On 21/07/2020 22:12, 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]
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.
On #1, I have lead acid batteries for lights and electric fencers in a
stable block. These are usually ex-car ones, so often a bit tired, and
they do sometimes get run right down. I often need to start them off
using an ancient transformer type with a moving iron ammeter. If you
don't have one of these, look out in car boot sales.
I also have an older version of one of these
https://www.machinemart.co.uk/p/clar...ngine-starter/
Mine has a transformer and I think this is likely to have one too.
Occasionally handy as it will run off a small genny.