Do floating batteries get stratified?

[Sunking]

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

Generator required regardless of battery type.

[Sundetective]

I guess you did not see my video comparing Lead Acid with LiFePO4

Lead Acid is already much more expensive over the life of the battery than LiFePO4.
The gasoline is already hugely expensive and considering the efficiency of small generators.
It will take about 1liter of fuel to produce 1kWh and that is around 1.2$ here in Canada so 1.2$/kWh is extremely expensive not even considering here the cost amortisation of that generator.
Where solar PV can produce 1kWh at a cost of around 3cent/kWh with under 1$/Watt and 25 years amortisation.
From my study real cost of energy storing for LiFePO4 is around 15 to 25 cent/kWh and Lead Acid at best 50 to 80cent/kWh in solar offgrid applications.

Large companies do not care about offgrid (this such a small market that it makes no sense to make any investment).
But most sell already LiFePO4 complete storage systems for grid tied applications where cost /kWh is higher usually in Europe.
Sony, Bosh and SMA are just a few that have this grid tied LiFePO4 battery systems.

Electro,

Actually I read and listened to thee fairly carefully.

I Likes your style however I don't think any numbers add up yet.

Let's just say a person decided on dual battery banks.

Say 820 Amp hours Each at 48 Volts for each bank.

Something like the Rolls 5000 Series Lead Acid job-ies.

Going with the 3 Cell, 6 Volt units it's

$15,984 for both Battery Banks

Delivered to my door (East of da Mississippi) at $999 each.

Simple wiring and routine charge controllers on top of that cost.

Now it's your turn.

How much $US for 1640 Amp Hours (or so) at 48 (or so) Volts

with all the Wire Harness and Labor Costs plus the BMS systems

doing it your way ??

Rap on

Bill Blake

[PNjunction]

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

Sunking's point is that everything has a tradeoff. Lifepo4 (I am a big fan) also has a huge upfront cost, and also the need for a bms. I suppose the serious off-gridd'er with lifepo4 would do well to have a redundant bms system just sitting around. More costs.

Lifepo4 is not a drop-in solution. Neither is AGM. Nor flooded. Salesman for products and services will disagree and do their best trying to make any one of these three a one-size-fits-all solution. We all know better.

[electrodacus]

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.

Bill Blake

I guess you did not see my video comparing Lead Acid with LiFePO4

Lead Acid is already much more expensive over the life of the battery than LiFePO4.
The gasoline is already hugely expensive and considering the efficiency of small generators.
It will take about 1liter of fuel to produce 1kWh and that is around 1.2$ here in Canada so 1.2$/kWh is extremely expensive not even considering here the cost amortisation of that generator.
Where solar PV can produce 1kWh at a cost of around 3cent/kWh with under 1$/Watt and 25 years amortisation.
From my study real cost of energy storing for LiFePO4 is around 15 to 25 cent/kWh and Lead Acid at best 50 to 80cent/kWh in solar offgrid applications.

Large companies do not care about offgrid (this such a small market that it makes no sense to make any investment).
But most sell already LiFePO4 complete storage systems for grid tied applications where cost /kWh is higher usually in Europe.
Sony, Bosh and SMA are just a few that have this grid tied LiFePO4 battery systems.

[Sundetective]

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'

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

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

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

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

I'm still looking for it.

Bill Blake

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

[electrodacus]

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

[Sunking]

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.

[Shockah]

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]

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.

[mapmaker]

They typically do not get stratified.

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]

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]

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]

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.

[inetdog]

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.)

[russ]

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