Know how to extend the life of a lead acid battery and what the limits are.
Adding chemicals to the electrolyte of flooded lead acid batteries can reduce the buildup of lead sulfate on the plates and improve the overall battery performance. This treatment has been in use since the 1950s (and perhaps longer) and provides a temporary performance boost for aging batteries. It’s a stopgap measure because in most cases the plates have already been worn out through shedding. Chemical additives cannot replace the active material, nor can cracked plates, corroded connectors or damaged separators be restored with an outside remedy.
Extending the service life of an aging battery can be useful as the additives are cheap, readily available and worth the experiment of a handyman. Suitable additives are magnesium sulfate (Epsom salt), caustic soda and EDTA. (EDTA is a crystalline acid used in industry.) These salts may reduce the internal resistance of a sulfated battery to give it a few months of extra life. Using Epsom salt, follow these easy steps to treat a car-sized starter battery:
Heat up about 250ml (8 fluid ounces or a cup) of distilled water to about 66°C (150°F), mix in as much Epson salt as the water can absorb (a few tablespoons) and stir until dissolved.
When pouring the warm solution into the battery, the electrolyte level will raise. Do not remove electrolyte and only add as much additive as the battery can take. The treatment is said to dissolve sulfate deposits (white crystals in the battery). Avoid using too much salt because a heavy concentration will also increase corrosion of the lead plates and internal connectors.
Be careful not to overfill. Do not place un-dissolved Epsom salt directly into the battery because the substance does not dissolve well. In place of Epsom salt, try adding a pinch of caustic soda. Charge or equalize the battery after service. The results are not instantaneous and it may take a month for the treatment to work. The outcome is not guaranteed.
Batteries have improved and additive treatments may have been more effective with older battery models in expanding battery life by a few months until a replacement is on hand or as part of experimentation. Modern batteries already include additives that reduce sulfation and corrosion. Industrial users seldom rely on additives to prolong battery life as these batteries become more maintenance prone.
Last updated 4/22/2015
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