leochbattery

As we know, VRLA battery would have an infinite life - especially if it is not being "used" (cycled) and only remains on continuous charge being maintained for eventual use. However, this is not the case. The typical VRLA battery will eventually decline in capacity and fail due to grid corrosion and drying of the electrolyte as a result of continuous overcharge. Everything else being equal, this will occur as a result of the design of the battery including plate grid thickness, oxygen recombination cycle efficiency and the quantity of reserve electrolyte. Since the grid corrosion and electrolyte during are a direct function of the float current, it is important to control the float current to that required to maintain the cell fully charged while minimizing overcharge due to excess float current.

The effects of temperature on valve-regulated lead-acid (VRLA) battery performance are quantified for the following areas:

(1) The capacity-temperature relationship (dC/dT) for discharge rates of 0.17 to 8.0 hours and a temperature range of 30 to 140°F (-1 to 60°C); (2) empirical equations are derived to allow the calculation of dC/dT for most discharge rates;

(3) The external surface temperature which best tracks the cell internal temperature during discharge was found to be the container wall surface, parallel to the plates;

(4) Tests in which the -3 mV/°C coefficient is applied to prevent thermal runaway are shown to cause negative plate self-discharge at temperatures as low as 37°C (99°F);

(5) A container wall surface temperature was found to be within 2°C of the internal cell in lift: tests at 50°C (122°F);

(6) Experimental results indicated that cell failure due to negative plate self-discharge at 25°C may not be detected in elevated ambient or life test temperatures.

If you want to know more about VRLA battery, you can just visit Leoch International, which is an excellent manufacturer of lead acid battery. The company is a public company which has over 10 year’s history and it is very reliable and dependable. If you are interested in the company, you can search for more information in the internet. The office website is http://www.leoch.com.

I own a Honda motorcycle which had not been riding since one month but I been riding it for a week. Today on my way home from work I stopped to put gas at the nearby service station. I pumped the gas which took about 5 minutes and I turned the motorcycle back on. Shit! The crazy thing happened, it would not start. I tried about another four times and by the last I hear was a “click”. I felt like the engine wanted to start but there was not enough power. I judged it was an electrical problem and tightened the motorcycle battery connection wire. Then I tried to start it again but failed and the “click” was still as before. I then called my friend to come and bring with cables. Waited 30 minutes he came and I tried to restart the motorcycle to show him what it was happen. But this time the motorcycle started perfectly like there was absolutely nothing wrong with it. So embarrassed, so crazy! I drove it 20 minutes home and it ran fine. When I got home I shut it off. After dinner, I wanted to see if it would start or not. OMG, it couldn’t start. And my felt is the same as before. It wanted to start but the power was not enough. And then waited 30 minutes and went to start it again. It could start. In order to ride to work tomorrow, I ride it to service center. When I told the service personal the situation, he laughed and said most motorcycles were the same as yours and asked how long was the motorcycle battery lasted. “This battery was about a year old”. Finally, he changed the battery for the motorcycle. Until today the motorcycle didn’t happen above situation.

 

I can’t imagine that there are no batteries in our life. Can mobile phones receive a call? May a flashlight illuminate your way? Will your watch turn? Could you still listen to your MP3 while riding a bike? Does your car get started? Of course, you and yours can’t!

Electric vehicles will become a joke without lead acid battery, which is a kind of batteries. It is well known that electric vehicles are completely powered by the battery. If the battery has any problem, you may need to push your vehicles when it stopped. Maybe this will happen to you one day if you don’t maintain your battery.

You may speak of Li-ion batteries that you never see they needs maintenance. So did I. A watch requires a Li-ion button cell battery which is small. And it is often thrown out when it is dead. It will be replaced by a new one frequently for it is cheap. However, if it were your car battery, I think you won’t throw it away. Car battery is lead acid battery which has long life. Of course, it is different from Li-ion battery. The lead acid battery stores energy through a reversible chemical reaction. The reaction of lead and lead oxide with the sulfuric acid electrolyte produces a voltage. Batteries operate in constant cycles of discharging and charging. During discharge, the lead dioxide (positive plate) and lead (negative plate) react with the electrolyte of sulfuric acid to create lead sulfate, water and energy. During charging, the cycle is reversed: the lead sulfate and water are electro-chemically converted to lead, lead oxide and sulfuric acid by an external electrical charging source.

Lead acid batteries are environmentally sound in that they are recycled at an incredibly high rate. Today, 98% of them are recycled. With low maintenance requirements, the battery includes no memory and no electrolyte to fill on the sealed version.

Has been used more than 150 years, lead acid battery is reliable, mature secondary batteries, globally manufactured and therefore a widely understood technology. In China, Leoch is the largest export merchant of lead acid batteries, supporting OEM production, which has high quality R&D team and unparalleled quality manufacturing standards.

With high technology, the lead acid battery will be improved to overcome its compact size and environmentally unfriendly, and then compete in modern times. In the future, lead acid batteries are still the major batteries in many applications. With constant improvement, they will have better future all over the world. No one can replace it regardless of past, present and future.

Source: http://d.hatena.ne.jp/leochbattery

What is a VRLA battery? It is valve regulated lead acid battery, which uses a dilute sulfuric acid electrolyte which is immobilized so as to eliminate the hazards of spills and leakage and which facilitates an oxygen recombination cycle. The oxygen recombination cycle eliminates the need to add water throughout the battery’s life and improves its safety of operation.

The name “valve regulated” does not wholly describe the technology, these are really "recombinant" batteries, which means that the oxygen evolved at the positive plates will largely recombine with the hydrogen ready to evolve on the negative plates, creating water and so preventing water loss. The valve is a safety feature in case the rate of hydrogen evolution becomes dangerously high. In flooded cells, the gases escape before they have a chance to recombine, so water must be periodically added.

VRLA battery is designed for less maintenance lead acid battery which doesn’t required addition of water to the cells. And it are commonly further classified as absorbed glass mat (AGM) battery and GEL battery (gel cell). While the AGM and gel battery designs share many of the same components, such as containers, pressure relief valves and plates, they have different separator systems and electrolyte immobilization systems which result in significantly different high rate performance, heat dissipation and cycle life characteristics.

The AGM VRLA battery typically contains more electrolytes and is of slightly higher specific gravity than the comparable gelled electrolyte battery. Consequently it will provide slightly more long duration capacity within the same container volume. Also, the AGM VRLA battery has a slightly more efficient oxygen recombination cycle and a low resistance than the gelled electrolyte VRLA battery. As a result it will draw slightly more float current resulting in greater internal heat generation. Note how the float current is affected by temperature, increasing with increasing temperature. To prevent premature failure and possibly catastrophic thermal runaway, it is important to operate the VRLA battery in an environment in which it can dissipate heat at a rate faster than it is internally generated.

A battery is in float service when it is continually connected to the power source and the load so as to provide instant uninterrupted power in the event of failure of the primary power source. The float service life characteristics at 77°F are essentially the same for the AGM and GEL VRLA batteries.

In cycle service the battery is deeply discharged as the primary power source for the application such as with wheelchairs, golf carts and photovoltaic systems. While the AGM and Type A gelled electrolyte batteries will provide good cycle service, the Type B gelled electrolyte battery is designed specifically to provide the longest service life in deep cycle applications.

No on design of VRLA battery is optimum for all the various types of applications. The type of electrolyte and its specific gravity and separator systems as well as the electrolyte immobilization technique utilized greatly determine the battery’s suitability to provide maximum power density, superior high rate performance, extended life at elevated temperatures and extended cycle life.

The attributes of higher density and equipment compatibility have the valve regulated lead acid battery (VRLA battery) emerging as the technology of choice for standby applications in telecommunications. There is now a general trend away from the concentration of power plant in the controlled environments of central office towards a much great geographical decentralization of power and back-up batteries. However, decentralized power plant is often installed in less controlled operating environments and the thermal behavior of VRLA batteries used for backup power purposes under varied ambient conditions is of concern. Telstra operates battery-backed power plant in varied climatic conditions throughout Australia. It is therefore important to understand the service-life implications of VRLA batteries in uncontrolled environments and the subsequent risks to Telstra network.

The thermal behavior of VRLA batteries has received considerable attention in the context of both service-life and thermal runaway. Thermal runaway of VRLA batteries describes the condition where the rate of heat generation within the battery exceeds its heat dissipation capacity, and is often linked to charging abuse or high ambient operating temperatures. For batteries on float service, thermal runaway is characterized by a cooperative increase in both charging (float) current and internal battery temperature over time which may lead to catastrophic and destructive failure. Evolution of hydrogen sulfide ahs also been reported during thermal runaway events. System conditions believed to be conducive to thermal runaway have been described and many thermal management strategies have been advocated. The physical geometry and internal design of the VRLA battery and the design of the battery installations contribute to the susceptibility of thermal runaway. Current-limited float charging or temperature compensation of the float voltage is often proposed as important in alleviating the risk of thermal runaway. However, either technique may not be easily applied in existing standby installations.

Thermal runaway may be difficult to predict and the causative agents often difficult to determine. It is therefore of interest to understand the conditions within an VRLA cell or battery which might exist prior to an thermal runaway episode. However, information about the thermal conditions and temperature distributions inside monoblock designs during both normal and abnormal operating conditions is limited. High resolution measurement of the internal temperature gradients and float parameters has been used to characterize battery system conditions prior to thermal runaway.

If you want to know more about VRLA battery, you can just visit Leoch International, which is an excellent manufacturer of lead acid battery. The company is a public company which has over 10 year’s history and it is very reliable and dependable. If you are interested in the company, you can search for more information in the internet. The office website is http://www.leoch.com.

Lead acid battery adopts a reversible chemical reaction to store energy. And it uses a combination of lead plates or grids and an electrolyte consisting of a diluted sulphuric acid to convert electrical energy into potential chemical energy and back again. The lead sulfate crystals is a very easy matter, when the battery electrolytic solution of sulfuric acid in the concentration of lead in the static idle time is too high or too long, they will “hold a” group, to form small crystals, and attract around these small crystals lead sulfate, as the inertia of the formation of large snowball as the crystallization of lead sulfate crystals after the charge not only can not be reduced to lead oxide, but also precipitated the board attached to the electrode, resulting in a decline in working area of electrodes, this phenomenon is called sulfide, which is often said that the aging. At this time the battery capacity will gradually decrease until unusable.

People aren’t sure about which battery to choose for their conversion of a conventional automobile into a pure electric vehicle (EV). They can either use a deep cycle lead-acid battery or a lithium battery. There are advantages and disadvantages for both these batteries. Some people are of the opinion that only a lithium battery can make an electric car work efficiently.

1. Lead batteries are cheaper compared to lithium batteries. An electric car which runs on 120V will require 20 batteries of 6V each. Each battery will cost something between $100-150. So the total expenditure on batteries will be just $2,000-3,000.

2. Lead batteries are easily available because they can be bought from any local battery dealer. It means that you don’t have to spend extra money on its transportation.

3. Lead batteries are powerful and when you use them on your electric car, you can speed along the freeway, and even join a race. There is nothing to prove that lead batteries are less powerful than lithium batteries. The only advantage that a lithium battery has over a lead battery is its being lightweight.

4. Lead batteries are safe to use. Whatever use you put lead batteries into, they are safer than any other batteries. Of course there are instances when the lead batteries leaked sulfuric acid when there was a car crash or produced flammable gases while they were being charged. These are very rare incidents and compared to other batteries, lead batteries are safe.

Lithium batteries are more dangerous than lead batteries. They can burst into flames if there is a short circuit or if they are over charged. So lithium batteries need special care. Now you can decide for yourself which battery is the most suitable one for an electric car.

From the above analysis, we can get one result that lead acid battery is better used in electric vehicles than lithium batteries. Besides, Seth Leitman, the author of Build Your Own Electric Vehicle book, on the other hand, is of the opinion that a lead acid battery is perfectly good for an electric car.