How do I convert kilowatt-hours to amp-hours?
In many cases, we need to convert kWh to Ah. With smaller 12V batteries, we also need to convert kWh to mAh.
We will look into how does kWh to amp-hours (Ah) conversion. You will also find a kWh to Ah calculator that dynamically calculated kWh from Ah and a calculated table of kWh to Ah and kWh to mAh. Let’s start with an example to illustrate.
Example: How to convert 13.5 kWh to Ah? First, we need to specify the voltage. Let’s say we have a 12V battery. We can calculate Ah from kWh using the basic kilowatt-hour equation:
kWh = (Ah × V) / 1,000
We express amp-hours (Ah) and insert our numbers:
Ah = 1,000 × kWh / V
Ah = 1,000 × 13.5kWh ÷ 12V = 1,125 Ah
That means that 13.5 kWh is equal to 1,125 Ah or 1,125,000 mAh on a 12V circuit.
Here is the kWh to Ah calculator that makes this calculation automatically:
kWh To Ah Calculator
Just insert kWh and voltage (V), and you will get the calculated Ah. You can also play around with numbers a bit and the calculator will dynamically calculate the ampere-hours:
For example, it is useful to know this basic conversion:
1 kWh to Ah in a 12V battery is equal to 83.33 Ah.
On the other hand, if you need an Ah to kWh conversion, you can find a similar Ah to kWh conversion calculator here.
Here is the full calculated table of kWh to Ah conversions for the 12V circuit:
kWh To Ah And kWh to mAh Chart (At 12V; For Batteries)
| kWh (kilowatt-hours) | Ah (amp-hours) | mAh (milliamp-hours) |
| 0.01 kWh | 0.83 Ah | 830 mAh |
| 0.02 kWh | 1.67 Ah | 1,670 mAh |
| 0.025 kWh | 2.5 Ah | 2,500 mAh |
| 0.05 kWh | 4.17 Ah | 4,170 mAh |
| 0.1 kWh | 8.33 Ah | 8,330 mAh |
| 0.5 kWh | 41.67 Ah | 41,670 mAh |
| 1 kWh | 83.33 Ah | 83,330 mAh |
| 2 kWh | 166.67 Ah | 166,670 mAh |
| 10 kWh | 833.33 Ah | 833,330 mAh |
| 20 kWh | 1,666.67 Ah | N/A |
| 50 kWh | 4,166.67 Ah | N/A |
| 100 kWh | 8,333.33Â Ah | N/A |
If you have any questions about how to convert these two electrical units, you can pose a question in the comments and we’ll help you out.
I am trying to determine how many Ah 12V battery I will need to power my 115VAC refrigerator for 48 hours.
I used a watt meter and found that my frig uses 1.04 kWh in 48 hours.
If I use an inverter that is 90% efficient I am coming up with approximately 91Ah of 12V battery. Does that seem correct?
Hello Brent, if your fridge uses 1.04 Wh in 48 hours, you basically need a battery that can produce 1.04 kWh of output. That would be 1040 Wh/12V = 86.7Ah battery (at 100% battery efficiency). Of course, you also have to account for 90% efficiency.
That 1.04 kWh should represent 90% of the battery capacity. Here is how you account for that: 86.7 Ah / 0.9 = 96.3Ah. So, you would need at least a 96.3Ah 12V battery. That’s practically your standard 100Ah battery. Hope this helps.
Hi,
I power 2 led lights of 72watts @ 220v. If a run these on battery setup of 24V with inverter how much will a 100Ah battery last…?
Hello there, so 2 LED lights with 72W each required a total of 144W power. A 12V 100Ah has a capacity of 1,200Wh and will run both of them for 1,200Wh/72W = 16.7 hours. If you have a 24V 100Ah battery, it will have double the capacity (2,400Wh) and will run the lights for double the time (33.3 hours). Hope this helps.
thank u for answering every comment, now im understanding better all of it
Hello I have a solar system 8 panels; inverter and 4 battery (200A each) for night
Can I keep the fridge (730kwh/year) all night in power without damaging the battery
Thanks for your help
Hello Lila, of course you can, that’s the whole point of having solar panels and batteries set up.
Hi
Please I want to know the difference between lithium battery rated in kWh and tubular batteries rated in ah and their application in designing a solar inverter system
Hi there, that’s completely understandable. The battery capacity should always be expressed in watt-hours (Wh) or kWh. That’s the ‘real’ capacity. In most cases, however, battery capacity is expressed in amp-hours (like your tubular batteries).
You have to put both batteries on the same denominator, and the kWh is the best unit for that. Here’s how you can do that: Let’s say you have 1000 Ah tubular batteries that run on a 12V DC current. To get the Wh, you simply multiply the Ah by voltage and you get 12,000 Wh capacity. This is a 12 kWh capacity. If you have lets say 10 kWh lithium battery, you can now compare these two battery capacities apple-to-apple. Hope this makes sense.
I have an extra second generation Toyota Prius battery, It is a 201.6-volt NiMH (nickel metal hydride battery) battery composed of 28 modules where EACH of the 28 modules is comprised of SIX individual 1.2-volt, 6.5 Ah (6500mAh) Prismatic NiMH cells which are internally connected in series. Each 7.2-volt module contains a charge controller and a relay. It’s basically a giant 201.6 Volt DC battery!
I was going to replace the bad cells & use it as a battery back up for my home.
Is is better to step down to 120v from 201.6 or re-configure it to 24 or 48 volts then to 120v ? or if you have any suggestions
Hi Simon, that’s quite an interesting question. The 201.6-volt battery is just awesome. We have to admit that we don’t have enough knowledge to adequately advise here. However, it seems like decreasing 201.6V to 120V directly just makes sense. Decreasing to 24V or 48V and then back up to 120V is maybe overthinking this. Hope you get it done, all in all it’s a brilliant idea.
This was super useful. Thanks for the info. The Q&A examples really helped me to understand.
On the last question they mentioned the 201V battery as lots of small batteries in series. Have you done anything on how that works? Series v parrel?
Hi Craig, thank you. Well, we are talking about in-series vs parallel wiring here; the voltage and amperage are different for each wiring. However, we are always looking at the net output (and input). When you have kWh, V, Ah, these are all net values and the difference between in-series vs parallel doesn’t reply apply here. Hope this helps.
Hi
Our electricity usage is 45kwh in summer to 70 kwh in winter per day.
it was recommended that we install the following
16kw Inverter
3 * 5Kwh batteries
12 * 540 watts solar panels
2 * 63amps circuit breakers
I have no idea it this is correct
Hi there, well, first you have to think about the kWh usage. 12×540W = 6480W solar panels. In the US, for example, we have 5-7 peak sun hours, which means such a system will produce 32.4 kWh to 45.4 kWh per day. This could fulfill all your electricity needs in the summer (45 kWh/day) but not in the winter.
With the 3×5 kWh batteries, you will have 15 kWh of storage. That is in line with what you should have (maybe a bit low). The 63 amp circuit can be loaded up to 80% max. capacity; so they facilitate 50.4 amp draw. At 12V (battery voltage), this is 604.8 watts. Two of them would facilitate 1209.6-watt power. This seems low for a 6480W system. Probably, you will have to talk to some installers.
Hello
is it correct the calculation above:
13.5 kWh is equal to 1,125 Ah on a 12V circuit.
and than
1 kWh to Ah in a 12V battery is equal to 83.33 Ah.
Thanks in advance.
Hi Winfried, both are correct; you have the right idea about this.
can you work out how many hours runtime for 4kw load of computer equipment, on a 48v inverter with 600AH lipo4 batteries, i want to know how much batteries i need for my inverter to run max of 6-8 hours with 70%-80% draw on the batteries to be safe im using lipo4 48v 100AH batteries
Hi Shaun, alright, so the 4kW computer equipment will require 4 kWh per 1 hour to run smoothly. The 600Ah 48V LiPO4 battery has this capacity: 600Ah x 48V = 28,800 Wh. This is 28.8 kWh. Timewise, this will run the computers for 28.8 kWh / 4 kWh/h = 7.2 hours. So, the max. runtime with this setup is 7 hours and 12 minutes.
If the draw is not 100% (4kW), but it drops to 70%-80% (2.8kW – 3.2kW), you can get about almost 10 hours of run time with a 600Ah 48V battery. Hope this helps.