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.
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: RESC704RESC706
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.
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.
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.
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.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.