Archive for batteries

Amazon Fire Remote Stops Working

Posted in house tech, household appliances with tags , , , on November 9, 2016 by marksun

The Amazon Fire started complaining about low batteries in the remote one day.  After a while I got tired of that so I replaced the batteries with new Duracell alkalines.  Then the remote stopped working altogether.  Lucky I have an Android app for fire TV which works. In the meantime- after a few tries to reseat the batteries, it started working again.

Couple days later, the remote is intermittent.  It turns on the device, we watch something, try to pause, the remote is not working.

This time, I tried Corrosion Block with a qtip, reinsert batteries.  Remote doesn’t work at first, then starts working.

Two possible things going on.   1) clean contacts may be necessary.   2) blue tooth or wi fi pairing may have to occur

A YouTube video demos  Amazon advice to hold the home button for five to ten seconds. This apparently starts the blue-tooth ( or possibly wi-fi direct) pairing process.  Once started, pairing completion can be immediate or longer – maybe many seconds, who knows.  My experience sounds like pairing lag and suggests that this time can vary. Wireless networking auto-connect is one of those voodoo processes that are hard to second guess.   When it works well great, but sometimes it take a while before it starts to work (or break, again).

Somehow I bet that it is the blue-tooth all along and the playing with the remote got the pairing started.  But I’m not sure about this.   Whatever, remotes working now.

Good luck – hope this helps.

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

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.

Rechargeable Batteries and Charging FAQ

Posted in house tech, technology with tags on November 6, 2010 by marksun

Rechargeable battery technology has changed drastically over the past 10 years. Chemistries evolved from the  Nickel Cadmium (NiCad), followed by  Nickel Metal Hydride (NiMH) technology,  and now Lithium Ion (LiIon).  LiIon an lithium variants are  the new wave – the current and rapidly maturing state of the art.    In miniature devices, NiMH cells have been largely but not completely supplanted by LiIon technology.  The battery chemistries have different tradeoffs in characteristics such as capacity, voltage, discharge, self-discharge, charging, stability, durability, and life expectancy.

Ideally, a rechargeable battery is like a gas tank.  Fill up, run until the gas is gone, then fill up.  Recharging should be like filling up a car and take little time.  So how are rechargeable battery technologies doing in approaching this ideal?  The NiCad cells were good enough to make portable electrical devices possible but as everyone who ever used them knows, left much to be desired.  Run time was too short and characterized by a brief period of great performance, then a gradual drop-off in voltage performance.  Engineers profile this graphically as the so-called discharge curve, where given a fixed power drain, the voltage declined with time until the battery “dumped”, voltage went to near zero.  Internally, this behavior was determined by the internal resistance of the cell.  A low internal resistance resulted in  a longer period of good performance and a fast dump at the end (like running out of gas in a car).  A high internal resistance produced lower voltage performance overall, a slowly declining voltage dump.  As cell chemistries advanced, internal resistance dropped dramatically resulting in flatter discharge curves and gas tank like performance.  NiMh cells overcame the limits seen in NiCad, delivering much lower internal resistance, higher cell voltages, and increased cell capacities by a factor of five or six in a few years of development.  Now,  Lithium Ion cells have the flattest discharge curves to date, can sustain voltage at the highest levels of discharge ever.  This contributes to cell capacities that equal and exceed NiMh capcacities. Perhaps the most significant of the LiIon advantages is the absence of memory effect, meaning that the battery can be recharged at any time without losing capacity.

In many areas, the LiIon seems to be superior to the previous generation of nickel based cells but with technology, as in life, getting something for nothing just doesn’t happen easily.  LiIon has an Achilles heel, thermal runaway, a tendency to self-destruct if discharged to too low a voltage or charged to too high a voltage.  By self–destruct, I mean that the cell shorts internally and then reaches temperatures high enough to cause the cell to vent, explode, melt or otherwise burn and destroy the equipment it is meant to power, such as that $2000 Dell laptop.  This tendency might give one pause given that the device is often in your pants pocket, the kids backpack, or the luggage compartment of your airplane.   Despite this feature, LiIon is now a mature technology  due to a dogged determination by engineers to overcome thermal-runaway. Ways have been found to prevent the cells from operating outside their voltage range.  The problem has not gone away but by building in defensive measures into how LiIon cells are charged, discharged, and physically packaged, the incidence of thermal runaway has been progressively limited to the point that the primary barrier to technic logical feasibility, the risk of a multi-million dollar lawsuit, is close to zero.

What about the charging process?  We already talked about thermal runaway and how LiIon does not suffer over-charging mildly.  How long must you charge? Can LiIon be fast charged like NiMh and NiCad could?

Here are some frequently asked questions about batteries and how to charge them.  There are three sections:  Lithium Ion, NiCd/NiMH, AA and AAA cells.   The information here applies primarily to consumer electronics and not necessarily to hobby applications like radio controlled cars or hi-performance flashlights that have   extreme charge and discharge requirements .

CELL PHONE, LAPTOPS, iPODS and other devices using Lithium Ion batteries.  The original equipment is shipped equipped with their own chargers from the manufacturer.  Charging is done using only the manufacturer’s charger.

  1. How long must you charge? Can LiIon be fast charged like NiMh and NiCad could?  Answer: Regardless of method, the charge voltage must stay well within the operating voltage limits of the cells, which eliminates the possibility of fast charging LiIon cells.
  2. Can I top off the charge or should I wait until the battery is low?   Answer: Charge the device at any time. The lithium battery is designed to work equally well within the limits of maximum and minimum charge capacity.  The equipment is designed for convenience and a fully charged phone is the most convenient, a dead phone most in-convenient.
  3. Can a device with an LiIon battery be overcharged?  Short Answer: No. Consumer devices with a lithium battery have battery protection built in to specifically prevent an overcharge.   There is a long answer (yes), but that is why consumer devices have battery protection circuits built in.  Protection circuits can be in the battery pack itself, in the device itself (special chip), and/or in the charger which plugs into the wall.  It is best to limit charging activity to getting a full charge and then disconnecting the equipment.  Why 1) trust the manufacturer more than you have to and 2) use more energy (i.e. money spent of electricity) more than necessary?
  4. Well, is it OK to leave equipment on the charger overnight?  Answer.  No.  But: Everyone does it, and manufactures know this so they build in overcharge protection (see the previous question).    Better to charge while you’re awake and unplug when you sleep.  LiIon can be charged anytime and a partial charge is better than nothing.
  5. What is meant the “dangers” of LiIon batteries?  Answer:   This applies to most kinds of batteries, including LiIon.  If the battery pack is short circuited, for example by contact with a metal object like a pin, tinfoil, coin, bare wire, or other metalic junk, the metal object and the battery pack can become hot.  Hot can be anything from red hot, posing a true hazard of serious burns, or, not as serious, just smoking, spitting hot with smoke, steam or jets of caustic  chemicals venting from the battery.  The heat can cause a pressure build up and a hazard of explosion, big enough to hurt someone within a couple of feet of the device for small devices.  The physical hazard increases with size.
  6. Ok, I didn’t follow the manufacturers guidelines and now gasses and smoke are shooting out of my battery pack.  What do I do?   Answer: Think people first and your safety, then property.   If there is fire, deal with the fire first.   If the problem is only with the battery pack or device, while you think about what you will actually do, unplug from wall power if that can be done safely,  put on work gloves and eye protection. Don’t breath the fumes.   A covered fireproof container would be handy to have about now.  Metal is fine, it is too late to worry about shorting the battery.  By any means possible, get the smoking fuming mess out the door and out of the house.

Nickel Metal Hydride (NiMh) or Nickel Cadmium (NiCd) Cordless Phones, Power Tools, Dust Busters and hand Vacs.

  1. Should I top off the battery charge or should I wait until the battery is low?  Answer:   With NiMh cells, there is  a trade-off between battery life (months or years before you need a new battery),  and convenience (how long you can use the device between charges).   Where convenience or need is more important, charge now.  Otherwise, the service life of the battery will be best served by fewer charge cycles. Do the same with NiCd but as soon as possible, let the battery discharge completely as soon as possible, then charge fully.
  2. Is it OK for the battery to sit on the charger?  For NiMh batteries – No.  After a full  charge,  remove from the charger, unless you have a charger that automatically stops charging.
  3. Is it SAFE for the NiMh or Nicd battery to sit on a charger?   Answer:  It depends on the design of the charger.  Safety depends on how hot the battery and charger get which depends on the charge current.  A trickle charge may be safe … e.g. cordless phones often use a very low amp charge and the phone can sit there indefinitely without getting hot.
  4. How do you know if the NiMh battery is charged?  Answer: A good peak detection battery charger stops the charge and indicates full charge.  Otherwise, with simple brick charges and no charging circuit in the device, there are at least two methods, one requiring measuring the voltage of the charge, and the other is temperature.  Because we’re talking about practical household applications, temperature of the battery is simpler indicator.   As a NiMH battery approaches full charge it gets warm.  When it overcharges it will get hot.   Unless you know what you are doing (there are situations when overcharge is acceptable and you will know what those are), don’t let a NiMh battery charge to a temperature over 125 deg which will be uncomfortably warm in your hand.  If you do, well that’s how it goes and you got away with it.  After you take a NiMh battery off the charger, it may increase in temperature for a few minutes.  The main enemy of a battery is heat, but then, the main cause of heat  is just using a battery , so you really can’t win.
  5. How do you know when a battery needs to be replaced?  Answer: If you are not happy with the device performance because the battery will no longer hold a charge for a useful period of time, that’s it.

Charging AA, AAA NiMH Batteries

You can get high quality rechargeable AA and AAA batteries at most hardware stores and even Costco.  Duracell, EverReady for example carry decent rechargeable cells, often packaged with a plug in charger.  I’ve found these  work well.  Some pointers: look at the mAH rating.  If you could trust the numbers, the higher numbers, e.g. 2200 mAH for AA for example,  mean a higher capacity and a better battery.  Low numbers, for example less than 850 mAH generally mean an inferior product these days.  Therefore most manufactures tend to exaggerate the numbers. At the current time, numbers greater than 2700 mAH are suspect.  Some brands that tend to be better are in decreasing order,  Sanyo, GP, Panasonic,  SAFT – these three are original manufacturers.    Duracell and EverReady are resellers of products from these, and perhaps other manufacturers.  When it comes to the best manufacturers of NiMH technology, some excellent Chinese manufactures license American technology, and produce excellent cells.  Sanyo and Panasonic develop their own technologies and are usually among the best.  Even within a brand, there can be a wide range of quality.

Battery and Light Links

Posted in light, technology with tags on May 3, 2010 by marksun

This is is the best site I know of  about the current rechargeable battery chemistries and charging information.

For AW Li Ions cells that I use, this is a pretty good link

I have lights from 4 Sevens : including two “Quarks”  which are a series of modular LED lights featuring interchangeable parts to support different battery types in different combinations  (CR123, 18650, AA, 2xAA, etc) to power the same LED “head”.  They feature different switch types as well, the so-called tactical switch, and standard “clicky”.