Battery chargers
Charging ahead…
Headset review
Ian Fraser urges us not to take our batteries for granted and offers top tips for charging…
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eliable batteries are essential to the convenience and safety of our aircraft (see LA June 2021 article). While they work, we take them for granted but if they quit, they will do so at the most inappropriate moment, causing maximum inconvenience, sometimes completely wrecking plans and even becoming a safety hazard. Our aircraft often spend days (or even weeks) doing nothing, then fly for an hour or two and go back to doing nothing. In low winter temperatures, with a hard ‘electricity consuming’ start and with all accessories and gadgets on, those few short flights can be nowhere near long enough to recharge the battery, and the battery’s charge level just goes down and down. This is exactly the wrong treatment for a battery, and it is not surprising that many fail prematurely. While traditional battery chargers can provide a much-needed boost, they can also cause long-term damage and do nothing to help the longevity of the battery. An they must never be left connected after the battery is charged. Fortunately, however, technology has moved on and today specialist chargers can be permanently connected to look after batteries without long-term damage, and some even help prevent or warn of impending trouble before it becomes critical. In this article we are looking at the challenge of safeguarding the battery, and how technology has met it.
Battery health
The main threat to battery health is a problem called sulphation in which chemicals from the electrolyte contaminate the electrode plates, gradually isolating them from the electrochemical process. As a battery discharges, lead sulphate builds up on the plates and, as you re-charge, should be ‘reabsorbed’ back into the electrolyte. But the charging process is not 100% efficient and for each charge cycle a little bit of the sulphate is left on the electrode, and it gradually builds up. It is a natural process, part of the battery’s chemistry, and will eventually be the main cause of the failure of the battery. While sulphation happens as part of the normal process, its rate is governed by the state of the battery. In a well-charged and maintained battery, it 46 | LIGHT AVIATION | August 2021
Top Concorde battery, typical of those fitted to many Permit aircraft. Above A traditional taper current charger, avoid using if at all possible
happens very slowly, but if the battery is allowed to remain for any length of time in an (even partially) discharged state, it accelerates. A key to battery life and health is to maintain it at full charge – and doing so can double its useful life. But, if you are not using the battery, it is not going to go flat, is it? Yes, I’m afraid it is. Another natural feature of a lead / acid battery is a characteristic called ‘self-discharge’. Notwithstanding drain from
