Connecting 4 x 6 Volt to make 12V Bank

[nigel1]

Thanks Bill, and the info on jumper length is useful to know in advance.
Cheers

[btrayfors]

S/V Alchemy, Yes, I believe load balancing DOES make a difference, because it addresses the issue of how much each battery in the bank contributes to total load as well as receives from charging sources.

How much a battery is "worked" relates directly to longevity. I'd consider any one of the three methods (Case #2, #3, or $3) shown in the SmartGuage paper to be acceptable.

Case #2 is generally the easiest to implement and, while not perfect, is still very good.

If there's enough room, Case #3 may be easy to implement and might be worth the effort if you were using particularly expensive batteries.

Bill

[Talbot]

Originally Posted by S/V Alchemy

Bill, what do you think of the setup here (SmartGauge Electronics - Interconnecting multiple batteries to form one larger bank)



....

A good system for 4 x 12v batteries, but doesnt work well when each battery is 6v!

[CeesH]

Originally Posted by Talbot

A good system for 4 x 12v batteries, but doesnt work well when each battery is 6v!

This NOT a good system, in Europe the system is also called "The backbone system". In the case of failure of a single battery, you not only destroy the other connected serial battery but ALL the batteries.

This discussion starts over and over again, in The Netherland the company Shiptron, experienced in thousands of installations in the proffesional yacht industry wrote the following document for yacht owners.

http://www.shiptron.nl/docs/accu-aansluiten.pdf

They claim that you need to keep the current through every battery equal.

Although the document is in the dutch laguage, i think that the pics are self explanatory.

Regards,
CeesH

[S/V Alchemy]

Yes, I see that. Oops! OK, for that example I was looking for general principles of "battery balancing" over the actual layout one would use for a 6V-based setup.

Bill, thank you for your answer. Did you mean Case #4 (assuming 12 VDC batteries), as there are four examples and I posted the diagram associated with the fourth.

[btrayfors]

Originally Posted by S/V Alchemy

........

Bill, thank you for your answer. Did you mean Case #4 (assuming 12 VDC batteries), as there are four examples and I posted the diagram associated with the fourth.

Yes. Case #4. Sorry for the mistyped "(Case #2, #3, or $3)"

Cases 2, 3, or 4 would be fine.

Bill

[Dustymc]

Originally Posted by Dustymc

herpty derp, some extra cables...

Originally Posted by btrayfors

load balancing

Thank you!

[nigel1]

Bill
I have shamelessly borrowed your connection drawing and added a couple of extra jumper cables.
Will this work, and if it does, will it make for better balancing, which is what I am trying to achieve.

Dusty, does the diagram reflect your set up??

Cheers

[btrayfors]

Nigel,

Two stars for creativity, but I believe you may be over-thinking this. To my mind, the KISS principle has merit.

The jumpers shown in the original diagram are sufficient to ensure an efficient hookup of the four batteries presuming, of course, that they are of adequate size (AWG1/0 or larger).

Anything more than this is overkill.

Bill

[nigel1]

Thanks Bill

Have a stock of 50mm2 cable, thats about AWG 0 I think.

[S/V Alchemy]

Thanks to all for clarifying my understanding on this topic. That Smart Gauge site is permanently bookmarked.

[David M]

There is no problem worrying abut a hydrogen explosion from either connecting them or disconnecting them provided you are not charging them at the same time and they have had a little time to vent after charging.

[Dustymc]

Originally Posted by btrayfors

The jumpers shown in the original diagram are sufficient to ensure an efficient hookup of the four batteries presuming, of course, that they are of adequate size (AWG1/0 or larger).

Anything more than this is overkill.

Bill

That is may be, but at least one well-respected author thinks there's something to the balancing cables, which cost something like an extra $10 as part of a $1000++ system. If they make my batteries last an extra 1% they've paid for themselves. That's a pretty safe bet for me.

Originally Posted by nigel1

Dusty, does the diagram reflect your set up??
Cheers

Buy the book...

Originally Posted by David M

There is no problem worrying abut a hydrogen explosion from either connecting them or disconnecting them provided you are not charging them at the same time and they have had a little time to vent after charging.

Having had one of the damned things blow up in my face (I didn't check to see if it was hydrogen or not - I was a little preoccupied...), I don't share your confidence. This one was hanging off the side of a John Deere tractor in OK, so I can only assume the wind was blowing like hell and ventilation wasn't a concern. (One gets used to that sort of thing there - and did I mention the preoccupied with exploding batteries thing?) I really don't remember what was going on, but I think it was new batteries and I suspect I hooked a cable up backwards (those old JDs use 2 6-volt batteries in a 12v system) - but I sure as hell remember that battery coming apart in my face! I suppose that's something like 1 in ten thousand for me, but it's one too many!