Wiring In Series (pro vs con)

[rwells36]

In order to get around the backorder of a particular battery supplier for their 12v product I am considering the purchase of their 4v products which have no backorders and then wiring three (3) of these 4v 450Ah in series to achieve 12v. However, I desire to have a total of 900Ah at 12v (not 24v). Is this possible? If so, how?

Also, what are the pros and cons of this approach?

[s/v Jedi]

Originally Posted by rwells36

In order to get around the backorder of a particular battery supplier for their 12v product I am considering the purchase of their 4v products which have no backorders and then wiring three (3) of these 4v 450Ah in series to achieve 12v. However, I desire to have a total of 900Ah at 12v (not 24v). Is this possible? If so, how?

Also, what are the pros and cons of this approach?

The best thing you can do is wiring in series. There are 900Ah Lifeline 2V batteries: GPL-6CT-2V. Six of those in series is your optimal configuration

[PaulinOz]

Originally Posted by rwells36

In order to get around the backorder of a particular battery supplier for their 12v product I am considering the purchase of their 4v products which have no backorders and then wiring three (3) of these 4v 450Ah in series to achieve 12v. However, I desire to have a total of 900Ah at 12v (not 24v). Is this possible? If so, how?

Also, what are the pros and cons of this approach?

Two banks wired in series that is 2 banks of 3 x 4 volt will yield 2 x 12 volt banks, these two banks are then in Parallel giving you 12v a 900 Ah.

The advantage of this over the 6 x 2 volt set up is if you have a battery failure you will still have 12 v at 450 Ah. With faulty bank disconnected.

If a 2 volt battery fails you will have 10 volts not a lot of use on a 12volt boat till it can be replaced.

[LoudMusic]

Originally Posted by PaulinOz

Two banks wired in series that is 2 banks of 3 x 4 volt will yield 2 x 12 volt banks, these two banks are then in Parallel giving you 12v a 900 Ah.

The advantage of this over the 6 x 2 volt set up is if you have a battery failure you will still have 12 v at 450 Ah. With faulty bank disconnected.

If a 2 volt battery fails you will have 10 volts not a lot of use on a 12volt boat till it can be replaced.

Do you feel there is any value in having a 3x4v series instead of a 1x12v (assuming same Ah end result)? The main thing that comes to my mind is that if you have a failure you're only replacing a 4v battery instead of a whole 12v battery. But you've also got 3x the chance of failure. I guess it potentially gives you more flexibility in installation space as well, and easier to physically move then onto and off of the boat.

[rwells36]

Originally Posted by LoudMusic

Do you feel there is any value in having a 3x4v series instead of a 1x12v (assuming same Ah end result)? The main thing that comes to my mind is that if you have a failure you're only replacing a 4v battery instead of a whole 12v battery. But you've also got 3x the chance of failure. I guess it potentially gives you more flexibility in installation space as well, and easier to physically move then onto and off of the boat.

Not a question of value. My original post explains the motivation.

[rwells36]

Originally Posted by PaulinOz

Two banks wired in series that is 2 banks of 3 x 4 volt will yield 2 x 12 volt banks, these two banks are then in Parallel giving you 12v a 900 Ah.

The advantage of this over the 6 x 2 volt set up is if you have a battery failure you will still have 12 v at 450 Ah. With faulty bank disconnected.

If a 2 volt battery fails you will have 10 volts not a lot of use on a 12volt boat till it can be replaced.

Something like this? Would this maintain amp balance?

[john61ct]

https://www.smartgauge.co.uk/batt_con.html

[Adelie]

Originally Posted by rwells36

Attachment 145016

Something like this? Would this maintain amp balance?

One of the leads to the circuit panel should run up and the other down as shown in the sketch.

[camel2012]

Originally Posted by Adelie

One of the leads to the circuit panel should run up and the other down as shown in the sketch.

No, diagram is wrong as well... shows an 8 volt 1350 Ah system...

Agree with Adelie that positive system tap should come from opposite battery (series and parallel wise) as the negative system tap). Doing that ensure even battery charge and discharge, as long as opposite interconnecting cables are the same gauge and length.

[Adelie]

Originally Posted by rwells36

Attachment 145016

Something like this? Would this maintain amp balance?

What do you mean by amp balance? Even charging across the battery pairs?

The sketch shows 2 batteries in series, with 6 fill points per battery (12v batteries) which would result in a 24v system. Ignoring the fill points the sketch would produce 12v if 6v batteries were used.

Did you intend to show 4v or 6v batteries?

For 4v batteries see the revised sketch in this post.

[rwells36]

Very nice.

[s/v Jedi]

As long as you have anything in parallel, all batteries should be the same. You can't just replace one a couple years later. Only in the all-series with 2V cells you can do this without any problems.
BTW when one cell fails you can jumper it and continue with just 5 cells in emergency mode. This is more than 10V and all critical equipment will work. Google for specifics.

[a64pilot]

Have to realize that if you buy one big 12 V battery, what it is is 6 2V cells that the manufacturer has wired into series for you and conveniently put them in one box.
By purchasing 6 2V cells your wiring them into series and accomplishing the same thing, just not in one box, and maybe it cost more, but six individual calls weigh a whole lot less to carry one at a time.
Assuming a 12 v battery under float is 14V, and you have six cells and lose one and you disconnect it, you will have an 11.666 V battery under float.
I'd want programmable charge sources, but I don't see why you could limp along on an 11 V battery, most electronics work down to 10 V ?

[mickelsen]

I confess to being not well versed on series or parallel. I thought they were very different. The diagrams are good however am I in series or parallel?

[Matsubob]

It can be confusing because of the "Plus" and "Minus" configuration, but if you ignore those and be sure that all of the "opposites" are connected, leaving two "free opposites" (minus and plus), you have a series setup.
Sure it will work! That is no problem. But looking out for one failed one, if not caught quickly, the others will tend to be drawn down because batteries tend to want to balance out. So it would be good to monitor them well.
One down side that I can think of is the amount of cabling. Maintaining that many cables and ascertaining that none have corrosion and that all have a good, clean and tight connection, would be one possible drawback.