Help - Battery System Advice Needed

[tronic72]

Now another question. Based on the blog above.

I have one bank of batteries for the and one starter (I'm assuming)

I'm also assuming that the 1,2,both,off switch refers to 1 as the start and 2 as the house bank (or visa versa)

My new question is: why are three two of those switches? (Not including the 3rd which is labeled invertor)

Thanks again, again, again ��

[tronic72]

Originally Posted by Tikka

Hi Tronic, my ex boat is still in Hastings, but I am in Qld now. My suggestion is first things first. Is it any problem with electrical functions. Somethings is not working?
Re - organising is last thing. If one of your bat. is weak ...whole system is discharging through weak bat. Can you find which one?. Regardless of different bat. capacity, system must hold the charge. Best cruising time in Westernport is now, you don't wont to spoil it. After Easter, time to dig in. Happy cruising , watch the huge breakers passing Phillip Island , I had 6 m high, they can be nasty.

Hi Tikka,

I have that in mind. Would love to get boat off hard stand and into water before Christmas. But I also want to clean the mess. Bit of a juggling act.

Unfortunately previous owner didn't have good batteries so have replaced all and got new battery boxes. Will also replace the cables that join the batteries.

I'm going to use 50mm to join them as this's seems common. And advice would be good.

Once I've got the banks sorted with all new kit ill approach redesign but if I can incorporate some redesign during this phase I will.

Thanks for the tip. I'll keep my eyes peeled. Hopefully none will hit the boat on the hard stand.

[hellosailor]

"Can anyone tell me me why it might have five?"
Ah, FIVE. Yes. It was once explained to me that while Islam preaches that a man may have many wives, FIVE is actually the perfect number. If you've never heard the longer version of that, do ask around.


But when it comes to boats with Previous Owners...especially larger boats which often have had stuff added on over the years...I'd suggest reading Charlie Wing or any of the other leading books on boating electrical systems. Casually, slowly, with a pen and pad to take notes, and rethink the entire system for YOUR purposes and YOUR budget. There are many ways to skin a cat, some work best if you want to make slippers, others work best for a fast dinner.
Often things were done because of price and convenience, and really clever elegant solutions can require simply tossing ideas around for a couple of weeks until one hits just right. (Like "Duh! I should have bought a Dremel Tool thirty years ago!" (G)

[tronic72]

okay so based on on the little I've learnt recently (no time for book before summer) I'm returning either three or four of the hydrid batteries and replacing them with 100 A deep cycle. Will keeping one cranking battery for 2x 350 mercruisers be okay (the batteries rated at up to 350 HP ).

So should I return 4 batteries and keep one as a cranking battery leaving 4 deep cell for the house set-..... or return three leaving 3 deep cycle for the house set and two crankin batteries.

Thanks in advance.

[Stu Jackson]

Originally Posted by tronic72

.................................................. ..................................

So should I return 4 batteries and keep one as a cranking battery leaving 4 deep cell for the house set-..... or return three leaving 3 deep cycle for the house set and two crankin batteries.

The answer is: It all depends on how you choose to wire the system.

I believe that is what we have been trying to explain to you during this thread.

The Electrical 101 link has one for good books. You reeally shouldn't put that off.

Good luck.

[phstol]

Tronic72:
Lots of good advise, but you have a very steep learning curve to do all this without professional help at this stage and not spend the summer trying to figure stuff out.
I'll try to answer your new questions:
1) Which batteries to keep or return, ditch the parallel bank?
Seems the 2 engines were started from the same battery, your #5. This will work, but you have no redundancy.
Seems your new 875 MCAs are not deep cycle. So I wd keep 2 to be starter batteries, one for each engine. Exchange the other 2 for 100Ah deep cycle.
2) Why have 2 house banks? Again, one will work, but 2 will give you management control and redundancy. Your load Ah that you added up will determine if you need parallel batteries in the banks. Don't forget, you have to charge these hi capacity parallel banks, so maybe the PO has this charging load shared between the two engine alternators.
3) Why two of these switches? Could be several reasons, you will have to trace the wiring and draw out the circuit diagram and figure it out. Your question seems to suggest that the starter motors are switched through one of these. If so, you might check that the switch is in good condition and can handle the 500A + or so that starter motors pull. If not, it will eventually fail, and having no redundancy, you will be up the creek without a starter (in a manner of speaking).
Good Luck!

[tronic72]

Okay.

So here's what I have opted for.

4 X Deep cell 105 AH to comprise 2 X deep cell banks (for redundancy). Returned three of the hybrids.

I use two of the other new 780 cca hybrids as starting batteries. I'll use one for both engines and leave the other as the spare (for redundancy). I'll have to figure out the best way to wire this so both get used and neither don't.

As I want to get some use of the boat this summer I will insert these into the exisiting wiring and over winter I'll map out the whole system so I can redesign it.

I know I'm sort of putting the cart before the horse but I'd like the family to get some local use of the boat. This will hopefully keep the missus happy and allow me to spend more over winter.

I appreciate all your collective advice. I'll be buying one of these books ASAP and mapping out the exisiting system to show you all.

Thanks again.

[GordMay]

Originally Posted by hellosailor

"Can anyone tell me me why it might have five?"
Ah, FIVE. Yes. It was once explained to me that while Islam preaches that a man may have many wives, FIVE is actually the perfect number. If you've never heard the longer version of that, do ask around...

I thought that the Qur'an permitted a man to marry up to four wives, provided he can support and treat them all equally.
➥ Surah An-Nisa - The Noble Qur'an - القرآن الكريم
➥ Polygamy in the Quran

I don’t believe that either 4 nor 5 are “perfect numbers”.
The four perfect numbers 6, 28, 496 and 8128 seem to have been known from ancient times.
➥ http://www-history.mcs.st-and.ac.uk/...t_numbers.html

[exMaggieDrum]

Originally Posted by tronic72

Okay.

So here's what I have opted for.

4 X Deep cell 105 AH to comprise 2 X deep cell banks (for redundancy). Returned three of the hybrids.

I use two of the other new 780 cca hybrids as starting batteries. I'll use one for both engines and leave the other as the spare (for redundancy). I'll have to figure out the best way to wire this so both get used and neither don't.

As I want to get some use of the boat this summer I will insert these into the exisiting wiring and over winter I'll map out the whole system so I can redesign it.

I know I'm sort of putting the cart before the horse but I'd like the family to get some local use of the boat. This will hopefully keep the missus happy and allow me to spend more over winter.

I appreciate all your collective advice. I'll be buying one of these books ASAP and mapping out the exisiting system to show you all.

Thanks again.

It sounds like you are making excellent progress in wrapping your head around this. Just starting is the hardest part many times.

Getting some local use of your boat is an excellent idea. You can enjoy your new boat and learn how it works now and get a better idea of what works for you and what does not. This will inform your planned upgrades later. Planning major projects on your own boat is always an issue. I am in the midst of the same type of rewire as you and the boat is torn up, access panels off, tools and parts all over, etc. I can start and move the boat but with the next step of taking the old out I will not be able to use it for the time (a couple of months at least) that I am doing the rewire. Take the wife out and bond with your boat.

Having said that I would encourage you to not set up two redundant house battery banks. They are very hard to manage and keep charged that way. It is easy to forget what setting you have and inevitably you either forget to keep one bank charged well, or you run both as one bank anyway. Much simpler and easier to have one larger house bank and a separate smaller starter battery for redundancy. You can make it work but experience has shown it is easier for you and your batteries to not have two redundant house banks.

The Maine Sail article is excellent at showing how switches may be set up. Regarding having two 1-2-B switches, often they are wired in fact as one 1-2-B and the other is wired as a on-off switch. You will be able to determine how yours is setup when you inspect and diagram it all closer. Just make sure you understand what your settings should be now even for local sailing.

Enjoy!

[phstol]

Welcome and enjoy!

If you like, pm me, I'd be happy to shoot you a copy of the wiring diagram I made for mine. Could be a useful starting point for you.

Peter

[tronic72]

Originally Posted by exMaggieDrum

It sounds like you are making excellent progress in wrapping your head around this. Just starting is the hardest part many times.

Getting some local use of your boat is an excellent idea. You can enjoy your new boat and learn how it works now and get a better idea of what works for you and what does not. This will inform your planned upgrades later. Planning major projects on your own boat is always an issue. I am in the midst of the same type of rewire as you and the boat is torn up, access panels off, tools and parts all over, etc. I can start and move the boat but with the next step of taking the old out I will not be able to use it for the time (a couple of months at least) that I am doing the rewire. Take the wife out and bond with your boat.

Having said that I would encourage you to not set up two redundant house battery banks. They are very hard to manage and keep charged that way. It is easy to forget what setting you have and inevitably you either forget to keep one bank charged well, or you run both as one bank anyway. Much simpler and easier to have one larger house bank and a separate smaller starter battery for redundancy. You can make it work but experience has shown it is easier for you and your batteries to not have two redundant house banks.

The Maine Sail article is excellent at showing how switches may be set up. Regarding having two 1-2-B switches, often they are wired in fact as one 1-2-B and the other is wired as a on-off switch. You will be able to determine how yours is setup when you inspect and diagram it all closer. Just make sure you understand what your settings should be now even for local sailing.

Enjoy!

Thanks for the reply. From what I've learned I won't be splitting the house bank. I think just separating the cranking and house will be adeqate or my needs while still providing a level of safety through redundancy.

I began the diagram last night. Below are new questions based on yesterday's works

Thanks again.

[tronic72]

Hi,

A quick collective thanks to all who have replied thus far.

I spent Yesterday in the boat and have a few problems based on my work.

1. I purchased battery box for each battery and installed them in their boxes. unfortunately no I can't fit them where they were. 52 cm of space and 66 cm of battery boxes.

Question: how much value is in these boxes? Should I included them in my long term plans? If so I will need to change their location.

2. Is the 10amp dolphin charger adequate to charge these when I'm plugged into mains.? I assume this is its purpose?

As previously mentioned I've gone with 4 X 105 Ah deep cycles for house and 2 X 730 cca for starting

3. What is the purpose of the voltage sensitive relay ( ignition protected) 100 "thingy" I found?
M

4. Where is the ideal place to put the batteries. There current location is terrible because it's not very accessible. I have to remove a big deck opening in the stern of the cruiser and then reach under. The batteries are very heavy and need to be Fed towards the bow to be installed and I can see my see my spleen popping out of my backside when I install the new batteries. It would be great to have them directly below an access hole. They are currently crammed between two ribs that are running from bow to stern. That's not a big deal but their current location has four of then packed in a "slot" 52 X 52. The new batteries in the battery boxes won't fit there.
M

4b. There are two ribs running bow to stern through the middle of the boat approx 52 cm apart. Then there are two "noggins" running port to starboard 52cm apart. Four batteries currently sit in this nook. While the fifth (suspected starting battery) sits forward of this nook.

Question. What would the ramifications be of removing and relocating the rear noggin? This looks structural. I would guess it would need to be cut then replaced then re glassed. I will post photos as soon as I figure out how. Leads me to .......

5. What's the best way to Post some photos for you all the see? I have taken many and I think they would help to explain some of my issues.

Thanks again to you all.

[Tikka]

You really should ask a question first.
Don't believe, a mix of deep bat. with normal starting bat. is good idea,
because very different charging characteristics.
The battery in your car is charged between 40 - 60 Amps.
You have 10A charger to charge 4 ..105 Amps batteries.
Considering the charge will limit the current, to protect itself,
you need a few days to top up your bank.

[tronic72]

Originally Posted by Tikka

You really should ask a question first.
Don't believe, a mix of deep bat. with normal starting bat. is good idea,
because very different charging characteristics.
The battery in your car is charged between 40 - 60 Amps.
You have 10A charger to charge 4 ..105 Amps batteries.
Considering the charge will limit the current, to protect itself,
you need a few days to top up your bank.

So it's not enough? I figured it mustn't be.

Thanks.

[phstol]

Tikka is right ref charging time. But think of it in terms of how you use your boat. Could be substantially different to this scenario, but if used on weekends, then usually you will start off with fully charged house batteries charged by your 10A Dolphin over the previous week on shore side power. (1 bank in your case, otherwise 2. ) If not fully charged, they will be by the alternator(s) by the time you get to where you are going for the weekend. Don't know your house Ah load but it seems you have enough in your 420 Ah bank to light a small village for 1-2 nights. What are you powering via the 1000W inverter, a power hungry referg? Will you be sitting on the pick all weekend without running your engines? Anyway you will be likely moving some and each time you do you will be charging at up to 40-60 A. Then you will have the run home, charging at up to 40-60A for hour(s). By the time you get back to the dock your bank(s) will not "want" more than a few amps to top them up over the next week.
And we are talking only using one alternator, for simplicity of description. You would have to trace and diagram the wiring, but you have 2 alternators, so maybe you are "wasting" another 40-60A from the (possibly) unused one.
So, spending megabucks on a 100A+ shore side battery charger will get you nothing, IMO.

For the following I defer to someone else on this post that is more knowledgeable. I think you should check the Amp rating of your alternators before charging your new 420A bank from a discharged state. Unless you have oversized marinerized alternators on your engines you are going to load the alternator(s) with potentially higher A loads than they were designed for. Even allowing for the peak load tailing off as the batteries charge. At minimum, you will probably be advised to up-size the alternator output wires and maybe also their regulators. Some good advise here could save a of of hassle.
Good luck!