changing to 6 volt battteries

[Monty VM]

I am going to replace my 8Ds with 6 volt golf cart batteries for my house bank. I have been reading about series vs parallel and doing both. It seems I want to wire in series to get to 12 volts, but then i need to cross them to get the increased amp hours. I would love to see diagrams, or be referred to a reliable source or two on how to accomplish this correctly and how to then attach them to my house system which is the typical 1, 2 both set up.

 

[JamesG161]

Remember your BOTH position means your Charging device will equally split both of your slots 1 & 2.
Although your battery well is placed near the Full sail Center of Gravity, that space is HUGE.
You will need to strap them down too.
There are few posts on a Copper Bar. that connects the 2 6's in series, to give them a solid connection and braces them together kind of like a 12 VDC 4D bank.

Also their orientation to allow electrolyte coverage of the plates in a 20° heel.
Jim...

 

[jssailem]

You guys with your big boats and lots of room.. Lucky...
@Monty VM
Here is a relevant link to the 1/both/2/Off switch. It offers ideas and consideration.

https://forums.sailboatowners.com/index.php?threads/1-both-2-off-switches-thoughts-musings.137615/​

Here is a good 4 6VGC battery image showing series and parallel connections.
Note that the wires have red and yellow heat-shrink to identify the stud attachment (POS or NEG).

​

When wanting to charge both a House bank and a reserve bank on of the best options is to use an ARC connection (Automatic Charging Relay) for the two battery banks.

https://forums.sailboatowners.com/index.php?threads/battery-bank-and-acr-question.189912/
​

Hope this helps...

 

[JamesG161]

This is from our Boat's manual....
Jim...

 

[JamesG161]

Great link @jssailem
It kind of showed the "Copper Bar" series connection idea. I was looking for that link too.
Jim...

 

[jssailem]

When you got it you got it.. Now to go back to my cage where I can wrap up in my mummy costume.
Hope you weathered the storm without too much drama.

 

[JamesG161]

If you look at the red series wires in that link, those are can be replaced with strong copper bar. I could not find that link.
_________

Hope you weathered the storm without too much drama.

What storm?
My marina got real busy on Sunday and Monday.
One poster in Panama City, said he had seen worst summer squalls.
Not making light of any in a storms path.
Jim...

 

[capta]

If you look at the red series wires in that link, those are can be replaced with strong copper bar. een worst summer squalls.
Not making light of any in a storms path.
Jim...

I should think it would be very dangerous to have that much energized copper on top of your batteries, unless you heat shrink it or something. A dropped wrench (not wench) could be catastrophic. I think I'd prefer insolated covered wire as in the pic.

 

[JamesG161]

much energized copper on top of your batteries

Good point as always. That is why I buy low cost wet cells 12 VDC 4D's. Cost is about half of the golf cart batteries on a $/yr basis.

BTW Monty has the same year and model Hunter as mine. The battery hold was designed for 2 - 12VDC -8D.
He has more than 25,000 sailing miles on his H430.
Jim...

 

[Solstice]

If you look at the red series wires in that link, those are can be replaced with strong copper bar. I could not find that link.
_________

What storm?
My marina got real busy on Sunday and Monday.
One poster in Panama City, said he had seen worst summer squalls.
Not making light of any in a storms path.
Jim...

The link that jssailem shared is my bank. I started with copper bar, which was heat shrinked in the middle of the bars. I got rid of them because they interfered with getting to the water caps...YMMMV

 

[Monty VM]

thank you for all of the ideas and reading. it looks like wiring serial and parallel will give me use of the amp hours of all four 6 volt batteries at 12 volts. but it looks like they have to be wired together as one bank not separated into two? is this correct? I am also wondering if each battery is 225 amp hours at 6 volts, do i actually gain 225 amp hours by wiring parallel or are two batteries still 225 at 12 volts due to the two batteries being joined are 6 volt. in which case wiring 2 in series to side one and 2 in series to side 2 would give me 450 amp hours at 12 volts. and i don't actually get 900 any amp hours at 12 volts with four 6 volt batteries

 

[Monty VM]

When you got it you got it.. Now to go back to my cage where I can wrap up in my mummy costume.
Hope you weathered the storm without too much drama.

looks like the weather passed to the east. I will be there thursday to check on things and change out these batteries.

 

[JamesG161]

all four 6 volt batteries at 12 volts

You can still put one pair of 2 -- 6VDC in series on Switch ONE and the other series pair on Switch TWO. Then both banks will charge on BOTH.
As to the Amp hours, I await the experts comments on that one.
Jim...

 

[JamesG161]

For those of you who wonder about how to store 2- 12VDC 8D's aboard the H430, here is the original Picture by the previous owner's broker, before we bought it.

Jim...

PS: that is why it is HUGE when smaller batteries are installed.

 

[jssailem]

Wiring the two 6 volt batteries (225 Amp Hrs each) gives you One 12 volt battery with 225 Amp Hrs.

You get real deep cycle batteries with an estimated 700 cycles.

 

[Maine Sail]

SERIES = ADD VOLTAGE - AH's STAYS THE SAME AS ONE BATTERY
PARALLEL = ADD AMPERE HOURS - VOLTAGE STAYS THE SAME AS ONE BATTERY

Two 6V 225Ah batteries wired in series is a 12V 225Ah battery bank

Four 6V 225Ah batteries wired in series pairs then the two series pairs get wired in parallel for a 12V 450Ah battery bank

Six 6V 225Ah batteries wired in series pairs then the three series pairs get wired in parallel for a 12V 675Ah battery bank


Think of it this way; It takes six 2V cells to make a 12V battery. So a 12V battery has six 2V cells inside it. A 6V battery has just three 2V cells. When you wire two 3 cell 6V batteries in series, - to + is series, you now have six 2V cells and a 12V battery.

For many reasons you will be best served to wire the bank as one large contiguous house bank with no 1/2/B switch in-between any batteries in the house bank. If you want a start or reserve bank as BANK 2 and house as BANK 1 that's a good use of a 1/2/B.

A 450Ah bank would get wired as shown. For 675Ah's you would simply add another series pair to the right or left and parallel them in. Take off points should remain at opposite corners of the bank:

 

[Maine Sail]

Good point as always. That is why I buy low cost wet cells 12 VDC 4D's. Cost is about half of the golf cart batteries on a $/yr basis.

??? Dollars per Ah and cycle I have not seen a 4D flooded battery beat 6V GC2 batteries on a $ to yearly basis, and I test many hundreds of batteries each year. Can you explain the math on this one... ??

Just staying within a brand (same brand West Marine sells) I just looked up my dealer cost on a 4D flooded vs. 6V GC2's.

4D flooded *dual purpose - 135Ah = $1.29 Per Ah - Rated at 200-300 Cycles
*They don't make a deep-cycle 4D

GC2 Flooded 230Ah = 92¢ Per Ah @ 12V - Rated at 1000 Cycles

 

[JamesG161]

You added the caveat of $/yr/Ah and I never argue with you, since I learn from you.

Can you explain the math on this one... ??

Check my calculations on my post #31 where I learned from that discussion.
https://forums.sailboatowners.com/i...ermine-a-batterys-real-capacity.185427/page-2

Jim...

 

[DayDreamer41]

Just a note on joining batteries with solid copper bar in addition to what @capta pointed out for the real short potential, I would also be concerned for the, vibration and torque being transmitted to the battery posts.

 

[Maine Sail]

Just a note on joining batteries with solid copper bar in addition to what @capta pointed out for the real short potential, I would also be concerned for the, vibration and torque being transmitted to the battery posts.

Absolutely, if batteries are bussed together with solid bar stock they can not be allowed to move at all. Using rigid bar stock is generally not advised on a boats multiple battery bank unless the installation is rock solid. It is one thing for a stationary UPS system or off grid use, where the batteries don't move, but on a boat, where batteries generally have some movement, flexible wire is a safer choice.