# Questions tagged [ampere-hour]

A unit of battery capacity configured for easy calculation. The SI corresponding unit is Coloumb ( unit of "C") which is a measurement of charge. A=C/s (A=Amps) so A*hour are dimensionally similar with a scale factor of 60*60=3600. This roughly tells you how much current a battery will supply for how long. Note that this is an estimate of the total power delivered, the voltage of the battery will vary with current level as well as charge level.

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### Calculate the ampere hour rating of a battery using current over time and voltage over time

I built a battery and measured the current and voltage of the battery over time. Is there a way I can use this information easily to calculate the ampere hour capacity of the battery?
3answers
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### Calculating 12v Battery Ah

Forgive the ignorance here, electricity is a weak point of mine and I'm trying to wrap my head around it all. I'm trying to find out how many Ah exist in an old lead acid battery. I hooked up an ...
1answer
48 views

### Peltier Kits Cooling [closed]

I bought 4 12V Tech-12706 Peltier Kits Room Temperature Average 30' C How many Kits I have to install to cool a Insulated ACP Sheet Box Area of 3 Cubic Feet / 90 Litre ? I tried Calculator but could ...
1answer
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### way to calculate the draw limit on a battery

Is there a way to way to calculate the draw limit on a battery, using any of Amp-Hour, C-Rating, etc... values to solve for the unknown? If so how do you do it?
3answers
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### (Capacity 20hr: 65AH) Does this mean 65amps per hour for up to 20 hours?

Cranking Amps: 675 Im trying to find a good battery for a project. That part where it says "20hr" keeps making me rethink what i sorta hope it means.
1answer
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### Calculating Battery Life with different working voltages

I have device that draws 30 uA in current continuously, and it is powered by a Panasonic CR2032 device (240 mAh - continuous standard load current: 0.2 mA ). There are two components on this device, ...
12answers
6k views

### Why is electricity consumption billed in watts and not amperes?

Basically the subject. Why would companies bill for wattage instead of amperes?
1answer
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### Confused about battery rating specifications [duplicate]

I'm confused about how to understand battery capacity by its ratings. I though I understood Amp-Hours, as a nominal rating where they usually specified a period of time where that rating was ...
1answer
107 views

### How to find how many Amperes does a equipment use? [closed]

In the specification of this miner https://www.asicminervalue.com/miners/bitmain/antminer-s9j-14-5th it says it uses 1350W power with ...
2answers
78 views

### Is there a reason why lower voltage batteries are preferred for high AH?

I was looking at these batteries and considering whether to use a 12V battery or multiple 2V batteries for backup power. In any case, I came across this battery by Exide Tech - GNB Flooded Classic H1T ...
2answers
442 views

### Is lithium battery charging speed proportional to the amps provided from the power source?

An interesting fact I came across recently - electric kettles in the US run at double the time for other countries - due to the US adopting a 110V power system. (And electrical kettle boiling duration ...
3answers
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### Watts - I think I'm getting free energy from a circuit?

Imagine I have a 10V battery with a capacity of 1Ahrs connected to a 100 Ohm resistor. I'll get 0.1A (V/R) at a power of 1W (current x voltage) for a total of 10hrs. As a watt is defined as J/s my ...
1answer
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### Is Multiplexing Fast Charger Safe? [closed]

I got a original Samsung 2A output phone charger. If I open inside and add some wires and USB port to the circuit board and try to charge 2 devices in same time, what happens? Is it safe? Can I get ...
2answers
880 views

### If I convert 10 V, 1 ampere to 5 V, do I get 5 V 2 ampere?

I know the current in the circuit is the same. And also, Power = 10* 1 = 10 watts. So, 10 = 5 V * (x) ampere, X = 10/5, X = 2 ampere, With some loss while using a voltage regulator, I will ...
3answers
129 views

### What happens when Amperes hour (Ah) and voltage regulation go together to the party?

This is the first time I ask on the Electrical Engineering site of Stack Exchange, please feel free to dismember my question. Please take into account: I am thinking about the hypothetical ideal case ...
2answers
15k views

### 9.5 ah replaced with a 8ah battery? [closed]

I'm trying to replace two Data Safe NPX-35, 12V, 8.5Ah SLA batteries. When I called support to figure out what to order (before pulling the actual batteries out) they said that any 12V 9Ah SLA would ...
2answers
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### How to calculate battery ratings for your solar panel?

If I want to choose a battery for my solar panel which is required to run a load of 5 kWh/day. Then I will be needing a battery with a rating of above 23 ampere hours since 5 kWh/220 V (since 220 V we ...
2answers
153 views

### Mistake in calculating the last time of battery (Ampere hour problem)

I've a question about the mAh rating of batteries. At the Dutch Wiki page of AmpĆØre-uur which is the Dutch word for Ampere hour, they say for example a $100$ Ah battery can supply 5 A for 20 hours ...
1answer
789 views

### Does Amp Hour Rating Take Into Account Voltage Drop Relative to State of Charge?

I'm looking at buying batteries, either 12v AGM or LI-Ion, for use in a backup power system. I have a choice between a Lifeline 8D AGM battery rated at 255 Ah @ 20 hr, or a Victron LI-Ion rated at 160 ...
4answers
42k views

### Battery Ampere-hour rating vs Battery Amps (not an experienced user)

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 ...
1answer
79 views

### Can not find or calculate ampere hour from the data sheet

Here is the data sheet of a ups: http://www.ups-service.by/PDF/Technical_Specification_PowerWave_60-500kW_English.pdf How long for a nominal 500A current drawing load would this utility last? How ...
0answers
1k views

### Converting battery capacity from Ah to Wh: Which voltage should be used?

I need to convert the battery capacity from ampere-hours to be Watt hours. I know that $P=VI$ in Watts, however I'm unsure of which voltage I will need to use in order to use this relation; there ...
2answers
118 views

### Simple question about power usage

My question is simple for humans but hard to search for in Google or somewhere else, so forgive me if this isn't the best place to ask. I was looking up the power consumption of an electronic device ...
2answers
2k views

### Smallest Magnetic Relay and how to choose the Ampere rating [closed]

I am building an automation system, where I don't have much space, so I require really small relays, 3.3 or 5 VDC controllable relays. I need to connect it to say a lamp, or a fan, equipment's that ...
1answer
5k views

### How much AH should my battery has for my sound system (3 Amplifiers)?

I would like to know if I can mount my sound system in my car. My current battery is 45AH, and the problem is that I can't go higher than a battery with 50AH, because there isn't space for it on the ...
2answers
1k views

### What is the 'continuous standard load' of a battery?

I'm currently integrating a coin cell power design into an electronics project. I am trying to verify my understanding of the 'continuous standard load' rating given for a battery (datasheet) When ...
3answers
37k views

### Batteries in series with different amp-hour ratings.

I have a 1.5 amp-hour, 12 V battery and I have a 10 amp-hour 12 V battery. I know the voltage will increase to 24 V when they are put in series, but I don't know what goes on amp-hour wise. Does the ...
2answers
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### Battery power required for a 2HP Motor AC at 1800 rpm, 56Hz?

So I will be using an Inverter to convert DC(12V) to AC(220v)(50Hz). The 2HP*(746w) = 2.3 kW / .85 power factor = 2.7 kW / 220V = 12.27A If I want it to run for 5 hours that's 62 Ah. Can I use a ...
0answers
62 views

### coulomb and ampere calculation reg

when I am reading the IC datasheet ,operating voltage is they were mentioned 5v,300mA.its means 300mA per sec/min/hour. Because I have to calculate battery power for a circuit. 1 coulomb= 1 ampere. ...
4answers
1k views

### What should be the watts of solar panel and battery size

I want to light one 70watt bulb for 12 hours at night time. I want to know what should be the Watts of the solar panel and how much Ah battery will I require? I searched many of the questions here ...
2answers
180 views

### What is the basic definition of an amp-hour?

What's the basic definition of an amp-hour? For example: A 12V battery is rated at 100Ah. Does this mean that the battery will be discharged in 1 hour if the load is 100A@12V? Thanks.
1answer
749 views

### How long will my battery last and how to calculate it? [duplicate]

I have a 12V 18Ah battery I wish to run through a boost converter at 40v and 2.5A to power a 100w led. Could someone figure out how long my battery would power my led and show the calculatins/...
3answers
4k views

### Do buck converters increase the amp hours of a battery?

I've read that they are 90% efficient compared to linear regulators so given the relationship between volts and amps and I want to power the project off of a 12v battery that has 18Ah and is charged ...
3answers
4k views

### Determine the amp hour rating of a home made battery pack

I'm thinking of making my own electric bicycle, and I need help determining what the amp hour rating of my battery pack would be. I'm going for 36v and 8 or 9 amp hours. So, with 10 batteries in ...
1answer
381 views

### Lead Acid Battery Charge C/20Ah

I need to charge a lead acid battery, I will be manually developing a program to set the current. Its the "US 12V XC2" Deep Cycle battery. Here is a link to the datasheet: http://usbattery.com/wp-...
1answer
9k views

### calculate Amp Hours when voltage is given

I'm trying to wrap my head around how exactly Amp Hours work. I have been trying to figure out this question for a while now, but can't seem to find the information that I need. This is the circuit, ...
2answers
651 views

### Figuring out battery life from amp draw?

I decided to take apart one of those cheap handheld fans. It takes 2AA Alkaline batteries. I wanted to hook it up to an arduino as a way to get into electronics, and I wanted to know what kind of ...
1answer
5k views

### Calculating mAh needed to run a device

I've got 15 devices each with a current of 20mA and I am interested in running them all for 10 seconds. How would I go about working out the amount of mAh a battery would need to provide for this? I ...