Is it safe to leave a battery charger conditioner plugged in to a cigarette socket

I do most of the time over winter or if I’m not likely to use the car for more than a couple of weeks.

If the cigarette socket is a permanent live and protected by a fuse then should be OK.

Personally I'd always fit directly to the battery, but that's a lot easier on a 4 seater.

However, a lot of modern trickle chargers have decent length pigtail leads available so you can wire direct to the battery and put the plug in a convenient place.

Mines plugged into this socket 24/7, unless I’m driving - in which case it auto disconnects!!!

It’s safe. However, I found that on my car the connection became unreliable over time. I now have a fused direct connection to the battery.

The name says it all - cigar lighter. It was never designed electrically or mechanically to power external devices although (sadly) adopted widely by the auto accessory world for such. The worst aspect is the spring loaded centre contact on the plug which simply touches a surface within the socket. The tiniest amount of corrosion or burning on this surface compromises consistent current flow. The outer ground connection is not much better.

The Hella/DIN type offer captive centre contact as well as higher current rating.

Mine is plugged in 24/7 when garaged too.

Do it properly and fit a flying lead and fuse suited to the charger to the battery

I agree with Paul F, my experience is that over time the cigar lighter connectors tend to work themselves loose. C-Tek offer a range of extension cables so as TBM says you should find a suitable location to route one of these for easy connection direct to the battery terminals and have the quick connector somewhere very convenient. Otherwise I also leave my car(s) always connected to a C-Tek when not in use, even if just overnight, as the "Conditioning" function of the C-Tek prevents calcification of the battery and this prolongs its CCA and life-span.

Mine is permanently connected via a fuse directly to the battery. I use a connector to the C-Tek that’s the same as model cars use so it’s quick and easy to connect.

At a show, one whit spotted the plug behind the passenger seat and I managed to partly convince him that my car was a hybrid and this was the charge socket!