Yesterday whiel doing a perfunctory cleanup I came across the Canon 580EX II flash I'd packed in a carrying case (when visiting a friend) almost a year ago. The 2700 mAh NiMH PowerEx (MAHA) cells had not been charged since then. When I turned the flash on, it came to full charge in less than three seconds.
The cells measured 1.274V, 1.283V, 1.285V, and 1.286V, all higher than the nominal 1.25V of a NiMH cell. (NiMHs generally come out of a full charge at around 1.4V.) That's pretty good performance for a cell that's supposed to "drop dead" within a few weeks of its last charge.
So I ask... Where did this belief that NiMH cells rapidly self-discharge come from? I never believed it, and here's strong evidence it just isn't true.
No, I don't know anything according to you. I worked on the design and manufacturing of test instruments that sold for up to $80,000. A claim like yours needs to be backed up.
You still use tungsten headlights in Europe? Halogen are standard in the US. My truck uses 65 W:
Part Number: 9007SU Weight: 0.157 lbs Notes: Dual beam Amperage Draw: 5.08 Bulb Diameter (In): 0.67 Bulb Technology: Halogen Color Temperature: 4100 DOT / SAE Compliant: Yes Filament Configuration: C-8 Headlamp Beam: Low & High Beams Headlamp Bulb Base Design: PX29T Headlamp Bulb Configuration: T-4 5/8 Headlamp Bulb Number: 9007 Headlamp Wattage: 65 High Beam Wattage: 55 Light Center Length (In): 1.75 Low Beam Wattage: 65 Lumens: 1345 Maximum Overall Length (In): 3.7 Operating Voltage: 12.8 Rated Life (Hours): 250 Vehicle System Voltage: 12V
Sigh. How long have you been brain dead?
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For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!
You certainly show your ignorance with every post. 'Halogen' is the inert gas used in some types of filament lamps. The filament is still likely tungsten.
However, none of that makes a difference in this context. A 55 watt (EU spec) headlight is a 55 watt headlight.
BTW, my car has HID units. Far more efficient than those ancient 'halogen' lights. 35 watts produces more light than your 65 watt whatever. They're pretty well the norm in the UK on new cars above base spec.
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Dave Plowman dave@davenoise.co.uk London SW
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Dunno. Mine have a colour temperature quite close to filament lamps and a very sharp cut-off beam pattern. The car also has self levelling suspension. The earliest versions of them did appear quite 'blue'. Rather like most 'white' LEDs. ;-)
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Dave Plowman dave@davenoise.co.uk London SW
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So? Just because they use that spec in a backwards, anti-engineering country is no reason for anyone else to.
Sigh. Still can't stick to what you post, can you? First you claim
55 W tungsten, then it's 35 W HID. No wonder you believe the hype about your magic toy battery tester. The actual Ah rating is determined by it's use. That 20 Ah rating is only one curve, of many. If you stuck to it, you couldn't start the vehicle's engine with it. you couldn't use most car radios without exceeding the proper discharge rate. You dismiss the total starting circuit resistance as nothing.
As far as HID lamps, they can be seen a lot further away, but most US drivers don't like them. You get a brighter spot, but don't light the sides of the road well enough to see animals or people along the side of a road until it's too late. There are a lot of very long, and high speed roads in the US where you need that extra illumination.
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For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!
Crikey. Where did that come from? Hate just admitting your mistake?
Crikey again. Do you actually think before posting?
More bollocks. Amp hour and the discharge rate are simply a standard way of *measuring* that parameter. Other battery parameters are given separately. For one who claims to be an engineer, this shouldn't need explaining.
You've never experienced decent HID lamps. With proper reflector etc design they can provide any beam pattern you want. Mine produce as even illumination as you could possibly want - no high spots at all. They also have a 'spike' at the nearside which illuminates the side of the road rather further than the main part of the beam. They only provide the dip beam - the high beam is by ordinary quartz halogen units, which are in addition to the dips.
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Dave Plowman dave@davenoise.co.uk London SW
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Don't blame the light source for poor optical performance. A good headlight will give a good beam pattern. A number of people have tried retrofiting HID bulbs into halogen lamps. The light position and shape can give a very poor beam pattern, sometimes worse than the original it replaced. As for long high speed straights, have a look at what they use in sports car racing. Last time I checked, every car at Le-Mans was on HID. 200mph on the Mulsanne straight needs good lights. Equally, rally cars also use HID. they only do about 130mph but that's on a forrest track between trees at night. I thought the US had a 55mph speed limit. Have they changed that? It's been some time since I was there.
A fascinating product, but I still don't see how it works.
The only method "obvious" (to me) would be to short the cell for a fraction of a second, and use the measured current to calculate the internal resistance. * This, in turn, could be used to estimate the cell's Ah capacity. But this assumes there's a direct correlation of the resistance with the cell's capacity, regardless of its age or charge condition. Is there?
This is the way Microsoft Hardware tested mouse batteries -- but to see whether they were primary or secondary, and whether the latter were "defective". The capacity was of little concern.
The US finally adopted EU vehicle lighting standards after US lighting engineers spent some 20 years pressuring to be able to use the safer, more effective, and more modern EU standards in the US, against the US car manufacturers who didn't want the expense of redesigning their ancient lighting systems and didn't want competition from foreign lighting manufacturers.
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I *think* that's the way it works. The crock clips have very sharp 'pins' to ensure a good contact with the battery terminals.
But having used mine on a variety of sized batteries it really does seem to give a good indication as to the condition rather than just the charge state of a battery. In other words if it says a fully charged battery has the capacity (in amp.hrs) as stated on the battery it is good. Works on batteries from 1.8 - 200 Ah. If it gives a reading of less than 65% of that figure, the battery should be replaced. The claim is it simulates a
20 hour test in 6 seconds.
It's no cheap DVM, though. Cost almost 200 gbp - and came with a hand written calibration certificate. Most decent battery sellers will have something similar. Even Halfords. ;-)
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Dave Plowman dave@davenoise.co.uk London SW
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From the current 'Brit Engineering kaput!' thread on news:sci.electronics.design where they are discussing why all engineering in England has gone to crap. From the public's attitude towards engineering, stupid HR staff and brain drain where people with talent leave England to work elsewhere.
Yes, unlike you. You keep comparing apples to crabapples.
I know how the damn 'standard' works. It works even better if it has a relevant base measurement. Starting a vehicle is a completely different function from a standby power application. Other than starting the vehicle, little current is drawn from a car's battery if the charging system works properly. Therfore a '20 Ah rating' is not the proper standard. That is why the US rates a car battery by CCA. A worst case condition for starting in cold weather when an engine is tight and the lubricants are stiff. Your miracle tester won't find a failing batery. I've had several show no signs of trouble that developed an open internal connection when you hit the key. Your DMM sized miracle box won't find that and give warning, but the old controlled discharge testers will.
Most of what I've seen are on imported cars. They tend to blind oncoming traffic.
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For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!
Older readers may remember Lucas spot light adverts from the '60s - 'are too powerful for use in some US states'
By the prince of darkness. ;-)
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Dave Plowman dave@davenoise.co.uk London SW
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In circuit, without disconnecting from the vehicle? Doesn't that tell you ANYTHING? It mesures ESR.
Have you read the manual?
The ACT 33 Battery Tester is designed for measuring the internal resistance, open-circuit voltage, and terminal temperature of secondary batteries, including lead storage cells, nickel-cadmium batteries, lithium-ion batteries and nickel-metal hydride batteries
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For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!
What else would you expect, with the built in reflectors for the Hallogen bulbs?
With loud engines and all traffic in one direction. That is nothing like driving a typical car at night on a country road. Have you ever had a horse step out in front of your vehicle? How about a cow that got out of the pasture's gate, or a large bear? Some areas have had to have
16' high fence built along the sides of roads and a tunnel under the road to stop the accidents.
No, 70 MPH has been restored in a lot of places.
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For the last time: I am not a mad scientist, I'm just a very ticked off
scientist!!!
You really need to see what UK groups say about the US. ;-)
Or perhaps you feel it's not in some similar form of 'decline'? If so, get your head out of your arse and look around you. At all the Chinese etc made consumer goods. Same as here. GM bankrupt yet again - despite having one of the largest markets on its doorstep. Etc.
I'm no 'my country right or wrong' type. I'll leave that to you.
Sigh. You're the one doing the comparing - and getting it wrong.
Who are you trying to educate? I'm well aware of the likely loading on a car battery. UK batteries also give all that information - the Ah one is in addition.
You really need to do some research before being so certain. Because you're wrong. My tester will show up a faulty cell - either high impedance or shorted. Your prehistoric 'controlled discharge' (just an ammeter) won't - unless you also do other measurements. It also needs skill and care to use. But perhaps you've never seen a battery blow apart when having a high discharge test done? I have. My tester doesn't apply the load until after it is connected.
I have no idea of the construction and use regulations in the US. If they are only fitted to imports, it shows just how far behind the times Detroit is. FWIW badly set filament lights can dazzle too. Or ones with just plain poor optical design. HID lamps are much more efficient. If they are designed to the same light output as 'halogen' you benefit from less energy use. If similar savings are made elsewhere in a car, you specify a smaller alternator and cable sizes. Etc.
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Dave Plowman dave@davenoise.co.uk London SW
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