### 12v battery charging?

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------------------  ??  ------------|

Question by infinity1   |  last reply

### Small 12V batteries

I'm trying to make a simple LED circuit with switch included in the circuit. Can someone suggest to me a 12V battery that is big enough to keep a 48 LED bulb system on for at least 24 running hours, but small enough to be the size of two fingers sticky taped together. Thanks guys, Nick

Topic by kritas   |  last reply

### 12v battery charger? Answered

My WiFi ISP signals were unable to reach my room. So my ISP arranged a device  on top of apartment & it was powered with 12 volts DC adapter. But makes me to work offline when power is OFF. So i want to make that device to work on 12V battery. So i need to make a charger for that battery to work as UPS. Can any one help me with circuit Diagram and components list??

Question by chinnuabhi   |  last reply

### 18v to 12v

Hey everyone, i need help on downgrading 18 volt battery to 12 volt battery, id like to do it for cheap or even free if thats possible.

Topic by sirus17   |  last reply

### Battery power

I am attempting to calculate my amp need for my garage in order to set up a 12v battery system. Using the formula; Watts / voltage = amps drawn, I have hit a question. If using a 12v battery system and converting to 110v, should I be using 12v or 110v in the formula?Example; 100 watt light bulb / 110 volts = .91 amps. Nice!But if I use the 12v; 100watt light / 12v = 8.3 amps.I'm believing I would be drawing 8.3 amps from the battery to power this light.Plus the converter draw...Please tell me which is correct?

Topic by olddawg   |  last reply

### 12v to 12v lead acid charger? Answered

Is there any way to make or buy a 12v battery charge another 12v battery?

Question by Daniel Deacon   |  last reply

### 7v from 12v?

I need to run a 7v / 1.6 A DC water pump and a 12v / 1.13 A DC fan from a small portable battery pack. If I use maybe 8 "D" cell bateries, do I need a converter to power the 7v pump or will it work with 12v? Thank you,

Question by fastrack777   |  last reply

### 12v UPS

With most UPS's there is electronic circuitry to reduce the home voltage to 12 or 24v to store in the battery, and then another circuit to raise the voltage back to the home voltage.  I know there is always a loss when attributes of electricity are changed. This seems very wasteful to me. I want to build a UPS for my notebook computer, that I use as a home server.  The power adapter for the notebook creates 19 volts but the notebook itself uses 12 - the other 7 is perhaps used to charge the battery while the computer is on.  I would like to put together a UPS made of 12 volt Ni or LiFe packs - would most likely be 13 volts but I don't think that would be a problem to avoid the double switching of the power.  Can anyone point me in the right direction?

Topic by haopengyou   |  last reply

### small DC 12v battery?

Hello all. i am currently working on an air powered rifle. my goal is for it to be self contained, so i took apart a testors airbrush compressor and i am fitting the compressor assembly to a 12v blower motor for an early 90s toyota 4runner. is there any way that i can make or purchase a 12v battery pack to power this thing?

Topic by dans89   |  last reply

### 12V car battery indicator

Hi, I have been trying to design a circuit to monitor my 12V leisure car battery, I'm thinking this should be fairly simple, but its been years since I did any real electronics. So the basic idea: Use the circular bargraph to indicate the level of the battery when a momentary push button is pressed the circular LED bar graph: https://www.sparkfun.com/products/11492 So the range of the battery would be something like 10.5V to 13.5V, there are 32 LEDs in pairs, so essentially 16. 1. So if we take the first LED pair, this should illuminate when less than 10.5V, so that should be easy, as long as there is some life in the battery it should illuminate 2. The next LED should only illuminate at the next step, 16 LEDs, 3V range 16/3= steps of 0.2V So at the following steps: 10.5, 10.7, 10.9, 11.1, 11.3, 11.5, 11.7, 11.9, 12.1, 12.3, 12.5, 12.7, 12.9, 13.1, 13.3, 13.5. So for 10.7V I guess I should use resistor before each LED. 3. The LEDs should light up after a momentary push switch is triggered, I would like this to be graceful, so the ring lights up smoothly one LED at a time as the voltage increases, I guess capacitors between the resistors and LEDs? This is the simplest way I can think of doing it, I have seen circuits which use a LM339 chip, but that can only monitor 4 voltages, perhaps 4 of these in series could do the job? http://www.electroschematics.com/7068/lm339-lm239-lm2901-datasheet/ I think this is the way to go rather than using inline resistor/ capacitor pairs? So I am a clear novice when it comes to electronics (but I'm enthusiastic), so if anyone can help me with this I would be more than happy to put together an instructables how to, something similar has been done before: https://www.instructables.com/id/Car-battery-tester/ In that example only one bar is lit, I want the other bars to stay lit. I can use Eagle to make the PCB diagram and get it printed, but I need to figure out what components I need and how to do it! Thanks for any help. Gary

Topic by garynobles   |  last reply

### Battery Pack

I want to start a battery pack but I don't know how to connect series/parallel to get most mAh but also 5V-12V output I plan to buy 8 3.7V 2600mAh Lithium Ion Battery but I don't know how to connect those together to get the most mAh as possible but also between 5V to 12V output . It is possible to do that with

Topic by Kyosoul   |  last reply

### Charging multiple 12v batteries

I have eight 12v 18Ah SLA batteries that I need to wire to get 48v. I need to be able to charge them all at once, but can't find a 48v charger anywhere. Is there a way I can wire a 12v charger to parallel charge the batteries while they're wired in series?

Question by Charlie_Szasz   |  last reply

### 12V LED to Battery Power?

Hello! I'm just getting my own cab company started in my medium sized town, and to begin I'll be using my personal vehicle - thus, I'm using items I can remove so I don't get harrassed on my days off, such as magnetic decals and a magnetic top light. My question is this: Is there a way to convert a 12V, 96 LED light over to battery power? The toppers use a direct cable to a car charger port, but I hate having that cord just hanging out in my cab. It is tacky and unprofessional - at the same time, I very much do not want to punch holes in the top of my car and wire it to my dome light. I have found several rechargeable, compact 12V batteries online, but I've no idea how I'd hook them up. I'm smart enough to know that I can't just wire it directly to the device - the battery would last minutes at most. I think I'd need some kind of transformer, perhaps? Any suggestions? And here's the battery I would use: Voltage: 12 Lead Acid Type: General Purpose Capacity: .8AH Chemistry: Lead Acid Lead Acid Design: AGM Product Category: Sealed Lead Acid Terminal Type: WL, Wire Leads Weight: 0.8 lbs Length: 3.78 in Width: 0.98 in Height: 2.4 in

Topic by NiteRide   |  last reply

### Any recommendations for portable 12v batteries?

Could you recommend a 12v battery that is: - light weight - 6Ah or more - quick charging - long lasting - preferably comes with a mains charger. Will be used to power a portable audio system. BTW: Anyone have experience with such suspicious looking solutions as http://www.discoverybargain.com/product/EB00185L/T-1298A_DC_12V_9800mAh_Super_Capacity_Rechargeable_Li-ion_Battery_(Blue)_29525.html ?

Question by suhajdab   |  last reply

### How do I go about having a 12v battery power a device that runs off of 2x AA batteries?

I am looking to run a receiver that is powered by 2x AAA batteries off of a 12v 12ah battery that is also running an amplifier. If there a way to do this without burning up the receiver? I am looking for a cost effective way to do this. Thanks.

Topic by jgalvin1   |  last reply

### Operate 12v air pump using 12v 8ah battery with relay?

Hello guys I want to connect a 12v electric air pump to a 12v 8h battery with a relay microcontroller.   The air pump has receptacle for a cigarette lighter. Is it possible I can  remove the receptacle and connect the wires to the relay? I want the air pump to turn on every 15 minutes. The battery will be connected to the relay also. Sorry I dont have any electrical experience.  Any help would be appreciated

Question by dabretts   |  last reply

### 12v footswitch help.

432-1212 from digi key.  http://search.digikey.com/scripts/DkSearch/dksus.dll?WT.z_header=search_go&lang;=en&site;=us&keywords;=432-1212&x;=16&y;=22 Can this be wired up to work with a 12v battery. I'm wanting to wire this between my battery and bilge pump for a on and off switch it probably will get wet or I should say soaked.  I couldn't find any cheap footswitchs online so I'm thinking maybe I could make one?

Question by micha3l87   |  last reply

### Portable 12v Power?

I need to power a 12v dc Digital Photo frame in an interior area with no available plugs. I can charge it at night, but need it to be self powered during the day. What can I use as power? I was thinking of possibly a Computer battery back-up or a portable battery used for jump starting a car. Any and all ideas would be helpful. Basically making a battery powered digital sign board. Thank you!

Question by larry925   |  last reply

### Powering 12v LED strips from a 12v battery?

My situation is this, theres this old farm building i want to do up and make into a chill out room, but the place is not connect the any type of power supply, or if it was im not gonna try and fix it. i just want to get some lights in the place to make it look good, nothing major just a strip of leds running along the floor lighting the walls.  If i bought a simple 12v led strip  and a 12v battery box ( the ones that support AA) how long would that last for? i need it to work for at least 3-5 hours. if this is impossible would a 12v solar panel be better ? something like this  http://www.ebay.co.uk/itm/NEW-12V-SOLAR-PANEL-BATTERY-CHARGER-CAR-CAMPING-CARAVAN-/230995256615?pt=UK_Gadgets&hash;=item35c863e527 i could just connect the croc clicks (or cut them down and solder) them straight onto the led strip ? if both these are bad ideas im open for suggestions also would i be able to have a controllable LED strip to be able to run off these two types of power ?  (and just a random add on question, if i wanted to power some speakers without it connecting to the mains how would i?) Thanks for any help or suggests and reading :) !

Question by iconicbuck   |  last reply

### load a 12V battery by the cigarete lighter

Hello guys, I want to make a publicity trailer with led's that will stand at party's (and on the side of the road in the week). This trailer will stand alone and will be powered by a 12V car battery. I would like to charge that battery while moving it with my car by a long cable to the 12V socket in the car. Should I place a resistor to limit the current or is this not necessary? The trailer is for my youth movement. (sorry for my bad english) Grts, Dieter Belgium

Topic by DieterD4   |  last reply

### Making a 12v or 18v (Volt) Battery

I am working on a project with my dad (36 volt powered Go-Kart) and we can't afford any fancy batteries or any at all. I found a solution on Youtube where you could make your own 12 volt battery by using mason jars, sulfuric acid, and lead but that sounds unstable and not powerful enough for our project, and even then that's only 12 volts. So, what i am asking is: Is there any way i could make my own 18 volt batteries (2x to make 36) that are stable and  powerful enough to power something like a Go-Kart?? (Go-Kart is 25-30lb as of right now) Note: My options are: 1.Run 2x 18v batteries in parallel. 2.Run 3x 12v batteries in parallel.  3. And any other voltage that can be combined to make 36 volts... Thanks in advance!  :D

Topic by SullivanS   |  last reply

### How to integrate a rechargeable 12v battery?

I am building a portable boombox and trying to figure out how to integrate a 12v battery into it that can be recharged using a input jack and the AC adapter charger that came with the battery., without having to disconnect the load.   Is it as simple as connecting both the charger and the load to the battery?  Would I need to wire in a switch to disconnect the load when I plug in the charger?  I'm an electronics noob so any help would be appreciated.  Thanks.

Question by banjopoker   |  last reply

### Robot battery

Hi everybody I build my robot actually I have a 12v 12ah lead acid battery ( https://www.battery-direct.fr/Batterie-BP12-12.html). I would like to change it but I don t if I choose lipo or lifepo4 or li-ion? My principal goal is loose weight and size, so I think about lipo but I am not shure

Question by LaurentP30

### Convert AAA battery power to 12V jack?

So I figured out a really good option for my external rumble pack I want to make, I see these Wii lightguns use X2 AAA batteries and have a micro switch that engages the internal rumble motor on the handle of the gun. The batteries are connected to a microswitch and the switch is pressed after the trigger is physically pulled. How can I convert the AAA batteries power method into an external 12V power connector for continuous use and stronger motor vibrations etc? Like I said this is my first DIY thing. I want the AAA battery method to be converted to a stronger more capable 12V. I plan on buying some strong force feedback motors that need 12V. Eventually adding a small Solenoid too.

Topic by JonathanH248   |  last reply

### How to light a 100V bulb using 12v dc battery?

Question by Daniel_lj4   |  last reply

### where's the best place were i can get a 12v battery? besides ebay?

Question by Ha4xor4life   |  last reply

### inexpensive high AmpHour 12V rechargeable?

I'm  looking to build a battery-powered speaker system for use on job sites, that will need to be louder than the equipment being used. For this purpose, I plan on using a tripath amp and some pretty decent speakers I have lying around, but the tough part is power. I need between 12V and 13.6V, with a relatively high AH rating. I considered a car battery, but don't want to have to trickle charge. I considered a Power Wheels battery and charger, but I've been seeing bad reviews on lifespan Any thoughts?

Topic by gschoppe   |  last reply

### 12v Portable Led lighting Help

I really need some help trying to power these led lights onto a portable table Im building.I need the power supply to be as small as possible. I honestly have no idea what Im doing except that i need a 12v power supply.I work on cars and custom put in leds all the time but the power supply always comes from main car battery.I have never tried to power them before from a small battery like AAs before for example. If anyone has any ideas please respond because I can not finish this project until I get the lights to work and I don't want to go wasting money buying stuff in the wrong places. I will also include a link to the ebay page where I bought the lights. Another thing is I have done research and cant find what the amps they draw are.

Topic by godfather29

### how to recharge a battery of 12V using a dynamo give 9V? Answered

How to recharge a battery of 12V ? I am trying to recharge a battery of 12V using a dynamo.Can I use a dynamo of 9V to recharge the battery of 12V?

Question by tarz_00   |  last reply

### Powering 12v LEDs from 12v Deep Cycle Battery

Hey all, I'm trying to power some 3528 LED strands to hang from a shade structure I have outside. I picked up a 115 Ah 12v deep cycle marine battery, but I just wanted to make sure I could wire them directly to a distribution block without blowing anything up. The strands draw 6A of current so I was going to find the closest fuse to that value (10A?) to prevent any chance of overpowering the control boxes. Does this seem correct? Image shows roughly what I'm trying to do (black boxes around red wire are fuses, 1-3 are the LED control modules) Greatly appreciate any help!

Topic by synaptech   |  last reply

### 18v dropped to 12v?

I want to limit two 9V battieries, in serial to 12v. I want to run a cold cathode off em, if the strain is too much, I'll join two parralell sets of two 9v batteries in the circuit. Anyway, how do I do it? I can't find any 12V regulators at all, and I don't know what sort of resistor I'd need, is there one that would limit it to 12V, with the standard 9V battery ampage? How could I archive this? Thanks.

Topic by Josho   |  last reply

### UPS battery ~ Help plz?

Help Needed!The 12v 7ah battery of my 500va UPS is very weak now & I have once 12v 40ah tubular battery and a solar charger for the same! So i am thinking of connecting this one to my UPS. My question is, Is there any problem in connecting this battery to my UPS ?

Question by technews   |  last reply

### Battery recommendation

Hello, I'm looking for a rechargeable battery for a project and I'm not having any luck finding a suitable one.  Here's what I need: The battery will need to be between 12 - 18v with between 1-2 amp.  This will be powering a set of speakers, so not really sure what type of amp hours I need.  The battery will need to fit into a tin lunch box.   An idea I had was to use a 12 or 18v battery for Power Tools - not sure if it will work though.  I also found this, http://www.altex.com/12V-Lithium-Ion-Rechargeable-Battery-Set-LBP-124500-P150057.aspx not sure if it is powerful enough though. Any thoughts/ideas is appreciated.

Topic by RabidNoodle   |  last reply

### Battery Pack?

Hello everyone,  I want to build a battery pack so that I can charge it with solar.  i bought some 12v 1.3ah sealed lead acid batteries but they don't do the job that I want to and they are not very appealing.  So I have seen the tesla powerwall and it is great and also slim, so what I want to do is to buy different batteries which are the panasonic 18650 and the stack them together to my own specifications so that they can power small things such as lights and pumps.  The packs that I will make would be small at first just to test and have an idea. So is it worth investing in these battery types or just buy some sealed lead batteries and then stack them together.  Thanks

Question by Chamburn   |  last reply

### 12v trickle charging rechargeable AA battery's?

Just wondering if anyone knows whether it is would be possible to charge 10 AA rechargeable battery's in series with a standard 12v solar panel without any specialist kit ? Thanks

Question by _TEAP0T_   |  last reply

### home made battery

How to make powerful home made battery  weight 3 to 4 kg voltage 12v

Question by vpsingh92   |  last reply

### 12v battery low voltage disconnect with relay? Answered

Could i make 12v battery low voltage disconnect with relay and resistor? I was thinking if put resistor in series with relay coil i could lower current so relay would barely work on 12v but when it drops to 10v voltage after resistor would be so small that relay would disconnect

Question by Cekpi7   |  last reply

### 12v timer to run a 12v dehumidifier for a few hours per day

I have a 80 w  solar panel on my caravan, wired to a 12 v leisure battery 110 amp. my question is how do I get  a 12 v  dehumidifier  to run for 2 or 3  hours per day on a timer.  unable to run continuous as not enough solar power yet as it is still winter. I have a basic knowledge  in electronics. I have not got 240 v available any help would be welcome   thanks in anticipation.

Question by cossiem   |  last reply

### Using two 12V batteries in series with both a 12V and 24V output

I have a tornado shelterthat I have wired for both 120V AC and 12V DC. All of the lighting is via 12V DC while the AC is used for recharging the batteries and running a 1500 VA UPS system that powers a small TV and radio. The UPS system normally uses two small 12V SLA batteries in series. To increase the run time of the UPS I want to use auto batteries instead of the small SLA batteries normally used. In order to cut down on the cost of batteries I want to use two auto batteries, one 100AH battery used for the main lighting and a 50AH battery in series with the 100AH battery to provide the 24 volts for the UPS system. The UPS system will only use the two batteries when the AC is out which is normally rare. Do you see any problems with this setup providing I install a diode in the UPS battery feed to prevent the UPS from recharging the batteries and use separate smart chargers connected to each individual battery? I feel I have overlooked something but I can't seem to put my finger on it.

Question by Uncorkvet   |  last reply

### Two batteries on one charger...request for advice.

Need some advice... I busk using a Fender Amp Can and a head set mic. The Fender amp can is a complete unit with speaker, amp, battery and charger (15v 400mha). The headset mic I run off a separate 12v SLA battery. I currently open up the Amp Can disconnect the internal battery, attach the external battery and charge it, then put the whole unit back together. I want to make an external terminal to connect the external battery for charging and this should be simple enough says I...hmmm...So I am canvassing for second opinions regarding possible problems and whether I should set the batteries in parallel or series? The Amp Can is an awesome little unit and Fender have stopped producing them so I don't want to do it any harm. I know I could just buy a separate charger for the battery but that would be more crap for me to carry and I don't have the \$25  to spare just now...it would also be lame... Thanks for listening, Luke Some specs on the Amp Can: DESIGNATION TYPE PR 327 PART NUMBER 022-1270-000  (100 V) 022-1200-000  (120 V) 022-1230-000  (240 V) Aust 022-1240-000  (230 V) UK 022-1260-000  (230 V) Euro POWER OUTPUT 14.5 W into 4 âï¿½¦ @ 5%THD with fresh battery  INPUT IMPEDANCE > 1 Mâï¿½¦ both channels INPUT SENSITIVITY 500 µV@ 1 kHz - gain switch in GUITAR 20 mV @ 1 kHz - gain switch out INPUT SENSITIVITY 5.7 mV, 1 kHz MICROPHONE SPEAKER 4 âï¿½¦, 30 W Special Design 6” speaker w/16 oz. magnet and paper coil former (P/N 050543) DIMENSIONS Height: 8.75 in  22.3 cm Width: 7.75 in 19.7 cm Depth: 6.75 in 17.2 cm WEIGHT 13 lbs 5.9 kg Amp Can™ is a trademark of FMIC. Fender ®, Tone-Master ® and Twin Reverb® are registered trademarks of FMIC. Product specifications are subject to change without notice.

Topic by unpredictableTP   |  last reply

### 12v DC battery amp measurement? Answered

HI, I have a 12v dc battery and I wanted to measure the amps. Can anyone show me how to hook up the multimeter? Thanks

Question by amantux   |  last reply

### Running 18.5v laptop on 12v battery ?

​How about 12v battery Plus + 6v battery and connect them so they make 18v current , I'm not really good in electricity and I want to ask about the amperage , what if my battery is 60AH  can I use transformer to step up the voltage to 18 V or 14 V

Question by Alhumaidi   |  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

### If a 12v car battery is down to 6v can you still charge it?

Question by danielemur   |  last reply

### 12v LED lamp+ Solar panel+ 12v car battery? Answered

I am new to electricity beyond a basic circuit, so I am at a point of being unsure about my current scheme for a relatively bright light that runs off a battery which recharges via solar power and doesn't go dead due to the continual recharging during the day and effective use of electrical energy. I do not know whether resistors, transistors, power inverters, or any other equipment is beneficial or necessary. I am also unsure of a high quality, relatively cheap solar panel that is compatible with the 12v battery and the 12v LED bulb (if anyone has any advice for that). I drew up a diagram of my possible setups, labeled 1, 2, and 3. Option 1 is the basic setup without any additional hardware. Is one of these setups correct, and the most effective way to go about my objective? If not, how can I modify it to be the proper setup? Thanks :)

Question by tyranasaurus tyler   |  last reply

### 6v to 12v system?

I have a 1929 model t that is curently a 6v system with no starter or generator. I would like to use a starter generator off of a modern galf car. Is there any way i can step the voltege down befor the battery or would it just be easyer to add a converter in to run the original lights and ignition system? Any help would be awsome!!!

Question by theoldway   |  last reply

### 9V-12V from portable battery to usb hub?

I have a portable battery: http://www.xpalpower.com/us/products/xp18000/ I would like to run the output labeled DC9-12V (or DC16-20V) to a 5v/2.1a usb hub that I have.  I was thinking I could strip down a 12v usbhub car charger, but I wouldn't know how to manage the connector.  Has anyone done anything like this? Thanks

Question by 9zpvwz   |  last reply

### how to increase 12v, 45A battery life.

How can i increase the life spam or strength of a 12v 45A battery

Question by agasco   |  last reply

### If i hook two 12v batteries in parallel will the amperage be higher?

And volt be same? will it last longer with two batteries?

Question by alpe_97   |  last reply

### How to connect a normal household fan to a battery? Answered

Hi everyone I'm trying to connect a standard 230V- 50Hz 25W fan to a battery to make it mobile for a project I'm working on. I want the battery to be able to power the fan for at least an hour before recharging it.  What type of inverter will I need for this and what kind of battery? Thanks!

Question by axelkaaber   |  last reply