Deep Cycle Batteries – Storing Power For Your Home PV System




A deep cycle battery is a special type of battery used widely in industries, hospitals, recreation facilities and residences. One of the major applications of deep cycle batteries is their use in residential Photovoltaic (PV) solar power systems.

It is quite a distinctive type of battery compared to a ‘shallow cycle’ starter battery for a car. Deep cycle batteries are sturdy, provides steady, high-quality power for much longer duration than the normal automotive starter batteries.

Many people having a PV solar power system at home are able to get power supply at nights or during cloudy days due to batteries or stand-by electric connection from the local power grid. Solar panels installed on the roof or erected on a pole or on the ground absorb heat and light from the sun and convert them into electric power.

If someone wants to have a PV system that does not depend on the local power grid or if that person is situated in a place where there is no local power grid, then it is necessary to store in batteries the surplus solar energy generated during the days of bright sunshine.

Although batteries may appear costly at the outset, the savings achieved by not linking up to the local utility grid will compensate for the heavy expenditure on batteries. Those having a solar power system at home and connected to the power grid should have an automatic cut-off mechanism from the grid a precautionary measure, whenever there is a power disruption.

There may be a situation when a Photovoltaic power system generates electricity, but it does not pass through the power cables and instead it accidentally gets diverted into a line that the electrician considers as inactive. When the solar system is equipped with a set of batteries, the power generated is transmitted to these batteries or inverter to convert the direct current (DC) into alternate current (AC).

A few solar panels are equipped with an in-built inverter that reduces the need for the wiring to a large extent and also eliminates the need for a large central inverter. Apart from inverter, it is necessary to have a ‘charge controller’ in the power system. This ensures that the batteries have a very long life-span, provided they are not damaged due to overcharging or get completely drained out.

The function of a controller is that once the batteries are fully charged, it stops any further flow of current into them. When the batteries are discharged to some extent, the charge controllers will not permit any further drain out till the batteries are recharged. It is necessary to compute ‘amp-hour’ parameter in order to assess how many batteries are required.

The storage capacity is generally expressed in terms of amp-hours. Assuming that the solar power system at the house has a 24-volt battery and normal 120 volt AC and the power load is 3 amps with a working cycle of 4 hours every day, then it works out to 12 amp-hours load. However, with a 120 volt system, there will be requirement of 5 batteries of 24 volts.

If this figure is multiplied by 12 amp-hours, it works out 60 amp-hours. This computation indicates how much current would be discharged from the batteries. While estimating the storage capacity in terms of amp-hours, it is better to add another 20% for banking power for a long duration to cover possible cloudy situations.

The normal car battery generates sudden surge of huge amount of electric current to crank the engine and start the car and after that it gets recharged while driving. On the other hand, deep cycle batteries, releases little amounts of electricity over a long duration such as at night and they are recharged in the day.

Most of the deep cycle batteries are either lead-acid batteries or nickel- cadmium (Ni-Cad) batteries. Although Ni-cad batteries are more expensive, they are durable and can release more current without getting damaged. A deep cycle lead-acid battery gets damaged if it is discharged completely.

On the other hand, solar power installations at home are so designed that that the deep cycle batteries in the system do not get discharged more than 40 to 50%. On top of this, sealed deep cycle batteries do not require either maintenance, watering or equalization charge. However, they are required to be recharged after every cycle.

Sealed deep cycle batteries are costlier than unsealed lead-acid batteries. With accelerated developments in battery technology, by the time one changes batteries a few times, he will be in a position to purchase much superior, more secure and durable batteries.



For instance, Ceramatec, a Utah- based company is producing a prototype of ‘deep-storage’ battery as big as a dormitory refrigerator that runs at room temperature, with power generation for the home costing around $0.025 per kilowatt hour.

The University of Maryland is undertaking research on batteries based on nano-technology and researchers at Harvard University are trying to develop ‘bacteria-powered’ eco-friendly batteries. The development of new technologies for batteries is an area of intense research and though deep cycle batteries are costly at present.

The chances of purchasing more efficient, long lasting and much cheaper batteries soon are bright with likely breakthrough in research efforts during the life-span of the existing PV array systems.

Calculation To Determine The Number Of Batteries For Solar System




If you have or are planning to have a solar powered electrical system at home, wouldn’t you want to know how big you have to build it to meet your entire household electricity requirement? To do this, you will need to consider the storage capacity required for maximum discharge rate, the maximum charge rate and the minimum temperature the battery bank will store it.

The capacity rate is directly related to the size of the battery. You will to have to remember that the temperature is critical factor where the batteries are stored as this is the main reason that the batteries performance gets affected.

The performance of the battery will be only 75% capacity at 40 degrees and at zero degree it will be only 50% capacity. The battery which does not get affected is the one known as Concorde PVX. This battery has been designed in a manner to withstand the temperature differences.

If your batteries are stored outdoor, you must use sealed gel type battery. You must keep the place well insulated even if the batteries are temperature resistant.

To determine the number of battery needed you’re your home Photovoltaic (PV) system, first you must calculate the total consumption of wattage hours in your home or office. This can be done easily by looking at the wattage rating of the electrical appliances of your home.

You then multiply it by the numbers of hours of each unit used per day, if there is no wattage rating available use the amps rating and multiply it by 120 volts and you will get the watts.

Here is a word of caution, if you are using an appliance with large wattage consumption, it will drain the battery reserve very fast. The best thing is those appliances which have wattage of 1500 watts or more should not be included.

Once you done that, add all the appliances wattage and you must do it separately for each day, you must multiply it by three, so that in case you use these appliances for three days you will come to know the size which would suffice your power needs.



To find the capacity of the battery, multiply daily watt hours by two, meaning you are actually using 50% of the battery capacity. The size of the battery bank in hours can be determined by dividing the total watt hours by size of the battery system you are using, it could be 12, 24, 48 volts.

If you have a 25,200 watt hours requirement, 25,200 / 12 volts = 2100 mps hours then divide by whatever is the battery amp hour rating and you can calculate how many battery unit you actually require for the system. You may require 12 volt system, for the consumption of 25,200 watt hours a total of 20 batteries.

The number will go on changing with the size of the batteries you use in your system. You must hook the batteries properly by making sure positive is connected to positive and negative to negative. This will increase the efficiency of your batteries. You can also wire your batteries in series to enhance the battery ampere capacity.

Getting Your Home Energy Efficient By Fixing These Areas




One of the best ways to reduce energy cost is by enhancing the energy efficiency of various electrical equipment existing in a household. Basically in every home, the heating and cooling system consumes a lot of energy. Hence we should pay special attention in installing qualitative electrical equipment that are generally energy efficient.

An incandescent light bulb consumes more energy that can be replaced with CFL lamp which is an energy saver. Above all, the best way to reduce the electricity bill is by sealing the air leaks in a home.

People generally incur a heavy expenditure for operating and maintaining the heating and cooling systems in their homes and hence the right step is to ensure that the heated or cooled air is blocked inside the house, to the possible extend. The first and foremost attention therefore needs to be in setting right the air leak problems, for which some ideal tips are indicated here.

Windows and Doors

A lot of money is spent by a person on maintaining the heating and cooling system of his home. Hence one should bear in mind that the cooled or heated air inside is costly and should not be let to escape through the gaps in faulty doors, windows or other cracks.

The investments on replacement of old and outdated doors and windows will never go to waste in the long run, but will help save a lot of electricity that may get lost otherwise. Some weather-strips are now available in the market for pasting and plugging the leakage points, which one can do at home without any professional help.

Similarly the inflow of heated air in summer and the chilly air in winter from outside can be blocked by curtains and drapes in a home.

Home Insulations

Every home should be fully insulated from basement to the walls, failing which, a large quantity of energy may be lost. Otherwise to continue to maintain a comfortable atmosphere inside, you will have to adjust the thermostat frequently that may leave you with a hefty electric bill.

In these days, gas and electricity are fast becoming costly. Hence the insulation in a home comes under the “must have” category that helps resist the heat- flow.

A thicker insulation is used for a higher resistance capacity, which protects a home from outdoor elements. Most of the home owners are aware of the need for keeping the houses insulated, irrespective of the weather being winter or summer.

By maintaining a home with the right type of insulation, winter and summer becomes comfortable inside, without greater dependence on air conditioners and heaters.


Home Internal Air ducts

The heated or cooled air from a heating or air conditioner system (HVAC) passes to various rooms through the air ducts in a home. Unless the air duct is fault free, the result will be heavy energy bills caused by the leakage in the ducts. Such leakages may result in a loss up to 40% of the heated or cooled air of a home, with shocking energy bills.

The faulty air ducts may not always need replacements, but can be got repaired with the help of a trained professional, who rectifies them through a cleaning process. The money you spend on such repairs will be negligible, comparing to the loss of energy from faulty ducts. If the air ducts are kept cleaned, you can continue to maintain energy efficiency and enjoy a qualitative air flow in the interiors.