How Many Amp-Hours Is A Tesla Powerwall? (13.5 kWh To Ah)

We are used to denoting battery capacity in Amp-hours (Ah). When we look at Tesla Powerwall’s specs sheet, we quite surprisingly don’t find the amp-hours specification. What we actually get is this “Usable Energy: 13.5 kWh”. How do we get from this 13.5 kWh to Ah?

Here’s the deal:

How much electricity any battery holds is referred to as battery capacity. We are used to looking at 50Ah, 80Ah, 100Ah, 200Ah solar or car batteries and, naturally, we wonder how many Ah is a Tesla Powerwall. First of all, we need to keep in mind that battery capacity can be expressed in these two ways:

  1. In terms of amp-hours (Ah). This is the conventional battery capacity unit we are used to. However, it doesn’t really tell us directly how much electricity is in that battery. In order to have a feeling of how much electricity is in the battery, we have to multiply amp-hours by voltage (usually 12V battery voltage). The result will be battery capacity in watt-hours (Wh), or, in the case of big batteries like Tesla Powerwall, we can express the result in kilowatt-hours (kWh).
    classic 50ah car battery
    This is a classic small 50Ah 12V car battery. By multiplying 50Ah by 12V, we see that it has a 0.6 kWh capacity (more than 20x less than Tesla Powerwall).
  2. In terms of watt-hours (Wh) or kilowatt-hours (kWh). This is the direct battery capacity; it immediately tells us how much electricity a battery can hold.
    how many ah is a tesla powerwall
    One Tesla Powerwall has a 13.5 kWh capacity. Here we see 2 Tesla Powerwalls with a combined 27.0 kWh capacity. How much is that in Ah? 2,250Ah for both Tesla Powerwalls as we have calculated further on.

The preferable way to report the capacity of bigger batteries is in kWh, and Tesla has done just that. It tells us that Tesla Powerwall+ and Tesla Powerwall 2 hold 13.5 kWh of usable electricity.

Nonetheless, since we have been using amp-hours for most of our batteries, we still want to know how many Ah is a Tesla Powerwall, despite already knowing the kWh capacity. Let’s calculate the Ah from the kWh rating:

Tesla Powerwall Ah At Standard 12V Battery Voltage

When we see, for example, a 100Ah 12V battery, we know that this battery can deliver an equivalent of 100 amp current at 12V voltage for 1 hour. We can calculate how many kWh of electricity that is like this:

Battery kWh Capacity (100Ah, 12V) = 100Ah × 12V = 1,200Wh = 1.2 kWh

With a Tesla Powerwall, we:

  • Don’t know its capacity in terms of Ah or kAh.
  • We do know its capacity in terms of kWh. Both Tesla Powerwall and Tesla Powerwall have a 13.5 kWh capacity.

If we presume the standard battery voltage applies to Tesla Powerwall (12 volts), we can calculate how many amp-hours is a Tesla Powerwall like this:

Tesla Powerwall Ah Capacity = 13.5kWh × 1000 / 12V = 1,125 Ah

As we see, we have multiplied the kWh by 1000 to get Wh and divided by voltage (12V) to get amp-hours. Tesla Powerwall has a 1,125 amp-hours capacity at 12V battery voltage.

In our photo above, we see two Tesla Powerwalls, and they have double this capacity: 2,250Ah.

Now we can compare Tesla Powerwall capacity to the capacities of common car batteries we are familiar with. Here are some comparisons:

  • Tesla Powerwall contains more electricity than 22 50Ah batteries. 22 50Ah batteries have a combined capacity of 1,100 Ah, while Tesla Powerall has a 1,125 Ah capacity.
  • Tesla Powerwall contains more electricity than 11 100Ah batteries. 11 100Ah batteries have a combined capacity of 1,100 Ah, while Tesla Powerall has a 1,125 Ah capacity.
  • Tesla Powerwall contains more electricity than 5 200Ah batteries. 5 200Ah batteries have a combined capacity of 1,000 Ah, while Tesla Powerall has a 1,125 Ah capacity.

We hope that this illustrates well how many Ah is a Tesla Powerwall and how it compares to regular 50Ah, 100Ah, and 200Ah batteries.

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