Hi All As per subject really. Is this at all possible/recommended? According to the 12S pinout, pins 4 and 3 are constant power and ground. Difficult to imagine as I would think that the local chavs would've put a paper clip in there by now.
The permanent feed should be fused. I'm not sure that miscreants have any great knowledge of, or interest in, such matters. The results of their attempt would not be particularly spectacular, indeed they probably couldn't tell if it had worked.
Is your question, "Is it possible to charge a car battery via the
12S connector, instead of directly connecting to the battery terminals?"
Personally, on the odd occasion it has been necessary, running a mains extension to the car, and putting the charger under the bonnet has worked fine.
Your proposal would increase the length of DC cable, both internal to the car, and possibly also externally, which is less than ideal, though not a job-stopper.
I'm not sure what the fuse rating is. Say it's 10A (maybe 16A) and the charger can only do 6A. Then the fuse can't blow can it?
Yes.
That's what I'm doing now.
It appeals as it is easier to plug something into an exposed socket than to keep lifting the bonnet. It's the cold mornings that cause the starting troubles. Both battery and charging have been tested and are ok. There may of course be a permanent drain elsewhere.
If it is wired to modern standards, then pin 4 should be fed via a relay that only energises when the engine is running/ the main battery is receiving a charge. Like wise pin 6 fridge supply, which is only live under the same circumstances.
Pin 4 is intended to charge the battery in the trailer.
My ciggy lighter socket is live all the time and I use a small maintenance charger which plugs in there. I have the charger mounted on the garage roof beam, with its 12v plug hanging ready to plug straight in as I stop.
Many years ago, I put a cigarette lighter plug on my battery charger so I could just plug it into the cigarette lighter socket, and leave it sitting in the dry car (in the footwell) whilst it was charging. That charger was only 4A max.
However, I don't recall ever needing to charge my own car batteries - it was always someone else's.
It should be a direct fused supply from the main battery. What I do is fuse one large cable at 30amps at the source, run that to a charge relay in the boot, then split it down to two supplies again fused, but at 15 or 20amp each for fridge and trailer battery charging. Large cable to avoid volts drop rather than rated for amps.
What temperature was the battery when it was tested? Really cold like it would be after standing overnight or just a few degrees warmer after starting and run to the garage to be tested?
When the battery was going in my car I knew it might be interesting starting if it was cold but just a few degrees warmer there wasn't a problem. Could almost use the ease, or not, of starting as a thermometer. B-)
Pin 4 is permanently live. However, and not relevant to the original question, latest caravan standards implement switching of this feed within the caravan in response to pin 6.
If pin 6 is energised, besides feeding the fridge itself, it initiates switching of the battery, isolating it from the load and connecting it to pin 4.
Rings a bell. I recall when I was young and penniless bump starting my Mini every morning there was a frost. I was hoping it would last until spring, and then I'd be all right all summer.
Then we had some snow. You can't bump start on snow :(
My dad had a Citroen GS and then a later model which I forget. You could use the wheel change spanner as a starting handle in both of these, and we did occasionally (damn hard work through).
Not sure the size, as in cc, makes that much difference it's the compression ratio. 9:1 (ish) for a petrol, 20:1 (ish) for a diesel.
If I forget to operate the decompression lever on my single cylinder diesel genset and try to pull start it it's like yanking a rope attached to a boulder, it doesn't move once the slack has been taken up. The single cylinder 4 stroke petrol mower is a doodle.
I've hand started a 4 litre petrol engine in a Leylend FG550 truck. It was a low compression version of the Austin Princess engine, with a massive 6:1 compression ratio.
I've often hand started my Land Rover 2286cc petrol engine, too.
HomeOwnersHub 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.