In the run up to Christmas, many parents will be checking on their battery supplies ahead of Santa bringing gifts that require them. But do branded batteries, that promise more power and longer life at a higher price point, really deliver it?

Listener Peter got in touch asking just that, as well as whether batteries have an expiry date?

Greg Foot recruits some year 7 pupils and their teacher to help him perform a test to find out, and speaks to one of the country’s leading scientists about what gives a battery more power, or helps it store more energy.

You can also hear more about the difference between single use, and rechargeable batteries in our longer podcast episode on BBC Sounds.

This series, we’re testing and investigating your suggested wonder-products. If you’ve seen an ad, trend or fad and wonder if there’s any evidence to back up a claim, drop us an email to sliced.bread@bbc.co.uk or you can send us a voice note to our new WhatsApp number: 07543 306807.

PRESENTER: Greg Foot PRODUCER: Kate Holdsworth