On Tue, 21 Jul 2020 22:26:18 +0100 (GMT+01:00), Jimk
wrote:

Theo Wrote in message:
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]

I would expect that mode to be a constant current mode, although they could
pulse or do other fancy things. But it should be able to deliver it
continuously without tripping out.

Requirement #2 is a display of voltage and current so I can see what's going
on. Little LEDs saying 'half' or 'full' do not cut it.

Nice-to-have #3 is a means of terminating charge when it's full, but I could
live without that.

Are there any 'smart' chargers that aren't also 'too clever for their own
good' chargers?

Thanks
Theo

[1] Instead I've been using a old 32V 2A bench PSU in constant current mode,
but 2A isn't very much and the case gets very hot (suspect a linear PSU).
It also isn't great to leave in the engine bay as it isn't weatherproofed in
any way.

[2] You might say the battery has had it by this point, but it's an AGM
battery in a hybrid so it lives an easy life. It only needs to provide 20A
for a few seconds to open contactors, it isn't used to start the car. I
might look at a LiFePO4 SLA-replacement next time.

Fit a switch for the boot bulb.

Could he rewire the boot light through the ignition circuit so there
is no need to remember to flip the switch?