After following the forum for some time, I thought I would put my head above the parapet. So here goes...
I assembled this collection of components two years ago and it has worked very successfully. After researching solar charging kits for battery maintenance, I had a chat with a marine solar power business. They recommended specifying a panel with enough clout to power a MPPT Solar Charge Controller in less than perfect lighting conditions.
This rigid Renogy 50 watt framed panel is ideal, it has a support stay and sits tight into the rear window. It will easily knock out 45 watts sitting on the drive next to the car, however put it behind glass and that immediately drops to 20 watts on a good day. There's the rub, "sun-dim" car glass is designed to do exactly that and I think that's why lower power kits always seem to fail.
The solar panel feeds into a "Victron MPPT SmartSolar 75.1.10 Controller" with Bluetooth and for the output side I have used the fused CTek cable into the cigarette lighter socket. The MPPT is fully programmable, and I've copied over the bulk, absorption and float parameters from my CTek charger booklet, the maximum charge amperage can also be specified. I've added a "Victron EnergySmart BatterySense Battery Voltage and Temperature Sensor" across the car battery terminals and it Bluetooth links to the MPPT relaying true battery voltage and temperature. The temperature information is a worthwhile additional parameter due to the large differences between cabin and battery compartment temperatures, especially in winter.
The benefit of the MPPT is that for any output wattage it holds the solar panel at the most efficient output voltage ie 17-18 volts by varying the amperage. It then converts the output voltage down to 12-13 volts, which boosts the amperage available to the battery, school physics in action. Power consumption is insignificant and the MPPT will not allow any "drain back" when its dark.
So for example, if you need to leave your car outside whilst on holiday, it is locked and fully alarmed but with no external charger cables to be tampered with. However the back end must be pointed at the sun!
It take less that 5 minutes to set up, and all performance can be checked via the Bluetooth Victron app, but only when you are by the car. The app stores 30 days of performance data. I've seen many consecutive days of float status confirming the kit is up to the job. I just make sure my CTek has pre primed the battery to a full charge before a holiday, but the car has sat in the winter for 6 weeks and been full of beans on return. I'm sure that this will help extend battery life.
Not a cheap solution, over £220 for the bits all bought on Amazon, but if you have a similar specific requirement, all I can say is it works for me. I think the Renogy solar panel has dropped off Amazon, but similar panels are available and probably cheaper now.
I hope this is of interest as I haven't found a post with exactly the same set up. I'm now going to have a bash at a couple of photos!
I assembled this collection of components two years ago and it has worked very successfully. After researching solar charging kits for battery maintenance, I had a chat with a marine solar power business. They recommended specifying a panel with enough clout to power a MPPT Solar Charge Controller in less than perfect lighting conditions.
This rigid Renogy 50 watt framed panel is ideal, it has a support stay and sits tight into the rear window. It will easily knock out 45 watts sitting on the drive next to the car, however put it behind glass and that immediately drops to 20 watts on a good day. There's the rub, "sun-dim" car glass is designed to do exactly that and I think that's why lower power kits always seem to fail.
The solar panel feeds into a "Victron MPPT SmartSolar 75.1.10 Controller" with Bluetooth and for the output side I have used the fused CTek cable into the cigarette lighter socket. The MPPT is fully programmable, and I've copied over the bulk, absorption and float parameters from my CTek charger booklet, the maximum charge amperage can also be specified. I've added a "Victron EnergySmart BatterySense Battery Voltage and Temperature Sensor" across the car battery terminals and it Bluetooth links to the MPPT relaying true battery voltage and temperature. The temperature information is a worthwhile additional parameter due to the large differences between cabin and battery compartment temperatures, especially in winter.
The benefit of the MPPT is that for any output wattage it holds the solar panel at the most efficient output voltage ie 17-18 volts by varying the amperage. It then converts the output voltage down to 12-13 volts, which boosts the amperage available to the battery, school physics in action. Power consumption is insignificant and the MPPT will not allow any "drain back" when its dark.
So for example, if you need to leave your car outside whilst on holiday, it is locked and fully alarmed but with no external charger cables to be tampered with. However the back end must be pointed at the sun!
It take less that 5 minutes to set up, and all performance can be checked via the Bluetooth Victron app, but only when you are by the car. The app stores 30 days of performance data. I've seen many consecutive days of float status confirming the kit is up to the job. I just make sure my CTek has pre primed the battery to a full charge before a holiday, but the car has sat in the winter for 6 weeks and been full of beans on return. I'm sure that this will help extend battery life.
Not a cheap solution, over £220 for the bits all bought on Amazon, but if you have a similar specific requirement, all I can say is it works for me. I think the Renogy solar panel has dropped off Amazon, but similar panels are available and probably cheaper now.
I hope this is of interest as I haven't found a post with exactly the same set up. I'm now going to have a bash at a couple of photos!
