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Rechargable NIMH Batteries Question

I have a laptop battery that was cracked, so i opened it up, and like any other, it had individual NIMH batteries strung together... how to i find out how much voltage the individual batteries can take? I want to make my own battery pack with several of these laptop batteries... battery pack is GP B905 NIMH 12 volt thanks

Topic by Hurdy Gurdy Man    |  last reply

DIY Rechargeable Cell Chemistry?

Hi i was wondering if there was any electrically reversible battery chemistries that can be made from around the house materials like copper wire, iron nails, galvanized nails, graphite rods, aluminum foil, and other items like those.

Question by LiquidLightning    |  last reply

Help with recharagables

First off I'm pretty expierenced with electronics, but I've not been using rechargables that much. I'm not sure how to build a charger for nimh batteries. I want to charge a 3.6v battery, 70 mah (3x 1.2 volts, 70 mah each, I know, it's a small battery for a small device) as cheaply as possiable. I also want it so that it can still power the circuit (takes about 20 maH to run the circuit) when charging. If possiable, I want to charge like 5 or 6 of these at once. Help please!

Topic by guyfrom7up    |  last reply

Using the wrong charger?

What are the risks of using the wrong charger for rechargable batteries?  Can you do it if you don't leave the batteries on too long?  Can you get away with it if you make certain the batteries don't get too hot?  Specificially for my 18V power tools the charger I have is only intended to charge NiCad batteries.  The company that made the tools has also made different types of battery packs that are interchangable in the tools, but each battery pack comes with a different model charger.  What if I used the NiCad charger to recharge a NiMh battery pack?  What if I use the NiCad charger to recharge a Lion battery pack?

Question by etcmn    |  last reply

How to charge rechargeable batteries for a project? Answered

I am going to build a solar powered USB/ Ipod Charger and I have a questions pertaining to it. A solar cell will charge 4 AA rechargeable batteries (NiMH) in a battery holder and these batteries will power a device through a Minty Boost. Now, I have little experience with creating electronics. So I was wondering if I can connect the solar cell directly to the battery holder (with a diode of course) or do I need to connect it to another component and then to the battery holder. Thanks.

Question by dom13marco    |  last reply

How to charge 4AA NiMH 1,2V 1100mAh in series? Answered

My project is a simple portable stereo box - using old USB powered speakers.I put the speakers with their little amp board in a box where I can put a 3-4NiMH rechargeble batteries 1,2V 1100mAh(in series for ~4-5V) to charge the amp board. I really want to make it so I can just plug an USB (5V) to the box to recharge the batteries when its not used so i dont have to take them out to recharge them with a wall charger everytime.I would like it to have LEDs to tell me when its charging and when its done , or even that it stops charging automatically when the batteries are charged. Im fairly new to electronics so I need the easiest way to do this if possible 

Question by AndrianS    |  last reply

Can I hold Rechargeable NiMH batteries together with magnets as a power source for some USB chargers and a Raspberry Pi

I just want to make sure that they work and won't explode, would the Raspberry pi also be damaged?

Question by Missile502    |  last reply

How to make a NiMh Battey charger for more batteries?

Hi all, I want to charge a large number of batteries at one time Say 16 X AA batteries. Can someone please guide me or point to a resource where i can get some information on how i can do this? Many thanks in advance for your feedback.

Question by muhammajunaid    |  last reply

I have a 1300mah battery charger, will it charge 2500mah batteries? Answered

I'm looking for cheap rechargeable digital camera batteries online, and 2500mah is the most abundant option. In fact, I haven't been able to find any 1300mah nimh batteries, nor 1600mah(which is what the now-dead ones are). I only have about 6 dollars to spare on this at the moment, as that's all I have in my paypal account, so there isn't much else I can do...

Question by chrispaccord    |  last reply

Why is it so hard to find lithium ion rechargeable AA, AAA, or other standard battery sizes in lithium ion? Answered

No real details here just though it would be nice to get standard battery sizes in lithium ion rechargeable instead of nimh.

Question by robbtoberfest    |  last reply

DIY or Mod a rechargable Battery for Old camera

Hello, I've got a great old 16mm Cine camera, but unfortunately the battery has corroded into non-existence. Fortunately I managed to get into contact with a guy who used to rent out the same camera and said that I needed to find or make the following battery. Voltage between 8 and 12 Volts, with 3.8Ah I would like to be able to recharge this battery as it would save a lot of money and obviously I would like an easy as well as safe way to charge them. I'm not much of an electrical guru, but I can solder, follow instructions and work some things out for myself, but I really need some help getting this machine working again. Any help would be greatly appreciated.

Topic by crudworks    |  last reply

how to make 6 volt .5ah battery power supply?

Is it possible to built by 1.2 volt 2500mah NIMH batterty. or any other way?

Question by atmhoque    |  last reply

Modified RC car

I've been working on this sucker, and I have so far added a battery pack to it that consists of 8X AA NiMh rechargeables and it goes like sh*t on a stick! 13v when it's fully charged! Check it out! Wheel cam:

Topic by Punkguyta    |  last reply

can i charge 10X1.2v 3000ma rechargeable batteries in series using a 12 volt 400ma current ?

I am building a r/c tank and i am using 30 1.2v 3A rechargeable nimh batteries. now i have tried charging them individually in my energizer battery charger, but they seem to get extremely hot (75 celcius) when i charge them for 2 hours. now in the tank i have these batteries in 3 battery packs that hold 10 batteries each and i want to know, if i put a 12 volt 400-500ma current through the battery pack, will that safely charge them without damaging them? recently i tested one of the hot nimh batteries out of the charger with my multimeter, and it read that the battery had 10.28 amps in it and had1.2 volts which is anbormal (exept for the voltage).also i was wondering, is it posible tocharge these packs which once run in parrell give a voltage and current of this (10X 1.2 =12 volt 3A) X 3 packs in parrell =12v 9A can i chareg all of those at the same time, or must i charge one pack at the same time now before you say anything ill just add that these are individual batteries that i have placed inside a battery holder pack, also ill add that i wont buy a sla battery as ive used quite alot of money on these batteries already and lastly, i am not going to go buy a 10 battery charger as they cost way too much, unless sopmeone can find one online that costs under $25

Question by oldmanbeefjerky    |  last reply

Can I connect a trickle charge solar panel directly to a battery recharger? Answered

I have a 1.8 W 125 mA solar panel, and a GP battery recharger. There is a connector that came with the solar panel that fits the recharger. I connected them and did a quick test with a bright light and it lit all four lights without batteries in the charger. Is it possible to connect a solar panel directly to the charger without some other device/inverter between the two and be able to charge NiMH batteries? I have attached a pic of the items including the information on the back of the electrical plug that came with the charger. It says input AC 120V-60Hz, output DC 12V 1.5A. The picture shows the rest. I look forward to the answer and will not attempt to connect these until I know it is safe and effective to do so.  Thank you.

Question by blodefood    |  last reply

Can a 7.2 volt battery with 3000 mah substitute for a 8.4 battery with 1100 mah ? Answered

Hi, I am Planning on going airsofting with my echo 1 m4 commando, but do not have enough batteries to make it. The batteries my gun came with were 8.4 1100 mah NIMH rechargable batteries but i have some 7.2 volt , 3000 mah NIMH batteries lying around that i use for my rc car. I would like to know whether using the 7.2 volt batteries will either harm the gun or the batteries.

Question by Whitedude0728    |  last reply

Battery Pack or Car Battery - Biking

To all of you night bikers out there, do you power your lights with a battery pack of NiMh or Li-Ion battery packs, or do you use a lead-acid car battery? The weight of the car battery kind of turns me away from it, but I don't want to have to recharge my batteries every day. I'm looking to power LEDs and maybe halogens. Thanks!

Topic by Bran    |  last reply

Can someone please help with a simple lighting circuit.?

I connected 7 NiMh batteries in series. I connected another set of 7 NiMh in series. Then, I connected the 2 sets together in parallel. A voltage check of the battery pack reads 9.4V. I want to build a miner style light out of it. I'd like to put the battery pack on a belt, and have a control box, also on the belt, with an on/off switch, a dimmer, and a battery recharging connection. I know how to solder and have a basic understanding of electricity. What type dimmer, bulb, etc. would be best? I'd like the light to be as bright as possible, without continually blowing bulbs. Something like this is what I had in mind, but I'm not sure what size/type components to use. Also, am I missing anything?

Question by coon_skinner    |  last reply

i need a very powerful battery (4000mah 10V or higher) and don't want to spend more then $30 please help! [answered]

I need a  VERY powerful battery (4000mah 12V or higher) and don't want to spend more then $30 please help! and i don't want i Puerkerts number lower than 1.2. can anyone help? oh, and the size of it has to fit in a 6V lantern. thats why lead acids bit the dust and (so far what i know) lithium polymer batteries bit the dust because they are way to expensive. with a 35W power consumption, its hard to find a power source that will fit in a 6V lantern, a affordable price (under $30) and powerful enough to power the load for more than an hour. (some calculations i did show i need at least 3500mah for 1 hour of usage ) but i think i might have a solution a 2 laptop batteries from amazon wired in parallel after they have been took apart. a drill battery doesn't even come close to the amount of i need and they suffer from memory effect and just plain out isn't near powerful enough (1.5 AH per cell) OR my second choice is to get many rechargeable AAA batteries and wire them to give 14.4V (BUT HOW DO I SOLDER THEM WITHOUT THE TABS? and what kind of array should i use? [68 AAA])

Question by -max-    |  last reply

Solar storage help

Hello! I'm new to the forums, but I've read many instructables. I'm looking to create a solar-charging messenger bag. I decided on a powerfilm flexible solar cell that is 7.2v 200mA. Amazon has them for slightly above $50. I originally wanted to use a xtreme mac Incharge portable to store the power,(PLEASE CORRECT ME IF I AM WRONG) but I think that may take too much to convert it from 120v in to 7.2v in. The benefit of this item is that it has two 1w usb output charging terminals. That means faster charging.  The second idea is to send the solar energy to four AA Energizer rechargeable (1.2v 2500mAh) NiMH batteries. The benefit of using AA batteries is they can be used for other things and that they can be easily replaced after running through charging cycles(I don't know the life cycle of rechargeable batteries anymore). Any assistance offered would be greatly appreciated. I have the bag, will be ordering the solar cell later this week, found the incharge portable at a thrift store, and always have plenty of batteries and wires. Thanks!

Topic by chokingjaik  

Simple circuit fix?(Novice)?

Built this circuit (see attachment) using 2 solar cells putting out about 5.5-6v (got crap meter atm) . 4 xAA 1.2v 2450mAh NiMH Duracell Rechargeable battery's. Found that its drawing charge from my Android phone quite rapidly. Will another diode before usb fix the problem and block current out of device? Or a 5v regulator in place?..... Although i read they need at least 7v to work or they will drop overall power? or am i just talking gibberish here and need a slap?! lol! some help would be much appreciated! Incase of attachment  failure or watever....Link:

Question by scott_shot    |  last reply

Camera/Battery Mystery

I'm trying to solve a mystery with an old camera of mine(a kidak cx 7330). It showed a low battery indicator with a fresh set of batteries, as well as some older ones-so i assumed it was broken. Once i had it replaced (which was overdue anyway, its like, 5 years old), i popped in a set of rechargables which i got with the new camera, and it worked. i tried with another, not so fresh pair of energizers ... and it worked too.  (all batteries are AA- i prefer cameras that use em, since they arn't toyishly small) Having gotten myself confused, i checked the voltages on all 3 sets of batteries. The fresh set was manganese, and 1.7v. The rechargables (nimh) were 1.4V and the not so fresh pair of energizers(alkaline) was 1.6 v and both worked. I'm wondering (other than what the hell is going on), if electronics have some kinda overvoltage protection, and if that was what was triggering off the issues, and if i ran down the manganese batteries to 1.6v or below, i could use them - that way i'd just use em for something high drain, and switch to them once its done.

Topic by faileas  

Convert 3rd party charger to charge cordless screwdriver battery

I would like to know if I can use this particular charger to charge my skil batteries. The problem I have with the manufacture’s charger is that there is no automatic shut off or protection from trying to charge a bad battery. When you charge the battery for to long or try and charge a bad battery the manufacture’s charger burns out the chargers transformer. My goal is to have a charger that I can just put the batteries in and forget about them until the next time I need them and then grab them out of the charger and have them ready to go. I can disassemble the manufacture’s charger for these batteries and easily remove all of the guts. Then could I just wire the ends of the Alpha charger to the ends of the manufacture’s charger? What do you think? Will this work? Thanks The battery is a skil 92940 Flexcharge battery 3.6-Volt 1.0-Amp Hour Nicad. The charger is an Alpha Power Battery Charger with the Specs: • 3 Easy Steps to Renewable Power 1. Insert battery (batteries) 2. Select Mode: Charge,Discharge/charge,Refresh/charge, Test/charge 3. Select Rate: 200mAh,500mAh, or 700mAh • Works with all NiCd & NiMH AA/AAA Rechargeable Batteries • Automatically switches to trickle charge when charging is complete to ensure maximum battery capacity • Automatically defaults to 200mA charge (the optimal setting for prolonging battery life) • Overheat detection to protect over-charging • Charges AA & AAA rechargeable batteries simultaneously • Will not charge defective batteries • Select different charging current for each channel • Charges Battery Types: AA/AAA NiCd and NiMH • Input Voltage for AC/DC Adapter: 100-240 VAC (works only with included AC/DC Adapter) • Charging Current Range: 200 mAh, 500mAh, or 700mAh • Max Charging Capacity: 3000 mAh • When charging is complete, LCD shows capacity in mAh for each battery

Topic by dp31959  

would putting a lead acid battery in a backpack damage it?

Im trying to find a relatively inexpensive way to run my laptop off of something that will fit in my backpack and will be something that i can carry. so far i found out that i need a deep cycle or marine battery for my inverter, and an enclosure to make sure i dont get sulfuric acid everywhere, but all of the research ive found were about home backup systems which are stationary. would putting a lead acid battery in a backpack and carrying it around damage it or make it leak? i also found a lot of lithium ion batteries on amazon around 700 to 1600 mah for $.50 - $1... the sellers that sell them for that much have good ratings, is there something wrong with these, or did i hit a goldmine? example:;=electronics&qid;=1273381311&sr;=1-20   if lead acid doesn't work (or the lithium ion), would 10 nimh d batteries work?

Question by the judge    |  last reply

DIY laptop battery pack (textbook size)

It took me a long time to find a suitable forum to ask this. I have a thread at Cnet, a tech site. I'd really like to have the power I need to last through the school day, and I'm sure other students feel similarly.  I thought about solar, but it's too low of a yield. Nimh and Ni-cad have shorter lifespans than Li-ion. What's necessary in this setup would be: small enough to fit in a backpack thin enough to leave room for my books if need be must be able to fully recharge a laptop at least once while in use. AC current preferred, DC if necessary, I can get an inverter. I have a soldering gun in my electrical kit and would love to show off to my friends next school year. edit: I forgot to include that this is to use with a laptop update: I've decided that I can use a briefcase if I get a slightly larger backpack next year. I found some batteries, and I'm trying to figure out the voltage and amp-hours for the PCB and charger To clarify: THIS IS AN EXTERNAL BATTERY PACK.

Topic by leaf26    |  last reply

Electric Motor Tricycle 6V4.5Ah

I bought a riding toy for my son and it's cool, but it doesn't have enough power sometimes.  It's fast enough in the house, but it gets stuck outside.  The plastic wheels tend to slip on rough surfaces and inclines, but I can address that issue at the wheels/tires to some degree.  However, the battery that came with it is a 6V4.5AH/20HR sealed lead-acid rechargeable battery (It has F1 contacts, so unless I change or adapt the wires/connectors, I think I need to stick with a battery that has these).  The AC-DC adapter has 6V DC 500mA output, but I think I could get a UNIVERSAL AC DC ADAPTER {1.5V 3V 4.5V 6V 9V 12V 500mA} that would work with a new battery. I'm hoping that I can increase the power noticeably but safely.  One constraint is the width of the battery area inside the "engine" compartment.  It fits the present battery (1.75 x 2.75 x 4), but I'll have to mod the compartment to fit a replacement that's more than slightly bigger. I've seen some 12V4.5AH batteries online, but most are larger in every dimension. Am I even on the right track thinking a higher voltage battery is what I need?  Could I use an NiMH or Li battery/batteries instead? What's the easiest, safest, cheapest route for this mod? Thanks, Dan

Topic by danhorowitz    |  last reply

Jobmate cordless screwdriver

Hey guys!!! Long time no see, I have been busy doing other things in my life and coming to check on here completely slipped my mind, I feel so bad now after seeing how many comments I've missed out on replying on. Also, I noticed some people around here have a PRO beside their name, what is that about? Anyways I have a question I wanted to ask. I bought this handy little cordless screwdriver at a yard sale yesturday, and got it home, plugged it in to charge, and it seemed to be holding a good charge, I used it to change some tweeters in my tower speakers, it has good torque, and good speed. Overall, for $1 I was happy with my find while out on my little adventures. Well, I went to use it this afternoon, and it was dead :( Apparently the Ni-Cads are toast. The problem here is, theres only one screw in the side of the unit, and it only lets me pry half of it open, I can't get the top off of it, there seems to be two metal tubes holding the top on. Does anyone have any idea how I'd pop this thing open?? I want to see about replacing the two cells inside with some rechargeable energizer AA's I have, would I not be able to charge them with the built in charger?? They are NiMh however..

Topic by Punkguyta  

Power supply switch for boombox project...

Could someone help me with some simple wiring questions? I've built a little boombox using a Lepai amp and some speakers. At the moment the back is off the box that houses the amp, so I can plug in a mains power adapter, but I've got a housing for 10 x rechargeable NiMH AA batteries making a 12v battery pack with maybe 20 amphours of life in it. I've only just ordered the batteries so I'll see. However, I was thinking that I'd still like to have a socket that I can plug the mains adapter into. So I was thinking about mounting a DC socket on the back plate, and some sort of switch to select the power source. 1. Does the switch need to be a 3 position one? There's an on/off switch on the front of the amp, so maybe a 2-way switch would be OK? 2. Does the switch need to be some sort of special one because it's switching power. Would something like this one do? 3. The switch has 3 terminals. How do I connect it up? I'll have +ve and -ve from the battery pack, a +ve, -ve, and earth from the DC socket, and a +ve, -ve and earth going to the amp. ...or maybe there's an easier way of doing it? Thanks.

Topic by contadino    |  last reply

Powering Multiple Servos From One Battery- What is my circuit missing?

Hey Everyone, I'm working on a robotics project right now and my limited DIYer knowledge of electrical circuits is failing me. I need to power 7 Rage Standard Metal Gear Servos (RGRS104-16-6vm) and 4 RadioShack Micro Servos using a Tenergy 6V 3300mAh NiMH Battery Pack. I've made a diagram of the circuit I'd like to make, but I feel like there's more to this type of circuit than I've planned for. There are only 9 servo connections because two pairs of Rage Servos will be wired together to share the same battery and signal connection. I'm also open to using a different battery if that's what it takes to make the robot run smoothly (It has to use a rechargeable battery though; It's meant to be portable.) Would you please point out what I need to add to my circuit to make sure it works properly? Thanks in advance! More Info: Rage Standard Metal Gear Servo RGRS104-16-6vm Dimensions: 40.8 × 20.1 × 38 mm Weight: 56 g Operating Speed: 0.18sec/60degree (4.8V), 0.16sec/60degree (6V) Stall Torque:, Operating Voltage: 4.8V~6V Control System: Analog Direction: CCW Operating Angle: 180degree Required Pulse: 500us-2500us Bearing Type: 2BB Gear Type: Metal Motor Type: Carbon Connector Wire Length: 30 cm. RadioShack Micro Servo Voltage: 4.8~6.0V Torque: 1.5kg/cm at 4.8V; 1.8kg/cm at 6.0V Speed: 0.12/60ТА at 4.8V; 0.10/60ТА at 6.0V Size: 23x11.5x24mm Weight: 8.6 g Use Angle: <=160ТА Tenergy 6V 3300mAh NiMH Battery Pack Chemistry: Ni-MH Cell Size: Sub-C Nominal Voltage (V): 6 Capacity (mAh): 3300 Max Continuous Discharge Current: 6A Battery Charging Current: Standard: 1A Weight: 10oz. Dimensions: 112 x 46 x 23mm (LxWxT) Connector: Hitech Link to Diagram:

Question by lukealbertson96    |  last reply

What's the best way to increase the power on my son's electric motor bike?

I bought a riding toy for my son and it's cool, but it doesn't have enough power sometimes.  It's fast enough in the house, but it gets stuck outside.  The plastic wheels tend to slip on rough surfaces and inclines, but I can address that issue at the wheels/tires to some degree.  However, the battery that came with it is a 6V4.5AH/20HR sealed lead-acid rechargeable battery (It has F1 contacts, so unless I change or adapt the wires/connectors, I think I need to stick with a battery that has these).  The AC-DC adapter has 6V DC 500mA output, but I think I could get a UNIVERSAL AC DC ADAPTER {1.5V 3V 4.5V 6V 9V 12V 500mA} that would work with a new battery. I'm hoping that I can increase the power noticeably but safely.  One constraint is the width of the battery area inside the "engine" compartment.  It fits the present battery (1.75 x 2.75 x 4), but I'll have to mod the compartment to fit a replacement that's more than slightly bigger. I've seen some 12V4.5AH batteries online, but most are larger in every dimension. Am I even on the right track thinking a higher voltage battery is what I need? Could I use an NiMH or Li battery/batteries instead? What's the easiest, safest, cheapest route for this mod? Thanks, Dan

Question by danhorowitz    |  last reply

12v solar panel/battery setup project- NOT lead/acid

Hi, I have a project that I'm trying to design/build and could use some help/advice with some of the electrical theory. I feel like this should be really simple but I'm having a lot of issues. I have done a lot of googling but can't seem to find applicable answers so I started my own thread. Any help will be greatly appreciated! If I can solve this, I will be happy to write up a detailed instructable so that others can use this information as well.  The short version: Trying to build a lightweight solar panel>battery pack>UHF radio charging setup. Nominal voltage is all 12v. I'm having difficulty regulating amperage between the units. The long version: My friend is in charge of a campsite which needs to have a 2-way radio on at all times. They need to be able to charge these radios on-premise because they are out there for a little over a week at a time. A solar panel seems ideal for this application. The whole charging setup needs to be lightweight since it is a >10 mile hike into the campsite. Ideally, I would like to use an array of NiMH AA batteries because they are small, relatively cheap, and can be replaced easily if there is an issue. I am also under the impression that they handle repetitive charge/discharge cycles well. I am not married to that though so if there is a compelling reason to use lipo or something else, I am open to that. The radio: is a Motorola Radius CP200. The wall charger that comes with it outputs 14v at 1.5 amps. The battery in the radio (according to the sticker on it) is 7.4v 16.21Wh lithium ion. Setup 1 that I've been trying: I have a 12v solar panel charging a pack of AA NiMH batteries. I started with an 8-pack holder but moved up to a 10-pack to increase voltage and total mAH a little. I've been using little voltage regulators in between the solar panel and the batteries as well as between the batteries and the radio. These function as diodes and help me get the correct charging voltage. My problem is that I can't regulate the amperage. The battery pack will pull as much as it can from the solar panel, and the radio will pull as much as it can from the battery pack. What ends up happening is when I first plug the radio into the battery pack, it works fine. But after a couple minutes, the amperage skyrockets to like 3 or 4 or more amps. The voltage regulator hits some sort of thermal protection limit and the whole thing shuts down. I tried throwing this amperage regulator in there as well to keep it below 1.5 amps, naively thinking that it would just affect the amperage and not the voltage. But what happens is when it's in constant amps mode, it just cuts the voltage to compensate and keeps the total power the same. Setup 2 that I've been trying: I thought maybe since I was having issues with the 'smarts' of these batteries charging and discharging, I would switch over to USB battery packs since they have a lot of built-in protection circuitry. I got this solar charger, an older version of this battery pack, and used the same voltage regulators to step up the voltage from 5v to 14v to charge the radio. I get the same issue of high-amperage discharging of the battery pack. I tried using this step-up converter between the battery pack and the radio but it doesn't seem to work or maybe I'm not using it correctly (I can't seem to get the adjustment pots to actually do anything...). It seems like I'm thinking about current wrong or something. Any suggestions or insight into what's wrong with my approaches would be super helpful. If anyone has any suggestions for radically changing my approach, I'm open to those as well. Thanks for reading!

Topic by Cking0987    |  last reply