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Old Mar 14, 2012, 11:21 PM
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United States, FL, Bradenton
Joined Jan 2012
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Low battery alarm question?

Do those cheap little Chinese Ebay $5. plug-in onboard low battery voltage alarms really work and can you hear them o.k.?
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Old Mar 14, 2012, 11:27 PM
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Ranandar's Avatar
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The ones with two buzzers work OK.
You can hear them on a fly-by.
Kind of depends on how good your ears are though.
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Old Mar 15, 2012, 12:01 AM
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Alameda, CA
Joined Dec 2006
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A waste of money in my opinion.

Find out how much time others are getting with the various batteries, and set your timer for somthing less than that. When you charge your battery, note how many mah you put back. If it was less than 80% of the rated mah for the battery, you know you can add a little flying time; if more than 80% you need to cut back.

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Old Mar 15, 2012, 12:51 AM
Crash or unscheduled landing?
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I have one and it works great. I was originally landing my plane after 10 minutes so as to be sure not to run out of power, but managed 20 with the alarm.
Initially, I kept flying low fly-bys to try and hear it, but when it went off I could hear it easily from quite a distance. There was minimal background noise.
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Old Mar 15, 2012, 02:24 AM
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United States, WA, Seattle
Joined Jan 2007
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I got one of the single speaker ones that also change LEDs from green to red. Used in a pusher delta (admittedly not quiet but not a screamer) I can neither hear the alarm nor see the lights in daylight even at close range. Might work in a quiet plane.
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Old Mar 15, 2012, 03:41 AM
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Letchworth, Great Britain (UK)
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I had a similar one in my heli, and couldn't hear it until the motor stopped. I now use a timer which activates a bank of leds on the heli, 'cause I can't hear the timer beeper on my trannie either while the heli's up close.
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Old Mar 15, 2012, 08:55 AM
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Crawley, West Sussex, UK
Joined Jun 2004
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I've tried one with two beepers, and it's not very good. It's not very loud and the trigger voltage seems a bit odd - maybe there are different levels and different beep codes, but it doesn't seem very predictable.

OTOH I've got one of these ( on my heli and it's great. The beeper is huge (30-40mm diameter, looks similar to the one from a smoke alarm) and easily audible over a 450 size heli doing aerobatics. If often causes people 100m in the pits to check their chargers.
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