Charging lead-acid batteries

A typical 100-cm silicon cell produces a maximum current of just under 3 amps at a voltage of around 0.5 volts. Since many PV applications involve charging lead-acid batteries, which have a typical nominal voltage of 12 volts, the solar modules often consist of around 36 individual cells wired in series to ensure that the voltage is usually above 13 volts which is enough to charge a 12 volt battery even on overcast days. 

One of the main reasons for the high power capability of the lead-acid battery is the high conductivity of the active materials. Lead dioxide is a semiconductor with a conductivity of up to 10 (Q cm) at room temperature, while 35% sulfuric acid has a conductivity of 0.8 (Q cm) Lead, which is a metallic conductor, is used for both the current-collector and the negative active-material. Because of the high conductivities of these materials, a fully charged lead-acid battery has a resistance of only a few mQ. 

Influence of Sulfuric Acid Concentration on the Self-discharge Processes of the Positive Plates of Wet-charged Lead-acid Batteries... 

The above reaction, however, proceeds at a very low rate. This may be due to the low solubility of hydrogen in sulfuric acid solution, which decreases further with increase of the acid concentration in the solution [19]. Oxidation of hydrogen on the positive plates is part of the complex set of self-discharge reactions which take place on positive plates during storage of wet-charged lead—acid batteries. 

What are the hazards in charging lead-acid batteries What are some controls ... 

Figure 7.16 Coup de fouet at the beginning discharge of a fully charged lead acid battery.

Charging Lead-Acid Batteries According to the W Characteristic... 

For application of NiCd batteries and charging lead-acid batteries above float-charge voltage the following measures are necessary ... 

The basis for charging lead-acid batteries is the redox reaction of lead ... 

FIGURE 23.6 (a) Capacity retention during stand or storage at 25°C. (From Sa-batino. ) (b) Loss of specific gravity per day with temperature of a new, fully charged lead-acid battery with 6% antimonial lead grids. (From Ref. 10.)... 

To quote a particular example, the concentration of sulphuric acid in a fully charged lead-acid battery is approximately 29% by weight (relative density 1.21) whilst that in a fully discharged battery is 21% by weight (relative density 1.15). 

Suppose that a fully charged lead-acid battery contains 1.50 L of 5.00 M H2SO4. What will be the concentration of H2SO4 in the battery after 2.50 A of current is drawn from the battery for 6.0 h ... 

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