Hi folks, I've joined the forum specifically to comment on this thread. I found the information in the thread really helpful, so thought I'd add my experiences with the HK3 hardwire kit in the hope that it might be helpful to others. In summary, I've tried 2 of the hardwire kits and have found both of them to cut off the power to my A129 Duo at around 12.2v, instead of the 12.4v as per the setting I've selected with the switch on it. It's annoying, but I'm relatively happy with the A129 and the hardwire kit overall for the price, so I'm keeping them in the car. Here's more detail if you're interested:
I bought the A129 Duo a couple of weeks ago and fitted it in my car using the HK3 hardwire kit.
At the weekend, having left the car sitting for a couple of days, I decided I'd do a quick check to make sure it was cutting off the power to the camera at the 12.4v I'd set. I looked in the car window and saw the camera's recording power light was still on. So I reckoned the battery must still have 12.4v or more. As soon as I opened the car and got into it I got my multimeter out and put its leads onto the power to the camera from the fusebox and to the grounding point. I was surprised to see it reading 12.0v, however at that point I checked the camera again and saw it had now switched off. At this point too my interior lights switched off and on checking the voltage again it had went up to around 12.2v (probably because the camera and the interior lights had stopped drawing power by then). I then turned the ignition switch on (not starting the engine, just turning the 'accessories' on). The camera turned on and started recording in driving mode. The voltage reading at this point was 11.9v (probably because the interior light and camera were drawing power again, as was the car heater). I then switched the ignition off and the camera went back into parking mode (if it's relevant, I've got it on the 5fps mode) and the voltage slowly went back up to 12.2v. Also, much to my relief, after about 90 seconds the camera switched off. I was happy that the camera was switching itself off, but not so happy that it appeared to be doing so around 12.2v and not at 12.4v as per my setting. So I thought I'd have a search on the internet to see if other folks were having similar issues and that's when I found this thread. After reading through it all, I decided to order another HK3 hardwire kit as I thought my original one might be faulty, or indeed this 12.2v cut off might be what many of them do. I've now received it and tested it too:
After fitting the new HK3, and not having the chance to leave the car sitting unused, I decided to run the battery down quickly (from the 13v it was at) by sitting in the car with the interior lights on and the outside lights on too. This meant the battery voltage dropped pretty quickly, around 0.01v every 10 seconds or so. I sat watching the multimeter intently and the camera turned itself off at approx 12.16v (I say approx because I had to keep moving myself around to be able to look at the multimeter and then back to the small light on the camera tucked behind my mirror!). It's worth keeping in mind though that the camera seems to run for around 90 seconds after the power has been cut to it (probably as the capacitor is running down during that time?), so that would mean it actually switched itself off around 12.25v (i.e. the battery was losing about 0.01v every 10 seconds approx, so the 90 seconds running time would equal about 0.09v). I then decided to re-wire in my original HK3 that I'd got a couple of weeks ago and see what results I got with it. I took the car for a fairly long run to get the battery back up to almost 13v. After that I did exactly the same test as I'd done with the new HK3 - I kept the interior and exterior lights on and, watching the multimeter intently, the camera turned itself off at around 12.15v (again, because of moving back and forward between the multimeter/camera, it might've been 12.16v or 12.14v).
So, it appears that the 2 units I've got are both turning the camera off at around the 12.2v mark. I say 'appears' because I think my testing isn't good enough to accurately catch exactly when the HK3 is cutting power to the camera. It could well be that it is actually turning off the camera when the battery hits 12.4v. In any case, even if it is turning off at 12.2v instead of 12.4v, that's less than a 2% variation and for the price, I reluctantly have to admit that's ok. I'd rather it protected my battery more and I saw it turning off when my multimeter was nearer 12.4v, but all said and done, can't really complain for the price imho. I am still slightly nervous that it doesn't turn itself off one day and drains the battery, but life's too short to dwell on that
Hope this is interesting/helpful. Cheers.