Author Topic: Battery Bank Configuration  (Read 16067 times)

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Offline ChrisOlson

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Re: Battery Bank Configuration
« Reply #45 on: February 06, 2012, 10:47:45 pm »
It's very inefficient to run the generator just to hold the cells in float for 2 or 3 hours, so it usually drops the generator fairly quickly - I think I have it at 30 mins of float.

Yes, when the generator starts because of an automatic start setting, I have float disabled to save on fuel, so it shuts it off as soon as absorb is done.  If I would enable that and let the generator float the bank for an hour or so before it shuts off, it would probably be better (for the batteries).  But I set a goal for this year to cut our gen hours in half for 2012 over what we ran in 2011.  So floating the batteries with the generator is not going to help me meet my goal    :)
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Offline Watt

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Re: Battery Bank Configuration
« Reply #46 on: February 06, 2012, 10:53:50 pm »
Back when I was starting this journey through the wastelands of RE, I studied up on batteries and read anything I could find on them. Most helpful (then) was RV and boating crowds. Solar and wind were kind of fringe stuff then. Mostly folks "selling" and not much historical data on the RE installations and long term battery health.

I got a lot of my battery "attitude" from the Blue water sailors. Their stuff has to work. Period. Can't pull over at the roadside battery mart any time you want on the high seas for a replacement.

A lot of what they did was not according to manufacturer specifications. Things like a bit higher voltage for float charging and numerous other little bits that I follow yet today but will not get into lest I set off a battery abuse intervention by some user(s).

I have routinely mixed sizes in parallel but would NOT do so in series. I figure they are both a source and a load and simple DC electric theory 101 tells me they will see exactly the same voltages (discounting cabling losses) and will draw or deliver the amperage it is capable of into or from it as if it were in the same situation alone if the load is X volts and Y ohms you get Z amps. The confusing bit is the big boy bank holds the voltage up and this seems to just put the baby battery into a form of stasis where it does not have to provide any current because the big boy is pushing the amps into the load until a point where the voltage is low enough that the little one can shove some amps and so on and so forth. They just act like any source or load in parallel because, ultimately that is what they are. Curiously enough at the same time sometimes.

Hope that was as clear as the mud spattered rear window on the Dakota!

Some of the seemingly complex puzzles are just as simple as this.

No quantum physics.

Loads and sources.

Thevenin would be proud of me ;=>

Or say **Cough**BULLSHIP**Cough**

That is my take on morphodite battery combinations.

There you have it so have a blast showing me I am full of it.

Same voltage batteries, obviously.

Tom

Thanks, I guess  ???

How about you share some of that " controversial " battery information you know.   ;D
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Offline ghurd

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Re: Battery Bank Configuration
« Reply #47 on: February 07, 2012, 09:28:27 pm »
Even so, I think that 100 amphours of generator charge "holds" the batteries for less time than 100 amphours of solar charge does, assuming neither of them actually gets the batteries to float.

I agree totally.
#1.  Git'r done.  I see it in real life.
#2.  Science.  The Peukert Effect works both ways.

How about you share some of that " controversial " battery information you know.   ;D

It is not controversial in most circles.
Kirchhof and Peukert stuff is over a 100 year old news.  Thevenin stuff is too.

simple DC electric theory 101 tells me...

Me too.
It is as basic as a higher voltage system is better for a higher power system, better batteries than 12V marine from wally-word are better for a higher power system, and fancy eBay Chinese inverters without a known brand name are junk.
But tomw, you knew that more than a decade ago.
Me too.