Posted on March 13, 2023
By Bryony Harrison

We have put together this guide, based on our years of experience on location and in the industry. We hope it’s helpful!

From lights and playback to heaters and even a kettle in the production office: there are numerous electrical items on set that consume power. How can you calculate the power requirements of all of this equipment in order to know which generator or battery pack to hire? How many will you need? And what are the cleaner alternatives if you don’t want to hire a traditional carbon-emitting generator? What’s better – a Wattman 10kWh, a Goat 4.8kWh, or the lightweight battery option the Instagrid ONE max 2.1kWh?

As the industry moves away from wanting or even being allowed to use petrol or diesel generators, film crews need to consider their power needs and their power usage throughout the shoot more carefully.

Our battery power solutions

Adding up your power requirements or ‘calculating power draw’

In the UK nearly all domestic electrical equipment draws under 3kW. A kettle for example uses up to 3kW of power but only for a short time. And a typical fridge will only use 300Watts while it’s cooling but will turn itself on and off throughout the day.

The power requirements of every bit of kit will state its maximum power draw on a label, usually on the back or underneath.

To calculate the total power draw if every bit of kit was turned on at once, you can simply add these numbers up to give your total power requirement. However, in practice, you’re very unlikely to run every bit of kit at once, so there is usually a lot of flexibility in this total figure. Best practice is to make sure you don’t have everything plugged into the same power source, so you can more easily monitor where the power is being used the most and act accordingly.

Understanding power capacity

Batteries all come with two very important pieces of information: how much power they can store and how much power you can draw out at one time. For example:

Kilowatt hours (kWh) lets you know how much power the battery contains in total. The number tells you how many hours the battery can produce 1kW of power. For example, a 2.1kWh battery can produce 1kW for 2.1 hours. You can divide the number of kWh by your total power requirements to give you the number of hours the battery would last if everything was drawing electricity at once. The output or ‘draw’ tells you the highest amount of power you can take from the battery.

Some examples using the Instagrid ONE max 2.1kWh:

A 32” TV screen uses 40Watts continually whilst on, so we can simply use 2.1kWh ÷ 0.04kW = 52.5 hours

A fridge drawing a maximum of 350 Watts is more difficult, whilst we have 2.1kWh ÷ 0.350Kw = 6 hours which gives your ‘worst case’, in reality, fridges do not constantly draw power, they switch themselves on and off and try to maintain a steady temperature. So the real figure depends on other factors like the temperature of the environment and how often it is opened. We have run a large freezer for over 24 hours with an Instagrid ONE max.

A kettle and an urn both draw 3kW, so like a lot of heaters they are at the heavier end of electrical requirements. An urn constantly drawing 3kW would not last long on any battery but with a kettle being turned on and off, you could estimate how many cups of tea you could make!

It’s important to try and gauge how much electricity you will use over time when considering your requirements.

A kettle typically draws 3kW but only needs 5 minutes to boil water for a few cuppas. So the Instagrid ONE max, the Goat and the Wattman will all give you enough power output to actually use a kettle. Using a bit of maths, we can see how many times that kettle can be boiled. 

2.1kWh Instagrid One Max / 3kW = 42 minutes, which means that if the kettle were used constantly you could boil it 8 times.

Wattman 10kWh/3kW = 200 minutes which would boil the kettle up to 40 times. The Goat 4.8kWh/3kW = 96 minutes which would boil a kettle 19 times.

At the other extreme, a fridge that only uses 350 watts while cooling might only use 1kW in a whole day. But this very much depends on the outside temperature, how many times it’s opened and what’s inside it.

Remember there are other considerations too. The Instagrid ONE max weighs only 20kg and can be carried, whilst the Goat 4.8kWh weighs 78.5kg, and the Wattman 10kWh weighs 90 kg but both come with rugged location-ready wheels. So, consider using the Wattman and the Goat when you can wheel them into place, and opt for the Instagrid ONE max when you want the most lightweight power.

After testing many different items of equipment, we have created the following as a guide. The table calculates the power required and the approximate operating time using the Instagrid ONE max for common on set electrical items.

Some extension lead safety

It’s also important to remember that typical extension leads, even the ‘four way’ types can only handle 3kW in total. So you can use the adding up method above to ensure that you don’t overload it. For example; if you plug a 3kW hot water urn into a four way extension lead, you should definitely not plug anything else into it because you will overload it. This means you could melt the plug, damage the kit, the location, or even start a fire. You can also easily melt a drum-type extension lead by not unwinding it fully when using it near its capacity. The drum extension lead should say on it the maximum power you can draw without it being fully unwound, typically 750 Watts.

The different types of portable battery power

So which portable battery gives you the energy you need to power up your electrical equipment?

Instagrid ONE max 2.1kWh

We have found this to be a favourite with our clients. The Instagrid ONE max 2.1kWh battery is a silent, small and portable battery that weighs only 20kg, it can be easily carried around, so is much more flexible than anything larger.

It has a 2.1kWh capacity, with 3.6kW power output, takes 2.5 hours to charge from a normal wall socket (or even from another generator). It has both a 13-amp and 16-amp socket, with an output voltage of 230VAC / 50Hz, and a 3600W power rating.

Made from recycled aluminium, this greener battery power pack saves up to 97% emissions compared to a diesel genny. Plus, the Instagrid ONE max doesn’t have an inverter, so it’s totally silent with no fumes and has an IP54 rating meaning it’s splashproof too.

The Instagrid ONE max has been priced with a view to a production using 3 or 4 or more of these packs to power different parts of a shoot, rather than relying on one big genny. You can run your LED lights, your production office, your playback and tea table, each with their own Instagrid ONE max (or two). We call this “decentralised power”. Or pair with some larger battery packs where your power needs are greater.

The Instagrid ONE max now has a docking station to enable two or more batteries to be linked together and an app to easily monitor electricity usage.

Wattman 10kWh

With a 6kW output, this rugged, portable battery can power your entire production or event.

With 2 x 16 amp and 1 x 32 amp outputs, and large wheels for easily navigating tricky terrain, it’s incredibly handy on location. It’s storage capacity is 10kWh, with a peak output of 12kW and charges in under 4 hours through a standard 13 amp plug.  Suitable for filming in temperatures from-10°C to 45°C.  It has an IP rating of 22 aso comes with a rain cover for those rainy days on location.

Goat 4.8kWh

The Goat, weighing less than the Wattman, with a higher IP rating of 67, this a powerful and portable Battery Generator that delivers 5kW of clean and silent energy with 4.8kWh of storage. With rugged wheels and a robust cast aluminium and carbon fibre housing, it is suitable for any environment and works well on any location.

With an inbuilt pure sine wave inverter to protect sensitive equipment, this portable powerhouse gives you the peace of mind you need against power surges during your production. A variety of charging options such as solar, DC, and AC ensure that you can always keep the Goat powered up. You can even charge it in less than two hours with a Type 2 car charger (seven-pin AC and DC charging) and gain extended runtime by charging while in use.

So, what does it cost to hire a silent, portable battery?

The Instagrid ONE max 2.1kWh – get a quote now

The Wattman 10kWh – get a quote now

The Goat 4.8kW – get a quote now

For more information on which generator or power pack to hire for your shoot, get in touch with the Get Set Hire team.  

Products that work well with a battery power solution