Battery Explodes!

[Art]

Man o' Manischewitz!

This is a great thread!

Personally I really like good ol' FLA's... starters and deep cycle [not the combos - they don't last long... so I've found].

Handled correctly; i.e., fluid level maintained, not too deep a discharge, and - NOT unnecessary constant charging till the cows come home... i.e. let em rest! Batts can be perfectly happy [when having already been fully charged] to sit undisturbed by anything.

For cost and service I choose East Penn FLA batts. Batteries Plus chain of stores gives good cost [often with 10% discounts] and good service.

When I leave my marine deep cycle FLA batt house bank [for any length of time] I make sure they are 100% charged and isolated by Perko switches off. And, I never leave them hooked up to any type of charger for the duration of my vacancy. When I return [be a week or two months] I immediately check with multi meter plugged into cigarette lighter to find charge level [seldom does it reach down to 70%]. Then I put the charger back on to regain 100%. Once the 100% mark is reached I continue charging for another 30 minutes. After that I use em till 55% to 60% charge remains. Then the charger is again turned on to regain 100%.

Our Tolly has Four 31M DC FLA East Penn in parallel. Last set went well for over 8 yrs. Replaced with the same. cost for all four = about $440. Divided by 8 yrs = $55 per yr. = 4.58 per mo. = $1.06 per wk. = $0.15 per da.!!

https://www.batteriesplus.com/productdetails/SLI31MDC?storecode=308&locationofinterest=&locationphysical=9032109&gclid=EAIaIQobChMIl5GWrszK4QIVCL7ACh38hQP9EAQYASABEgJASPD_BwE

What's not to LUV!!

 

[Steve DAntonio]

No, this is a myth. Also, you are using the term SVRLA too broadly.

SDA: In the marine industry SVRLA or VRLA has been used to describe AGM and gel batteries for 20 years, but that's not just me saying this, from Wiki...

"A valve-regulated lead-acid battery (VRLA battery) sometimes called sealed lead-acid (SLA) or maintenance free battery.[1]

There are three primary types of VRLA batteries, sealed VR wet cell, absorbent glass mat (AGM) and gel cell.[2]"

1) SVRLAs (gel types) are vastly inferior to flooded lead-acid in charge acceptance rates (C.A.R.).

The C.A.R. of a gel-type SVRLA is typically 1/5th of FLA.

SDA: 1/5? I'm really curious as to where you get this, it flies in the face of common charging wisdom and experience in this industry. Can you cite your source? For a high quality gel battery, Sonnenschein for instance, the initial charge acceptance rate is 4x C20 or 320 amps for a 80 Ah battery, which then tapers to 1/2 of C20. the 1/2C CAR for gels is common. The CAR for flooded lead acid batteries is generally accepted, again in the marine industry, at roughly 25% of C (higher at initial charge, lower toward the end of charge).



2) SVRLAs (AGM types) and FLAs are both far superior to SVRLA gel types.

SDA: Superior...by what measure? When comparing equal quality/capacity, typically gel battery CAR is lower than AGM's and higher than FLA, however, they (GELS) are capable of more cycles than comparable AGMs.

There's no meaningful difference between them, except that AGMs are more suceptable to damage from overcharging.

SDA: No meaningful difference? Among other things AGM's maintain higher terminal voltage than FLA under high loads. This is desirable for high loads found in large inverters, thrusters etc. FLA's, if treated properly, will provide more cycles than AGMs.



3) SVRLAs (liquid electrolyte types) are (slightly) superior to AGM in C.A.R.s

SDA: But by your own admission the valve regulation has no affect on CAR, so you are saying any flooded lead acid battery is slightly superior to an AGM in CAR? Again, that flies in the face of common marine industry practice and experience, AGM's have a significantly higher CAR than flooded lead acid batteries. If so, you are also contending that every AGM manufacturer is providing grossly misleading charge information.

Confusion about (S)VRLAs:

Inside a "Valve Regulated Lead-Acid" (VRLA) battery (sealed or not)

SDA: By definition, on order for a battery to be 'valve-regulated', it must be a sealed case...

you will find either a simple liquid electrolyte, an electrolyte gel, an electrolyte-impregnated glass fiber mat, or (recently) Carbon Foam technology. All of these are VRLAs.

SDA: No argument there, and quoted above. There is no technical difference between VRLA, SLA and SVRLA, all describe the same thing, a sealed battery case that operates under slight internal pressure, usually about 1.5-2 psi, which is regulated by a valve. Again a battery cannot be valve regulated without being sealed.

In and of itself, VRLA (sealed or not) does not meaningfully affect charge acceptance rates.

SDA: Agreed, the valve regulation affects the recombinant process, thereby negating the loss of water, not charge acceptance rate.


However, marketeering hype from manufacturers of AGMs is designed to confuse people, and it frequently succeeds. This is understandable since they want to sell you a battery that costs 5% more to make for 3-5x the price...

SDA: 5% more compared to what? You are painting with a very broad brush, some marketing is misleading for all products, and why single out AGMs, I've seen misleading claims from manufacturers of all battery types. However, there are battery manufacturers, AGM and otherwise, whose data is accurate.

I've designed and/or installed a couple of hundred high capacity battery banks with advanced charging systems for power and sail cruising vessels over the past 30 years, using flooded lead acid (never sealed), AGMs and gels and now lithium ion phosphate (LFP). If the bulk of tech data was faulty, at least for the brands I use, the industry would have figured this out long ago, and we'd still be using flooded batteries for large banks. AGM's such as Lifeline and Odyssey TPPL are capable of accepting an initial bulk charge acceptance rate of 100% (more for the Odyssey) of their amp hour capacity. It's a fact, I've tested it. In practice it's not commonly done because of the size of the bank capacity, I recently completed a project whose bank is 1,800 Ah, far too large for most charge sources to even approach that threshold.

SDA: Your experience is with data centers? If so, perhaps different terminology is used there, and because those batteries are in float for most of their lives the performance characteristics are different, but beyond that I can't explain or understand why your understanding of the operation of these batteries varies so widely from mine.

 

[FF]

" an 800A charger would bring you back to fully charged in 4.6 hours (at CAR = 1.0). This is using the manufacturer's math.

If you have a house bank of 800Ah FLAs, discharged to 45%, a 400A charger is going to bring you back to fully charged in 5.1 hours (at CAR = 0.5)."

The key takaway here is 4.6 hours or 5.1 hours even with massive charging.

The folks that maintain the house batt set with an hour or two a day (usually while cooking) should not be shocked at short battery service life.

Bringing batts up to 100% charged frequently is needed .
Solar is the simplest answer for most folks.

 

[Steve DAntonio]

" an 800A charger would bring you back to fully charged in 4.6 hours (at CAR = 1.0). This is using the manufacturer's math.

If you have a house bank of 800Ah FLAs, discharged to 45%, a 400A charger is going to bring you back to fully charged in 5.1 hours (at CAR = 0.5)."

The key takaway here is 4.6 hours or 5.1 hours even with massive charging.

The folks that maintain the house batt set with an hour or two a day (usually while cooking) should not be shocked at short battery service life.

Bringing batts up to 100% charged frequently is needed .
Solar is the simplest answer for most folks.

You'd be lucky to see a charge acceptance rate of 0.5C on a FLA battery. At a 50% SOC, a FLA battery can absorb about 25% of its rated Ah capacity. As it gets closer to full charge, and the internal resistance increases, that number of course drops off, which is also true of AGMs and gels. AGMs have a CAR of, initially, up to 100% of Ah capacity, in some cases such as Odyssey's TPPL, in excess of 100% of Ah capacity.