Like a USB battery bank but bigger - How to make a battery bank for your laptop

This post describes how I solved camping laptop & camera battery charging for a short trip to Somerset. I chose a small car battery as my power storage. There are plenty of adapters and voltage converters around for cars and camper vans and boats. Car batteries can hold a lot of power, hmm doable.

So I needed a breakaway cable for supplying power from the terminals and a project box to house the isolation switches and fuses.

I picked up:

a 12v to 2 x 5v USB converter from ebay for £2

a car cigarette lighter socket for £5

two 12v switches with in built LEDs (12v rating is important)

two waterproof blade fuse holders

A range of blade fuses

Specification:

1 x 12v output (cig lighter)

2 x 5v USB sockets

Voltmeter (to check status of battery)

Both circuits isolated and separately fused

Fuses to be accessible outside the project container

Optional extras - I wanted to have the facility of charging this second battery with my car and or a small solar pannel (this is still tbc but I have a plan)

The missing link - a single 12v Cigerrette lighter plug to 240v UK plug socket £13.99 bargin! (75w max)

Here's a link to product: https://www.amazon.co.uk/dp/B00HZE2BFG?ref_=pe_1365641_54848841

Pics and results to follow!