Lead Acid Battery Usage

The Inverters which are used , does not have equalizing charge facility.Just Charging at Constant Voltage does not take care of stratification. Any other thoughts?

Could you give further details about your battery problem, what you mean for"stratification of Electrolyte" ?

Is it sealed battery or flooded type ?

Is it car battery?

It is flooded type. With starting gravity of electrolyte at 1.250 , after 15 to 20 cycles of 80% depth of discharge, the gravity at the top is around 1.080 or lower and gravity at bottom of cell is high.This is stratification. With constant voltage charge of common Inverter say at 14.4/14.2 volts ( for 12V battery)the gravity does not come back to original state, and so capacity is lost. The charging is on constant volt only. Constant current is difficult to do , as battery does not discharge fully all the time.

Something that may be of interest to you.

http://www.windsun.com/Batteries/Battery_FAQ.htm

Other than once in a while you disconnect the batteries and boost charge them.
I'm surprised you say the inverter charging system doesn't have an equalise facility.

Constant voltage charging does the battery no favours.

Consistently discharging the battery to 80% of its rated capacity is going to significantly shorten its life...No matter what charge regimen you use.

The dischrage is not full always and depends on Power outages.

Anything more than 50% discharge will kill your batteries quickly as was pointed out. Sounds like a bad system design.

Hello,

Have you considered option of replacing Lead Acid Batteries with other type of better batteries available, like LiFePO4, large format Lithium Batteries.

LiFePO4, large format Lithium Batteries are safe and cost effective in long run.

Compared to Lead acid batteries, they have

1. Small Volume/ Lower weight
2. Built in electronics for cell charge equalizing / balancing, both while charging / discharging, data logging / monitoring, over charge / over current protection, temp compensation etc
   
3. Rated at 3 C discharge and 3 C Charge ( compare this lead acid battery with C / 10 discharge and c /10 charge)
   
4. Cycle life more that 2000 cycles at 100 % DOD (compare this with Lead acid having 180 cycles at 80% DOD)
   
5. Round trip Columbus efficiency more than 95% (Compare this with Lead Acid having less than 60%)
6. Lead is not environmentally friendly.
7. Totally maintenance free and do not need acid protective installation
   

The more advanced Lithium batteries with anode / cathode material with more advanced chemistry are tested for 20,000 cycle life and 60 C charge / 100 C discharge.

We are introducing large format batteries LiFePO4 batteries in India for Mobile and stationary applications.

If you are interested please contact ( sweetechnologies at gmail dot com )

Regards

Madhav Chowdhary

SWEE Technologies

Pune City (India)

The Li battery is quite expensive compared to Lead acid. So can not be considered here. Almost 12 million inverter batteries are sold in India in an year with flat plate accounting 75% of it. Tubular battery perform better ( although more expensive) as it can take over charge without significant drop in life. Flat plate overcharge can kill faster. Some bad areas in country, consumers using flat plate flooded battery experiences 4 to 6 hrs of power cut in summer. The batteries fail to provide the capacity after 2/3 months itself. While all cycles may not be 80% , but stratification is the failure mode. Is there any method to keep electrolyte in convection , other than bubbling by overcharge? It has to be cheap. As customers are not rich enough to go for any expensive system..

Could you please inform me what is "flat plate" mean ?

Hello,

The Lithium batteries are actually cheaper in long run than Lead Acid Batteries if one calculates the cost of ownership (kWhr / day) for the customer to have electrical energy storage solution.

The cost of the large format Lithium batteries also depends on quantity and the source.

In Inverter application to replace the 12 volts / 100 AH of Lead Acid battery you do not need 12.8 volts / 100 Ah Lithium battery, you will need only 12.8 volts / 50 Ah Lithium battery, to get same amount (in hrs) of back up.

The Round Trip Colubic Efficiency of Lithium battery is more than 95%, compare this with the less than 60% of the Lead Acid battery, that to when it is new.

In case of Inverter users, the price of electrical energy (that will be required to charge the battery) paid to the Electrical Utility is increasing day by day.

Consumer will be saving for every charge discharge cycle.

25 years back the total no of people who were using Molded luggage and conventional Plywood based suitcase / metal trunk.

A time came when consumer realized the utility of the molded luggage and they switched over to the costlier molded luggage.

There was time when consumer use to use kerosene based lamp / candle, when there was power failure / power cuts in India. Then he switched over to Emergency Lights and then to the Inverter

I first saw Inverters (Square Wave o/p, using 2N3055 Transistor and NE 555 based oscillator) being marketed in Delhi in 1987. Today we have IGBT / DSP based pure sine wave products.

The time of lead acid technology based batteries are over and future is in Lithium batteries.

In India the consumers purchasing power is increasing day by day.

Last but not the least, if you take it in to consideration the cost of Two Bed Room Flat in city like Pune, then offering the owner of the flat a Inverter solution based on LiFePO4 batteries, does not make much difference to the total cost of the living.

The Inverter buyer will eventually opt for Lithium based solution, looking at the performance of other buyers.

The transformation / shift from Lead Acid to Lithium will start with top end buyers having purchasing power and higher budget for capex.

Regards

Madhav Chowdhary

Dear Mr.Chowdhury, Thank you for your inputs. Since you have the experience in India ,which sales more inverter battery than all types of SLI battery, Li battery must take inroads anytime now. You can interact with me :chakraborty02@gmail.com

Could you please inform me about LiFePO4 operating temperature range,i know Lead Acid battery has a very wide range and can even work at -40 degree Centigrade ?

Hello,

Are you confidant about the low temp performance of Lead Acid bayyery, when you say

"i know Lead Acid battery has a very wide range and can even work at -40 degree Centigrade ?"

Please have look at

http://corrosion-doctors.org/Batteries/high-disch-temp.htm

LiFePO4 is far better than this above data

Regards

MRC

Thanks for Lead Acid battery temperature graph,but it is still workable at -30 oC with less efficiency, but what about the other battery at that low temperature ?

Hello,

Lithium batteries offer full capacity at low temp.

Please have look at document below.

Advantage with the Lithium technology is that you can virtually design battery to match any type of application by selecting different type of electrode materials and using nanotechnology for producing electrode materials Lithium batteries can offer unthinkable performance.

Regards

Madhav Chowdhary

============

A low temperature, high performance lithium sulfur dioxide battery for a personal locator beacon

Abstract

The authors describe an improved personal locator beacon (PLB) battery in which cell and battery design have been chosen to withstand high frequency vibrations as well as a number of other environmental conditions. A new technical specification for the PLB battery is described. The specification defines the performance and safety requirements for the battery and prescribes cell and battery level testing to evaluate performance over a wide range of temperatures and environmental conditions. The results of the performance tests are presented in detail

http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=145785

=================

Unfortunately, i 'm not subscriber with IEEE to see the Abstract you referred to , can you give small idea about the operating temperature range of the LiFePO4 battery , I'm quite sure it can't work below zero degree Centigrade.

Hello,

My request to you is that please subscribe IEEE and get all the information you need.

I can not pay from my pocket and provide information free of cost to you.

I have provided sufficient hint.

Lithium chemistry based battery technology is far versatile and one can design / manufacture cell / battery to match the requirement of any application, by using the suitable electrode material manufactured / synthesized using nano technology material design / manufacturing process.

The higher end Lithium battery technology for low temp, has application in defense / space applications and getting data is not that straight forward process.

Regards

Madhav Chowdhary

^{Li-ion batteries are designed for operating environments from 0ºC to 60ºC.}

Hello,

Please do search the net.

You will find the special Lithium based batteries specifically designed for sub-zero temp well bellow zero degree centigrade.

The present state of Lithium Technology is just the start.

The future Lithium batteries, built with electrode materials developed / formulated / manufactured using the nanotechnology will offer performance that will make all other batteries absolute.

Please look at what happened to the other type of batteries those were being used in the Mobile phones ten years back.

Regards

Madhav Chowdhary

It is cost prohibitive to periodically do an equalizing charge (no bubbles), so the Lead-Acid Battery's electrolyte will stratify ... this is your situation. Yes?

Sounds like a business opportunity to me. Equalizing service. Cost of replacing vs fee to maintain. You do the math on that.

------------------------------------------------

When technology is not an option ... labor can be.

If stratification is your main concern and sulfation is not, you could just give the battery(ies) a shake now and then. How well is the typical battery sealed ... I'm guessing that these batteries aren't even the deep cycle type. You could also use a turkey baster type device and withdrawn some electrolyte then replace it ... do it a few times and that should mix things up ... IE ... Lots of maitanence (labor). But hey, if that is your only option ... not difficult, just time consuming.

Sulfation is still going to be a problem ... try this link http://home.comcast.net/~ddenhardt201263/desulfator/desulf.htm

Sir, i can see that your post is not for discussing the guy's question but rather for advertising "in smart way"about your "Lead Acid Battery Desulfation Pulse Generator".

Sir, can i have copy of the schematic diagram of your generator with explanation about how it works ?

CREDIT

From Home Power Magazine

------------------------------

C2 in the original publication was a misprint of 0.022. It is corrected in this scheme at 0.0022.

------------------------------- OR

-------------------or

Connect ... leave on for 20 minutes ... test. If battery temp is over 50C wait till it drops to 40C to repeat. If battery gets over 55C stop process. (read about thermal runaway).

If you do not see good results after 5 attempts the battery is not going to improve in my experience. Large 12 volts sets have needed 10 'treatments' over 3 days before the leveling out.

As part of a maintanence program, I would connect for 20 minutes every 2 weeks of deep discharging ... once a month if you don't discharge past 60% very often.

To overcome the loss of capacity you should have a better charging circuit in Inverter.

And the other problem is of power outages which gives not sufficient time to charge the batteries. So you have certain options:

1.) Charger should have + power ratings than the power drawn on full load on Inverter in normal cases where power outage is rare say after 12 hours.

If the outage is more frequent during which the full chaging is not possible with the built-in charger then an additional external charger in parallel is needed; may also additional batteries.

I think you are also from a under developed country like me. I fully understand the problems.

While power is there but low voltage [Brown-outs] verse condition.

2. ) Keep only critical load on Inverter.

3.) Consider to de-sulpherizing or re-build if you cant afford new battery

Have a nice day

Try this link

http://redarc.com.au/home

Acid stratification is a common problem in "Calcium Technology" batteries that are everywhere these days. The calcuim is used to harden the lead in lieu of antimony. The reason for use is less self discharge so batteries can be shipped wet from China.

Good information about batteries is available from Venkat Srinivasan of LBNL - his blog is at http://thisweekinbatteries.blogspot.com/

Venkat knows his 'stuff' and is in a good position to see what is coming - he is working on it.