Archive for the batteries Category

Amazon Fire TV remote issues, Android Fire TV Application Problems

Posted in batteries, Electronics, technology with tags , , , on May 2, 2016 by marksun


The Amazon Fire TV remote crapped out over the weekend. I have a feeling  Duracell AAA alkaline battery corrosion did it in.  I cleaned up a bit with iso and with Corrosion Block but no dice.  AA and AAAs  leak on you especially if there is a long term low current drain. Sometimes it’s just a shiny film and hard to see if you don’t really inspect the battery and battery compartment. The remote has telltale signs of corrosion around the batteries. Hard to tell what went wrong but I suspect a leaky battery burned through a trace in the battery compartment.

This event sparked a brief effort into learning a little about FireTV and FireTV remote apps.  I’ve dug up a few random bits of information about FireTV  workings underneath the opaque black plastic packaging.

Random factoids:

  • The earlier remotes used Bluetooth.  So you don’t have to point the remote at the TV? Seems like I had to but could be wrong about that.
  • After about October 2015, new FireTV remotes use wifi-direct and not Bluetooth.
  • I suspect the broken remote I have is the “old” bluetooth model.
  • The FireTV menu system provides a means of pairing more than one remote to the FireTV unit.
  • I have seen the Wifi-direct access point belonging to my FireTV show up on my phone’s wifi access point list now and then, but not consistently.  It shows a secure connection.  I have no idea what the password is to it or whether and why one would connect to it.
  • To their credit Amazon support will replace the remote. No warranty issue at all.

I did something like this picture – an exploded view of a remote control:


Warranty? What Warranty? Six screws, not four hold the remote together. To get at the other two you have to pry off a second plastic cover piece on the back of the remote.  It’s stuck on with two sided tape and also snaps in.   There are a few clues on google images..


Here is one way to pry that second plastic back cover.  The fifth and sixth screws are under this piece.  I used a small flathead screwdriver and didn’t break any plastic.  The double sided tape however…

Did I fix the remote?


It may be possible to repair an open trace caused by corrosion, but so much easier to call Amazon for a replacement.  Losing the remote is not the end of the FireTV I found.

Next- did you know that you can plug a USB keyboard into the Amazon Fire?   By chance I found I could control all the functions of the Fire TV this way ( I have the model that came with the remote and external brick power supply, not the “stick”).  So while I’m waiting for the remote, this will keep us connected to the big screen TV for Netflix.  Hint. You use the TV screen as the monitor see and set the TV input to the AmazonFire HDMI port.  There is some mumbo jumbo about the USB port being for developers.  That’s a bit further than I want to go with this.

Next – The Amazon FireTV app… …  the obvious alternative to the Amazon TV remote control is to use the Android device with the FireTV app.  This normally worked well,  I’ve used it on and off for a while,  and only recently on my phone, but today I managed to kill the app somehow.   The symptom … the app begins with the “elect a Device to Connect and Searching for Fire TV devices,  but cannot “find” the FireTV device.  The “Troubleshooting” link suggests rebooting android device, rebooting the FireTV (restart), deleting all data from the FireTV app,unistalling and reinstalling the app, multiple power cycles of the FireTV.  No dice.  ( I did not do a factory reset of the FireTV – it can be done with the USB keyboard for example if you don’t have a remote.)

Several hours later …

The app is working again.  Why?  I don’t know.  I decided to try it, then for the sake of form,  power-cycled the FireTV.  Suddenly the device showed up on the app and we’re in business.  There is still an issue with the app finding the FireTV device.  Or having found it, it Cannot Connect. The app is unreliable now.

But what is the cause of the app failure? What changed?

I wonder if this is a software problem in the FireTV …  gotta be.  The user can do nothing.  There don’t seem to be any easy ways to pry open the software like you can the remote control case.


Amazon’s Fire TV Remote Control


Kindle 3 Battery Usage and Charging

Posted in batteries, house tech with tags on December 31, 2010 by marksun

Basics about the Amazon Kindle 3 battery and how to charge it.

Out of  the box, the Kindle is equipped with two  ways of charging – one the supplied charger, the other is to use your computers  USB port as the charger.    The USB port on the Kindle is one of the newer miniature narrower types (micro B),  standard on many cell phones and blue-tooth devices.   Both of these methods work great.  I  don’t recommend trying any other charges unless for some reason, circumstances force you to take a chance on a third party charger.

The Kindle 3 Battery

The Kindle 3 has a 3.7 volt, 1750 mah Lithium Polymer battery for a fairly hefty battery capacity.  The battery is made in China,  which manufactures much of the industrial worlds batteries. The battery is likely to be a fairly generic unit selected for size and capacity.   Charging techniques are well established for LiPo battery chemistries and is basically the same as for Lithium Ion.  The key is control of the current used in charging, and to monitor and control the voltage applied to the battery.   A typical charge curve for a generic 3.6 V LiPoly device employs an initial  850-900 mah constant current charge (CC) for the main charge phase until the voltage climbs to a maximum 4.2V, followed by regulated constant voltage of 4.2V (CV) while  the charge  current drops to approaching zero.  Deviating from this strict regime invites the  destruction of the battery.  All consumer charging circuits are designed to protect the battery while charging it.  By convention, LiPo batteries can be charged at a maximum charge current of 1C (where C is the capacity of the battery) and most commercial chargers provided by the manufacturer  provide less than this 1C charge which, for a 1750 mah battery,  would be 1.7A (amps).    However, if you want the battery to have a long life,  the charge rate should  be less than 1C

The Kindle 3 comes with a  compact 4.9v 850ma charger with a  USB socket for the charge cord that doubles as the USB link to the computer and enables  the Kindle to charge while attached to a  computer USB port.    The computer’s USB 2 port supplies 500 ma,  a lower charge rate than the included charger. Higher charge currents charge faster, so expect the wall charge to charge faster.  850 ma is about 0.5c  rate for the battery so  a full charge is mathematically about 2 hours,  but because of the charge algorithm, charging will take longer for a full charge.   When the battery approaches 4.2V a “smart” charger  switches from a constant current to a constant voltage (CV) for the remainder of the charge while the current drops as the battery approaches a full charge.  For the USB port, the calculated full charge time is more like 3.5 hours, again with a large fudge factor.

I don’t think I’ve ever charged my Kindle as long as 2 hours using any charger.  That’s probably because I don’t let the battery level drop too low.  It’s best to top off the charge whenever you get the chance with Li rechargeables and never let the charge get to the point that the device cuts off the power.

The charge circuit is built into the Kindle.  It is possible the charger is relatively “dumb” (I don’t know and haven’t tried to test it), but the job of even a dumb charger is to  stop the charge as the charging voltage reaches 4.1V.    If the charger did not follow up with a constant voltage charge at 4.1 v, the result  would be a reduction in run-time, but a likely gain in overall battery life, which is fine for me since the run times are already some of the longest you’d see in an e-reader. Otherwise the charge goes on longer and the run time approaches the maximum possible.  Either way works for me but a smart CC/CV charger shows a better engineering effort.  Hopefully I’ll find out what the deal is with the Kindle and get a chance to update this info.

How about using a cell phone (or other device) charger?

While I don’t recommend it,  there are situations where this would be convenient.  I’ve read several posts on the web of people who have used cell phone chargers on the Kindle with no issues.  The problem is that there is a very wide variety of chargers out there, some of which may be incompatible with the Kindle.  Here is some information that I hope reduces the risk to your Kindle if you.  Beware, unless you know the charger and what it is designed for, it is not possible to know what will work and what won’t with 100% certainty.  It’s your call!

Make sure the output voltage is  4.9-5.0v DC  (the voltage “V” will be stamped on the charger).   I don’t know whether the Kindle can handle outputs above 5.0V at this time, so I would avoid higher voltages as unknown and possibly unsafe.  If anyone has tried it let me know.   It is safest to use chargers that are designed for miniature LiPo/Li-Ion batteries in personal electronic devices.  These have the best chance of sharing the same level of technology with the Kindle.  The USB plug must fit.    Most cell phones use with lower capacities than the Kindles so using those chargers should be OK  unless the charger has a higher voltage than 5v or a charge rate exceeding 1750 ma at the extreme end.   Something between 500 ma and 850 ma is optimal.   Most of the time,  the current supplied by the charger to be lower than the Kindles charger,  resulting in a longer charge time.  This is because most cell phone batteries are not as beefy as the Kindle’s as far as total capacity.

More comments on generic, after market chargers, or a charger you have laying around the house. Assume that using any third party charger  not recommended by Amazon will void your warranty.  Common brick chargers  used for cell phones rated at 4.9V – 5.0V and 500 MA or less are probably safe.  Don’ts: If the rating exceeds 1750 ma (or 1.7 amps), don’t use the charger.  Any  charger that puts out AC and not DC is definitely incompatible – this is rare but not impossible with very specialized chargers.  Don’t use chargers designed for printers, dust busters, phones or anything but miniature Li-Ion/Li-Poly devices manufactured recently.   A hobby charger, a specialized charger, or a “smart” charger may be incompatible with the Kindle.  Don’t use these specialized chargers.    If you don’t know what a charger was designed for, don’t use it.

A few charging guidelines.  This would apply to all chargers including the OEM Kindle charger. As always, let common sense and temperatures be the guide in charging electronics.  If the device  ever feels hot while charging,  stop.  Hot is seldom a good thing (unless you race RC cars, in which case safety, economy, and all else is sacrificed for speed).  120F degrees  for anything but RC car batteries is  hot.   Warm… well charging is a warm activity. My Kindle on it’s original factory charger seems to charge without getting warm except possibly at the very end of the charge when the light turns from amber to  green.  The brick itself is warm throughout the charge and cools toward the end.

Run times.   Naturally, the longer the better for convenience.  Some things that affect run time include the following:

  • listening to music (reduces run time to a few hours – too bad…)
  • wifi/network turned on
  • indexing new books (internal processing that occurs soon after downloading new books)
  • turning pages

Most rechargeable devices  batteries will survive more charging cycles if they are never fully depleted and never fully charged to their rated capacity.

Some internet research brings up a few factoids regarding the internal components of the Kindle 3.

– 3.7V, 1750mAh (6.5Wh) Li-ion battery . Type number 170-1032-00 model number GP-S10-346392-0100

– AnyDATA DTP-600W HSPA mini PCI-E module
– Freescale ARM 11-based i.MX353 multimedia applications processor. Part number: MCIMX353DJQ5C
– Samsung K4X2G323PB-8GC3 DRAM
– Samsung 4GB moviNand storage chip — KLM4G1DEHM-B101
– EPSON KCRE7000 F10203TYV E-Ink display controller
– Atheros AR6102 ROCm WLAN chip (AR6102G-BM20)
– Wolfson Microelectronics WM8960G stereo codec



When it comes to  using the information found here and especially trying out third party chargers, please understand that the reader  assumes all risk and liability.


Making Replacement Cordless Phone Batteries

Posted in batteries, house tech with tags , , on November 26, 2010 by marksun

My 3 year old cordless phones  started to die.  They would seem fine, show full bars of charge, but then fade out, usually in the middle of a conversation,  or while the phone was ringing.   #1 went first a few months ago.  Then a couple more just seemed to be dead all the time.  One actually seemed to have some life left, but as the handsets were quadruplets, who knew which was the good one?

Replacements packs average $20 and more ready made.   Although I knew it was a rip-off  I bought one from Radio Shack a few months ago.  It is now dead, in fact the worse of four.  Fed up with the high price of incovenience and bad quality I decided to build my own.

As usual, we start in the middle.

This is what my setup looked like after  I pulled out the old packs, taken off the wrappers, pried off the battery leads or “pigtails” that plug into the phone with needle nosed pliers, and stripped about 1/8″ off the ends to bare copper wires.    These we have to solder to the new battery pack we are about to make.

Here you see the new bare cells, an old pack, a soldering iron, a roll of solder, a wire stripper and wire cutter, and a tube of flux.

I should say that this job is much easier if you already know  how to solder.  Soldering is not for everybody, but if you find you want to try, sure,  do it.   Do consider that tools make this job possible, needle nose pliers, wire cutter, wire stripper,  a soldering iron, solder,  some wire (four 2.5″ lengths of  of #22 stranded copper),  flux.   If  you buy tools you  may not save money this time around.   ( The cost of ready made batteris  =4 x $20 or $80.   The cost of 12 AAA eneloop  batteries + shipping is around $28,  a 40 watt Weller soldering  iron $20, solder ?$5,  flux ? … well, maybe you can save money).  I recommend practicing on the old battery pack first to get the  soldering technique down.   Cut off the shrink wrap because you will need the leads.

Soldering is fun and to make things even more fun, there is a little bit of danger to go with it.  You work with your hands,  high temperatures,  melting dripping metal, lead/tin and rosin fumes.   For this job, you will  need at lease a 40 watt iron.   Less than that … may not be enough heat.  It’s important to not put a lot of heat into the battery while soldering  so a hot iron is required.  The high heat make the joint heat fast before too much heat flows into the cell.    Some major soldering advice – use a little bit of  rosin flux, and apply it to all wires ends to be soldered and the battery terminals (aka “the work”) – just a thin smear is enough – this will make a huge difference in how well the solder flows.  Flux is usually a translucent amber colored fluid something like tree sap in consistency and stickiness.   It helps the solder flow out onto the work – if it doesn’t the joint won’t be any good.  OK – so if you know the soldering basics, including some way of holding the  two wires, the tree batteries, the solder, and soldering iron with your two hands  at the same time, you are good to go.

These packs are built from 3 AAA rechargeable NiMh cells.  If you buy a pack of 4 AAA rechargeables from Radio Shack or hardware store, they still cost around $20.   I went online to Battery Junction where you can buy 850 mah Sanyo Eneloops, $8 for 4 cells. Shipping raises the price somewhat.  Eneloops are among the best consumer NiMh AAA cells you can get.  Sanyo produces a good product; consistency and quality control.  I needed 12 cells for four batteries.  3 packs of four then.

Here is the finished battery pack in the phone.   It looks passably like what I took out.

Above, the bottom of the 3 cell pack soldered together.  The cells are taped together to keep things together. Note the bridge joining two cells in series with a short piece of copper braided wire.    This example is of a barely passable solder job.  The solder did melt and flow although there is a blob like appearance, the joint is not the dreaded “cold solder joint”.  You get the idea.  Make your own.

A note on battery life.  Cordless phones usually sit in a charging cradle which trickle charges the cells with a low current.  After a few hours the cradle proceeds to slowly overcharge the batteries.  The batteries will get mildly warm with the trickle charge.  Because the current is so low, there is no fire hazard and the cells will  bleed heat, but not vent or explode from gas pressure or hot electrolytes.    The overcharge is probably the reason the batteries last two years instead of five.  If the phones are used a lot, it’s possible that they won’t necessarily get overcharged – that is probably ideal.  In my household, convenience over-rides economy so the phones do tend to sit in the cradle unto death.