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All About Batteries, Part 3: Lead-Acid Batteries
1/13/2014

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Terminal voltage verses duration of discharge for several rates.
Terminal voltage verses duration of discharge for several rates.

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eetcowie
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Re: Comparison Tables?
eetcowie   1/14/2014 9:03:50 PM
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...comparison tables..

Yes, at the end it will be useful to see it all, so they say. I'll decide a good format as I get closer to the end.

Adam-Taylor
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Specification
Adam-Taylor   1/14/2014 3:33:41 PM
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A great series of blogs, when it comes to specifying a battery what are the cardinal points of the specification (technology, end of life votage, amp hour etc) that the engineer needs to consider.

 

David Ashton
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SLABs
David Ashton   1/14/2014 3:06:28 PM
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Hi Ivan....another informative article, thanks.  I know VRLAs as SLABs (Sealed Lead Acid Batteries) which in Australia can be confused with a box holding 24 cans of beer :-)  

Can you explain how the technologies for this overcome the gassing that is usual with the wet-cell types?

And how do the so-called Deep-cycle batteries avoid the sulphation that happens with ordinary batteries if they are deep-discharged?

antedeluvian
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capacity Mesurement
antedeluvian   1/14/2014 1:28:59 PM
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Recent Brad Albing blogged about a new TI chip that acts as a gas guage for lead-acid batteries. It looked good to an innocent like myself, and I was wondering if you thought the product had any merit. Looking at it, it does seem to need to apply a load to guage the remaining charge, but so much of the topic is new to me that I would like an expert's opinion.

antedeluvian
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Lead Acid Batteries
antedeluvian   1/14/2014 1:22:58 PM
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As Mark Twain might have said, Everyone would like to get rid of the lead-acid battery, but nobody does!

I have been working on a battery backup unit design for industrial power supplies (24VDC) for 12 years or so. There is an old English joke-

Q: How do you start a pudding race?

A: Say go (ask Max to explain)

The project has not gone anywhere because management has never allocated the resources, but the need remains. Part of the issue of the design is that you need to charge a nominal 24VDC battery with a 24VDC power supply. There are several approaches to this, buit our current proposal is a buck/boost switchmode power supply. Boost for when the battery exceeds 24V and buck for the other case.

Anyway one of the considerations is that in order to test the battery, I am told you need to drain the battery through a load. The problem is that once this test is done, the battery needs to be recharged- what happens if backup is needed during the charge cycle? Do you concur with this concept that lead-acid batteries be regularily load-tested?

 

Duane Benson
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Answered before I asked
Duane Benson   1/14/2014 1:16:51 PM
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re "Sealed lead-acid technology is sluggish and cannot be charged as quickly as other battery systems" - You just answered a question I've had for quite a long time. This has been a good series.

Batteries are a bit of a mystery but too important to be left as a mystery.

Max The Magnificent
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Comparison Tables?
Max The Magnificent   1/14/2014 11:52:35 AM
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Hi Ivan -- at the end of this, once you've worked your way through every battery technology known to humankind, will you be presenting an overall comparison matrix showing the various technologies in relation to each other?

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