SUN REAL Renewable Energy Systems

About Batteries - Part 3: Maintenance

Looking after your battery bank is a good idea. Not only will it help prolong its life and help you get the most out of your investment in it, it will also reduce the possibilities of having "problems". Problems of course, are those things which occur at the most inconvenient possible time, generally at night and usually in Winter.

Of all the components in a power system the one most likely to suffer neglect is the battery bank. It is also the one that can cause you the most difficulties. Without a functioning battery bank you have no power. Nothing. Let's start with where the batteries are. They should be in a dry position and not exposed to extremes of heat, cold or humidity. Batteries should never be placed directly on a concrete floor. Always put some reasonable sized timber between the batteries and the floor. If they are on wooden shelves or racks make sure they are strong enough to take the weight of the batteries. Sagging shelves are not safe, make the electrolyte level in the battery uneven and increase the risk of the plates being exposed to the air. You should be able to get to your batteries easily so you can carry out the sort of periodic maintenance described in this article.

Remember that the batteries must have adequate ventilation. Before doing any work on the battery bank make sure that all charging sources are turned off and there is no load applied (turn the inverter off and take out the battery fuses).

The most common problem is loose and corroded battery terminals resulting in intermittent power to the inverter, erratic voltmeter readings and eventually system failure.

A quick visual check for any sign of corrosion every week or so is not too hard. At the same time a gentle wiggle of the terminals can uncover a loose connection. You will more than likely have to remove the terminal shrouds (you do have terminal shrouds, don't you..) to do these things. Only remove one shroud at a time, check that terminal is tight and then replace the shroud. Refer to the previous article on battery safety.

A more thorough look every three months is a good idea. This time actually check the tightness of the terminal bolts with an appropriate spanner. If there is any sign of corrosion take the bolt out and clean the terminal thoroughly with a wire brush. Clean the terminal with a dry cloth, coat with petroleum jelly and do the bolt up again. Make sure that the entire battery is clean and dry.

The other part of the battery bank that requires a bit of attention from time to time is the electrolyte. Remember, this is acid so treat it with respect. When checking out the battery bank take a look at the electrolyte level. Does it need topping up? The level indicators should only show full immediately after a good charging session when the batteries have been gassing. The gassing leaves bubbles of hydrogen and oxygen in the electrolyte. If the battery is full before charging this extra gas can push the electrolyte level up even further causing it to overflow. This makes a big mess and adds to corrosion problems. So do not over fill. When adding water to the electrolyte (and you only ever add water) use only distilled or de-ionised water. Do not use rain water collected in a goats bladder under a full moon or anything else. Impurities in the electrolyte will drastically shorten the life of a battery. Distilled water is available from any supermarket and has the added advantage of being the only substance suitable for mixing with good Scotch.

Only perform maintenance on a battery bank if you feel confident to do so. Otherwise, contact SUN REAL.