On Wed, 22 Jul 2020 14:56:04 +0100, "Dave Plowman (News)"
wrote:

In article ,
Scott wrote:
On Wed, 22 Jul 2020 11:25:26 +0100, "Dave Plowman (News)"
wrote:

In article ,
Theo wrote:
I think I might need a new car battery charger. However I'm failing to find
anything suitable and wonder if the team can recommend any models.

Requirement #1 is to be able to charge flat batteries.
My boot lid sometimes doesn't latch properly and leaves a dim little light
on - which if you don't drive for a week or two empties the battery. My
current 1980s dumb-charger can't handle delivering current into a low
voltage battery for more than a few seconds before the thermal trip goes[1].
I've seen smart chargers say 'we handle flat batteries 7.5V' which is no
use when the voltage drops below that.[2]

Most modern chargers won't work with a totally flat battery. They use
battery volts to pull in the reverse connection protection relay. So you
may need to use a jump battery to get it started. Other than that, most
will limit the current demanded to what they can deliver.

I cannot imagine any of this is good for the battery. It seems to me
a destructive way of solving a minor issue.

If the battery is totally flat it will be damaged anyway. With such an
expensive item best to charge it long before it is flat.

True, but OP must be planning to flatten the next battery as well
(otherwise he wouldn't need the charger).