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When it's time to change the battery?

My Concorde RG-35AXC battery is due for a replacement after about 5 years. However, there doesn’t seem to be anything wrong with it, it cracks as a new one and I never had any issue starting so far.

Using a battery tester, I can see a 490 CCA (Cold Cranking Amps), while the battery is rated for 450 CCA.

Do I really need to change it only because is it’s due time, or should I wait for any signs of degradation? Of course I have some issues with inconsistent voltage/amperage indications in flight, that maybe can be credited to a bad battery, but I could as well buy a new voltage regulator, and alternator, and so on, that wouldn’t be too economical.

What do you think? Is there any golden rule on when should the battery be replaced, if the regulations don’t specifically force you to buy a new one?

LRIA, Romania

Do/ have a capacity test. Recently did mine, 6 years old, still at 90%+. 80% is limit I recall
Peter has written about how to do it on this forum if I remember correctly.

Last Edited by PeteD at 06 May 08:52
EGNS, Other

I don’t know the situation for batteries, so would be interested too in the outcome. I assume that there should be the possibility to have it tested e.g. each year and extend operation, just as with a prop, an engine and so on.

Germany

Unless it is mandated in your maintenance program, I don’t see why to change a good battery. As long as it works, fine. Most of the time, it will give you ample warning such as low voltage when switching on the master switch or so.

Obviously it can happen that they die on the spot. but that is rare

LSZH(work) LSZF (GA base), Switzerland

I wouldn’t change a good battery, on condition, and yes, 80% capacity is usually the criteria.

That said, during one long and very remote arctic trip, I had constant electrical nuisances. It started just fine every time, but sometimes radios did not work well (’didn’t matter much in the arctic anyway, few people to talk to). It was a fairly new battery, so I was not suspecting it first. It turned out that I had a fully shorted cell, and the battery was not putting out 12.5 volts – more like ten at best. The starter works fine on a strong ten volts, but other systems not so much. The alternator was working hard to keep a shorted cell up over 12 volts in flight. I completed the trip, but learned to pay more attention to basic battery voltage.

Home runway, in central Ontario, Canada, Canada

Some data is here.

I would just do a load test and all the time it passes, fly with it. My last Concorde RG24-15 battery made something like 8 years and still passed, but I don’t think it would have passed a year later, so changing it cost me only 1/9 of the cost of the battery

Gill wet ones usually die suddenly. Mine did.

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Shoreham EGKA, United Kingdom
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