Ping Dave Plowman

[Davey]

Dave,
You have often referred to your having a smart charger permanently
installed in your SD1. Is the output permanently connected to the
battery, as I have visions of a huge current draw, frying the charger,
when the starter motor is activated? Or is there a switch or plug that
disconnects the charger low voltage side?
Interested in fitting one in the same way as yours.

[Dave Plowman (News)]

Post by Davey
Dave,
You have often referred to your having a smart charger permanently
installed in your SD1. Is the output permanently connected to the
battery, as I have visions of a huge current draw, frying the charger,
when the starter motor is activated? Or is there a switch or plug that
disconnects the charger low voltage side?
Interested in fitting one in the same way as yours.

It's permanently connected. There is a second fuse box in the boot with an
always live feed. Connected to that via a suitable fuse.


This Lidl one has a button which has to be pressed to active it - LEDs
then show the state it is in. You have to press the button twice to get
full charge for 12v. When fully charged, it changes to a maintenance
setting.

Don't think I've ever tried starting the car with it in operation. Driving
off with it plugged in to the mains wouldn't be good. ;-) But it is short
circuit protected, so would be most surprised if it came to any harm.

It does draw a tiny current from the battery at all times. The resistance
between the leads is 42500 ohms. So tiny compared to other things that
take current from the battery at all times - I make it 0.2mA.

There is a snag with this type of charger. If you were using it left on
over the winter on a stored car, and there is a power cut, it doesn't
revert to on after power is restored. You'd have to push the button again.

[Indy Jess John]

Post by Davey
Dave,
You have often referred to your having a smart charger permanently
installed in your SD1. Is the output permanently connected to the
battery, as I have visions of a huge current draw, frying the charger,
when the starter motor is activated? Or is there a switch or plug that
disconnects the charger low voltage side?
Interested in fitting one in the same way as yours.

I will let Dave provide you with the details of how his one is fitted,
because he has the practical experience.

However, I bought a smart charger[1] to keep a spare battery in a
charged condition (because I have an inverter to produce mains voltage
from a car battery when I need it) and I have looked at the instruction
manual.

The "smart" bit watches the battery voltage and knows when to give a
maintenance charge which is 0.8A, compared to a normal charge which has
a maximum of 4A. This suggests that you are unlikely to fry the charger
when operating the starter motor, and because it is monitoring the
voltage, once the engine is running and putting charge into the battery,
the smart charger is likely to be dormant.

[1] Ring do two smart chargers, and the manual helpfully says there are
on-line references:
RESC704
www.ringautomotive.com/uk/products/Cars/Battery+Care/SmartChargers+European+Specification/RESC704

RESC706
www.ringautomotive.com/uk/products/Cars/Battery+Care/SmartChargers+European+Specification/RESC706

The first one works, I didn't bother to test the second. The manual
advises how to correctly wire in the smart charger if the battery is in
the car.

Jim

[Davey]

On Thu, 23 Dec 2021 14:07:20 +0000

Post by Indy Jess John

Post by Davey
Dave,
You have often referred to your having a smart charger permanently
installed in your SD1. Is the output permanently connected to the
battery, as I have visions of a huge current draw, frying the
charger, when the starter motor is activated? Or is there a switch
or plug that disconnects the charger low voltage side?
Interested in fitting one in the same way as yours.

I will let Dave provide you with the details of how his one is
fitted, because he has the practical experience.
However, I bought a smart charger[1] to keep a spare battery in a
charged condition (because I have an inverter to produce mains
voltage from a car battery when I need it) and I have looked at the
instruction manual.
The "smart" bit watches the battery voltage and knows when to give a
maintenance charge which is 0.8A, compared to a normal charge which
has a maximum of 4A. This suggests that you are unlikely to fry the
charger when operating the starter motor, and because it is
monitoring the voltage, once the engine is running and putting charge
into the battery, the smart charger is likely to be dormant.
[1] Ring do two smart chargers, and the manual helpfully says there
RESC704
www.ringautomotive.com/uk/products/Cars/Battery+Care/SmartChargers+European+Specification/RESC704
RESC706
www.ringautomotive.com/uk/products/Cars/Battery+Care/SmartChargers+European+Specification/RESC706
The first one works, I didn't bother to test the second. The manual
advises how to correctly wire in the smart charger if the battery is
in the car.
Jim

Thanks, both of you. I have an Aldi charger, probably the same one as
the Lidl, and it is great, but it mentions nothing about this scenario.
I would hate to assume it was going to be ok and then fry it when I
tried it. Those Ring ones look interesting, I will do some research on
them.
Thanks again.

[Dave Plowman (News)]

Post by Davey
Thanks, both of you. I have an Aldi charger, probably the same one as
the Lidl, and it is great, but it mentions nothing about this scenario.
I would hate to assume it was going to be ok and then fry it when I
tried it. Those Ring ones look interesting, I will do some research on
them.
Thanks again.

I'd not be surprised if all those similar chargers - Aldi Lidl Ctek etc
have basically the same internals.

Pretty well every charger ever made is protected from overload - even if
only a fuse in olden days.

[Davey]

On Sun, 26 Dec 2021 11:13:32 +0000

Post by Davey
Dave,
You have often referred to your having a smart charger permanently
installed in your SD1. Is the output permanently connected to the
battery, as I have visions of a huge current draw, frying the
charger, when the starter motor is activated? Or is there a switch
or plug that disconnects the charger low voltage side?

I've definitely started a petrol ride-on lawn mower several times
with a Lidl/Aldi smart charger still connected. It is likely that I
have started a car like that too.

Thanks. I might try it, then, it does seem to be favoured as viable.

[Davey]

On Thu, 23 Dec 2021 12:25:23 +0000

Post by Davey
Dave,
You have often referred to your having a smart charger permanently
installed in your SD1. Is the output permanently connected to the
battery, as I have visions of a huge current draw, frying the charger,
when the starter motor is activated? Or is there a switch or plug that
disconnects the charger low voltage side?
Interested in fitting one in the same way as yours.

Follow-up.
As luck would have it, I connected my trusty Aldi charger to one of my
spare batteries today, and I immediately got the smoke escaping effect,
and a flashing display and lights, and the DC wire pair melting at
several places. Once it had cooled down, I opened it up and inspected
it, and could see no damage except for the fatally damaged output
leads, which had in several places melted together. I cannot say for
sure that the battery is still good, and not the cause of the charger
meltdown, but I replaced the wires, reckoning that there had been a
twisted wire short-circuit somewhere. The battery was last top-up
charged about a week ago. But even with an open circuit output on the
charger, the same flashing lights and display and failure to settle was
the result, implying some fatal internal corruption, so I pronounced it
dead. I will get a Ring unit this week.
C'est la vie.