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Lead acid battery bank.
#1
Been reading up on large lead acid battery banks, and was wondering is there any mileage in separating the batteries using something like changeover solenoids to charge them individually before switching them back into a bank for discharging?
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#2
No. Just more work.
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#3
Would it not solve some of the problems that cause parallel lead acid to go badly out of balance?
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#4
If its wired in parallel how could it go out of balance? They would all be the same voltage.

If you have a very large bank, you should wire in reverse return which allows for equal resistance if you are concerned with uneven current draw in high load conditions.
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#5
(09-06-2019, 10:05 PM)Crimp Daddy Wrote: If its wired in parallel how could it go out of balance? They would all be the same voltage.

My understanding is that any small differences with internal resistance, can lead to some batteries not been fully charged properly, while others are been over charged. Over time leading to the death of the battery bank. Obviously if they are charged separately this is avoided.
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#6
(09-07-2019, 04:31 AM)dragonfly Wrote:
(09-06-2019, 10:05 PM)Crimp Daddy Wrote: If its wired in parallel how could it go out of balance?  They would all be the same voltage.

My understanding is that any small differences with internal resistance, can lead to some batteries not been fully charged properly, while others are been over charged. Over time leading to the death of the battery bank. Obviously if they are charged separately this is avoided.

I can understand that… especially on a large battery bank, but its a ton of work.  If you google my above comment on wiring in “reverse return” it helps contribute to solving the exact issue you are talking about.
 
Wiring in reverse return helps level out resistance issues you would have with the cells “furthest away” from the load or charger.

Its a method used often in hydronic piping, but also applies to electrical.

[Image: 13-Figure21-1.png]
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#7
What about if you were to use different age or brands of battery, they could be separated for charging, but would there be any negative effects when they are reconnected aslong as the voltages are all in line?

What about during discharge?
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#8
Have You ever heard of Kirchhoffs Law? Unless You have a considerable distance between loads "with extra resistance in the leads", Your "reverse return" is not going to mean a hoot.
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#9
There are battery equalizers for lead acid batteries. They are probably a worthwhile investment. These go between the series batteries.

Lead acid batteries otherwise very different from Lithium. To balance cells in a lead acid batteries, they are float charged, and therefore equalize. There are different methods for doing this, dependent on the type of battery. (Flooded, AGM, or Gel).


Battery University is a great place to start, to familiarize yourself with them.
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#10
(09-13-2019, 12:07 AM)Geek Wrote: There are battery equalizers for lead acid batteries. They are probably a worthwhile investment. These go between the series batteries.

Can you point me towards some decent battery equalisers? Most I see are for lithium these days. And those that do list lead acid seem to list every type of battery, and have very little if any details etc.

Edit: actually just found some, think I must have searched differently in the past like balancer instead of equaliser or something.
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