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Recombination or tall tubular Batteries

Recombination or tall tubular battery is the recent development in the lead acid batteries. These batteries are also called gel cell batteries due to their construction. Recombination batteries or jell cell batteries don’t use liquid electrolyte. But they use special kind of separators which holds electrolyte gel in them. This gel type material is a cream type acid electrolyte. These separators are places between the plates and they make good and low resistance contact with plate grids. They have a spiral construction like a capacitor.

Tall tubular battery

 The spiral design provides more plate area compared to the conventional straight plate type plates. Also the close plates design provides less resistance. Due to this design the output voltage and current have greater value than the conventional lead acid batteries. These higher voltages usually 0.6V provides more power in cold cranking and starting. In these kind of batteries the gas formation is virtually zero and battery can be charged faster than usual.

The recombination batteries have more safety features and advantages. Following are few:

1.       These batteries can more provide much more cold cranking current. The cold cranking current could reach up to 900 amperes.

2.       The combination or tall tubular batteries can withstand real deep cycling and they would not be damaged.

3.       Combination or tubular batteries life expectancy is more. They can last four time more than conventional lead acid batteries.

4.       Combination or tall tubular batteries could be installed in any direction as there is no liquid electrolyte in it so they don’t need any specific direction for installation.

5.       Combination or tall tubular batteries have no liquid electrolyte so they don’t spill even if the case of the battery is cracked.

6.       These batteries and their terminals are corrosion free.

These batteries has very low maintenance as there is no electrolyte or water loss in them.

Hybrid Batteries

Hybrid batteries are type of battery which combines the advantages of both maintenance free and low maintenance battery. Hybrid battery can withstand seven deep cycles without losing its charge retaining capability. The grid construction of hybrid battery is special and it contains somewhat 2.76% antimony as alloy in the positive plate and calcium as alloy in the negative plate. Such formulation of the battery plate allow it to withstand the deep cycle performance and also it provides better performance on cranking. The use of antimony in positive plate as alloy reduces grid growth due to which the plates shorting together and corrosion also. Another material lead calcium in positive plates producing less gasses than conventional batteries are producing.

Hybrid battery pack

There is another difference of these batteries manufacturing that their plates have lug which are located very close to the center of the grids. Another difference is the horizontal and vertical grid bars are arranged in radial shape. These two arrangements the center lug location and the radial grid bars design makes the plates less resistive and provides shorter path to the current produced by the battery. This makes the battery producing and delivering more current at faster rate.

In this kind of batteries glass separators are used which are coated with resin. Glass separators have low electrical resistance and high chemical contamination and less reaction with chemical. They have prolongs life and strength. Such a construction of the battery provides more battery life and much better cranking performance.

Some people confuse hybrid batteries with batteries used in hybrid vehicles. This point must be cleared that hybrid battery in this article don’t mean the battery that is used in hybrid vehicle instead this is a type of battery which is the improved form of sealed lead acid maintenance free battery and the low maintenance batteries.

Hybrid battery cell

Although hybrid vehicles do used such kind of batteries as their battery bank but that is not a must. Now a days an new kind of battery have been invented by two scientists which have a very prolonged life or about 20 years with very good charge capacity to weight ratio. These batteries have charge discharge cycling expectancy of 10,000. These two scientists have been awarded with Nobel Prize for their invention.

Maintenance-Free Batteries

Maintenance free battery is same like a regular lead acid battery. The chemistry of the battery is little bit change for sealed battery. The other difference is such kind of battery is sealed and there is no provision of addition of water in cells in sealed batteries. This kind of battery plates material is little different than the regular or conventional lead acid battery. This type battery plate grid contains calcium, strontium and cadmium to reduce gas formation during charging. In conventional lead acid batteries water electrolysis takes place and water molecules are broken down into Oxygen and Hydrogen molecules and the Hydrogen gas escape out from the battery vents. Whereas in the sealed lead acid battery the addition of the extra materials mentioned above reduces this gas formation during charging.

Sometimes additional support is provided to the plates which increases the conductivity of the plate to its connecting tab. The plates are wrapped on an envelope shape separator which covers the plate perfectly from all three sides. The separator is made of porous material and it gives path to the electrolyte but is seals the active materials effectively not to escape them from the battery plates. These batteries are sealed but small vent is provided on the top to the valve regulated chamber where water vapors are accumulated and regulated back to cells. This way water and gases cannot escape from the battery so there is no need to add additional water or distilled water periodically to maintain the electrolyte level like in conventional lead acid battery.

Maintenance free battery

Some maintenance free batteries have a built in hydrometer on the top of the battery case. That indicates the state of the charge of the battery. A hydrometer is an instrument which shows the specific gravity of the electrolyte in the battery. The specific gravity of the battery is directly proportional to the charge of the battery. The hydrometer on such batteries when they are charged more than 64% shows green indication. The black indication on the hydrometer shows partial charged battery less than 64% charges. Whereas a silver indication indicates that the battery electrolyte is completely used and become water and there is a need of battery replacement. This indication is an easy way for a driver to understand the battery condition and replacement interval.

Several battery manufacturers have changed the maintenance free batteries to another type low maintenance battery. For those batteries caps are removable for testing the electrolyte and to emulate the level of electrolyte.

There are a few advantages of sealed lead acid batteries:

1.       They have longer shelf life. Approximately 2 years.

2.       They have larger quantity of electrolyte in the battery compare to conventional batteries.

3.       These batteries are shipped with electrolyte in them and ready to use. There is no more need for bothering electrolyte refilling and charging when shipped.

4.       They have ability to provide more current even if the batteries are cold. They have higher cold cranking amperage.

5.       They have more resistance to overcharging. They withstand overcharging better than conventional batteries.

There are certain disadvantages also of the maintenance free batteries. These are:

1.       They have faster discharge rate on parasitic loads.

2.       They have low reserve capacity.

3.       They have a shorter life span. Their life is shorter than conventional lead acid batteries.

4.       They are not good on deep cycling.

These batteries are not suitable for high temperature exposure. At high temperature they become faulty due to grid growth.

How lead acid battery works

Lead batteries when they are shipped, they are dry. No electrolyte in them. Instead electrolyte is supplied in plastic containers separate with batteries. When battery is needed to be installed in the place where they are needed, electrolyte is filled in it. Most batteries are dry charged and they are ready to use when electrolyte is filled in. But a slow starting charge is always recommended. The electrolyte starts chemical reaction in the battery. The reaction is done between the positive plate lead peroxide and the negative spongy lead. The electrolyte works as ion carriers. It reacts with plates to produce electricity and also it carries ions produced.

The fully charged automotive battery has specific gravity 1.266 at 81 degree F or 28 degree Celsius. The plane or distilled water specific gravity is considered to be 1. So the battery electrolyte is 1.266 times heavier than water. When battery is used, the specific gravity for it reduces as the acid in the water reacts with plate material. This way specific gravity is a measure of battery charging state. Following detail shows how battery charge relates to the battery specific gravity.

Fully charged Battery: 1.266

75% charged Battery: 1.226

50% charged Battery: 1.191

25% charged Battery: 1.156

Discharged Battery: 1.121 and lower

Specific gravity figures could vary little with design and manufacturing parameters of battery. But one thing is common regardless of battery manufacturer and design, the battery electrolyte specific gravity reduces with battery discharging. Temperature also effects the specific gravity of electrolyte. When the temperature increased beyond the standard temp rapture 81 degree F, the specific gravity of electrolyte decreases and when the temperature reduces the stated limit, the specific gravity of the electrolyte increases. The electrolyte specific gravity is temperature sensitive and the reading drastically changed with the change in temperature. A general rule of thumb is to minus 0.004 to specific gravity reading at each 10 degree F increase beyond 81 degree F or 5.5 degree C above 28 degree Celsius and add below this temperature limit.

During the operation of a lead acid battery the battery is never discharged completely instead partially discharged and then charged again to compensate for the discharge. This cycle is repeated for the entire life of the battery. During this charging and discharging cycles the battery plates active materials reacts with the acid and slowly wears away from the cell plates. This sulfates the battery plates. Also the active materials are removed from the plate and accumulated in the bottom of the battery. These materials are conductive to electricity. Sometimes these accumulated materials shorting the positive and negative plates in battery cells. And also when the materials removed from the cell plates they become basic lead grid plates which are no longer able to produce electricity. In such a condition the battery must be replaced with a new one. The older battery should be sent to manufacturer for recycling. Some people try to repair these worn out batteries by putting different items like Epsom salt or Coca Cola. Such techniques don’t work and this is just waste of time and resource.