usually well forward. If the batteries have been moved the balance may be wrong (or better). It will be a major investment to move the batteries as your existing cables will then be too long or too short - so I'd think carefully and check before you change. If you want to see how the balance might be changed - simply disconnect the batteries and move them to the new location, having made marks at the water line previously, bow and stern and port and starboard.

If you have a vision of lithium batteries - now is a good time to think it through as well.

Take care, stay safe.

Jonathan

 

[Tranona]

Not sure why you would want a 12B switch when the trend now is to have a split charge system. The house batteries can be located where convenient for the DC distribution panel and perhaps for weight distribution. The star battery is best close to the engine and does not need to be large - indeed you can have a small AGM like a Red Flash which is a fraction of the size of a normal battery and can be mounted in any orientation.

I am just redoing the batteries on my new to me boat and it will have a small (around 65AH) dedicated start battery in a locker next to the engine with a B2B charger to charge the anchor windlass battery in the bow and 2* 100AH house bank under the floorboards just forward of the engine. A BEP Marine switch cluster with VSR will give independent switching for each bank and a parallel switch for emergency start. I had this system on a previous boat (except that both house and start battery were in the same location) and it is simple and idiot proof.

There are other ways of wiring , for example my current Bavaria has a split charger system from the alternator to the start battery in a locker behind the engine, 3 battery house bank in the saloon and bow thruster in the forecabin. The key thing though is to keep the differnt banks separate and split the charge in such a way that the engine start is always charged first and is never used for house as you would with a 12B.

 

[pandos]

Thanks for the replies.

I don't think moving my house bank 2 feet forward will alter the weight distribution on an 8 ton boat so no issues there..(especially as I am going to put storage where the batteries were.)

I think the engine battery is an additional fitted by a previous owner.

The cables will all be shorter so a few quid in new terminals will be the only cost in terms of them. There will only be two heavy gauge cables leaving the battery area: one to the starter and one to the windlass both of which will be shorter and more direct.. at the moment two starter cables measuring about 20 feet in total converge on the 12b switch and then go about 5 feet back to the starter.

I am going to fit more fuses anyway, and I probably will replace the batteries with new AGMs, the existing set are 16 years old...

For me a 1 2 b switch is the best solution to emergency starting, and isolating the feed to the engine bay...(I also like CQRs?? but I have a Rocna )

 

[Spirit (of Glenans)]

Thanks for the replies.

I don't think moving my house bank 2 feet forward will alter the weight distribution on an 8 ton boat so no issues there..(especially as I am going to put storage where the batteries were.)



(I also like CQRs?? but I have a Rocna )

I know ball- hopping when I see it?

 

[PaulRainbow]

Thanks for the replies.

I don't think moving my house bank 2 feet forward will alter the weight distribution on an 8 ton boat so no issues there..(especially as I am going to put storage where the batteries were.)

I think the engine battery is an additional fitted by a previous owner.

The cables will all be shorter so a few quid in new terminals will be the only cost in terms of them. There will only be two heavy gauge cables leaving the battery area: one to the starter and one to the windlass both of which will be shorter and more direct.. at the moment two starter cables measuring about 20 feet in total converge on the 12b switch and then go about 5 feet back to the starter.

I am going to fit more fuses anyway, and I probably will replace the batteries with new AGMs, the existing set are 16 years old...

For me a 1 2 b switch is the best solution to emergency starting, and isolating the feed to the engine bay...(I also like CQRs?? but I have a Rocna )

With respect, you talk of making some very minor changes, that will cost time and/or money (AGMs in particular) but want to stick with the 1970's 1-2-B switch ?

 

[pandos]

I know ball- hopping when I see it?

No ball hopping intended...just reference to two of my dinsaour like predilictions

 

[pandos]

With respect, you talk of making some very minor changes, that will cost time and/or money (AGMs in particular) but want to stick with the 1970's 1-2-B switch ?

The modifications will cost very little apart from the Agms but they are needed anyway.

As for the 1-2-b.
My actual 12b came off my previous 1974 boat, I removed it in 2004 when I fitted a complete system supplied by Merlin with vsr isolating switches, red knobs, tinned cable, batteries, fancy connectors etc. It was expensive but excellent quality.

On at least 2 ocassions I had flat batteries due to an issue with the VSR. I cannot remember the issue but it was logical at the time and I think was caused by my habit of doing something in an incorrect sequence. (Possibly starting engine whilst connected to mains power)

When I bought my current boat it had no way to disconnect the feed to the starter motor or to parallel for charging from the basic charger on board, or to use both banks to start the engine (it had very bad fuel lines, and compression so it required loads of cranking and heat to start when it had fuel problems, so it needed the ability to access the house bank)

I salvaged the 12b and fitted this and a blocking diode , and a new smart mains charger, and 3 agm batteries in 15 years I never had a problem until this year after I fitted solar...

That problem is sorted and I will be fitting the victron cyrix you recommended instead of the diode, that is a clever device which is better than the diode so I have no problem with that piece of progress.


Generally it is in the 1 position, if I leave the boat it is off, if I need more starting power I'll use both or 2... I then switch back to 1 when the engine is running.

My alternator is wired directly to the diode so even if I change the switch whilst engine running there is no issue.

So as I see it a 12b does what I need it to do perfectly. It is robust and has no mysterious innards so I see no reason to change.