### Power bank

Hello everyone I recently found a 12v 9a.h battery in my stuff and now i decided to make a portable power bank with it.this is what i am thinking about:i want to make a portable power bank with several voltage outputs for using in car and etc. 1- I want to get a 5v output and use it to charge my devices when I am in a car.2- i want to connect some power led lights so that i have a light bar.3-maybe I also connect an amplifier to it to play music when walking or etc.now that you understood what i want to make these are my problems:1-when the battery slowly drains and the input voltage decreases will the output of the charger module also decrease?2-different devices need different currents for charging for example my tablet needs 2amps while my phone needs 1 amp. do i need to set the output current to any special value?3-what kind of solar panel will be suitable to charge the battery?

Question by Electronic guy   |  last reply

### How can I make my own usb to charge batteries then use that to charge my phone?

So I am in the field a lot with the army.... and looking to make my own battery bank.... well I was thinking of using six 18650 3000mAH batteries in a parallel and series setting. Now if I set it up like this what would I use to charge these battery?

Question by dominick.j.pezza   |  last reply

### Circuit for power bank? Answered

Hello, Need a circuit design for the following requirement. Checked online available circuit designs but not sure if they meet all needs.  Looking for circuit design as per following details. 1. It will have one or two, 3.7 volts 2600 mah 18650 lithium batteries 2. Batteries will be charged using smart phone mobile charger or solar panel 10 to 20 volts and around 500 mah to 1 ah input 3. Will have mini usb connection for the same on pcb 4. Circuit should have battery level indication. While being charged, when they are fully charged LED should turn on indicating battery full. Also there should be one LED to show that the charging is in progress. When the battery charge drops below specific level another LED should turn on. 5. If we use 2 batteries then they will be connected parallel 6. Output voltage of the batteries should be 5 volts (so step up is required) and current should be appropriate for mobile charging 7. There should be provision for 2 USB connections. Load can be mobile charging / USB mini fan / USB mini keyboard LED (could be 2 at a time) 8. Circuit should be safe enough so no damage is caused to batteries / load etc.

Question by rahuldj   |  last reply

### Batteries and charger? Answered

So I got one of those one cell battery bank that come also with a little crank generator. So far I took both of these apart to make one into a 2cell. So now these batteries are a parallel, my ? is if the voltage stays the same with the charging board and the mah is double this should not effect the board correct? and or the batteries. So far its been working both batteries reads the same voltage so the charging board must work. Now hear is the thing that I am concerned with, if I was to add 6 more into a parallel then all batteries would be the same MAH right. This should not damaged the board?

Question by dominick.j.pezza   |  last reply

### Portable battery bank to charge a laptop?

Let me start off by saying that this problem may well have no possible solution and I'm probably a fool for asking. I was wondering if there's any simple(ish) way to use an external battery bank with 2 USB ports on it to charge a laptop? The bank has 18,000mAh of capacity, one 2.1A, 5V USB port and one 1A, 5V USB port (total 15.5W). The laptop charger in question runs at 19.5V, 2A DC (total of 39W) and the laptop battery has a 3800mAh rating. Thanks in advance for any replies :)

Question by CustardInc   |  last reply

### Usb battery bank help and questions ?

Well i want to add like a battery pack instead of the 9 volt batteries i have now and this a ruff model i made today, but i will make a better case but back to my question is would this work? http://www.amazon.com/Tenergy-2000mAh-Capacity-Battery-Security/dp/B001BA292A/ref=sr_1_11?ie=UTF8&qid;=1347244925&sr;=8-11&keywords;=9-Volt+Rechargeable  or do you recommend something else it has to be rechargeable,

Question by imnew59585   |  last reply

### how many batteries in your bank?

Great project Steve! my dad lives offgrid in the high desert of oregon: state thus far he uses several dc mills and solar panels.i greatly look forward to building this project with him in the future.also i wanted to compliment you on your willingness to explain and re-explain already stated facts......i first read and looked at your steps then took the time to read all the "Q&A" (yeah all 562 of them).after having done so i have no questions other than how large is your bank and what type of batteries did you go with?(we started with a bank of 32 12v ,but are now replacing them with long life deep cycle 6v cells)<large investment cost has us gathering them a few at a time.its great to see so many people gaining interest in going green.This project is without a doubt the best mill ive seen and your patience/willingness to let others pic your brain and promptly kick back thorough and accurate answers is commendable..most prodigous!looking forward to checking out all the links you provided. best personal regards, Luke A.R.S KV7M

Question by Coolhand Luke   |  last reply

### HOW TO MAKE SMARTPHONE POWER BANK AT HOME ?

I have samsung s duos gt s7562 and the big problem is its battery. whenever i have to go out for a day long, i have to suffer for its poor battery back up. in market several power bank is available, but its costly. i want to make myself. i need atleast 3000 mah capacity power bank. So what should i do ? please tell me.

Question by pprasara   |  last reply

### How i can make 400dc-450dc from a 9 volt battery??

I want to charge a capacitor bank of 400-450volts, but I don't know how.

Question by Kurt Gerhard   |  last reply

### How to make a 230v AC power bank?

I would like to make an AC power bank but don't know exactly all the parts to get any help.

Question by OTKZuki   |  last reply

### How to make power bank with 8 rechargable AA batteries?

I'm a nobody at electronics, electricals and stufs. well i have some rechargeable batteries for some reasons,. 2 of my friend has a portable power bank for their phone. then curiously thinking if i can make that kind of stuf.. (DIY),.. if it possible please help me make this... my AA batteries is 1.5V with 500mah of power if i'm right. , then multiply by 8 so that will be 12V with 4000mah of power? right?. then i want this to charge my phone... recently searching i need to drop the voltage to 5, because if not, my phone battery will or might explode., then my phone will be damaged?.. so i need to make a circuit,, then that my problem, i dont know any thing about resistors and things like LM317, just i don't know anything about that.. i need it be able to be recharge and charge my phone, so here's another question, expect the wee did make something like that, then how will i be able to charge it?, it's 12v right from the inside? right?.. that all, hope we can make something like this,, if there's a related post, which has been already answered, if this is not possible.. That all.. Advance Thanks for helps...

Question by ZoneOne26   |  last reply

### Convert 48V battery bank to 12V for boat appliances - Is this inefficient?

I need a 48V bank for an electric motor on my boat. I also need 12V for my appliances. Obviously keeping both a 48V and 12V bank would be most efficient but the space required and cost of maintaining 2 banks is a bit much. So I was thinking of using a 48V DC to DC convertor to convert a 48V bank to 12V for my boat appliances(lights, pumps, etc.) http://pt.mouser.com/ProductDetail/Murata-Power-Solutions/HPQ-12-25-D48N-C/?qs=sGAEpiMZZMtwaiKVUtQsNaluUzA10QGezHFBNv8sYMI%3d But how much would I lose in terms of efficiency? Would the losses be too great? Would the bank of 4 x 12V 100AH batteries connected in series give me roughly 4800W ( 4 x 12 x 100 = 4800) or 16 hours of 300W use when drawing only 12V after the conversion?  Or would the available AH be much less due to the losses from the conversion?

Question by mchin2   |  last reply

### can I use AA battery bank to power an inverter (3000ma 12v)? Answered

Can I use AA battery bank to power an 50w inverter (3000ma 12v)?

Question by celalboz   |  last reply

### is it good idea to replace my car battery with super capacitor bank? Answered

Question by HarishK95   |  last reply

### Charging mobile with a 6V lead acid battery?

Hello, I want to make something like power bank. i want to charge my mobile with a 6V 4.7Ah battery. My mobile charger is rated 5v 500mA. How to make this circuit?

Question by Rahul Mitra   |  last reply

### What is the right way to connect the cells of this battery pack, and tips on making a power bank? Answered

Greeting makers, I have a few questions about connecting Battery cells, and making a DIY Power Bank. And I'd like to hear your opinion on it. I have 12x Ni-Mh 1.2v 3000mAh AA betteries laying around. They are brand new and I thought of using them to make a Power Bank. Since most phones use 5v for charging I wanted to connect 4 cells in series giving me 5v and 3 of these packs in parallel for an end result of a single 5v 9000mAh Battery Pack. But when I started to connect them I realized that there are 2 ways it can be done, and I am not sure which is the right one. Is there any difference at all?  I will add a picture below, as it says more than thousand words. Furthermore I would like to ask for your opinion on how to proceed making a functional power bank. Just wiring the cells straight to an Usb port doesn't seem like a smart idea.  What would I need to make sure it is safe for the devices it charges? And how could I make the Power Bank rechargeable via Usb? Thanks in advance.

Question by icemaciop   |  last reply

### Wiring Two Ports on a Phone Battery Bank in Parallel?

If a power bank claims that each port on it can charge a device at 2 amps, if I connect both ports together in parallel, am I able to get 4 amps? Or would it be just like trying to double the voltage off of the same battery, and not work? I have an Intel Compute Stick, which requires 3 amps to run. However, battery banks that provide more than 2.1 amps per port are super rare. Would it work to wire them in parallel?

Question by RocketPenguin   |  last reply

### Capacitor-bank safety issues

Okay, so I'm going to be the wet-blanket old guy.... Has anyone considered adding a topic to this group (or an I'ble) on electrical safety with supercaps? Even the low-voltage ones put out tremendous current, enough to put you into convulsions or stop your heart (50 joules) if applied correctly. These devices are amazingly cool to work with -- better than batteries when you need high current, outstanding AC line filters, and terrific party toys when you need some bang for your buck. They can also turn around and bite you on the arse without warning...

Topic by kelseymh   |  last reply

### Could a 12v LED light strip be powered by a portable power bank

I don't know the exact specifications for my LED light strip but i know a 12v 2500mah lithium battery powered it for at least 2 or 3 hours, unfortunately it was a crappy Chinese knock off battery that damn near blew itself up after repeated use and i can't find a replacement that doesn't look like exactly the same battery. with that in mind are there any small power banks with a 12v output that i could use? or is there some means of boosting a 5v output power bank which seems to be the most widely available type?

Topic by ambientvoid   |  last reply

### Modifications to LED Bar Graph Volt Meter for 12volt batteries(and Battery banks) Answered

Hi I found this LED bar graph voltmeter athttp://www.solorb.com/elect/solarcirc/vom/index.htmlI want to understand how to build this voltmeter.But please read the solorb website page before posting, for more info.1. What is an offset resistor???2. What is a 'span'(see pic notes)2. For 12v operation,short J2 and J5,but what to do to all the other unconnectd 'J 'wires, just join the wires or what?3.To use without the Blue LEDs, just remove the two LEDs or any other connection/shorting is required????4.What is switch S1 used for ???, I do NOT want to manually push switches while the meter is in operation.5.How to stop the blink-LED mode, I want the constant display mode always.6.There is also two arrows shorting two pins on the IC with words 'Adjust for 12v'?????????7.How to calibrate the circuit accurately???PS:- If you want to know more about a larger part of this project,visit https://www.instructables.com/community/Voltage-Regulator/Kabir

Question by mhkabir   |  last reply

### Big battery bank project. Circuit related questions?

Hello everyone! I have a project in my mind and I would love some guidance and some ideas if possible. I already have a lot of 18650 batteries in an “acceptable” state (1800-2100mAh each) and I am planning to make a large battery bank, for use in camping mostly (smartphone charging, led bulbs, electrical air pumps 12v, etc) I did read a lot of articles in here about battery banks, but i didn't find something as complex as my idea. I have already made a 12v battery pack with 12x18650, 3 rows in parallel, of 4 in series in each row. My goal was to operate a 12v air pump for inflatable mattresses. It worked like a charm! (Also created with instructions from here! Thanks for that!) But since my “DIY disease” does not leave me in piece… I want to build a large enough pack that can support the following: 1) 12v car plug 2) 5v/1A + 5v/2.1A USB plugs 3) charge circuit for the battery pack, so I will no longer have to remove the batteries to charge them separately 4) switches in each plug 5) led voltmeter also with switch ?) at some point I would like to add a circuit to charge it with a solar charger or a mini wind turbine that i will create at some point with my 3D printer, but for now let stay with the basic stuff! For the case i will use a modified screw organizer case, with those classic 18650 black holders from ebay. (photo below) The case will fit almost 8 to 10 holders (4x18650), so we are talking for 32 to 40 batteries... My main concern is the circuit design. I have done a few simple things in the past, but this is a bit more complicated and that is why I want your guidance/ideas. How to safely connect all those things together or maybe suggest a different plan/design, cable thickness, etc... Links gathered so far: I am thinking about 4S in a row. Is that too much? Or should i consider 3S? 3S Li-ion Charger PCB with BMS For charger... something like this maybe? 12.6V 5A Charger optional... maybe i could fit sothing like that, for laptop charging? 150W DC-DC Boost Converter for 5v 1/2.1Amp charger i m looking at this. 5A Charger Step down Module for usb/12v plugs/voltmeter i am considering this option. Thanks in advance for your time!

Question by the_phantom_boy   |  last reply

### Best way to light small bank of LEDs?

I was trying to help someone put together a small lighted prop for a Halloween costume, and quickly realized I knew enough just to be dangerous.  The result should be simple, for someone who better knows the intricacies: 9 superbright 3V LEDs, arranged in a circular pattern about 4in dia., powered by a small pack of batteries which CAN be located elsewhere on the costume, with a small wire run. Initially the thought was "oh, well, 2 AA's gets you the 3V, you're good..." Then we thought, "to make hooking up the LEDs simpler, attach them end to end, and then each end of the loop of LEDs goes to the two batteries."  Of course, totally wrong.  After realizing the glaring problem, it occured to us that 3 9V batteries would instead get us the requried voltage to light them up. Then, realizing again this should work but that there might be some finer points to know, I started looking up some information online for similar projects.  My big fears, having not tried this out yet, are that: 1) The string of LEDs or batteries may get hot. (Seen a lot of posts like this.) 2) There is some glaring inefficiency in this setup that could be more simply redone. For example, is it better or worse in any way to run three strings of 3?  Would batteries last longer if a different configuration of batteries or wiring were used?

Question by dcenteno   |  last reply

### Which battery should i use?

VOltage dosent matter, all that matters is that it gives a minor shock when touched. The bank of batterys wil be going through a auto ignition coil to amplify the voltage. What should i use?.

Question by DonkeyDeathMan   |  last reply

### NiChrome Power Source? Answered

So, I'm doing a project that needs to boil maybe 8-10 drops of water very quickly. I was thinking of using NiChrome wire to do this as in the included diagram (sorry low quality, MS Paint). However, I can't seem to find an appropriate power source. So, I need some easy to obtain powersource that is also relatively small. Something like batteries, a capacitor bank, or anything similar. Remember, it has to be able to boil of those 8 drops pretty fast, lest they condense in another part of the pipe before the desired pressure is reached.

Question by LiquidLightning   |  last reply

### Battery Powering an Rpi3 and Monitor?

So I have plans to assemble an Rpi3 laptop with a battery and display and all that. So I need a way to battery power my Pi. Could I power my Pi3 (5v@2.5a) a usb power bank (one that could provide 5v@2-2.5amps obviously) with perhaps a step down/set up regulator? But I still would need a way to power the screen. Most driver boards want 11-12v and I don't know how to provide that. Maybe wiring batteries in series or parallel? I'm not exactly sure on how that works but I'm new to LiPo's so I'd like some help please. Thanks!

Question by gupperino   |  last reply

### When building a capacitor bank, is it necessary to have a charging circut? Answered

So, I am going to build a capacitor bank in parallel, only a few regular caps from cameras, how would I go about charging these? Do I have to use the circut or can I just hook the battery to the bank for a bit?

Question by Speedmite   |  last reply

### How can you charge a capacitor bank from 9v without a flash circuit from a camera? Answered

I need to charge a capacitor bank but the only easy way i can fid is to use the flash circuit from a camera. Here in Aus these are hard to obtain and i really need a portable and reasonably cheap Capacitor charger for a project. Please help me, any links to sites i can buy materials for a charger and especially circuit diagrams. Thank you.

Question by Doddity   |  last reply

### Can a laptop charger be modified to charge capacitors?

Well. I've been wanting to build a coilgun for some time now, so I decided to look into it. Capacitors are safely (or as safe as you can get) charged with DC current (batteries). But I don't want to go out and buy batteries whenever I want to use the coilgun. So... can I somehow wire it to charge a "capacitor bank". I was thinking start somewhere with cutting off the computer-plug?

Question by Crail   |  last reply

### Retrofitting a battery pack into an ebike.

Ok I was just looking at this ible. And noticed the type of battery the guy used.  So I did some googling and ended up here. Wondering to myself about trying to retrofit this type of battery into a veloteq challenger from 2008 or so. Remembering that its a 48 volt pack built from 4x 12volt lead acid 20amp batteries(cells) wired in series thus to stack the voltage and not the amperage.   Now I know amperage is simply a measurement of consumption so I'm guessing that these Yellowtops are way above the usual 20amp's that the veloteq asks for but I'd imagine that shouldn't make much of a difference.  Seeing as I only want to throw on two of these as to not blow way past  the weight restriction on the ebike itself by hitting 48 volts with four of these also to avoid breaking the bank with an 800\$ purchase.  Could I not add some sort of transformer to step up the voltage to 48 volts or something like this? Any suggestions are welcome but I can't imagine this would really be all that bad of an idea.  I'd imagine it should boost the range somewhat if not a fair bit.  I'd imagine that my assumptions here are not far off but I'm here to either be validated or corrected. Or even educated if someone has any suggestions or advice.

Topic by chamunks   |  last reply

### My coilgun capacitors aren't going above 30v

I made a coilgun out of disposable cameras. i have 6 capacitors running in parallel. I followed these instructions  https://www.instructables.com/id/DIY-How-to-make-a-coilgun-from-disposable-camera-/?ALLSTEPS   .When i power it on the capacitors make their usual noise and they start charging fine then when they hit 25-30v they shut off and don charge any further. What is going wrong? The power source is 2 AA battery running in parallel

Topic by eric95204   |  last reply

### Where to find lightweight 12v batteries? Answered

I need a set of lightweight 12v batteries with a lot of power (15 ah or higher). I have an air conditioner that draws 3.33 amps and runs off 24 volts. My idea is a battery bank with two 12 volts in series to make 24v. I hope to run it ~5 hours off a full charge. I found these on eBay but they weigh 10lb each, which means 20lb for 2 of them. My goal is 10lb or less total weight: goo.gl/KcdIfW A single 15ah+ 24v would work but I cannot find one anywhere. Thanks!

Question by benbl19   |  last reply

### How to get constant 5.2V from ~1-7 Volts?

I have multiple solar panels (3V, 6V). I want to build a charger for bicycle, to keep my battery powered lamps (DIY) battery alive. Currently, I use my DIY lamp with a USB Power bank (5,2V , approx. 50k mAh), but my lamp contains 39 LEDs, and they are ultra-bright LEDs, so they drains the battery fast. So I thought if I connect some solar panels to it, I can charge power bank during daytime.

Question by Sp1k33   |  last reply

### convert 12v cordless battery to solar charge

My first post- great site! I'm a complete idiot when it comes to electrical; does anyone out there know of a way to charge a 12v cordless drill battery with a solar panel- the eventual end result being to power a bank of LED lights and can all LED lights be powered with DC, if so how many could I expect to run?

Topic by screefer   |  last reply

### can i set up a capacitor bank to start up my car if the battery is dead?

a huge advantage to capacitors is low leakage (for some types) and i want to know, first of all, how much energy a starter motor needs to start the engine? one of my constraints is money (>\$200) so if it works, but i can't afford the capacitors, then oh well. also, i want to know if i can make a simple circuit that would sense if the battery is dead and then switch to using the capacitors and also be able to recharge the capacitors. im also worried about the amount of leakage of capacitors with such high capacity (which might defeat the purpose of this idea), and where i could actually put the rig that would be safe from heat, and still have access to the starter motor. if this is feasable, i just might make my first instructable out of it: the invincible starting car

Question by the judge   |  last reply

### 18650 battery pack question

Hello everybody, I need to install (build) a recharging battery pack for my plant shelf.  it will be running an arduino nano, just 3 leds (3mm 20ma each) 1xNTC and 1x water sensor probes (nails).--  no LDR no yellow LED. . I was thinking about getting a 2x 18650 battery holder - I need more battery hours, should we wire the batteries in parallel to get more mAh and boost them 3.7V to 5V. so basically this is what I am trying to custom build to get more hours; DIY Mobile Power Bank Case Kit . I would just buy the mentioned product BUT under specifications>battery it says the capacity range: 1000mAh and below. but the batteries I have are 3.7V @ 5000mAh. does this mean that the remaining 4000 will be lost because the system can't handle it?  . basically what I am asking for is how can I make a long lasting arduino nano powering 18650 battery pack BUT also with a recharging module. these are the items I found that may work together, please remember that I have no electrical experience from before. I have learned everything that I know from instructables, this is a too advanced build for me to figure out without asking a few questions. thank you for your patience, let me know if I have to clear anything out. batt holder:  recharger: boost: am I even in the right track with this thing? can these be connected together and a switch. again, the goal is max battery life.. maybe add 4x 18650 - 2in parallel + 2in series, 7.4V to arduino Vin, eliminate the booster, even more battery life ? . thank you in advance, love & peace akin,

Question by Akin Yildiz   |  last reply

### What is the most efficient and portable way to convert 3 volts (Battery power) to around 400 Volts?

I need a portable and efficient way to convert battery power (3 volts) to around 400 volts. I will be using alkaline batteries... This will be used to charge a high voltage capacitor bank.

Question by brooklynlord   |  last reply

### How do i go about choosing LEDs for a project? Answered

So i'm planning on building a battery bank to charge my phone and other usb devices . I wanted to also use it as a flashlight, My size is limited, since i was planning on using an altoids tin, and i'm already stuffing two 18650 batteries inside. What i want to know is what is the brightest led i can use that wont need a heat sink? or at least one that will dissipate enough heat into the tin alone.

Question by Tomahawk92   |  last reply

### Exactly what components do i need to charge a bank of our four (or however many it takes!) 18650 batteries {we will be using a dynamo} with an LED to show that the batteries are being charged ?

(if needed ?)Hello & Good day to you all, Me and a friend have plans to build a miniaturized 'Rolling Road' platform for our RC 1/10th scale nitro cars!! What we both agreed on is that the Rolling Road platform is to be made out of acrylic and using skateboard bearings and other hardware, but we are completely stuck, we have an idea to add lights to the platform, the kind of cold-cathode tube lights that are for inside-pc-use... We want the tube lights to run from a rechargeable battery bank from the Rolling Road but incorporate a charging system "built-in" to the platform and a system based on renewable energy because as our cars are nitro powered, they will be turning the rollers of the platform for many hundreds of thousands of times and we wanted to harness that mechanical energy to charge the battery bank - in turn to operate the tube lights! We are both ok the structural aspect of building this rolling road platform but dont know where to start on fabricating an electronic set of components culminating into a sustaining system that produces (almost) free energy! The system must be able to run 4 sets of these tube lights, each tube light set is comprised of 2 tube lights each, so 8 tube lights in total ! The tube lights are rated at 12 volts. What our dreams are : (lol) - The system must collect the electric being made to charge a battery bank, - The system must have an LED 1 to only show the battery bank bank is being charged, - The system must have an LED 2 to show that the battery bank is fully charged, - ALSO ! if at all possible, include a simple row of 6 or 7 LED's (LED BANK?) to indicate how full/empty the battery-bank is & - Lastly, there must be a switch to switch off the circuit that charges the battery bank (when batteries are fully charged !) Ingredients: (what we DO have, lol) 20 x 18650 batteries Plenty of spare motors Lots of different grades of wire soldering skills a few switches 10 Pairs of 12v PC Tube lights (Both 4" & 12" ) Small to medium range of "ON Semiconductors" (Voltage Regulators) Max Input Voltage is 40v of one of these! What we dont have: - Knowledge of electronics! - LED's - Capacitors (if needed ?) - Resistors (if needed ?) - Transistors (if needed ?) - Semiconductors (if needed ?) - Diodes (if needed ?) - Help ! Please please please could anyone help us to even roughly 'sketch' a set of components that we could solder together, lol, a Circuit, lol x2!, so we can start ordering the needed items to enable us to make this miracle happen ?!!? But to make it idiot-proof (dumb-it-right-down for us!) and extremely simple circuit diagram, not the actual way you geniuses write em, if say to draw a semiconductor, i would draw a square then draw 3 lines coming out the bottom of it to show the legs of it! We were only-just able to follow the circuit diagram HERE - ONLY BECAUSE there was a picture of exactly how the circuit looked, in-real-life! So we followed the wires exactly to make the solder fume extractor but were only able to, again, because of the pics! please help! i feel like crying! lol ! We have both spent a few years trying to read electrical diagrams and we get lost very easily ! Is there even a way to dumb it down for us ??? Is there any hope ?!!?  lol A very-Many thanks in advance to all for reading this and even more for any help received !!!!

Topic by offtherails2010   |  last reply

### Power source for coilgun? Answered

I have built 2 coilguns already using a camera circuit for charging the capacitor bank, but because it is a disposable camera, the quality of the circuit wasnt very good so it stopped working like in a week or so,, so i was wondering if i could build a circuit for charging a capacitor bank (so i wont need to buy any more cameras), but i've already looked in a lot of pages for a schematic but i've got no luck anyone knows how to build a circuit for this purpose? i do not have a lot of experience in building circuits, thats why i dont figure it out myself thnks

Question by tato312   |  last reply

### how much backup can be obtained from 18650 (2600mah) battery and 5w led bulb as a load?

Hello; i have some basic questions and want to clear my mind. i want to create a portable power bank using 2*18650 (2600mah) rechargeable battery and 5w usb plugged led bulb (5v). So keeping in mind the above values how can i determine the maximum backup this setup can provide? i would highly appreciate if you provide some real life examples to calculate the above mentioned values.

Question by askfriends   |  last reply

### Led powered by 9v

Hi all. I am new to this forum and need some help. I want to mount an led strip to the bottom of a roller skate. Everything I find already made up requires 12v. I need to keep the setup as small as possible for mounting reasons. How could I go about making a 12vdc led circuit work off a 9v battery or how could I wire up some led's on a flexible strip powered by a battery. I am thinking 9v because I can purchase a rechargeable set without draining the bank account each time. Any suggestions are welcomed. I have about 6" in length to mount the strip to. I would like multi color led but one solid color would also be fine. Thanks again for any suggestions.

Topic by rsfaze   |  last reply

### Cheap powerbank shows light but than stops?

Hi, I have bought a cheap power bank, it worked good! But now there's something strange, I know it's cheap so it doesn't work long but if I charge my powerbank it shows a light and than the light stops showing and the powerbank doesn't do anything anymore. I saw somewhere that you can take out the battery inside and plug it in to a battery charger? Does that help?

Question by SimonU2   |  last reply

### How do I charge two marine cycle batteries at 24v? Answered

Hello, I've built a mobile stereo ice cream cart that I have posted here on instructables. https://www.instructables.com/answers/Got-any-cool-ideas-for-our-Arduino-run-LED-dance-f/ We've been having a hard time with our SLA batteries. We have two 12v banks of three 7.2 sla batteries, run in series to make 24v. (six batteries total) We then use a car charger on trickle to charge the two banks separately. This is a pain, and the cells have been swelling. We desire a bit more battery life. (currently at about 6 hours) and simpler charging. My thought is two small marine cycle batteries (maybe 40 Amp/hrs each) and some sort of 24 volt charger. Would this work? Is there a better way to go?  Extra Points for Light, Cheap and Simple. Thanks so much! Tor BTW totally open to a battery lecture, or to get pointed to a good read. I feel like I need to get schooled.

Question by torclausen   |  last reply

### Is My Solar Panel Design ok to achieve 60A charge rate for 1000AH 24V battery bank?

Please I need your advice on a propose project in my office. we have an Inverter (Xantrex TR2424- 24V 2.5KVA) which charge rate capability of 70A. The Inverter battery bank is rated 1000AH 24V total ( 2V 1000AH x 12 in series). I am sure of 5Hrs sunlight a day. and I want my project to charge the battery at 60A rate per hour. Our DC-current consumed when on Inverting mode is 26A DC (Approx 3A-4A AC inverter output). Our ac load on the inverter output is around 540W. In my design as attached, each group of PV (4pcs in parallel) should produce around 30A). total amperage should be around 90A. since during the day (sunny) we will be draining 26A continously from the battery, deducting that from the total pv current, we should have around 64A left to charge the battery bank. My request: kindly look into my propose design and advice where am wrong or need correction/adjustment and recommend with your experience. I assumed a DOD of 60% on the battery hoping to charge the battery to full capacity within 5 hours of sunlight daily. we have standby generator which we can power on to charge the battery in situation where it is cloudy. Thanks for your anticipated recommendation & advice

Question by jisaac6   |  last reply

### How do I build a solar chargeable NiMH power pack to run AC appliances? Answered

At a thrift shop I found a new 1.8 W (125mA) solar panel with all the parts that is used to trickle charge car batteries. It has three connectors, one a cigarette lighter, pos and neg cable clips and a regular connector for a power pack. Is it possible to use it to build a solar charger for a NiMH battery pack that will power a low end AC item like a cordless phone base or broadband modem during a power outage? If so, what else do I need and can it be done cheaply? Why I want to do this is because I don't want to have lead acid batteries in the house. Answers to this would be much appreciated as I know there are issues with differences in voltage, etc.

Question by blodefood   |  last reply

### How to make a USB charger from a tablet battery? Answered

I have a tablet battery, L10C1P22 and it's in good condition. I was scouting through Instructables to see if anyone has made a USB charger based on a tablet battery. And I couldn't find one. So may be I haven't found it despite it being there. Can anyone direct me to a source that instructs or at least provides a brief idea of how I can make this happen. Or if someone knows how to, please please share it with me. I'd be very grateful. Thanks Amol

Question by amoljoshi_bangalore   |  last reply

### any possible way to make this led ring flash run off of a usb power bank?

I have a  MK FC-110 LED Macro Ring Flash that runs off 4 AA batteries, is there any way to add a usb wire and make it also be able to run off a power bank? please let me know thank you.

Question by HectorV39   |  last reply

### What to use to convert U.S.A. standard outlet input to a DC output with the voltage of a battery to charge caps. ? Answered

I pretty much want to use the oulet at home to charge a capacitor, and I wish to know if anyone has knowledge of an AC-DC converter that would be suitable to take the high voltage current to about that of a battery allowing me to charge my capacitor bank w/o any batteries

Question by StartedBullet   |  last reply

### Idea DC-DC converter step up from usual power bank as external battery for nikon DSLR

Can anybody build a circuit to convert the 5v-2.1A to 8.4v-2.5 to be able to power on the DSLR camera USB output 5V*2.1A=10.5W Camera input 8.4V*2.5A=21W The idea inspired from ifootage Electric Ray E1  ,I don't believe in would power on my DSLR nikon D7100 probably, plus it's too expensive for me

Topic by assem555   |  last reply

### Old Dynacharge battery Charger good for other tech?

I Picked up an old Dynacharge NiCd battery charger at a local Garage sale. What I am wondering is this, Can I use this old wall plug battery charger for the current NiCd Batteries? And If so.....wait for it.....Can I extract the guts from it and use it to make a self charging power bank? can I hard wire a charging circuit and a discharging circuit onto the batteries at the same time? would I need to put diodes in there? Is this even worth doing? I know that I can get all kinds of circuitry from online sources that can do the trick, but I'm wanting to use as much old stuff as I can. Input please?

Topic by OculumForamen   |  last reply