It needs to be replaced every two years regardless of the expiration date. The installation date should be in the log book. If not then you can not demonstrate that it is a current battery and must replace it anyway, even if it is only a few days old.
FWIW, after a little over two years, my AKC-04 started failing the 3-month self-test. The beep code indicated HIGH VSWR OR HIGH CURRENT, not LOW BATTERY. I removed the battery and it failed the "Load Test". I replaced it and that fixed the problem....but at least they are good for 5 years...
FWIW, after a little over two years, my AKC-04 started failing the 3-month self-test. The beep code indicated HIGH VSWR OR HIGH CURRENT, not LOW BATTERY. I removed the battery and it failed the "Load Test". I replaced it and that fixed the problem.
The ACK-04 batteries cost more, but at least they are good for 5 years, not the two years you state...
But don't the FAR's require a 2 year replacement? If I am not mistaken the rule for certified ELT's also applies to experimental.
I suppose it's possible, but during my troubleshooting, I replaced it with another piece of coax and got the same failure. During that test I also bypassed the static suppressor and 90 degree BNC fitting. It still failed. The coax in question is a 24" length of RG-142. The factory admitted that a low battery could cause the VSWR failure mode. Don't ask me how the battery could have gotten low after two years with no activations other than the self-tests and annual G-switch test. I'm thinking that the "5 year life" may be on paper only.Could you have a bad co-ax causing the ELT to use more power than expected during the 3 month testing?