dead unused NiMH AA cells

Started by Adam Funk in sci.electronics.basics2 years ago 6 replies

I recently opened a pack of NiMH AAs that I'd had lying around for a while, & some of them wouldn't charge at all. I tried putting them in the...

I recently opened a pack of NiMH AAs that I'd had lying around for a while, & some of them wouldn't charge at all. I tried putting them in the fancy German charger as well (I can't remember the model name, but it's the one that has discharge, test, & refresh modes) but it just showed "null" for them, as if they weren't even there. Is there some need to charge NiMH cells as soon as you buy ...


Reviving 'dead' PP3 NiMH?

Started by Terry Pinnell in sci.electronics.basics2 years ago 6 replies

Some of my PP3s steadfastly refuse to recharge. Neither in my 'intelligent' nor basic chargers. Despite being years old, I'm reluctant to dump...

Some of my PP3s steadfastly refuse to recharge. Neither in my 'intelligent' nor basic chargers. Despite being years old, I'm reluctant to dump them. Any tips from others who have managed to bring these back into service please? -- Terry, East Grinstead, UK


# of batteries to cause polarity reversal

Started by Anonymous in sci.electronics.basics11 years ago 22 replies

If I have two NiMH batteries in series under a load, and one is weaker than the other, is it possible for the stronger one to force the...

If I have two NiMH batteries in series under a load, and one is weaker than the other, is it possible for the stronger one to force the weaker one to reverse polarity?


Soldering onto NiMH batteries?

Started by DeanB in sci.electronics.basics9 years ago 9 replies

Hello all, I've only done a little soldering before, but I want to rebuild a battery pack for my TI-59 calculator (which is basically 3...

Hello all, I've only done a little soldering before, but I want to rebuild a battery pack for my TI-59 calculator (which is basically 3 AA-sized batteries soldered together in series). Can I just solder directly onto the battery terminals? With a copper wire. Should I use flux? Will this overheat the battery and/or blow it up? Thanks for any tips!


NiMH charger recommendations?

Started by DaveC in sci.electronics.basics6 years ago 20 replies

First of all, this is a request for a *recommendation*, not a request for someone to do Google searches for me. - - - I need a charger for AA,...

First of all, this is a request for a *recommendation*, not a request for someone to do Google searches for me. - - - I need a charger for AA, AAA, and 9v batteries. Four of the AA or AAA at a time is OK. I see very few that support all these batteries (Maha makes a separate charger for 9v). Of those that do, not all use delta-V termination (or don't specify). Of those remaining th...


OT: cordless screwdriver

Started by Pimpom in sci.electronics.basics5 years ago 15 replies

Is anyone familiar with the cordless screwdriver in the link or a similar one? I'd like to know if using rechargeable 1.2V NiCd or NiMH cells...

Is anyone familiar with the cordless screwdriver in the link or a similar one? I'd like to know if using rechargeable 1.2V NiCd or NiMH cells instead of the specified 1.5V alkalines will result in a severely reduced torque. http://www.ebay.com/itm/Black-Decker-6-Volt-Alkaline-4-AA-Battery-Operated-Cordless-SCREWDRIVER- NEW-/251240800353?pt=Power_Tools&hash=item3a7f1e6061


Help me build a bicycle phone charger

Started by BikePilgrim in sci.electronics.basics10 years ago 18 replies

Hello, I recently built-up a front wheel for my bicycle that has a 6v/ 3.5w dynamo. These are designed to power headlamps, but I'd prefer...

Hello, I recently built-up a front wheel for my bicycle that has a 6v/ 3.5w dynamo. These are designed to power headlamps, but I'd prefer to store the electricity in a battery which could charge my phone. I believe iPhones charge on standard USB. My first question is about the battery. Of course, any cell or chemistry would do, but I'd like to use NiMH AA cells so that I could easily repla...


lm555 timer problem

Started by Cliff Hartle in sci.electronics.basics7 years ago 18 replies

I have a basic off the shelf astable timer circuit with the diode for less than 50% duty cycle thats on this...

I have a basic off the shelf astable timer circuit with the diode for less than 50% duty cycle thats on this page. http://www.doctronics.co.uk/555.htm#more_astables I hooked it up with 4 AAA NiMH batteries. I used an LED to get the resistors correct for the timing I need and it all works. I'm going to drive a relay with this circut so I hooked up a 5v reed relay with a protection d...


=?ISO-8859-1?Q?Rechargeable=A0Batteries?=

Started by alice in sci.electronics.basics4 years ago

Hi all, Rechargeable Batteries: High capacity rechargeable NiMH batteries for digital cameras that use AA, AAA batteries, handheld radios at...

Hi all, Rechargeable Batteries: High capacity rechargeable NiMH batteries for digital cameras that use AA, AAA batteries, handheld radios at long life. Shop online huge selection of rechargeable batteries. If you are looking for batteries and other related items then visit: http://www.greenbatteries.com/rechargeable-batteries.html for more details.


OT Lipo battery charger

Started by George Herold in sci.electronics.basics1 year ago 1 reply

So my son is into RC... He's bought some old RC cars back to life and watns to run them with new Lipo batteries. We are now looking for a...

So my son is into RC... He's bought some old RC cars back to life and watns to run them with new Lipo batteries. We are now looking for a battery charger. Any recommendations? price ~$100. This one in particular, http://www.ebay.com/itm/Venom-Pro-Duo-80W-X2-Dual-AC-DC-7A-LiPo-NiMH-RC-Battery-Balance-Charger- /401004922785 TIA George H.


ATTiny13 voltage and current ratings

Started by Anonymous in sci.electronics.basics10 years ago 11 replies

I was reading the datasheet on my ATTiny13, and noticed the following ABSOLUTE MAXIMUM ratings: Maximum Operating Voltage 6.0V DC Current Vcc...

I was reading the datasheet on my ATTiny13, and noticed the following ABSOLUTE MAXIMUM ratings: Maximum Operating Voltage 6.0V DC Current Vcc and GND pins: 200 mA I was planning on powering my device with 4 1.2 NiMH batteries. Do I still need a 78L05 voltage regulator, or can I skip that? (I've got one just in case, but wondering if it's necessary with 4.8V nominal...) Why the res...


Overcharging NiMh batteries?

Started by Bill Bowden in sci.electronics.basics2 years ago 3 replies

My neighbor has a solar powered outdoor decoration light that cycles through several colors but only runs for maybe an hour at night. It has a...

My neighbor has a solar powered outdoor decoration light that cycles through several colors but only runs for maybe an hour at night. It has a single 1200 mAh 1.2 volt rechargeable battery and a couple small solar cells to charge the battery. I measured the load current at 15 milliamps and the charge current at only 1.3 milliamps so it appears the solar array is not charging the battery ...


AA Battery capacity tester- resistor & clock

Started by Jim Elbrecht in sci.electronics.basics10 years ago 14 replies

I've got a couple dozen Nimh batteries that are starting to show signs of age. [some are 7yr old 800mAh, the newest are 2000 mAh & 3-4...

I've got a couple dozen Nimh batteries that are starting to show signs of age. [some are 7yr old 800mAh, the newest are 2000 mAh & 3-4 yrs old] I googled for capacity testers and found a post that said to wire a 1 ohm resistor in series with a aa battery operated clock. Set the clock to 12, insert battery, wait until clock stops. I have a box of clock parts so I set up a 4-battery test...