Hello sir,  Im intrested in solenoids feild and wanna have practical experince in that.can you please tell me how to generate electrical charge by using solenoids and storing that charge in mica capacitors with less voltage rating high storage capability..which also has slow discharge. The time of storing the charge should be high.Hope will guide me. Thankyou. Raghudeep,

I was wondering if anyone had any ideas on how to make a circuit so that I could charge a battery, but that I can also power an amplifier when the battery is not charging. Currently I have a switch that switches between a charging circuit and powering the amplifier, but I was looking for a way to do this without having a switch that I have to control

So i would like to make a simple wireless charger for an ipod (ok ok its not so simple once you factor in the ipod) but i want it to be able to show a charging sign.... also it would be nice if it waould work from one or two feet apart minimum. I heard guys at MIT made one for a 60 watt lamp that worked 2 meters away... so its possible... i can probably order any circuitry if it is reasonably priced and available at digikey or mouser. :) I have access to several ipods so it doesnt really matter what model i use. I also know that this would probably make a huge electromagnetic wave... possibly? idk... but if it is big enough to destroy nearby electronics i might not want to try... So i am all for distance- the farther the better.... Also base power is not an issue, i can use a wall wart if i need to...i can just see an ipod touch with 500 passes of wire around it 5 feet away from a 2 foot square power station..... all while erasing my hard drive :) Soo.... im coming back to reality for a min.... anybody know any sites....any formulas too!! Thx! :) :)

If i charge a battery when it's half full will ruin the battery life between charges?

I just joined today and my bank notified me that I was charged twice for this membership. Please explain and correct. MilDoc

Does anybody know how to charge a nihm battery extremely fast?

How can i charge my battery, i've lost my charger. the battery is 14.4V 1.5Ah Li-ion

I have a nokia 6061, just got it a week ago and when i went to charge it today nothing happened. The outlet is turned on and the phone works fine it just won't charge! Any ideas on why this is happening!

Hi, pls suggest me for the following A 20Watt ( 20V , 1000 ma) solar panel is connected to charge a 12V, 80AH battery . What is the value and wattage of a Current limiting resistor to be added?

How do I charge a capacitor rated for 450v at 1150uf using 2 AAA batteries? I tried using a mini transformer but it takes a very long time. Is there a quicker solution? Thanks in advance, IndianHacker

I have battery 1cell NI-MH AA 1.2 v 1500mAH   and i need to charge it by using smps and diode for detect peak voltage of battery   i prefer fast charge for maximum 2 hours for my project  how much voltage and current i need in output of smps ?

Hello, So I have a 9.6 volt  NI-CD 4 hour quick charger and the battery(600mah) that goes with it, but I was wondering if I could charge a 7.2 volt 2000mah, Ni-Mh battery with it. If i can for how long?

Question for you all. I have a solar powered spot light I really like, when it's charged up. It has a 6vdc 4ah battery in it and I wish to re-charge it from my 12vdc system. Source power will be my 12vdc 160 ah battery and I'm thinking of using my extra 12vdc charge controller with a 3.5 ohm / 1 watt (or better) resistor attached to reduce the power to 6vdc. I believe that will work, but I don't know if the controller will know when the battery has reached capacity? The other thought is to just by-pass the 6vdc battery and run the light from the 12vdc system (using the resistor to reduce the power). Any thoughts?

Hello, So I have a 9.6 volt  NI-CD 4 hour quick charger and the battery(600mah) that goes with it, but I was wondering if I could charge a 7.2 volt 2000mah, Ni-Mh battery with it. If i can for how long?

Recently I've had an idea for a project that requires a relatively low voltage (5 to 30 volts) capacitor bank. However, that capacitor bank needs to be charged. While I do know you can easily just hook it up to power, I find that too simple, and lacking of safety, and knowing when it is fully charged. So, could anyone please enlighten me on how i can charge my cap. bank relatively slowly, with, say, an LED that lights up when charged (to avoid them blowing up in my face), and a kill switch/button that discharges the capacitor bank in the event of an overcharge. If anyone could provide an explanation or circuit diagram that would be great, thanks. BTW, the capacitors I was planning on using are http://www.goldmine-elec-products.com/prodinfo.asp?number=G17623 or http://www.goldmine-elec-products.com/prodinfo.asp?number=G16573.

Having had to buy a dedicated charger for some 18650 cells (at my wife's insistence) I took an interest in these cells for the first time and their smaller cousins the 123a. At with maximum capacities I've come across so far of 3700mAh and 2000mAh respectivley that's twice the capacity of the battery in my smart phone and 2.5 times the capacity of the one in my basic bar phone. The smart phone width would accommodate 3 of the 18650 cells (6 days without charging at my rate of use) and the bar phone possibly 4 of the 123a's (70 hours talk time or 10 months on standby). Yes this would mean a custom made back, but there is at least one instructable on molding a GRP/ carbon phone back adjusting it to take extra cells and maybe ports just needs modeling clay. I suppose I could just carry a power bank, but why if the phone can be its own power bank? Removing the guts of a power bank and building a new phone back to accommodate them may be the simplest answer to this but, my questions are:- A) I've got old mobiles laying around could I use their charging circuits to charge these standard Li-ion cells? Assuming that is a yes that would mean a long charge every 6 days/ 10 months. I gather there are problems associated with parallel charging/ discharging of Li-ion cells and over discharging so, B) Any advice on doing this other than don't? On the assumption that's a don't or even if its not this strikes me as a safer possibility. C) Could a micro controller be configured to discharge one cell to its limit then switch to the next full cell. D) Could a micro controller be configured to charge one cell to capacity then look for the next under capacity cell and charge that. E) if so could it do both at the same time? If A is possible and the rest not then a multi position switch is  probably the answer.

OK, I have disassembled a old electric tooth brush and I am trying to reduce the size and one of the things I have deemed unnecessary is the PCB that runs the timer built into the toothbrush. However, one thing I am wary of at this moment is that the toothbrush is a induction Charger which is a A/C and I don't know if I can just remove the board and be OK or do I need to rectify the current into D/C to continue charging the battery. If the latter is the case what do I need to achieve this?

I have the cm3024z charge controller. i have 240 watts going in, controller going to batteries, no conection on the load,   have 1500 watt converter hooked to batteries. set the controller as such,,, HvD-14v, LvR-12.5 v'  LvD-10.8 v . my voltage comming in to the controller is good, when i get to the hvd it kicks out at 14v as it should, but my lvr doesnt want to kick back in. i have let the batteties drain below the lvr but will not kick back in ..  is there anybody that can help with this, i have retured the first one and this is my second one with same problem. i have left the system hooked up as acording to manual,but after it kicks out it just wont kick bavk in unless i disconnect the panels and reconnect them.   all help would be appreciate, thanks

I recently got a few of the 3000 farad 2.7 boost caps from electronic goldmine.  I have a quick question about charging them.  Applying a higher than rated voltage before the capacitor is charged all the way would be fine, right?  The voltage drop should cause the source voltage to approach 0, thusly below the 2.7 volt rating.  As an extreme example, lets say you simply hooked up a 9 volt battery to it.  Since the battery can only supply like 200mA, the voltage drops to nearly 0 as the capacitor appears to be a dead short.  The dielectric (or ion exchange or napheon membrane or whatever it is in a ultracap, lol) should be fine, correct? My main goal is to later hook up one or two of these for a regenerative brake system of something like a small gokart or bike or something.  Stopping at 30mph is like (assuming 200kg total mass) 20k joules, and each one can hold about 10k joules, and assuming a max efficiency of like 30 or 40% (I think itd be much lower, though), these capacitors could brake a gokart going fairly several times without having to be discharged inbetween cycled (but of course they would be).  For braking, could these essentially be hooked up directly (of course with pwm, and other things, but in essence:) to the motor with a little protection circuitry to prevent overcharging the capacitors?  Or would the higher voltage instantly puncture and destroy the boostcap?

I want to know if my lead acidic battery is charging.can i use a volt meter to know that ?and how?

I read some where that you need a rising amount of volts to charge a capacitor, but I also always see around that you can just charge a capacitor on just a straight battery that is DC. I am very confused how you can and should charge a capacitor.I think the formula for charging a capacitor is i=C(dV/dT)Thanks

I'm modding something (secret, Instructable later) and there's going to be some integrated NiMH batteries to replace the one 1.5 AA battery that the device use to use. Due to funky space constrictions, I'll be using 7 tiny 320mAh 1.2V NiMH coin cells in parallel (to get a decent amount of maH). How hard is it to charge a bunch of batteries like this? Could I get a chip from a place like Maxim or TI? All of their chips require the batteries to be in series... Thankyou!

I dont have much experience designing circuits but i can soldier. I need to design a circuit that can charge 2 aa rechargable batteries and power 2 leds. Each rated at 25ma and 2.0~2.2. I want the circuit to be charged by usb and use a 3 way switch. Off, on (both leds) and charge. The usb will be plugged into a mains usb charger, not a pc port. I think i have included all important details. So please help me by explaining what i need to do and possibly schematics.

Hello everyone, I'm new to electronics and while I can usually find what I need by asking good ole' Google, I decided to try asking a forum of people more knowledgeable on the subject. My question relates to the charger input on devices with internal batteries. I have a Braun razor that can be used in the shower, and I was curious how it can go in water with the two charging prongs exposed? Thanks in advance! 

Hi,every body its my first post here . i like this site a lot .i want to say that i have to do a project soon but i don't know what to do am good at programming with microcontroller  but  i was surpresid that no one here use it i mean you use ready things and hacked ones. could any one help me to choose a good project i want also to ask about the charging .if i want to make a charger for many things i saw some project in this site from usb port to charge a mobile you calculate the voltage but the current>???? i mean this will not burn the mobile or anything how do you ensure that the current is suitable? i want also to ask about the solar cell?how we can create it from scratch or where can i find a ready one?if i don't want to buy it thanx sorry about my bad english

Quick question about charging SLA Batteries, I haven't really dealt with battery charging too much in the past.  I have two 12v 5Ah SLA batteries, in series, and I have built an under/over voltage protection circuit for each of them, but while charging I noticed that testing voltages across each battery, they are different, however, as soon as I remove the charger and test them as is, they have the exact same voltage (+/-0.05 volts, they are very close).  Is this just because the charger is hooked up, or should I be worried at all about that? I am charging them to 14.75 volts each, or would like to, they say they should be charged to 14.5 to 15v right on the front of them.  While charging they both climb, but one climbs faster and stops once the voltmeter reads 15.2v across it.  0.2v over the rated value really doesn't seem to be of major concern, I just find it odd the different voltmeter readings across the batteries are different while the charger is connected and identical when its not.  Does it have something to do with charging them in series?  I did read that you really can't measure batteries while charging, you have to disconnect the charger first, but any insight would be appreciated.

Hi Everyone, I am creating a 6 cell pack (first time as you can tell) of LiPoly batteries 14.8V 5A it will have 3 groups in series of 2 in parallel for a 44.4V 10A pack. In order to properly charge and maintain the batteries does anyone have any recommendations for a good balance charger from hobbyking or elsewhere? Also in order to properly charge them should I charge each of the 6 cells individually, or charge the 3 packs of 2 in parallel using these?  Thanks for your help.

I need some help from all yall out there. My idea is a wirelessly charged mouse. The mouse pad acts as the transmitter coil, and the receiver is in the mouse. The concept might not be phenomenal for gamers, but would be a step into getting rid of wires on our peripherals and really making wireless charging reality. Perhaps a .2 farad super capacitor (.2 Farads ~ 400mAh) could be used to prevent the mouse from dying if you drag if off the pad for a few minutes. I'd need help conceptualizing it and for those of you who know about electronics, assisting me in designing a schematic. The design would be open source so we can have literally anybody contribute and improve the idea. Leave a reply if you want in!

I got this from a lightbulb. (three way)

Hi,  im a student, i just  wanna ask if i can use the charge controller CM3024Z to a Magneto (alternator) and coupled with a solar panel 50watts? does the solar charge controller are for solar panel only? thanks godbless

I was charged twice on the same day when I signed up for my membership!  How can I get this corrected?

What happens if you connect some form of dc power source that supplies 100 volts to a capacitor that is rated for 100 volts, and leave it plugged in for a long period of time. would it eventually "over charge" and explode? would it over heat? would it loose its  ability to store energy?

I don't know how (actually I don't know what to use) to charge capacitator .Someone help me? I know i need at least 5kV power supply but where to find it?

How do I charge my 450v capacitors with a 120v outlet? I am building a rail gun and need to get these up to a high enough voltage. 

I'm making a prop that has 6 12v 6800mAh rechargeable batteries, but i wanted two ways of charging them, a normal plug in to a wall adapter, but also jump lead connectors, so I'm able to charge it of a reving car, or a leisure battery, all my questions are, is what would i need in the circuit to make it safe, and work, imbetween the jump lead charge wires, the normal adapter charger lead, and the batteries them selfs. JUMP LEAD------------  ??  ----------------------------       WIRES                                                          |                                                                             |------------------  ?? -------- BATTERIES ----------12v -------                                                                             |                                                                             POWER ADAPTER------------------  ??  ------------|                       

I was charged for a full year of pro membership when I only signed up for a month of pro. I did not even select the year. So I want to know what I can do to get a refund for the year when all I wanted was a month.

I was thinking, wall transformers only transform so much energy(70-90%?) the rest goes off into heat. so, wouldnt it be better to charge 160 AA batteries at the same time in serial (thus making 240V) directly off the wart? i know this is just theory, since its not practical, not managable or anything, but i just wondered if it could be done. would this solve the energy loss from heating the transformator up?

I salvaged a battery pack from an old laptop and i was wondering if i could charge the cells in the pack using the laptop charger that came with it. can i connect the power connector rom the charger straight to the control board inside the pack or do i have to get a different charger to charge each individual cell? bottom left of the picture is where i think the power goes in and out (red and black wire).

Have been looking at the instructable on the micro solar generator, and wondering if there is a formula to calculate how big a solar panel is needed to charge a battery. I'm looking at maybe using a car battery to run some LED globes such as the one below on my deck, they run at 1w 8mA 12v. Any ideas?

I need a nice, simple charge indicator. I have a battery pack that holds 4 AA NiMH batteries. Normally they charge up to 1.3V per cell or 4X1.3=5.2V total. I have a solar trickle charger on there too and I'd like to have a little charge indicator.   Requirements are: -low part count -under $10 -small (it's on my bike helmet) I was thinking something with a pushbutton an LED or two and a zener diode. Something that turns on the LED at  greater than 5.2 volts. But I don't have experience with zener diodes. Has anyone seen a system like this around? Can you think one up? -Cheers

Anyone thing this kind of thing can be done?http://crave.cnet.co.uk/greentech/0,250000598,49301285,00.htmim not sure if flexible solar panels are avaliable

Will this work? please reply with this LED work for me.....If i put the  USB cable from my phone or mp3 player  instead of the diode...Will this work? P.S.  my english is not very well

I've just got hold of a Union 6V 3W dynamo with lights. I'd like to charge 4/5/6 x AA batteries during the day then switch to the batteries for the lights at night. I'm switching out the old bulbs for LEDs. Any pointers or relevant 'ibles would be great. Thanks in advance people.

I have recently bought this solar charger kit from amazon.com (http://www.amazon.com/gp/product/B004FOEUI0/ref=oh_details_o00_s00_i00?ie=UTF8&psc;=1) and was curious if i could charge two of these small sla batteries hooked in a parallel to power a project. If it is too much power how would i bring it down to a safe level for the batteries? help would be appreciated thanks: Harry

Has anyone built a Casio Commando Dock?

So I bought one of these to play with: http://www.ebay.com/itm/130935883579 The transmitter board always gets really hot and smells faintly of something burning.  Is this normal?  Should I use some type of heat sink? Anyway, I discovered that you can add another coil of the same-ish size to the transmitter, and both coils will work.  However, if I remove the coil and add a single coil twice the size, it does not work.  I'm curious as to why.  What determines how large the coil can be? 

How to make a simple multi mobile charging box? this charging boxes are mainly used on airports. that charging box should be simple and innovative.it should have different usp

I bought some cheap 360 battery packs on the internet and big surprise they don't work.  The problem is that the built in charging circuit charges the packs to around 2.26v when my controller wont turn on until closer to 2.5v.  My idea is to use the indicating LED (that came as part of the pack) that has a forward voltage of around 2v to drop the 5v charging voltage down to 3v and charge the packs to that voltage.  Theoretically when the packs reach 3v the LED will not be able to sustain the forward voltage and will turn off stopping current flow to the batteries and thus stop charging.  I have a lot of knowledge about electronics, however my knowledge of batteries and their sensitivities is just about nill so I thought I'd ask here before I rig this together and get an idea of the likelihood of the batteries blowing up.  I've attached an image of the proposed circuit any knowledge would be greatly appreciated.

Using Neodymium magnets on the spokes of a bicycle rim, and coil around both forks.

A while ago (a few months maybe?) I bought a cheap robot vacuum cleaner from a car boot sale. I decided to take it apart as it was pretty useless as a vacuum cleaner. When I took it apart I kept the battery and the charging plug (wall wart) together. Now I want to use the battery but I am not sure how to connect it to the charger. (I tested the battery and it still works.) The battery is a 6V 2.8Ah valve regulated sealed lead acid battery. On the front of the battery it says it needs a constant voltage charge of 7.25-7.45V and less that 0.84A.  The plug that came with it is a 7.5V 600mA wall wart.  I have a vague recollection of how it was connected up. I remember that there was a diode in the mix. The positive terminal was connected to a switch and then the main control board. The negative terminal connects to the main control board and there is also a small wire that was connected to something else. I would like to know how to connect this up in such a way that is safe for charging the battery?