[RE-wrenches] 5 battery strings

[tom at wagonmaker.com]

Separate out the individual series strings and run each string to a buss 
bar setup.  Remember it isn't just resistance differences between 
batteries but resistance difference between cells as well.  In a setup 
like the existing one the resistance differences can really add up and 
if one battery fails the entire system will be offline.  Running each 
string to a positive and negative common buss bar means you can remove 
individual strings without disrupting the entire storage and the system 
can continue operating.  Also, it means the only resistance issues of 
substance are within individual series pairs not the entire 
interconnected bank.

I ran 10 series pairs of 12v AGM batteries, each pair to a common buss 
and it was the longest lasting, most stable battery bank I had.  That 
was years ago and now it would require fusing each string but for 
longevity and stability it is the best bet.

Tom

On 2018-07-23 03:56, Dave Tedeyan wrote:
> Since we are on the topic of bad battery practices...
> 
> I may be fixing up a system that was both designed and installed very
> poorly.
> They have a 24V Outback VFXR inverter, and ten 12V AGM batteries wired
> into
> 5 parallel strings. I know that is a bad idea, but since they already
> have the
> equipment, are there any safety issues by re-using this equipment? It
> is for a
> grid tie battery backup system that will remain in float most of the
> time. I assume
> that the batteries will not last particularly long, but is there any
> harm in using them
> and then just getting new batteries once they fail?
> 
> Stringing is shown in the attached picture.
> Cheers,
> Dave
> 
> --
> 
> Dave Tedeyan
> 
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