Kitz Forum
Chat => Tech Chat => Topic started by: sheddyian on February 06, 2014, 09:57:03 PM
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Just an observation really, but have you noticed how some battery operated things will carry on working right until there's almost nothing left in the battery at all? Whereas other devices seem to be unusable when there's apparently 50% left?
A few weeks ago I noticed my LED torch was a bit dim. Still working, but not as bright as I'd like. I looked at the batteries in it, was surprised that it still had the original ones from when I bought it a few years back (cheap generic Chinese ones). When I tested them, they were so flat that my meter needle briefly twitched then went back to zero on both the AA batteries. Yet the torch was still working! A new set of batteries of course made it much brighter though.
Contrast today when the LCD cooking timer in the kitchen was looking a bit faint. I tested the battery, the needle rested right on the edge of amber/green, so it was far from dead.
However, a new battery restored the LCD display to a nice crisp black.
I've noticed this before with some infra red remotes for TVs, they start being very unresponsive when there's still a fair bit of life in them.
Technology, eh?
*grumble*
:D
Ian
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What are you using to test the batteries?
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<Nods> Also noticed. :-X
What I have done is to list those devices that require dry cells holding a full charge and those devices that can operate with cells holding a minimal charge. Then when the cells are replaced in a device on the former list, the old cells are "put by" for use in devices on the latter list. ;)
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What are you using to test the batteries?
Hah! I'd written, then deleted, a long rambling few paragraphs about my battery tester from my original post!
I'm using the Philips SBC169 tester (and charger!) of which everyone is obviously familiar ;D
I've had it for a very long time, and unlike some testers it seems pretty good at deciding between marginal and good batteries - the display seems pretty linear in response to battery condition, - with some testers I've tried, the needle either flies to the end or does very little and not much in between.
Looking inside it some years ago, there are some surprisingly chunky resistors, so I imagine it puts a small load on the battery as well as simply measuring the voltage, which seems to me to be A Good Thing.
It also tests a few battery types that are no longer available ;D
It's got a 9 volt input jack, though quite why you'd use this to charge 1 size of battery at a time is a bit beyond me.
Saw one a while back on ebay for around £50! :o
Ian
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<Nods> Also noticed. :-X
What I have done is to list those devices that require dry cells holding a full charge and those devices that can operate with cells holding a minimal charge. Then when the cells are replaced in a device on the former list, the old cells are "put by" for use in devices on the latter list. ;)
I've not gone quite as far as that, but when my meter (illustrated above ;D ) shows them to be 50% or above, I put them in a tub to be used as spares for anything else (Christmas tree lights, whatever). This is where the kitchen timer's AAA has now gone.
Local council has recently started collecting batteries in the fortnightly recycle collection (have to be put out separate, not in the green bin) which is very handy. Despite using a lot of rechargables, I seem to also have a lot of dead alkalines every month or two.
Ian
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The reason I asked about the tester is that LEDs only require a very small current, and it could be that the tester was loading the batteries with quite a lot more than that current, hence the brief blip followed by nothing. They would have had to have a voltage of at least 0.6V (possibly more) to get anything from the LEDs.
All of which is a bit nit-picking, because you're quite right about the variation in the minimum batter ycharge required by different devices. :)
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The reason I asked about the tester is that LEDs only require a very small current, and it could be that the tester was loading the batteries with quite a lot more than that current, hence the brief blip followed by nothing. They would have had to have a voltage of at least 0.6V (possibly more) to get anything from the LEDs.
All of which is a bit nit-picking, because you're quite right about the variation in the minimum batter ycharge required by different devices. :)
Not nit-picking, I agree with that, it's the reason I like this tester, as it does seem to load the battery and weeds out those that are on their last legs, unlike some other testers I've used that gleefully show a full battery when they're nothing of the sort.
Hadn't thought about the current requirement of LEDs, but yes, that seems very likely.
I've another larger torch that's a Maglite-style one, with 3 or 4 D cells in it, and has LEDs as well as an ordinary torch bulb. You can switch between the two. It's impressive how bright the LEDs remain when the torch bulb is a barely glowing orange colour.
Ian