Is there an app which will stress TEST a cellphone battery?

I use a spare battery pack for my iPhone - it gets me an extra day or an extra 2 days when Im traveliing. It recharges (the batterypack) from my laptop. I could of course recharge the phone via liaptop, but I don't like charging and using it at the same time. Not sure if thats dangerous but with an iPhone costing near enough 800 for a 32 gig and replacing a battery costing 100, I take little or no chances :-)

If you're going to use miniinthe box dot com or lightinthebox dot com, do use paypal and a throwaway address - they're notorious for spamming and selling on your address :-)

Ok. I'll spell it out in the common vulgar tongue. After 5 or 7 years, Apple will pretend the product you bought no longer exists. In addition, they may also pretend that you don't exist, as current Windoze XP owners are finding out from Microsoft. In my never humble opinion, this is suicide as the best customers are existing customers and it's far easier and cheaper to sell to existing customers than to find new customers. Due to Apple customer loyalty, that may work for Apple, but not Microsoft. Incidentally, I read somewhere the 78% of iPhone 5 sales in the first few months were to existing iPhone 4/4s owners.

Actually, they do, and the manufacturers does everything it can to make that happen. Design for a specific lifetime is a very real science and is practiced with a vengeance. After about 5 years, most companies evaluate the condition of their products solely to determine which ones have lasted too long. Then, they cost reduce those parts to conform to the design spec target lifetime. Do that a few times and the end product will produce a fair number of near simultaneous failures, making the product uneconomical to repair. Actually, I'm surprised that they haven't built a "warranty timer" into the firmware and just had it blow itself up after 5 or 7 years operation.

I know of one company that I thing (not sure) destroys all their spare parts after the required 5/7 years. No names, because I'm not certain.

My 486 laptops still work. I need them to program ancient Motorola radio programming software, that only runs on ancient hardware (or requires slow down software (i.e. DOSbox, MoSlo). Replacement parts are difficult to find even on eBay due to lack of demand. Working 486 machines typically go for about $150, mostly to hams and 2way radio shops.

Ditto. I have a Panasonic Toughbook CF-25 P133 that amazingly works well for radio programming. However, the battery is dead and working replacements are unavailable. I've rebuilt one, but it wasn't worth the effort because the brain dead charger will kill it in a few months.

Well, let's see. I'm using an LG VX8300, which was released in 2006. Not bad for an 8 year old phone. Mine has been in use for about 6 years. I collect them, and give them to friends. However, they're not so careful and usually trash them in less than a year. Batteries are another problem. LG was into protecting their batteries (just like ink jet printer carts) and made

3rd party batteries unworkable (for a while). So, I have a large collection of nearly dead batteries. If you're careful, they'll last. If your a typical American consumer, it soon becomes eWaste.

You're in the minority. Also, marketing products to people who hold onto their hardware for >7 years is kinda unprofitable. Much better and easier to target people that trash their electronics.

Forgive me, for I have splurged. I just bought a Google Nexus 7 and just ordered an Asus Chromebook. Now, I can look cool in the coffee shop.

Mine does, but then I don't use the cell phone part of the smartphone. I talk on the VX8300 and use the Droid X2 as a PDA. Yeah, I know that's not fair.

Actually, I've had problems with my Droid X2 running some of those battery meter apps and have removed them all. Having the app running tends to make the touch screen unresponsive. Removing it restores the touch screen to normal operation.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

When we measured a pile of LiPo batteries a few years ago, the 1/5c curve looked pretty much like the bottom curve (1c) in the above.

We found it to be more like 3.2V with pretty much nothing left at

3.0V.

Same batteries. They're all 3.7v nominal Li-whatever batteries. Of course there are variations between different chemistries. However, the biggest variation is the difference between the discharge curve of a shiny new fresh off the boat battery, and one that's nearly dead. The discharge slope, sharpness of the knee, and voltages are all somewhat different. All the discharge curves that you find are for brand new batteries. I did some old/new tests on various Li-Ion cells in the distant past, but can't find the results. Time permitting, I'll re-run the tests, if I can find some nearly dead batteries, or post the old results if I can find the numbers.

Incidentally, I spent quite a bit of time re-running those tests trying to determine why the discharge curve for all the batteries looked more like a resistor curve. It turned out that I had a high resistance (if you call about 0.5 ohms high resistance) connection in the battery fixture. At 1C, you can get amazingly bad curves if you have any contact resistance.

Yes, that's normal. The actual voltage of the knew, and it's with varies with umm... everything. Discharge rate, temperature, battery chemistry, internal protection circuitry, contact resistance, age, abuse, brutality, etc all have an effect.

From your graphs below, the knee is quite sharp at 0.2C discharge, and quite rounded at 2C. Old batteries look more like 2C at any discharge rate. It's really difficult to select a number which defines the cutoff point when the current drain of the device varies radically with use.

Incidentally, none of the Android battery monitor apps I could find would display instantaneous current drain. If you find one, I would be interested.

Ok, how would suspect that the 10% is calculated? I might be wrong, but I don't think that there is any current drain monitor or logging in most cell phones. They estimate the 10% of capacity value from the terminal voltage probably based on a brand new battery with a peak value based on the highest terminal voltage after the last full charge. That's roughly the way it's done in laptop batteries.

Note that some Android devices don't measure battery or charger current. NOTE: The electric current reading doesn't work on all devices. The reason is that the manufactures (mostly Motorola and Samsung) don't support this in the battery driver or in the hardware. I just tried it on my Motorola Droid X2 and Google Nexus 7. It failed on both.

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Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Jeff Liebermann posted Tue, 29 Apr 2014 16:18:10 -0700

I know. What I had in mind was, that standalone battery has only its Low U/High U/T safety cut cut off circuitry. Devices can add their own, e.g. to turn off the phone sooner that battery would turn off itself.

E.g. My old Siemens feature phone MT50 with BW passive display, so battery at phone usage was very light. I had activated service menu with voltmeter available. It lasted typically 4 days. With U=3.8V There was 1 day left. With U=3.7V there were 8 hours left. The phone performed cut off at 3.55V, where voltage started already falling.

There is said several times higher resistance of old batteries. Typically 100mS versus 500mS, but all depends on chemistry and size.

It is obvious. Curves for old batteries will be more similar to curves of new ones under higher load, so particular voltage during load would come sooner on the curve.

Yes, 0.5 Ohm is big.

This is obvious and expected, as well the old ones. Phone usage is closer to 0.2C than to 2C.

I use this one.

My phone has a current sensor. The estimation is percentage gets recalibrated by charge needed to get from low cut off voltage to cut off current at 4.2V. My low is near 3.2V.

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Poutnik

The ad-supported free version? the Pro version, $4.99? or other?

Thanks. -- tlvp

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Avant de repondre, jeter la poubelle, SVP.

[snip]

It sounds like a four-wire battery test fixture would be useful. One pair of wires provides the current to the battery terminals, and a second parallel and independent set of wires carries the voltage to the voltmeter.

In short, a Kelvin setup, which makes contact resistance not matter.

..

Joe Gwinn

Maybe. Battery contact resistance doesn't matter only if the sense wires are connected directly to the battery terminal. If the sense wires are connected to the load tester side of the connection or to the wires, it can be just as bad as having a high resistance connection or cable. With cylindrical cell batteries, and marginal battery holders, it's really easy to do it wrong.

I've suggested a 4 wire connection, as found in all lab power supplies, to West Mountain Radio several times. They seem to be ignoring me (and others). Even their 120A power amplifier has only two terminals.

I tried taking apart my CBA-II and trace out the wiring, but could not find an easy way to separate the sense wires from the power wires. They're all mixed together on the PCB and not easily brought out to external connections. The guts:

The West Mtn Radio last resort solution for low contact resistance: Sigh...

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

I'm assuming that they have no competition.

Joe Gwinn

True, in the price range. There was another such device that I once saw in one of the RC forums, but I can't find it now.

There are other dedicated discharge analyzers but they are much more expensive.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558