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Old 11-08-2016, 10:43   #61
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Re: Multiple battery banks or one big one

Separate electronics from the battery bank with DC DC converters. It's just not the equalizing voltage even charging voltages shorten the life of most electronic devices. Some do have dcdc converter inbuild. In cold the charging voltage should be higher (if the charger is smart enough) like 0 deg C 15.8v or there about for 12v battery even worse..
And while doing that put the whole bank in series 18v to 48v , no worries if one battery turns bad, no runaway heating just disconnect one and get new later. Charging the batteries for a while with higher voltage/cell is not dangerous just no float chargin for a while..

That all just IMHO
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Old 11-08-2016, 11:11   #62
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Re: Multiple battery banks or one big one

The thread was about 4 - 6V batteries ($450), take reasonable care of them and replace them every 5 years and stop obsessing.
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Old 11-08-2016, 18:42   #63
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Re: Multiple battery banks or one big one

Quote:
Originally Posted by ramblinrod View Post
This is a serious safety hazard. A boat fire waiting to happen.

Develop a high impedance connection, or dead windlass battery, and all windlass current (plus dead windlass battery charge current) will be drawn through the #6 or # 4 AWG wire.

Common DIY mistake.

The only practical way to run cables from the house bank to the windlass (or windlass battery) using lighter gauge wires than will support the max current of the windlass is to install a current limiting charger like an echo or duo charger.

It has to be a very big boat (or windlass), for the advantages of a dedicated battery forward, to be more economical than running proper sized cables from the house bank.
Come on guy......

Have you even seen a number 4 awg cable?

Have you priced 70 feet of 0 gauge wire? ( btw 0 is bigger than 4 )

You don't think I haven't thought about fire hazard, I believe that was my whole point and one of the reasons I use a heavy duty battery forward.

And fyi it is large enough boat, w 300 feet of pretty heavy chain.

Here....


Bow thruster batteries on Beneteau oceanis


Go over to the thread about bow thrusters... They seem to understand basics.

Please don't comment about DIY mistakes (Common or otherwise) till you actually try this stuff or your have an electrician x - plane it to you.

P.S. If you were any kind of electrician like the one I had approve my installation then you would have asked for more info before you accused me of making a common DIY mistake.

PS.PS. Have you heard of fuses? You should check them out. Not using them is a very common DIY mistake.

Seriously you should think about things and ask questions if you don't know the slightest thing about what you talking about. You could mislead folks into thinking you just put 2 giant cables from the front of a 40 + foot boat to drive a piece of equipment all the way from the back and that is that.

Have you heard of vibration damage?

The bow of the boat takes a bigger pounding than other parts of a boat ( unless your sailing backwards, which judging by some of the comments I've read on this thread wouldn't surprise me. )..... Putting a nice battery charger in the bow, is truly a failure waiting to happen.
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Old 11-08-2016, 23:02   #64
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Re: Multiple battery banks or one big one

Quote:
Originally Posted by Thorne View Post
Come on guy......

Have you even seen a number 4 awg cable?

Have you priced 70 feet of 0 gauge wire? ( btw 0 is bigger than 4 )

You don't think I haven't thought about fire hazard, I believe that was my whole point and one of the reasons I use a heavy duty battery forward.

And fyi it is large enough boat, w 300 feet of pretty heavy chain.

Here....


Bow thruster batteries on Beneteau oceanis


Go over to the thread about bow thrusters... They seem to understand basics.

Please don't comment about DIY mistakes (Common or otherwise) till you actually try this stuff or your have an electrician x - plane it to you.

P.S. If you were any kind of electrician like the one I had approve my installation then you would have asked for more info before you accused me of making a common DIY mistake.

PS.PS. Have you heard of fuses? You should check them out. Not using them is a very common DIY mistake.

Seriously you should think about things and ask questions if you don't know the slightest thing about what you talking about. You could mislead folks into thinking you just put 2 giant cables from the front of a 40 + foot boat to drive a piece of equipment all the way from the back and that is that.

Have you heard of vibration damage?

The bow of the boat takes a bigger pounding than other parts of a boat ( unless your sailing backwards, which judging by some of the comments I've read on this thread wouldn't surprise me. )..... Putting a nice battery charger in the bow, is truly a failure waiting to happen.
I am very familiar with common DIY mistakes. I fix them almost every day.

I would never suggest a windlass be wired without a properly sized breaker.

Properly sized bow thrusters usually draw much more current than windlasses for a given size of boat, which could very well warrant a dedicated battery. You never indicated you were also powering a bow thruster. If so, then the issue is even more serious.

Sorry if I didn't ask sufficient questions for your liking.

1. What model windlass?
2. Where is the 4 AWG cable run?
3. What type of battery is powering your windlass?
4. If the bow is subject to excessive vibration, how is it good to have any kind of battery up there?
5. What size and type of fuse did you use?
6. Where is the fuse installed?
7. What is the fuse protecting?
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Old 12-08-2016, 00:39   #65
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Re: Multiple battery banks or one big one

on a boat with a house bank and thruster bank joined by ACR (and fused at both ends of the bank) is is not uncommon for 50% of current to come from house bank. Ie a 500a thruster will pull 250a from a group 31 thruster battery and 50% from the house bank far away. this was with 2/0 "charge" cable. in this case a standard 120a acr is not up to task and the big 500a one should be used. even though it's only "charging"

I would never direct connect a bow battery to a house / start battery. (you can't properly install a battery monitor for starters) you should have an ACR or echo charger. and the cable needs to be fused at both battey ends. this is different then the thruster / windlas breaker which would also be there off the bow battery. those fuses and cables need to be able to handle near full load of that device, unless you have a way to stop that current coming from house bank. IE echo charger.

on smaller thrusters sometimes I tie the ACR start interupt to the thruster controls so the ACR shuts off while thrusting. that way you only get charge current on that cable and not thruster current.

for a windlass only on a smaller boat (30-40' I would not have a battery in the front. and 50'+ are probably 24v so same thing no battery needed.

thrusters are another issue and I've seen them work so much better after adding a battery to the front. even with 4/0 run on a 40' boat. 4/0 became the charge cable.
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Old 12-08-2016, 05:49   #66
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Re: Multiple battery banks or one big one

We are getting a bit off my original question. The battery manufacture was questioning my use of one bank (4 six volt golf batteries) of House batteries as I only have one charger and battery monitor. I could use a combiner but I already have a Smart combiner for my starter battery. One cell on one battery went bad and the manufacturer had to replace four batteries under warranty instead of two if made into two banks. I was trying to find out what the best PRACICAL WAY to install house batteries. It would seem from this thread having one big bank is best with single switches to remove a pairing in the event of a failure.
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Old 12-08-2016, 10:42   #67
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Re: Multiple battery banks or one big one

Quote:
Originally Posted by smac999 View Post
on a boat with a house bank and thruster bank joined by ACR (and fused at both ends of the bank) is is not uncommon for 50% of current to come from house bank. Ie a 500a thruster will pull 250a from a group 31 thruster battery and 50% from the house bank far away. this was with 2/0 "charge" cable. in this case a standard 120a acr is not up to task and the big 500a one should be used. even though it's only "charging"

I would never direct connect a bow battery to a house / start battery. (you can't properly install a battery monitor for starters) you should have an ACR or echo charger. and the cable needs to be fused at both battey ends. this is different then the thruster / windlas breaker which would also be there off the bow battery. those fuses and cables need to be able to handle near full load of that device, unless you have a way to stop that current coming from house bank. IE echo charger.

on smaller thrusters sometimes I tie the ACR start interupt to the thruster controls so the ACR shuts off while thrusting. that way you only get charge current on that cable and not thruster current.

for a windlass only on a smaller boat (30-40' I would not have a battery in the front. and 50'+ are probably 24v so same thing no battery needed.

thrusters are another issue and I've seen them work so much better after adding a battery to the front. even with 4/0 run on a 40' boat. 4/0 became the charge cable.
Thank you for the information about the ACR charger and its ability to have a start interrupt circuit. I'll look into the ACR charger, sounds better than just having fuses protecting the set up.

As for one or 2 banks it sounds like the consensus is to have 2 separate house banks that can be tied together with the "Both" setting on switch or isolated by choosing one or the other bank for diagnostics or emergencies, where you run with both selected as a normal setting.

I was running my 2 house banks separately and switching them every two weeks, but after this my "Old School" thinking has been adjusted and I am now running in the Both Mode. If there is a problem I have a gen set so I can recover from something that would drain "Both" banks because it is set on both.

I really do learn from everyone's thoughts and appreciate them very much.
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Old 12-08-2016, 11:38   #68
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Re: Multiple battery banks or one big one

Quote:
Originally Posted by Thorne View Post
...it sounds like the consensus is to have 2 separate house banks...
No, it isn't.
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Old 12-08-2016, 12:24   #69
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Re: Multiple battery banks or one big one

Quote:
Originally Posted by Thorne View Post
Thank you for the information about the ACR charger and its ability to have a start interrupt circuit. I'll look into the ACR charger, sounds better than just having fuses protecting the set up.

As for one or 2 banks it sounds like the consensus is to have 2 separate house banks that can be tied together with the "Both" setting on switch or isolated by choosing one or the other bank for diagnostics or emergencies, where you run with both selected as a normal setting.

I was running my 2 house banks separately and switching them every two weeks, but after this my "Old School" thinking has been adjusted and I am now running in the Both Mode. If there is a problem I have a gen set so I can recover from something that would drain "Both" banks because it is set on both.

I really do learn from everyone's thoughts and appreciate them very much.
Acr's best use is to provide charging to your a house bank and a start bank from a single source. I highly reccommend a switch to still isolate the start banks from house bank. If you had 2 start banks/ 2 engines or eng and gen start batteries you would want two ACR's. In a way they add to the total overall amp hour dark of a house bank until the voltage drops to their disconnect level. The problem here is if you have a true bank monitor, it can throw off the true soc reading as it's not taking Into consideration the added amp hours from the start batts being consumed. I have never seen more than a handful of cruising boats with separate house banks, and the ones I've seen were a mess and made no sense.

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Old 12-08-2016, 23:48   #70
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Re: Multiple battery banks or one big one

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We are getting a bit off my original question. The battery manufacture was questioning my use of one bank (4 six volt golf batteries) of House batteries as I only have one charger and battery monitor. I could use a combiner but I already have a Smart combiner for my starter battery. One cell on one battery went bad and the manufacturer had to replace four batteries under warranty instead of two if made into two banks. I was trying to find out what the best PRACICAL WAY to install house batteries. It would seem from this thread having one big bank is best with single switches to remove a pairing in the event of a failure.

if you have 2 banks of 2 batteries and one went bad I'd still be changing all 4. the house banks will still be combined for different reasons here and there and you'd be combining banks of different age. batteries are cheap.
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Old 13-08-2016, 02:41   #71
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Re: Multiple battery banks or one big one

Agree with you; we gave up on 6v batteries years ago. In a push you can buy lorry batteries to supplement if required. We did this in Madagascar years ago and the hybrid worked just fine for about a year.


Quote:
Originally Posted by barnakiel View Post
One big bank and a separate starter battery.

And use 12 V not 6 V units (if your boat is 12 Volt wired) - bad battery? remove the bad apple from the bank and keep on going.

Must be some US 6 Volt taboo or something?

b.
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Old 13-08-2016, 04:42   #72
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Re: Multiple battery banks or one big one

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Originally Posted by Maine Sail View Post
This is the wiring I tend to prefer to use if an owner desires the ability to isolate series pairs of a house bank.

The isolation switches and busbar remain out of sight but easily accessible and the main ON/OFF is all you or guests see.

The bank is always in parallel unless you are servicing it, EQing or have a failure..

Great post, this is the stuff I look for on CF
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Old 13-08-2016, 04:49   #73
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Re: Multiple battery banks or one big one

The problem I have experienced in the past is finding a replacement. Not so easy in some location and 6v makes it even harder or even impossible dependent on where you are. I guess whilst you are in first world locations it it is not an issue but when you move further afield........



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No, you replace it.
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Old 20-08-2017, 13:31   #74
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Re: Multiple battery banks or one big one

So folks, why not have just one single bank, period. no starter battery?

I did read there is an advantage to be able to separate a bank in case one bat in one of the two separate combinable banks goes bad, but other than that, wouldn't a single bank be much more simple and a total cheaper investment?

Say one has plenty of solar (600W or more) with a good programmable controller, a 1000W windlass, and a 450Ah bank of 4 Trojan T105 bats stored midship, 12V system? 50hp Perkins diesel and just average alternator, nothing fancy.

Peukert's law would give you less DOD, no? As opposed to splitting the bank.

No need to worry about multiple bank charging, with possible different charging voltages due to starter batteries being "starter" type and house bats Trojan T105.

Other than the ability to isolate the banks, what am I missing?

If 450Ah sounds like not much, then how about 675Ah?`(6 x T105)

(Oh and by the way, I would say a battery monitor would be a must in this case..)

Can anybody shoot this down, please?
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Old 20-08-2017, 13:46   #75
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Re: Multiple battery banks or one big one

Just one large house bank. If you have room, add a single dedicated starting battery (not to be used for house power). Add an interconnect switch so you can start the engine with the house bank if needed. Using a 1, 2, both switch on two house banks is old school. The goal is to minimize the lowest discharge point on the house bank.
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