I have an aftermarket stereo installed from @SiMsound (see his thread here -- I am super happy with the improvement in sound). If I turn off the ignition the sound stops unless I turn on the Power and Int 1 overhead switches. I rarely need that feature though so have only used it once to test until last week when I was working on the Grenny and turned on those switches so I could listen to music without the car running. Of course I forgot to turn it off and when I came back five days later there was not enough charge to turn over the engine.
I jumped the Grenny (using the connections under the hood) and since I knew I had about two hours of driving ahead of me, I figured I'd just let the alternator top-up the batteries. From the screen on board, after 2 hours it read 14.2 V and 85% charged. Returning home another 2 hours and it read 14.2V and 99% charged. The head scratching thing was that during all of this driving, I couldn't get the amp to turn back on. So I did all that driving with no sound.
Confused this morning as to why the amp wouldn't power back on, I went back to my local installer who had installed the SiMsound unit for me and had him look at it to see what the problem might be. He first checked the fuse on the wire from the amp to the second battery (it was fine) and then checked the voltage on the second battery, turns out it was only at 3V. So apparently while doing all that driving, the CTEK 120 had not allowed the second battery to receive any of the charging.
When I got home I hooked a 6amp charger directly to the second battery and after only a few seconds I decided to check the voltage on the second battery again (with the charger disconnected) which suddenly was now at 11.8V. I tried the stereo and it worked as it should.
What I am guessing happened is that the CTEK 120 isolated the second battery from the starter battery when the second battery got too low (sadly not soon enough to keep that from drawing the starter battery too low). As a result, when the alternator was charging the starting battery, the second battery was not getting any of that charge. I guess that when I connected the 6amp charger directly to the second battery, that "tricked" the CTEK to think that the second battery was now ok to re-connect and as a result, when I read the second battery with a volt-meter only a few seconds after having the charger connected, the second battery read 11.8 because it was pulling power from the starting battery (through the CTEK). Hopefully the alternator will now charge both.
I don't trust my 6amp charger to leave it unattended (its literally from the 1970s), so I now have a 1.25amp "trickle charger" directly connected to the Second battery and I'll leave that connected for a day or two and see how things look.
As an unrelated aside (at least I guess its unrelated), to see if the amp now works, I turned the ignition to Aux and powered up the head unit first (I did not turn over the engine). I had the air conditioning fan in the off position before doing this (I always turn off the fan before I turn off the ignition). After verifying that the amp works, I turned the ignition to the off position and removed the key. When I did that, I noticed the vent fan had turned on low (i.e. I could hear the fan turn on and a small amount of air come out of the front vents, despite the vehicle being off and the fan switch being all the way off). When the computer finally went to sleep the vents stopped blowing. This air con system really does have a mind of its own.
I jumped the Grenny (using the connections under the hood) and since I knew I had about two hours of driving ahead of me, I figured I'd just let the alternator top-up the batteries. From the screen on board, after 2 hours it read 14.2 V and 85% charged. Returning home another 2 hours and it read 14.2V and 99% charged. The head scratching thing was that during all of this driving, I couldn't get the amp to turn back on. So I did all that driving with no sound.
Confused this morning as to why the amp wouldn't power back on, I went back to my local installer who had installed the SiMsound unit for me and had him look at it to see what the problem might be. He first checked the fuse on the wire from the amp to the second battery (it was fine) and then checked the voltage on the second battery, turns out it was only at 3V. So apparently while doing all that driving, the CTEK 120 had not allowed the second battery to receive any of the charging.
When I got home I hooked a 6amp charger directly to the second battery and after only a few seconds I decided to check the voltage on the second battery again (with the charger disconnected) which suddenly was now at 11.8V. I tried the stereo and it worked as it should.
What I am guessing happened is that the CTEK 120 isolated the second battery from the starter battery when the second battery got too low (sadly not soon enough to keep that from drawing the starter battery too low). As a result, when the alternator was charging the starting battery, the second battery was not getting any of that charge. I guess that when I connected the 6amp charger directly to the second battery, that "tricked" the CTEK to think that the second battery was now ok to re-connect and as a result, when I read the second battery with a volt-meter only a few seconds after having the charger connected, the second battery read 11.8 because it was pulling power from the starting battery (through the CTEK). Hopefully the alternator will now charge both.
I don't trust my 6amp charger to leave it unattended (its literally from the 1970s), so I now have a 1.25amp "trickle charger" directly connected to the Second battery and I'll leave that connected for a day or two and see how things look.
As an unrelated aside (at least I guess its unrelated), to see if the amp now works, I turned the ignition to Aux and powered up the head unit first (I did not turn over the engine). I had the air conditioning fan in the off position before doing this (I always turn off the fan before I turn off the ignition). After verifying that the amp works, I turned the ignition to the off position and removed the key. When I did that, I noticed the vent fan had turned on low (i.e. I could hear the fan turn on and a small amount of air come out of the front vents, despite the vehicle being off and the fan switch being all the way off). When the computer finally went to sleep the vents stopped blowing. This air con system really does have a mind of its own.
