Do i need to disconnect the battery if leaving it in the car on a trickle charge? its a 1999 mk2 1.6. thanks in advance.
no… not when using something like a ctek battery conditioner…
Not when using any 12v charger
R-b
I use an Optimate, which is left on continually, with the battery connected.
It keeps the battery fully charged.
Excellent. Thanks.
I would disagree with “any” battery charger.
The smart chargers are designed to be left on the battery while still connected to the car and will switch off for a while when fully charged. A number of normal chargers may have a less than smooth DC output that could go for delicate semiconductors on the car and also will not switch off for a while and could tend to cook the battery after a while.
So smart chargers only!
Is it OK to connect a CTEK 5.0 via the ciggie socket on a Mk4?
Is it live with the ignition off?
According to the wiring diagram I’ve seen, that socket is only live with Ignition ON. I assume the car matches the wiring diagram…
Easy test; does the dash-cam/sat-nav/phone-charger plugged into it switch off following ignition switching off.
However the OBD2 socket is live all the time, pins 4, 5 are 0V and pin 16 is +12V Battery. Just keep the current low, and if trickling (ie less than C/100) maybe use a 1A fuse to protect the fuses in the car.
I would definitely NOT put the 5A CTEK (or another meaty charger) into an OBD2 connector.
Weedy solar is fine into OBD2, with the vast majority of domestic 12V panels struggling to produce even 100mA in UK (C/500 in our batteries), even if well aimed at midday. It is helping my Mazda3.
This thread prompted me to have another check on the Mazda3. A fortnight ago when I put the solar on it the battery volts were 12.52V, today down to 12.24V. It is now a month of no use since the last full charge. Time to put the proper Smart charger on it.
The car started easily enough and I moved it next to the garage and let it run for at least five minutes, maybe as much as ten; I didn’t time it but waited until the exhaust was running dry, and tick-over down to its lowest, and it was filling at 14.45V all this time.
When I turned it off I watched the battery volts for a couple of minutes or so longer and they dropped from 12.8V down through 12.5V quite quickly as the surface charge on the plates was absorbed by the body of the plates.
Ten minutes later, the Smart charger still reckoned it was only 50% charged despite the time with the engine running, the equivalent of maybe three miles driving, and not forgetting there was a start. I’ll leave the charger on overnight to guarantee it is properly full, and the 3.5A rate will do a proper C/15 deep body charge and finish off with C/150 maintaining charge.
The long term “Dark Current” (Parasitic Discharge) on this car is between 25mA and 45mA, plus battery self discharge, ie between about C/200 and C/100, or a bit less than 1Ah per day.
When I park it again I’ll aim the car South, less tidy but better for maximum ‘insolation’ on the solar panel.
The panel did help a bit during the last fortnight, but nowhere near enough. This is partly because it was only getting half the sun time possible (car facing East), partly because of excessive pollen or overcast blocking the sun on a few days, and partly because it is just too small.
Edit 1.
This morning the Smart charger had backed off from its full rate of taking 57 Watts from the mains to about one watt and was holding the battery at 12.98V. (The power monitor plugged in the wall socket saves me going outside to check when it’s done.)
After removing the charger the battery was stable at 12.90V. Adding the solar again, now aimed for best at midday, took it to 12.91V.
With any luck the battery will not need a plug-in recharge for at least a month. I have no idea when our ‘vulnerable’ lock-down might end.
Edit 2. 14 days later.
The battery is 12.68V today, somewhat better than after the first fortnight a month ago where it had dropped to 12.52V without solar. It is still not enough but might last a few weeks more than it did previously before it needs a proper charge.