9v battery terminal blanks?
in [Repair]
|
Prev: Viewsonic VG150 logic board 0171-2242-0153 3150-0122-0150 repair help
Next: Service manual or schematics for Kenwood KR-7600 reciver
From: Ron Johnson on 18 Dec 2008 04:18 jakdedert wrote: > John E. wrote: >>> ... and I never ever use rechargables in radio packs. >>> ROn(UK) >> >> Why? [if you wouldn't mind a newbie question...] > > See my multiple posts on the subject. For most presentation purposes, > the proven reliability of the good old alkaline--fresh out of the > box--is superior. One less thing to worry about in a complex and > demanding environment. > > The cost of having a show 'go down' is much more than that of fresh > cells...especially if the cost is losing your job. > What he said. The risk just isn't worth it for the price of a few batteries. There`s also the factor that some low end radio mikes seem to object to rechargable batteries (certainly nicads) It`s possibly the batteries internal resistance changing as it discharges. I`ve not really studied it, but when the rechargable discharges beyond a certain point, the transmitters agc seems to get screwed up and unstable, feedback is the result. Maybe someone with more technical understanding can explain. Ron(UK)
From: Peter Hucker on 18 Dec 2008 14:52 On Thu, 18 Dec 2008 00:08:20 -0000, Dave Plowman (News) <dave(a)davenoise.co.uk> wrote: > In article <0001HW.C56EAB4200C5FF44B01AD9AF(a)news.sf.sbcglobal.net>, > John E. <incognito(a)yahoo.com> wrote: >> > ... and I never ever use rechargables in radio packs. >> > ROn(UK) > >> Why? [if you wouldn't mind a newbie question...] > > My answer would be is you can virtually guarantee the performance of a > decent make alkaline. And I sometimes use a great deal - my personal > record for number of radio mics is 38 at once. It really is rare to get a > faulty battery. > > Trouble with rechargeables is they don't maintain the same performance > throughout their life - which makes knowing when they must be changed > rather hit or miss. Plus the fact that most give little warning of running > out - unlike an alkaline - due to the different voltage discharge curves. > So what might be a benefit on a high power demand device like a drill etc > is a liability on a low current one. > > Of course if you know they will only be used for a short time - like say a > church service - rechargeables can and do make sense. But this isn't > usually the case for film, TV and conference etc use. Then use the new type of NiMH, the pre-charged ones which don't lose power sat on the shelf. Take them out the packet and they are as good as alkalines. Only keep them for a fraction of their life if you want a nice long charge, and put them in a trickle charger when not in use. -- http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com "It is generally inadvisable to eject directly over the area you just bombed." - U.S. Air Force Pilot training manual
From: Geoffrey S. Mendelson on 18 Dec 2008 15:14 Peter Hucker wrote: > Then use the new type of NiMH, the pre-charged ones which don't lose > power sat on the shelf. Take them out the packet and they are as good as > alkalines. Only keep them for a fraction of their life if you want a > nice long charge, and put them in a trickle charger when not in use. There are three problems with them. The first is that they are supplied charged, but only about 80% charged. While they take longer to discharge on their own, if they sit on the shelf for a year or so, they very well may be flat. The second is that they do not reach their full capacity when recharged until they have been through 3 or 4 recharge cycles. I have found with the ones I bought it took even longer, sometimes 10 cycles to get any useful life out of them. The third is that they have a higher internal resistance which limits their output current. That is why the rechargeable alkelines that came out around 1995 never really took off. They were lower in capacity to the disposable ones (about 80%) to allow room for expansion, and they did not put out the current that nicads or regular alkelines did. They also do not charge as fast. I charge mine in a 7 hour NiMH charger, but have to do it twice. Using the little fixed rate charger that came with a set, I have to charge then for at least 24 hours. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel gsm(a)mendelson.com N3OWJ/4X1GM
From: BobW on 18 Dec 2008 16:03 "Geoffrey S. Mendelson" <gsm(a)mendelson.com> wrote in message news:slrngklbiq.9fq.gsm(a)cable.mendelson.com... > Peter Hucker wrote: > >> Then use the new type of NiMH, the pre-charged ones which don't lose >> power sat on the shelf. Take them out the packet and they are as good as >> alkalines. Only keep them for a fraction of their life if you want a >> nice long charge, and put them in a trickle charger when not in use. > > > There are three problems with them. The first is that they are supplied > charged, but only about 80% charged. While they take longer to discharge > on their own, if they sit on the shelf for a year or so, they very well > may be flat. > > The second is that they do not reach their full capacity when recharged > until they have been through 3 or 4 recharge cycles. I have found with > the ones I bought it took even longer, sometimes 10 cycles to get > any useful life out of them. > > The third is that they have a higher internal resistance which limits > their > output current. That is why the rechargeable alkelines that came out > around > 1995 never really took off. They were lower in capacity to the disposable > ones (about 80%) to allow room for expansion, and they did not put out > the current that nicads or regular alkelines did. > > They also do not charge as fast. I charge mine in a 7 hour NiMH charger, > but have to do it twice. Using the little fixed rate charger that came > with a set, I have to charge then for at least 24 hours. > > Geoff. > Geoff, Do you have any info that indicates that they can't put out as much current and/or have higher internal resistance (over time) compared with alkalines? I have been using the Hybrio hybrid batteries in a Canon SX100IS digital camera for about a year now and I haven't noticed anything problematic about them. They last a LONG time without any special conditioning. I use a Maha MH-C401FS charger (set to 'slow'). I've used alkalines in several different cameras and have had horrible results with them. Bob -- == All google group posts are automatically deleted due to spam ==
From: jakdedert on 18 Dec 2008 17:56
Peter Hucker wrote: <snip> > > Then use the new type of NiMH, the pre-charged ones which don't lose power sat on the shelf. Take them out the packet and they are as good as alkalines. Only keep them for a fraction of their life if you want a nice long charge, and put them in a trickle charger when not in use. > In a word; no. We don't have trickle chargers in the truck that takes them to the next city; nor the time to monitor their health. A new Procell is a 'known' resource. It always works, IME. It always lasts about the same amount of time. When it's exhausted (actually long before) we discard it--or switch it to less demanding tasks--and grab a new one (which will last exactly as long as the last one did). I have a box of used ones right across the room. Want some? They're great for kids toys, flashlights, portable radios etc. You're not listening. Use them yourself if you want to. I value my job and my reputation much higher than the price of a new battery...or a thousand of them. jak |