Dry Charge Negative Plates

Oil Processed Negative Plates

Dry charged batteries, from the time they are completed with vent caps or closures in place until they are made wet, gradually lose their charge while in the dry condition. The negative plates, which are at this time mostly pure sponge lead (PbO), slowly combine with oxygen in the surrounding air, thereby become lead oxide (PbO). It has been found if an oxidation inhibitor is used, one that does not otherwise interfere with the wet battery operation, this slow oxidation can be reduced, thereby increasing the average shelf life of the dry charged battery before it is activated. This increased shelf life may be as much as two or three times longer than an untreated battery. Of the several methods to accomplish this, an effective one is by the use of oil in the negative paste intended for dry charged batteries. The amount of oil required is approximately 1 pint (500 cubic centimeters) for every 1000 pounds (450 kilograms) of dry oxide. The oil should be a standard non-additive motor oil, 30W grade. The oil can be added during the past mixing operation after the acid has been added. As far as is known, there are no adverse effects through the use of oil in the negative paste.

A performance check test of production dry charged batteries may be made by selecting a sample battery and adjusting its temperature to 80° degrees F. +/- 5° degrees (27° degrees C. +/- 3° degrees) following the schedule given below:

Fill the battery with acid of 1.250 specific gravity +/- .005 in a temperate climate at 80° degrees F. +/- 5° degrees (27° degrees C. +/- 3° degrees). In a tropical climate, fill it with acid of 1.210 specific gravity +/- .003 at 80° degrees F. +/- 5° degrees (27° degrees C. +/- 3° degrees). Record specific gravity and temperature.
Record specific gravity and temperature again after 20 minutes standing. Dry charge the battery and note the specific gravity decrease, corrected to 80° degrees F. (27° degrees C.). This should not be more than .015 specific gravity.
Dry charged temperature increase should not be more than 8-12° degrees F. (5-7° degrees C.)

The above test battery may then be tested according to “filled discharge” requirements for initial electrical characteristics.

Oxygen Analysis

When analyzing the SmartDry™ Dry Charge for oxygen, we recommend that an Orsat Analyzer or a Testo Analyzer be utilized. It is also suggested that the gases be monitored at five minutes into the start of a given cycle. This allows the atmosphere to be balanced out, and will in all probability give you the best reading. The Orsat not only gives you an oxygen reading, but it also gives you a carbon dioxide as well as a carbon monoxide reading. With these other two readings, it is possible to determine if the gas mixture is rich or lean. In an analysis where carbon monoxide is present, this says that the gas mixture is rich. UNDER NO CIRCUMSTANCES SHOULD THE ADJUSTMENT SCREW BE OPENED (COUNTER CLOCKWISE) BUT ONLY CLOSED (CLOCKWISE). If oxygen is present with carbon monoxide, it is a definite indication that the seals around the loading door are defective, which is causing contamination from the outside air. Erratic readings are due to a faulty zero governor.

Orsat Analyzer

The Orsat Analyzer is a laboratory instrument, and should be restricted to laboratory personnel. However, the industry has several other ways to monitor oxygen, such as the Fyrite Instrument, which determines the amount of oxygen by the rise of the liquid it absorbs. This system is simple to use and can be utilized by the machine operating personnel. However, there are several precautions that must be taken to give viable readings:

1. The pumping bulb must be removed and the hoses connected directly to the loading door of the Dry Charge Machine, where the pressure of the machine is adequate to obtain a gas sample. Count to 20.

2. The problem with the pumping bulb is that it needs 2 one-way reed valves which tend to become blocked and, as a result, no gas sample can be obtained. Because the hose is under no ambient air can get into the instrument once the hose is connected. In the standard Fyrite Instrument, the hose is not long enough. It is suggested that additional hose be used and coiled into a pail of water in order to condense the moisture of the gases so that they do not get into the Fyrite Instrument and how up as an oxygen reading.

3. The procedure then is to zero the liquid level by depressing the entrance valve and zeroing the scale. The instrument should then be shaken several times, and the small quantity of air that enters into the instrument as it is being equalized will now cause the liquid level to rise a small amount as it absorbs the oxygen. It is essential to zero it again, and this must be done several times until no further rises of the liquid level are obtained. Then the hose which is attached to the loading door is depressed on the entrance valve of the Fyrite Instrument, allowing the gases to flow in. Upon the count of 20, the hose is removed, and the Fyrite Instrument is shaken several times and the oxygen reading is obtained. Good laboratory practice would be to take three readings in order to insure that the proper result has been obtained.

Testo

This unit monitors both the oxygen as well as carbon monoxide. It does not monitor CO2 like the Orsat, which can assist in reaching stoichometric ratio, where CO2 is at a peak.

Testo

This unit monitors both the oxygen as well as carbon monoxide. It does not monitor CO2 like the Orsat, which can assist in reaching stoichometric ratio, where CO2 is at a peak.

State-of-the-art battery manufacturing equipment can be purchased from MAC Engineering & Equipment and members of the Energy Storage Equipment Manufacturing Alliance