Rechargeable Batteries: Overcharging, Deep Discharging

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Rechargeable Batteries: Overcharging, Deep Discharging

If you go to their online store, you can see the Ah or Storage Capacity of a range of Exide Lead Acid Inverter batteries. With a terminal voltage of 12V,  you get Ah ratings of 180.00, 165.00, 150.00,  130.00, 100.00,  88.00, 80.00 and  65.00. To know which battery to pick, you must know your load current and duration. You are now on shifting sands because in Bangalore, the load shedding can be both scheduled and unscheduled. Let us assume that a typical power cut lasts for 1 hour. Let us say that you have good old 60 W tungsten bulb directly connected to your 12 V battery as the only load on it.

  • Your desired load current is 60W/12V = 5A.
  • Duration is 1 hour. So simplistically speaking, you are looking at an Ampere-Hour requirement of 5.

Let us say you are using a 12 V 65 Ah battery and it was fully charged before the power cut. Now you have ‘used up’ 5 Ah. The Depth of Discharge is now 5Ah/65Ah*100 = 7.69% . In a real situation with greater loads and battery losses etc., this number will be different. When the power is back, your battery will charge up again. If you leave the headlights of your car ON all night, the DoD of your car battery will be 100%. ie., it will be fully discharged. It is not a good idea either to overcharge your battery or to completely discharge it. Since a lead acid battery is just a chemical reaction, it is possible to pile up or remove too many electrons from the plates in the charging and discharging processes. In a fully discharged state there are two lead sulphate plates separated by dilute sulphuric acid. In a fully charged state, the negative plate is elemental lead and the positive plate is lead oxide. In contrast to the SLI (starting-lighting-ignition car batteries), the batteries used for Solar PV systems are deep discharge batteries. Each kind of battery has a maximum allowable DoD. Even if a manufacturer specifies an 80% tolerable DoD for a lead-acid battery, it will decrease battery life to discharge it regularly to this level. Typical design values allow a DoD only to 50%. So do not discharge a 12V 65 Ah battery on a 5A load for 13 hours. Stop at 6.5 hours. Or if you want to run the inverter battery all night, then draw a lower load or use a bigger battery. Eco Soch retails Super fans, which draw half the current load of regular fans. Using LED bulbs and Super Fans, has the added benefit of extending your battery life too. Environment Note:

  1. Exide’s list of manufacturing plant localities also shows Hosur, near Bangalore. Usually anything manufactured near your home, does less damage to the environment in terms of the transport costs to the environment. Of course, anyone who lives near an industrial area will also tell you how much the pollution affects their health and happiness.
  2. Exide has a Battery Recycling Policy and will give you a rebate on your used batteries. You have to return it to an authorised dealer, they collect used batteries at regular intervals from their dealers in closed trucks and have them recycled by smelters, authorised by the Ministry of Environment. Both the Lead and the Sulphuric Acid used in Batteries are not good for the health of Human and other Life Forms.

Featured Image: The featured image is from wikipedia:

By | 2018-01-17T18:20:58+00:00 August 7th, 2014|0 Comments

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