As you are planning your migration to battery-powered home and business a quick review of the advantages of Lithium-based batteries over Lead-Acid is useful to have at your fingertips.
Lead -Acid batteries have been around a long time. They were invented in 1859 and are well known as the batteries in our petrol or diesel cars. They use lead plates surrounded by Sulphuric acid which is the electrolyte. They have also been used in backup power roles for off-grid enthusiasts, for remote high availability installations like cell phone towers and to meet certain industrial UPS requirements. They are however being replaced by Lithium batteries for a number of good reasons. When used every day they can be expected to last for a much shorter time than Lithium-ion batteries.
Lead-acid batteries come in a few different formats and different terms are used to refer to them in off-grid conversations, sales brochures and spec sheets. We’ll cover the different types of Lead-acid batteries in this section and then get on to the difference between them and Revov Lithium Iron Phosphate (LiFePO4) batteries.
(Pic from itcindia.org)
These are the batteries most of us use in our petrol or diesel cars also known these days as ICE (internal combustion engine) vehicles as opposed to EV’s (electric vehicles). Flooded Lead-Acid batteries need monthly maintenance and cleaning and proper specially designed spaces to be installed in. These batteries are classified as “Dangerous Goods” and stocks of them can only be transported by specially licensed carriers.
These batteries have long been the cheapest and most widely available battery on the market, but that price advantage is disappearing. Lithium-Ion batteries are being produced in massive quantities to support the burgeoning electric vehicle and stationary storage market. According to Bloomberg over 10 years from 2010 prices have fallen by 90% and will continue to fall further. Flooded lead-acid batteries require proper regular maintenance to continue to deliver power and reach their advertised. My friends and I all learned with our first cars to check them every month and top them off with distilled water to ensure the longest possible lifespan. The same care is required if they are used to power your home or business.
Flooded Lead-acid batteries require you to mount them upright so that the electrolyte liquid inside does not leak out and spill on the floor or cabinet you keep them in. You will need to clean the terminals as well as they corrode over time and this reduces the efficiency of the battery.
Flooded lead-acid batteries release toxic hydrogen gas when charging. They need installed in a specially designed space which keeps this gas away from people and animals. Proper venting is will prevent this “outgassing” being trapped and creating a hazardous environment.
Sealed Lead-acid or VRLA (valve-regulated lead–acid) batteries.
There are two main types of valve-regulated lead-acid (VRLA) batteries. Those that are filled with a conductive jelly mixture of Sulphuric Acid and Silica (called Gel VRLA) and those that are filled with Glass mat (like fibre glass) that is soaked in the Acid (called AGM VRLA).
(Pic of Panasonic VRLA range at indiamart.com)
Gel VRLA Batteries
- In Gel VRLA batteries the electrolyte has been turned into a jelly. A very fine powder of Silica fume is mixed with the Sulfuric acid turning it into a gel instead of a liquid. This creates lead-acid batteries that are maintenance-free and cannot spill. GEL batteries don’t have to be kept upright.
- GEL VRLA batteries handle very hot or very cold temperatures and vibration better than the flooded type. They are better at dealing with overcharging but can be irreparably damaged by the wrong charging procedure. They require specific charging practices and need to be charged with a GEL specific battery charger. GEL VRLA batteries are generally much more expensive than the AGM and Flooded lead-acid types.
Absorbed Glass Mat (AGM) VRLA Batteries
- The battery is filled with a fine, highly porous, micro-fibre glass material that absorbs the electrolyte. This lowers internal resistance and increases overall battery efficiency, boosting capacity. This also allows then to be smaller and recharged quicker than the flooded type. They also do not have to be mounted upright.
Deep Cycle Lead-Acid Batteries
- In the Lead-Acid world, a Depth of Discharge (DOD) of 50-60% is considered deep. Batteries designed to be discharged to 50% of their nominal capacity (the capacity on the label) and then re-charged are called Deep Cycle batteries.
- These batteries a battery usually supply lower max current, than batteries that do not support as deep a DOD and are used in applications that require the battery to provide constant current for long periods of time.
- Generally, when buying lead-acid deep cycle batteries it is recommended that you buy a pack with a nominal capacity approximately three times the size of your estimated daily use. You will need to ensure that you set aside time to re-charge your battery pack back up to full charge every few months to maintain their levels true capacity. Failure to do so will reduce the batteries life and over time it will provide lower and lower capacity. Deep Cycle Lead-acid Batteries are usually categorised by their amp hour rating (AHr). Amp Hour is a measure of the batteries capacity.
- Deep Cycle batteries are available in both AGM or GEL variety
Lead Acid batteries conclusion:
These batteries are widely used in petrol and diesel motorcars, automatic gates and alarm systems and in the third world to provide power for homes. They have a limited lifespan and their performance degrades significantly over time. They are severely damaged by draining them too deeply or re-charging them incorrectly. Charging them wastes a lot of electricity because of their internal resistance.