On 11/04/2020 09:53:03, Mike Clarke wrote:
On 10/04/2020 22:35, The Natural Philosopher wrote:
On 10/04/2020 20:28, Bert Coules wrote:

Â* Do I need to disconnect the car's own connecting leads
first?

no

Some manufacturers recommend that you do disconnect the battery. Some
cheapo chargers might have a very spiky voltage pattern that could upset
the onboard electronics.

I would hope the electronics are designed and tested to a variant of
ISO7637.
https://en.wikipedia.org/wiki/ISO_7637

It shouldn't be a problem.