Do floating batteries get stratified?

**Mike90250** · 04-14-2014, 09:19 AM

Batteries stratify in a complex way, but yes, batteries in shallow or float cycle will stratify. They (flooded batteries, not AGM) need a weekly charge that will gas them a bit, to stir the electrolyte up a bit. Or drive them around the block!

**Sunking** · 04-14-2014, 10:05 AM

Originally posted by mapmaker

I believe that the 'equalization' is really a bulk/absorb cycle.

Incorrect. EQ is Constant Voltage controlled over charge. EQ voltage is approx 2.6 vpc for FLA.

As Mike said FLA batteries in Float can become stratified. A quick EQ to gas the batteries will stir the acid up but not recommended.

**mapmaker** · 04-14-2014, 10:12 AM

Originally posted by Sunking

Originally posted by mapmaker

I believe that the 'equalization' is really a bulk/absorb cycle.

Incorrect. EQ is Constant Voltage controlled over charge. EQ voltage is approx 2.6 vpc for FLA.

I agree that equalization is not bulk/absorb. My point was that the 'equalization' that Iota provides every 7 days is the same as the Iota bulk/absorb cycle.... It's not what you or I would call 'equalization'.

--mapmaker

**russ** · 04-15-2014, 07:22 AM

Do batteries really float? I thought they would quickly sink!

**inetdog** · 04-15-2014, 02:39 PM

Originally posted by russ

Do batteries really float? I thought they would quickly sink!

You could try using a tub of mercury. I am sure they would float in that.

(Once upon at time mercury fluid bearings were used for vibration isolation. Not so much anymore outside of laboratories.)

**Sunking** · 04-15-2014, 09:51 PM

Stratification is a complicated subject. Mostly occurs in a systems where batteries are cycled frequently and taller in shape like a LR16 cell on high discharged rate batteries for SLI and traction. Not much of a problem deep cycle batteries, or with more uniform cube shaped batteries. There are two ways to reverse stratification.

1. Not practical for RE applications is a pump that circulates electrolyte.
2. Is a controlled over charge that produces gassing over an extended period of time. Gassing voltages occurs at roughly 2.4 vpc @ 25 C. Not something you want to do frequently.

**mapmaker** · 04-16-2014, 06:39 AM

Originally posted by Sunking

Stratification is a complicated subject. Mostly occurs in a systems where batteries are cycled frequently and taller in shape

That has been my understanding, but then why would a floating battery get stratified? A battery on long term float is NOT being cycled.

Here's a quote from another battery charger manufacturer:

The Charge Wizard will automatically select its STORAGE MODE of operation (13.2-volts) once the battery reaches full charge and remains unused for a period of 30 hours. This feature is standard on all of Progressive Dynamics Marine Battery Chargers.

At a charging voltage of 13.2 volts, the converter/charger will maintain a full charge, reduce gassing and water loss. However, this lower voltage does not provide enough gassing to prevent a battery condition called Battery Stratification.

In order to prevent Battery Stratification, an Equalization Charge (increasing charging voltage to 14.4-volts) must be applied periodically. The Charge Wizard automatically selects its EQUALIZATION MODE (14.4 volts) every 21 hours for a period of 15 minutes.

--mapmaker

**Sunking** · 04-16-2014, 12:00 PM

Originally posted by mapmaker

That has been my understanding, but then why would a floating battery get stratified? A battery on long term float is NOT being cycled.

They typically do not get stratified.

**mapmaker** · 04-16-2014, 02:24 PM

Originally posted by Sunking

They typically do not get stratified.

Originally posted by Sunking

As Mike said FLA batteries in Float can become stratified. A quick EQ to gas the batteries will stir the acid up but not recommended.

Well, that makes everything clear

So what's with these battery chargers that include weekly or daily "equalizations" of batteries on long term float... Does it make any sense to you?

--mapmaker

**Sunking** · 04-16-2014, 03:07 PM

Originally posted by mapmaker

So what's with these battery chargers that include weekly or daily "equalizations" of batteries on long term float... Does it make any sense to you?

--mapmaker

Yes it is just Bells and Whistles. You only EQ a battery when under specific conditions. It depends on what type of battery and how it is used. Batteries for float service are not compatible with regular cycle service. They are made for very high charge and discharge rates. Many are VRLA which never get a EQ charge or like those found in a UPS. RE applications are unique in that the batteries rarely ever get fully charged because there is not enough sun hours in a day to complete the cycle. I have said many times including others that Bulk = Absorb. Today manufactures are specifying higher voltages for RE applications on solar. Every battery is unique and one must have a hydrometer and knowledge of how to use it along with a genny. There is not a one size fits all answer. When you go off-grid you have a new part time job 7 days a week with no days off monitoring batteries and power usage.

**Shockah** · 04-16-2014, 03:46 PM

Originally posted by Sunking

Yes it is just Bells and Whistles. You only EQ a battery when under specific conditions. It depends on what type of battery and how it is used. Batteries for float service are not compatible with regular cycle service. They are made for very high charge and discharge rates. Many are VRLA which never get a EQ charge or like those found in a UPS. RE applications are unique in that the batteries rarely ever get fully charged because there is not enough sun hours in a day to complete the cycle. I have said many times including others that Bulk = Absorb. Today manufactures are specifying higher voltages for RE applications on solar. Every battery is unique and one must have a hydrometer and knowledge of how to use it along with a genny. There is not a one size fits all answer. When you go off-grid you have a new part time job 7 days a week with no days off monitoring batteries and power usage.

Sunking, do you sometimes feel like Biff?

I'm here for another knock on the head...

Isn't that a hidden beauty of AGM,,, no internal way to monitor them,,, kind of relieves you of the part time job?
Design the off-grid system mathematically correct, using top rated components, and (hope to) get 3-5 years of trouble free service.
Cross the bridge of failed components as they come?

Monitoring power usage will become discipline as 2nd nature kicks in.

**Sunking** · 04-16-2014, 04:51 PM

Originally posted by Shockah

Isn't that a hidden beauty of AGM,,, no internal way to monitor them,,, kind of relieves you of the part time job?

AGM certainly has it benefits, but like anything else has trade-offs starting with expense and shorter cycle life.

**electrodacus** · 04-17-2014, 01:32 AM

So you need a generator to properly maintain Lead Acid in an offgrid situation?
Another point for LiFePO4

**Sundetective** · 04-17-2014, 02:40 AM

Perhaps you can have it both ways someday using a smaller LiFePO4 bank as a Slave bank to service
a poor, but much larger Lead Acid Battery Bank.

That way as far as the LA Bank knows the charging just continues to finish at sundown.

What the Sun couldn't finish your modern marvels do finish.
Yes the LiFePO4 bank charged quickly, efficiently and then
kind of liked hanging around partially charged to boot.

This after being of service to the temperamental and needy lead acid.
Like hand and glove.

Today it may not make sense unless money was not the biggest consideration.
If fuel was $15 or $20 per gallon (for whatever reason someday) the concept may begin to look real good.

I've been waiting on Panasonic to make it happen since they got some people excited in 2009.

'Panasonic's new home battery could store a week's-worth of electricity'

Just a moment...

http://venturebeat.com/2009/12/24/panasonics-new-home-battery-could-store-a-weeks-worth-of-electricity/

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http://evworld.com/news.cfm?newsid=22465

'Panasonic Begins Mass Production of Energy Storage Solutions for the European Market'

Energy Storage for Homes from Panasonic in Europe (Coming Soon)

http://cleantechnica.com/2012/06/06/energy-storage-for-homes-panasonic-europ/

Panasonic is about to start mass production of energy storage systems for the European market

I'm still looking for it.

Bill Blake

Originally posted by electrodacus

So you need a generator to properly maintain Lead Acid in an offgrid situation?
Another point for LiFePO4