Jump to content

12 volt battery bank hookups


parrotguy

Featured Posts

Ahhh! I see the 4 in series at 208 Ah does make 832 Ah...Good catch, I was just testing you guys...LOL

 

so my next question is will the difference in using 24v still out way the 932Ah in the 12v setup. As I understand 24v is more efficient.

Link to comment
Share on other sites

The 24v one looks totally wrong!

 

24v should be 4 batteries (6v) wired in series. That isn't!

 

24v has the advantage of been able to use smaller cable sizes, but slightly higher priced and availability of equipment.

Link to comment
Share on other sites

 

so my next question is will the difference in using 24v still out way the 932Ah in the 12v setup. As I understand 24v is more efficient.

 

Depends what you mean by more efficient.

 

It is true that to do a certain job at 24 volts will take half the amps as it would at 12V BUT to get the 24 volts you will need the same capacity of batteries as you would to do it at 12V. e.g. To obtain 200Ah at 24 volts would require 2 x 100Ah batteries connected in series. To do the same job at 12 volts would require twice the current flow and thus twice the battery capacity so you end up with 2 x 100Ah batteries connected in parallel.

 

The other definite advantage is that the cables can be half the size at 24 volts but this is only an advantage if it is a new boat or a total rewire job. Against the slightly lower cost of cable you need to think carefully about the non-availability of certain 24V equipment and thus the need for 24 to 12 volt reducers for things like car radios plus the ready availability of 24 volt equipment at typical marine outlets. I always say think about having a 24 volt water pump fail on bank holiday Saturday when the local chandlers only stock 12v ones and they can not get a 24 volt one until Tuesday.

 

The only time I would use 24 volts is if a particular engine I needed to use was only available with 24 volt equipment but this is not very likely in the sizes inland boats use. On big engines the lower current drawn by a 24 volt starter is a real advantage, hence most trucks are 24 volt.

Link to comment
Share on other sites

 

 

 

I came up with these two battery setups after reading the info posted here.

Are my connections correct? No and Yes

Are my calculations correct?Yes and NO

 

 

To get 24v from 6v batteries, you need to wire four in series, positive to negative.

 

So four in series, 208 Ah each will give 24v with 208 Ah.

 

With another four in the same configuration, you can then parallel the two banks positive to positive and negative to negative

 

This will be two banks of 24v 208 Ah each, so giving a total of 24v with 416 Ah

 

You 12v diagram is correct just the calculation is incorrect.

 

When wiring batteries in series.... voltage is cumulative, amp.hours remains the same

 

when wiring batteries in parallel....amp.hours is cumulative, voltage remains the same,

 

 

 

edit: to remove double quote

Edited by bottle
Link to comment
Share on other sites

Ok...well since my really neat looking 24v system was incorrect and after careful study I have concluded that this is the only way I can figure to correctly connect 8 - 6v batteries in a 24v system. someone with a few more brain cells might find a way to make a perfect balanced load but I can't see one until I add another 4 to 8 - 6v batteries to the mix.

battery setup 24v

As for the system it is actually land based. It is for a off grid cabin/hideaway I have the necessary converters from 24v to 12v and DC to AC inverter.
Mostly trying to keep from having a melt down or starting a fire. Nether one is good when your out in the woods.
Link to comment
Share on other sites

 

Ok since this looks exactly like my first 24v setup with only 4- 6v batteries and not 8. I can only see one difference and that is where I made the parallel connections.

Is it not possible to connect the 2- 24v banks of 6v batteries in that manner? Am I adding to many connections?

 

battery setup 24v

Edited by mrhoward69
Link to comment
Share on other sites

 

Ok since this looks exactly like my first 24v setup with only 4- 6v batteries and not 8. I can only see one difference and that is where I made the parallel connections.

Is it not possible to connect the 2- 24v banks of 6v batteries in that manner? Am I adding to many connections?

 

 

That looks perfect balanced system for 12v smile.png

 

24v would be like this (for 8 6volt batteries)...

 

med_gallery_4543_1084_2252.png

Edited by Robbo
Link to comment
Share on other sites

Remember to keep all the link cables the same size and length as each other, the ones going between the positive and negatives, the two between the different banks (joining the rows of batteries together) can be a different size/length to the links but should be the same size/length as each other. The cables going to the install can be different length and it's wise to make the positive as short as possible to your fuses/isolator/bus.

Link to comment
Share on other sites

 

 

batteries3-1.jpg

 

Have to say, each to their own but nowadays I'd prefer not to 'crosslink' the batts like this.

 

Reason being that as the batts get old, if one develops a shorted cell then the other 6V batt in parallel will discharge into the 2 good cells of the defective batt, which may cause a boiled batt with much gassing and risk of explosion.

 

For 24V bank with 6V batts I think it'd be much better to have 4 batts in series, then parallel these sets of 4 to get more capacity if required.

 

So for a 24V bank comprised of 8 6V batts, something like this:

 

24vsystem.gif

(pic from http://www.solarray.com/TechGuides/WireDiagrams_T.php)

 

cheers, Pete.

~smpt~

Edited by smileypete
Link to comment
Share on other sites

Very good info smileypete...I think I will do it the safer way and not try to over think it.

 

Now I'm trying to decide if I want to go 24v or 12v...After looking at the price of inverters it's a hard choice.

I don't think I will have a cable issue using 00 cable, my longest run is only 50' and that's from the battery to the inverter or panel box to the charge controller haven't figured out what would be the better placement.

 

Dang the more I work on this the more work I have to do...

 

Thanks a ton for all the help and input guys now some of my work is done.

 

James

Link to comment
Share on other sites

Very good info smileypete...I think I will do it the safer way and not try to over think it.

 

Now I'm trying to decide if I want to go 24v or 12v...After looking at the price of inverters it's a hard choice.

I don't think I will have a cable issue using 00 cable, my longest run is only 50' and that's from the battery to the inverter or panel box to the charge controller haven't figured out what would be the better placement.

 

Dang the more I work on this the more work I have to do...

 

Thanks a ton for all the help and input guys now some of my work is done.

 

James

 

50 foot is a long way!

 

Or is it http://www.dailymotion.com/video/x28p3n_spinal-tap-stonehenge_music

 

If it is 50foot and not inches, I would investigate going 48v!

 

It's a lot easier to extend 12v, as you don't need as many batteries when extending. Less cabling for 48v tho.

 

Also look at Rolls Batteries and 2volt traction batteries, if you have the room these are better than 6 volt ones and will last 15 years instead of 10.

 

I compared prices between Rolls and Trojan for cycle per ah's. The Rolls came out slightly better but if you are deep discharging they will be able to stand more abuse than the Trojans.

 

Edited by Robbo
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.