9v battery terminal blanks?
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From: Geoffrey S. Mendelson on 19 Dec 2008 01:44 BobW wrote: > 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? Sorry, I said two different things in the same paragraph and may have created some confusion. First the slow self-discharge rechargable batteries have a higher internal resistance and lower output current than the "regular" ones of the same chemistry. Therefore "slow" NiMH batteries have a higher internal resistance, lower output current and longer recharge times than regual NiMH batteries. "Slow" alkeline batteries have a higher internal resistance, lower output current and longer recharge times than regular alkeline batteries. I mentioned the alkeline ones as their high internal resistance was a deal killer for me. I could not use on HT's (handheld radios). They worked fine with 1 watt output (low power), but on high power (3-4 watts), they failed. Going back to the NiMH batteries, I can't say how well they will hold up over time. I only use them on MP3 players that take a single AAA battery. So far it has not been good, the first batch to almost 10 cycles to have any usefull capacity. It may also have been my fault, because I charged them with the included charger which needed 24 hours or more to charge them. The second batch has been charged only with a higher current charger and they seem fine. Note that the players are low current devices, they discharge at about a rate of 100ma or less. > 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. All alkelines have a higher internal resistance, which is probably why you have the problem with them. If you are a camera buff, that was one of the two differences between the Canon T-90 and EOS-1. The T-90 used AA batteries, the EOS used lithium. Canon was unable to get the current they needed for all of the electronics in the camera from AA batteries. Geoff. -- Geoffrey S. Mendelson, Jerusalem, Israel gsm(a)mendelson.com N3OWJ/4X1GM
From: ian field on 19 Dec 2008 10:59 "Ron Johnson" <ron(a)lunevalleyaudio.com> wrote in message news:nr2dnZHkN6rliNfUnZ2dnUVZ8sXinZ2d(a)bt.com... > 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) You don't need much technical understanding to know that NiCd & NiMh batteries have a lower terminal voltage.
From: Ron Johnson on 19 Dec 2008 11:13 ian field wrote: > "Ron Johnson" <ron(a)lunevalleyaudio.com> wrote in message > news:nr2dnZHkN6rliNfUnZ2dnUVZ8sXinZ2d(a)bt.com... >> 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) > > You don't need much technical understanding to know that NiCd & NiMh > batteries have a lower terminal voltage. > It`s not to do with the terminal voltage, it`s something to do with the batteries internal resistance. Wireless packs are designed for replacable batteries. The internal battery metering is calibrated for Alkalines. Remember the OP was talking 9v (PP3) batteries here, You're asking for trouble using anything other than Procells or Energisers. Ron
From: Peter Hucker on 19 Dec 2008 15:01 On Thu, 18 Dec 2008 20:14:01 -0000, Geoffrey S. Mendelson <gsm(a)mendelson.com> wrote: > 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. I wasn't aware of that, although 80% sounds pretty good to me. You can always fill them before use (which is what we always used to do with the old type). > 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 manufacturers claim they only lose 10% in a year. > 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. Odd, I've bought Eneloop and Hybrio and had nothing but perfection. > 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. If you're using them in something that needs a high output current, I dread to think how much it's costing you in alkalines. > 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. How long?!?!? I bought a Uniross FIFTEEN MINUTE charger. It charges them in 15 minutes *using a cooling fan) to 80%, then the final 20% in another 15 minutes. -- http://www.petersparrots.com http://www.insanevideoclips.com http://www.petersphotos.com "Flashlights are tubular metal containers kept in a flight bag for the purpose of storing dead batteries."
From: Jamie on 19 Dec 2008 15:18
DaveC wrote: > I want to keep some NiMH rechargeable 9v batteries in my tool bag (well, my > meter bag, actually). I am currently running a double loop of electrical tape > around the entire battery to insulate the terminals. > > I'd like to use something more durable (one battery has had a terminal peek > through the tape) and was thinking about something like a battery terminal > connector but made of insulating material like nylon (probably of some > cheaper plastic). > > Does such a thing exist? I did web searches, but maybe my terminology isn't > spot-on... > > Ideas? > > Thanks, You mean something like this. http://www.organize.com/storage-battery.html?gclid=CNO9jpq_zZcCFQhMGgodgG0uSw http://webpages.charter.net/jamie_5" |