Heres a couple of questions for someone who knows about batteries. I have two hand held radios which I rarely use. An Alinco dual bander with Nmhi batteries, and a commercial UHF with Nicad batteries. Both sets of batteries are in good order and hold a charge well. I can leave them for months and when I pick the radios up, they still have a good charge in them. Today I lifted both radios, the first time in a month or two, and both had totally flat batteries. I know both were fully charged when I last switched them off. What happened? The weather has got warmer in the last month, and the humidity levels are up. But nothing else has changed. What flattened them both? Also... Last time I took a hand held radio abroad, I took 2 sets of batteries. Both were fully charged when they were packed. Both were flat when I reached my destination. Same with my mobile phone and camera batteries as well. All were nearly flat and had not been switched on during the journey. What is it that makes batteries go flat when travelling in a pressurised aircraft? I hope someone can advise. I've been thinking about the aircraft one for ages :o) 73 -- Jack VK2CJC / MM0AXL FISTS #9666 CW Ops QRP Club #753 Mid North Coast Amateur Radio Group www.mncarg.org

Jack VK2CJC <vk2cjc@look-me-up-at-qrz.com> wrote: > Heres a couple of questions for someone who knows about batteries. > I have two hand held radios which I rarely use. An Alinco dual bander with > Nmhi batteries, and a commercial UHF with Nicad batteries. Both sets of > batteries are in good order and hold a charge well. I can leave them for > months and when I pick the radios up, they still have a good charge in them. > Today I lifted both radios, the first time in a month or two, and both had > totally flat batteries. I know both were fully charged when I last switched > them off. What happened? The weather has got warmer in the last month, and > the humidity levels are up. But nothing else has changed. What flattened > them both? > Also... > Last time I took a hand held radio abroad, I took 2 sets of batteries. Both > were fully charged when they were packed. Both were flat when I reached my > destination. Same with my mobile phone and camera batteries as well. All > were nearly flat and had not been switched on during the journey. What is it > that makes batteries go flat when travelling in a pressurised aircraft? > I hope someone can advise. I've been thinking about the aircraft one for > ages :o) Nothing in an airplane makes batteries go flat. Commercial aircraft are pressurized to an equivelant altitude of around 7-8 thousand feet. I regularly fly at those altitudes in my unpressurized aircraft with the backup handheld in a seat pouch and the batteries are just fine. Perhaps the batteries aren't as good as you think or the last charge was longer ago than you remember. -- Jim Pennino Remove .spam.sux to reply.

> Heres a couple of questions for someone who knows about batteries. > > I have two hand held radios which I rarely use. An Alinco dual bander with > Nmhi batteries, and a commercial UHF with Nicad batteries. Both sets of > batteries are in good order and hold a charge well. I can leave them for > months and when I pick the radios up, they still have a good charge in > them. > > Today I lifted both radios, the first time in a month or two, and both had > totally flat batteries. I know both were fully charged when I last > switched them off. What happened? The weather has got warmer in the last > month, and the humidity levels are up. But nothing else has changed. What > flattened them both? > > Also... > > Last time I took a hand held radio abroad, I took 2 sets of batteries. > Both were fully charged when they were packed. Both were flat when I > reached my destination. Same with my mobile phone and camera batteries as > well. All were nearly flat and had not been switched on during the > journey. What is it that makes batteries go flat when travelling in a > pressurised aircraft? > All secondary batteries have a self discharge rate, some types are higher than others, a couple of months is more than sufficient to self discharge a battery pack. Another factor to take into consideration is that most modern handhelds do not have a 'hard' on/off switch. There is always a small standby current drawn. It is best to actually remove the pack from the radio. As far as batteries on aircraft; I have never had any problems, and I can't think of a mechanism that would discharge them. regards Jeff

> Perhaps the batteries aren't as good as you think or the last charge > was longer ago than you remember. 4 sets of batteries were all good order and fully charged the day before leaving and were all flat or almost flat on arrival. I cant think of any reason why either. Its an odd one :o) And it wasn't a one off, I've done this journey a few times, and had the same results. Its a long trip, UK to Australia, 3 flights, 22 hours in the air. But radio, camera and phone were not switch on during this time. Suggestions welcome................

> If these are commercial flights, are they going through > any kind of imaging screening equipment? What kind? Excellent point Richard. In recent years all luggage is x-rayed. My wife is a radiographer and always takes an interest in the machinery. She has never seen this particular type of imaging before. It shows different types of metal as different colours. Despite the commonly used name, its not really x-ray, indicated by the lack of concern of leaked radiation :o) Its definitely magnetic. Could this be the battery killer? Jack

"Jack VK2CJC" wrote ... >> If these are commercial flights, are they going through >> any kind of imaging screening equipment? What kind? > > Excellent point Richard. > > In recent years all luggage is x-rayed. My wife is a radiographer and > always takes an interest in the machinery. She has never seen this > particular type of imaging before. It shows different types of metal as > different colours. > Despite the commonly used name, its not really x-ray, indicated by the > lack of concern of leaked radiation :o) Its definitely magnetic. > > Could this be the battery killer? So are they just discharged? Can you recharge them? Or are they destroyed? Were the radios affected? If you can see the scanning equipment, can you at least get a manufacturer name from it? And maybe a model number? With that, you could do some internet research to discover what method it uses and if there are any other reports of bad interactions with batteries, etc. Richard KE7GKP

> So are they just discharged? Can you recharge them? > Or are they destroyed? Were the radios affected? Just discharged. The radios are OK. I have never noticed any names on the "x-ray" equipment. I should imagine thats the sort of detail they will keep to themselves. Giving the specs away would make it easier for the "bad guys" to figure out how to beat the scan.

Just out of curiosity, does this happen when the batteries are removed from the radio also? Try carrying the batteries in a separate battery holder next time and see if they suffer the same fate. "Jack VK2CJC" <vk2cjc@look-me-up-at-qrz.com> wrote in message news:fgjoo7$29l$1@victor.killfile.org... > Heres a couple of questions for someone who knows about batteries. > > I have two hand held radios which I rarely use. An Alinco dual bander with > Nmhi batteries, and a commercial UHF with Nicad batteries. Both sets of > batteries are in good order and hold a charge well. I can leave them for > months and when I pick the radios up, they still have a good charge in > them. > > Today I lifted both radios, the first time in a month or two, and both had > totally flat batteries. I know both were fully charged when I last > switched them off. What happened? The weather has got warmer in the last > month, and the humidity levels are up. But nothing else has changed. What > flattened them both? > > Also... > > Last time I took a hand held radio abroad, I took 2 sets of batteries. > Both were fully charged when they were packed. Both were flat when I > reached my destination. Same with my mobile phone and camera batteries as > well. All were nearly flat and had not been switched on during the > journey. What is it that makes batteries go flat when travelling in a > pressurised aircraft? > > I hope someone can advise. I've been thinking about the aircraft one for > ages :o) > > 73 > -- > Jack VK2CJC / MM0AXL > FISTS #9666 > CW Ops QRP Club #753 > Mid North Coast Amateur Radio Group > www.mncarg.org > > >