Project idea?

Started by bitrex in sci.electronics.design6 years ago 9 replies

I have 20 feet of EL wire, a HV inverter, 500mAH LiPo battery with charger, and one of these wearable microcontroller...

I have 20 feet of EL wire, a HV inverter, 500mAH LiPo battery with charger, and one of these wearable microcontroller protoboards: https://learn.adafruit.com/introducing-gemma/introduction I think there's a fixed-point FFT code snippet that runs on the ATTiny85, though the resolution is probably rather limited. Halloween is coming soon, what should I make?


Charge time

Started by Andy K in sci.electronics.design8 years ago 11 replies

6 VOLT 4.5AMP HOUR RECHARGEABLE SLA 4.5AH SEALED BATTERY If I use a 500 Mah charger to charge it, is there a formula to determine the charge...

6 VOLT 4.5AMP HOUR RECHARGEABLE SLA 4.5AH SEALED BATTERY If I use a 500 Mah charger to charge it, is there a formula to determine the charge time based on the starting voltage ? Thanks gentlemen and scholars. Andy


Rechargeable "AA" Lithium Ion

Started by Mark Hopkins in sci.electronics.design10 years ago 12 replies

Are there any name brand "AA" or "AAA" Lithium ion cells on the market that can be RECHARGED? Or anyhting that looks roughly like good...

Are there any name brand "AA" or "AAA" Lithium ion cells on the market that can be RECHARGED? Or anyhting that looks roughly like good quality. Please advise source for cells and charger. All I can find are Chinese ones on eBay. Mark Hopkins


Decoupling

Started by Raveninghorde in sci.electronics.design10 years ago 29 replies

I've always used parallel capacitors such as 1nF and 100nF to get good decoupling. I have the impression this doesn't really apply with...

I've always used parallel capacitors such as 1nF and 100nF to get good decoupling. I have the impression this doesn't really apply with surface mount capacitors. I'm redoing a 250kHz 5A charger design which has 4u7, 470n, 47n in parallel with the same the other side of a sm ferrite bead. What would you do to keep crap in?


Li-Charger IC: Searching for datasheet

Started by Reinhard Zwirner in sci.electronics.design5 years ago 3 replies

Dear experts, I'm searching for the datasheet for this IC: Manufacturer obviously is Microchip Technology, but that's all what I've...

Dear experts, I'm searching for the datasheet for this IC: Manufacturer obviously is Microchip Technology, but that's all what I've been able to find out. Therefore I do hope to find help here. Thanks in advance Reinhard


moving the B down the curve

Started by Yzordderrex in sci.electronics.design3 years ago 14 replies

I am wondering if it is possible to use an anti-current to push the B down the curve. Let me explain. I need a large inductance at a high...

I am wondering if it is possible to use an anti-current to push the B down the curve. Let me explain. I need a large inductance at a high current for a 60 Hz battery charger. 50+v at 80amps should do fine. Of course, We =LI^2 is going to determine the physical size of this unit, and it will be large. (Obviously PFC would be a natural way to go, but time is a factor. ) I s


Sepic Charger

Started by captoro in sci.electronics.design7 years ago 13 replies

Hello all, I am attempting to design a sepic converter ( DC to DC) design. Basically s= olar panel to charge a battery. Therefore Input will...

Hello all, I am attempting to design a sepic converter ( DC to DC) design. Basically s= olar panel to charge a battery. Therefore Input will be anywhere from 6 to = 20v and OUTPUT 12v. I am making the following circuit: http://jordanofoz.com/tunecharger/52_mtc_43_evaluation_module_d.pdf I am doing the software part new and having nig problems with the duty cycl= e. I want to keep a con...


How do i choose a IC Battery Charger ?

Started by R. Hernandez in sci.electronics.design8 years ago 9 replies

regards about current set-up current? output current? Battery current? the goal is for a 3v6 1 cell Li-on Battery Tnx!!

regards about current set-up current? output current? Battery current? the goal is for a 3v6 1 cell Li-on Battery Tnx!!


Battery charging

Started by Anonymous in sci.electronics.design6 years ago 27 replies

Hi, I am looking for Lead Acid battery 24V, 12AH. The problem is that I am unable to find one under 30 bucks. Can anyone give a...

Hi, I am looking for Lead Acid battery 24V, 12AH. The problem is that I am unable to find one under 30 bucks. Can anyone give a suggestion? The alternative is to is to add two 12V batteries in series but I do not have any information about the related complexities of charging them with a 12 V or 24V battery charger. Erica


Solar Power for Dataloggers ? - Few Commercial Choices

Started by Mr. B1ack in sci.electronics.design7 years ago 23 replies

OK ... this has been driving me crazy for awhile now. Solar battery-charger products generally assume you need hundreds of watts - enough to...

OK ... this has been driving me crazy for awhile now. Solar battery-charger products generally assume you need hundreds of watts - enough to light a house or RV or something. Dataloggers need maybe 20 mA, perhaps a brief surge to 250 mA when peripherial devices switch on for the measurements. Dataloggers also need tightly regulated voltage OUT of the batteries - WHILE they are being...


Lead Acid puzzle

Started by Tabby in sci.electronics.design1 year ago 34 replies

Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's...

Cart with 2x 12v 33Ah progolf AGM lead acids. 1.5 years after fitting new batteries the available range is down to below 10%. I'm not clear what's gone wrong. The charger in use has been a cheap chinese one with 2x13.7v=27.4v output. Single stage charging only. It has always been promptly charged after use, and never run below 50% charge. I checked the battery voltages after charge, they wer...


Tek TPS20xx battery life? JL?

Started by Frank Miles in sci.electronics.design8 years ago 3 replies

I bought a Tek TPS2012 scope (not sure; maybe 2 years ago) for one of my techs. He hasn't used it very much, but its battery is kaput - it won't...

I bought a Tek TPS2012 scope (not sure; maybe 2 years ago) for one of my techs. He hasn't used it very much, but its battery is kaput - it won't even boot unless the plugged into the charger. The charging indicator immediately indicates that it's fully charged (solid green). We should probably try to repeat these conditions so we can verify that the battery is actually getting charged a...


6v battery charger conflict

Started by Dave, I can't do that in sci.electronics.design9 years ago 19 replies

Hi All, Recently bought a weather station that wireless transits data to an inside = console. It has four AA Alkaline cells and a small (about...

Hi All, Recently bought a weather station that wireless transits data to an inside = console. It has four AA Alkaline cells and a small (about 1" square) solar = panel to help trickle charge the batteries. All good, but the batteries are lasting only about four weeks. It is a majo= r thing to get the station down from the pole on top of the garage to repla= ce the batteries. Because i...


Need help with 555 timer circuit development

Started by Toyin in sci.electronics.design7 years ago 40 replies

I need a consultant to help me with my project for a fee. I would like to u= se a 555 timer circuit to generate a variable 1 to 5 minute timer to...

I need a consultant to help me with my project for a fee. I would like to u= se a 555 timer circuit to generate a variable 1 to 5 minute timer to altern= ate between 2 bank of batteries that are connected to a charger and a load.= There are four switches where two are on when the other two are off. Plea= se send me a private email to if you are intere= sted and c


Seeking: ~120V DC 20A supply

Started by David Lesher in sci.electronics.design9 years ago 35 replies

Three of us are working on an electric car conversion. We're now working on the "home" charger for it. For that, we are seeking a digitally...

Three of us are working on an electric car conversion. We're now working on the "home" charger for it. For that, we are seeking a digitally controllable switcher supply with ~120V output, at up to 20-30A. At these power levels, 240VAC supply is more likely. Obviously new this will be $$$$, but I wonder if anyone knows of a surplus candidate. We currently ^H^H^H presently have a 48V 750...


Yellowish substance covering circuit board

Started by Andy in sci.electronics.design4 years ago 3 replies

This is a contact-less charger from an electric toothbrush.(NiCd) What is the yellowish substance that is covering the circuit...

This is a contact-less charger from an electric toothbrush.(NiCd) What is the yellowish substance that is covering the circuit board? https://www.dropbox.com/s/9azo34ohkppdho6/NiCd_Charger.jpeg?dl=0 Thanks.


Sense When No Phone is Plugged Into a USB Charger In Vehicle

Started by sms in sci.electronics.design4 years ago 78 replies

Periodically, including today, my wife heads off to work without her phones, and when she gets to work she either has to come back home, about...

Periodically, including today, my wife heads off to work without her phones, and when she gets to work she either has to come back home, about nine miles in heavy traffic, or if I haven't left yet I detour on my way to work to deliver them, or my son happens to be home from college (like today) he delivers them. What I want to do is to have a device that sounds an alarm when the car i...


Guess what I found

Started by Bill Bowden in sci.electronics.design7 years ago 152 replies

I found a HP-25 programmable calculator from about 1975 at a swap meet for $3 and it works. Complete with owner's manual, charger and...

I found a HP-25 programmable calculator from about 1975 at a swap meet for $3 and it works. Complete with owner's manual, charger and applications programs.It does 49 steps and records the keys used. The battery pack and leather case were missing so I used the battery pack and case from my HP-21. I always wanted one of these but couldn't afford it, and now I have one 40 years late. I bou...


Maybe Charge

Started by Anonymous in sci.electronics.design5 years ago 4 replies

A new electronic product will be sensing a Lithium battery while it charges to make a thermal shutdown available. It costs $4 to make. Sell for...

A new electronic product will be sensing a Lithium battery while it charges to make a thermal shutdown available. It costs $4 to make. Sell for $14. Any smart phone can sit on the "Maybe Charge" and if its Lithium battery gets too hot, a Silicon chip comes to the rescue. The socket cuts off the power to the charger if it exceeds a temperature of 454 Fahrenheit. Then you can feel you


General constraints for inductive power transfer

Started by Don Y in sci.electronics.design5 years ago 13 replies

I'm trying to get a feel for the pertinent issues that would drive the design of a wireless power coupler. [I state it as a "wireless power...

I'm trying to get a feel for the pertinent issues that would drive the design of a wireless power coupler. [I state it as a "wireless power coupler" and not a "charger" even though there will be a storage device on the "far side"; but, the item essentially remains in situ semi-permanently (the wireless aspect simply to *allow* it to be temporarily moved, as required; it is almost always *u...