It is essential to maintain car battery in full charging condition lying idle for long periods. It often so happens that while the car is attempted for a start it fails to do so. Usually battery capacity falls in unused cars for some small gadgets like remote etc still drawing little power besides bit self discharge of the inherent features of lead acid batteries traditionally fixed in cars. Submitted below a very few low cost DIY tickle charger, as commercial ones are quite expensive. Option1&2 as explained below= Rs 400/-(excluding the power bank ). Option 3= Rs 300/-
- If your car is parked outdoors with some little chance of sunlight ( even shaded) falling on the car, then the best option is to use any available solar cell phone power bank of around 10,000mAH along with procured a dc to dc booster(refer diagram) to derive adjustable 13.4 volts from the power bank output of 5 volts.
Take any USB cord, cut it from the smaller connector end to find 4 wires. Red and black are usually the +ve and -Ve terminals.
Use this free end to connect to the DC to DC booster .Then connect desired length of twin wire from the output of the DC to DC module to reach the car battery terminal. Leave it connected to the battery terminals.
Alternatively in place of solar power bank any low power solar panel can be used as input to the DC to DC module.
2. In case the car is parked indoors having zero or too little chances of sunlight then use any mobile power bank of 10,000 mAH and above along with a DC to DC booster as stated above. In this case get the power bank from the car back to home for charging every alternate day.
3. If the parking place has mains power availability close by then best is to use any commercial low cost tickle battery charger DC directly to the car battery terminals with unit being fed from the wall plug of the utility supply.