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Noob solar/wind charging question

BlueAndGreen

Jul 18, 2010
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I have just put up a small 24v wind turbine on my sign post. I have yet to connect a charge controller or batteries. The question: if I use 12 volt batteries (automotive) in series for 24volts, can I still tap an individual battery for 12 volt devices?
 

Resqueline

Jul 31, 2009
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No, not unless it's only a clock or some similar very low power device..
 

davenn

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Sep 5, 2009
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No, not unless it's only a clock or some similar very low power device..

out of curiosity what is your reasoning there Resqueline ?

I wouldnt have seen a problem .... unless you are thinking of a seriously hi current device
that would be causing one battery to "used harder" than the other, with that causing problems with an imbalance of recharging ??

Dave
 

Resqueline

Jul 31, 2009
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Yes, it's charge imbalance I'm thinking about. When (ordinary) storage batteries are fully charged there's less than 500mA passing.
I'd figure that a (one-sided) current of 50-100mA would be the max to not upset the balance. (Well, it all depends on the charging conditions I guess.)
If you tap too close to the trickle charge current then one battery will never get full and the other will get overcharged, losing water and active material.
Of course LA batteries are quite robust and can take abuse for years, but eventually they could be too damaged, getting years taken off their life.
If one could have a bank switch so one could tap one side one day and the other side the other day then the batteries would be a lot happier.
Also, with a 24V wind turbine there should be a 28V shunt regulator. In this case that could consist of two 14V regulators across each battery. That would help too.
With heavier drain there's no option but to use a 24-12V converter. Today's switchmode units are cheap, efficient, & powerful - compared to what they used to be.
 

davenn

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Sep 5, 2009
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yes thanks mate assumed as such :)

the other thing that went through my mind would be to use deep cycle marine batteries they would serve much better than car batteries !! :)


cheers
Dave
 
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