I have 2500 mAh on the battery and 3.7 V normal voltage and I get 55 watts for the pack in DC, then after changing my voltage to 120 AC, how can I calculate the wattage? I mean multiply the 120 V ac with same DC 2500 mAh on the battery? point is does it change? the mAh on the battery ?
121650
let me say if I have a pack of lithium batteries connected in series and parallels, and i want to connect it to an Inverter, BUT...BEFORE I connect it to inverter, lets say it gives out 12 volts "hypothetically" some informations like 3.7 volt batteries, and 2500 mAh,  lets say then the pack gives 12 volts in DC and hypothetically again I calculate it ((still in DC)) is .....  W = V* Amp ... then it means wattage = 11.1 V * 5 Ah which is 55.5 W. then we got 55.5 watts, THEN....after we want to change the dc into ac it gives you 120 volts "please hypothetically" just answer me this, ARE the Wattage And Ampere are remains the same as DC? what would it be the result after AC?
65384
I want to make a power DC supply with voltage rating 0-200V. I want it to be a variable power supply with voltage from 1V to 200v. What should be my approach?
96763
Thanks to the help of a few of the other guys I have my AC to DC rectifier working, and the rest of the power supply working.  Now while testing the power supply, my 18V AC transformer gets rectified and put into my circuit below   And I end up with 1.3-26V DC output selectable via the pot R2.  Now while running this @12V with a LED strip light, running about 600mA my heat sink got quite hot. Not hot enough to cause the thermal protection in the LM317 to cut in but hot enough to get me thinking.  Power dissipated = (Vin - Vout)*Il = (26 - 12)*0.6 = 8.4W  My heat sink is rated at 11 C/W and I pasted the LM317(TO-220) on.  Max C/W is = (MaxRunningTemp - ambientTemp) / power = (60-25)/8.4 = 4.2 C/W  Does that sound right, never done any heat sink calculations before. So I would need a heat sink rated at &lt;4.2 C/W  I would not see my self running this over 500mA again but running this circuit at 5V would change a lot? The power dissipated would be 42W if 5V @ 500mA. What can I do to prevent needing a HUGE heatsink? and are my calculations above correct?
60572
These tp4056 can charge at lithium battery up to 1A.   I would like to use them in series but charging each battery separetely because the TP4056 modules cannot be wired in serial due to common ground.  But i've made a schematic and i would like to know if it will work or explode.  Here :   In this circuit each module have a tp4056 chip, a dw01 single cell protection ic and a dual mosfet.  The switch is used for the charge or for out 11.1V so you won't be able to use the +11.1V while charging it and it's a dpst switch so no common ground problem.  Can I wire these modules in series?
102321
I currently have a 72V e-bike.  The configuration of the batteries directly from manufacturer is 6 12v 20AH valve regulated lead acid batteries connected in series. In taking the  limiter harness out of the mix my speed went up roughly 15kmh (this is being done strictly as a learning expierience and only driven on my own private property.) I have a 12V 14 Ah lead acid and another 12V 6.5Ah lead acid. I was wondering if connecting the two 14Ah and 6.5 Ah in a parallel circuit and then adding to overall power bank in series thus having 96V.  Will my speed increase any more? Is this an idea worth pursuing and if my configuration won't work is there any other that is worth pursuing?   Alternatively I'm taking one 12V to power an amplifier on bike.
46886
How would one go about using a 12 V DC power source to power something which needs 4.5 V DC using resistors? Is there a way to determine how much adding a resistor would drop the voltage?
45266
Below is a picture of a battery shell for a NiMH circuit for a power assist wheelchair battery.  I'm taking a guess that each of the 20 batteries is 1.2V because the entire circuit is 24V.  These are rechargeable.  I'd like to convert this circuit to the same voltage (24V) and same capacity (3Ah).    First, is this possible given the space you see in this wheelchair battery shell, and the circuit board in the pictures?  Second, what are the material requirements to be able to convert this circuit from NiMH to Li-Ion and the type of charger as well?  What materials will I need to solder/weld the materials together, etc.. for the actual labor?  I'm an electrical novice, so please ask me more questions (as comments) and I'll do my best to answer.  Note: right click image and open in a new window to make it larger!
21367
What exactly does mAh rating means? I know that it means the milliamperes supplied by the battery in one hour but i need a more conceptual and practical definition/example.   How does mAh rating tell the current supplied to the load? How does it vary with the load specification.   Also, suppose a mobile phone's battery has 3000mAh, if i supply it with 1000mA, then does it mean that the battery will be fully charged in 3 hours?   And will a 3000 mAh battery deliver a current of 3000mA for 1 hour to a load? Will this rating degrade in a practical scenario. Please explain.
123976
I would like to know about the workings of mobile phone battery chargers. I know the basic principle, you take a transformer to bring it down to 9/6/3.7 volts then a bridge rectifier circuit and a capacitor input filter to rectify it into DC. Then you apply it to the battery. But I know this should not be enough, I need at least two things,   Protection against back current flow Switch off power when the battery is fully charged.   Can someone point me to something simple (apart from this )
21243
I'm looking for a high current DC switch (able to switch something like 5V@30A) and I've encountered several DPDT that might do what I need, however they are only rated for AC applications (3A@250VAC or 6A@125VAC). Are these rating convertible to DC? or is that something that only the facturarer would know?
78096
How long can I run a water pump which requires 12V and 50W from a 12V, 40Ah, 400A car battery?  Can you explain how this was calculated?
84243
I've just bought a portable battery, but the portable battery don't comes with an adapter for the house current; it only comes with a USB cable so I can charge it with my laptop. My mobile phone came with a charger, and I want to know if is safe to use that charger with the battery without problems, even though the output has a higher amperage. These are the specifications:  Battery input: 5V, 1A Charger output: 5V, 2A  Will the output only give the quantity that the input is requesting, or will the input overheat because it cannot handle all the current it receives?
103844
I have almost no experience whatsoever with the technicals of electronics so this is probably a very easy question for someone who does.  Do you know if a battery with a 200Ah rating can put out 200A for one hour or are there limitations? According to this website's third paragraph (), you can.     For example, an average automotive battery might have a capacity of about 70 amp-hours, specified at a current of 3.5 amps. This means that the amount of time this battery could continuously supply a current of 3.5 amps to a load would be 20 hours (70 amp-hours / 3.5 amps). But let’s suppose that a lower-resistance load were connected to that battery, drawing 70 amps continuously. Our amp-hour equation tells us that the battery should hold out for exactly 1 hour (70 amp-hours / 70 amps), but this might not be true in real life. With higher currents, the battery will dissipate more heat across its internal resistance, which has the effect of altering the chemical reactions taking place within. Chances are, the battery would fully discharge some time before the calculated time of 1 hour under this greater load.   But wouldn't that mean you could hook up a 200Ah battery and ask it to put out 12000A for one minute or 720000A for a second?  That seems very unrealistic, lol.  I'm trying to find the proper kind of off grid battery that can power a microwave through a 3000 watt power inverter.  The microwave needs 1800 watts and the battery needs to be 12 volts so that would mean I need about 150 amps, I'm wondering if a battery with a 200Ah rating could do it?
54180
I hope you will not mind answering. This question has long been on my mind.  Normally, the adapter output voltage is higher than that of the battery. In my laptop's case, the output voltage of the adapter (or charger or power supply) is 19.2V. (That .2V itself is also a big question for me. Is that so sensitive?) But the voltage of the battery is 10.8V.  My question is, why is the adapter output voltage different from the battery's voltage?  This is not about asking how it is regulated by the internal circuitry, but asking why.
77989
I've got two solar panels set up in series as shown on the below schema. I connect positive on panel A to positive on battery, and negative on panel B to negative on battery. The two panels produce 9V each, and 18V in series on a good sunny day. That's what my multimeter says.    If I disconnect cabling between panels and battery, my multimeter shows that the panels produce about 15V (a bit cloudy today). However, when I connect the cables between panels and battery, my multimeter shows about 12.2V. I believe this is the battery voltage.  Why is it that when I connect my multimeter at point A and B it shows 12.2V (when solar panels are connected to the battery). As you can see on the schema, there's a diode in front of point B. Shouldn't that diode make sure that current from the battery not flows back to the panels?   If this is how it is supposed to work, how do I check the voltage my panels produce when the panels are connected to the battery.
13124
I am using NCR18650 batteries with the tp4056 charging module.  When I connect the charger at 2.8&nbsp;V (fully discharged), the tp4056 IC is getting hot at a 1&nbsp;A charge current. Is it OK to reduce this charge current by changing the charge current selecting resistor? So the tp4056 IC heat would be reduced, wouldn't it?  For my application I don't need a quick charge. With a low current, charging time will be increased, but it does not matter for my application.  Will reducing the charge current affect the battery's lifetime? Or will it damage the battery?  I am trying to reduce the heat of the tp4056 IC by reducing the charging current, maybe from 1&nbsp;A to 500&nbsp;mA or less. The 18650 battery never heats for a 1&nbsp;A charge current.
67804
I have a computer power supply that I'm hacking together as a bench supply. For this particular model to power on, I need a minimum load across both +5V and +12V.  "Easy," I thought, "I'll just connect both +5 and +12 to my power resistor!" And it worked, but then I started thinking, what does it mean to have these two different voltages connected in parallel? If the voltages were the same, then I would be . But what about different voltages?  Also, what if I connected +5 and +12 in series, and then put a load on that? The equivalent voltage would be +17V; what would be the difference between that and parallel?  Or am I going about this the wrong way; should I put a separate resistor on each rail? It seems like I can do better than that.