How do you imagine what an ampere hour is?

stabilizator 29 Jul 2020 18:23

The receivers draw a certain current from the battery or accumulator. How long they can operate depends on the capacity of the cells that make up the battery. If the receiver draws a current of 1A, it will take a 1Ah charge within an hour. A 10Ah battery could theoretically power a receiver requiring 1A for 10 hours. In theory, for a receiver requiring a current of 2A, the working time on a 10Ah battery will be shortened to 5 hours (in practice, the higher the discharge current, the smaller the actual battery capacity). Resistive loads (e.g. a light bulb) will consume lower current as the battery voltage drops. Receivers equipped with a DC / DC converter can receive constant power with changes in voltage, i.e. when the supply voltage drops, they will consume more current.

We left out the voltage of the battery and only focused on the ampere-hours for its capacity. Both the 12V 10Ah battery and the 6V 10Ah battery can power a receiver using 1A current for 10 hours, but in the case of 12V the receiver will use 12W and in the case of 6V it will be a 6W receiver. Therefore, the capacity of the batteries is often specified in Wh, i.e. a 10Wh battery can supply a receiver with 1W power for 10 hours. The aforementioned batteries have a capacity per Wh, respectively: battery 12V 10Ah -> 120Wh, while 6V 10Ah -> 60Wh. You will also find watt hours, or rather kWh, in electricity meters in the home power supply system.

Information about the basic parameters such as voltage, current, power, more information can be found here: Voltage, current, power - what are these values and how are they related by Ohm's law?

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sanfran 29 Jul 2020 18:53

Ampere-hour as a unit was (and is) used for families of fixed voltage batteries, e.g. on-board batteries in passenger cars, which was closely related to the current capacity of the device - including the... [Read more]

stabilizator 29 Jul 2020 19:05

Thank you for developing the topic well and maintaining the description that will facilitate easy understanding of the issue for people who are just starting their adventure with electronics. :spoko: [Read more]

Tomek515 29 Jul 2020 20:36

Recently, I was wondering what it is like when I have a 12V 7Ah battery. I could get 1A from it for 7 hours. But whether this capacity is given to the safe level of battery discharge, i.e. in the case... [Read more]

sanfran 29 Jul 2020 22:43

From what I can remember from the old days, the value was 10 hours for standard lead-acid batteries. So in the above case 700mA for 10 hours until full discharge - that is, voltage drop to a certain level.... [Read more]

electro 30 Jul 2020 00:03

For acid batteries, the so-called Peukert's law which determines the dependence of the available capacity on the current consumed from the cell. In short, the more current we draw, the smaller the... [Read more]

stabilizator 31 Jul 2020 19:10

In small UPSs, the batteries have difficult operating conditions, the discharge currents are high, as you write, then the available capacity and back-up time are reduced. In larger UPS units, the batteries... [Read more]

kowal011 06 Aug 2020 21:21

For small AGM batteries, or the popular "gel" batteries from UPS, capacity is given as 20 hours. [Read more]

gold-game 30 Aug 2020 21:39

It is worth mentioning that the use of battery 'protectors' is becoming more and more popular. It is about preventing excessive discharge of the battery in a domestic installation, e.g. in a motorhome.... [Read more]