Reliable Starting Solution for Aging Batteries and Ignition Systems
The super starter offers a practical solution for initiating cars with aging batteries and outdated coil-based ignition systems, especially in cold or damp weather conditions. In such situations, the voltage from an aging, possibly cold battery may not be sufficient for the coil to generate a strong spark across the spark plugs. This circuit ensures that the coil receives power from a NiCd cell battery, allowing it to function effectively for up to ten minutes even under challenging circumstances. Once the engine starts and the dynamo voltage increases, the coil switches back to being powered by the car battery.
Engine Running Detection and Relay Activation
To determine if the engine is running, the circuit utilizes the D+ terminal of the charging current indicator lamp (La1), which is directly connected to the dynamo. When the engine is not running and, consequently, the dynamo is not generating voltage, relay Re1 is energized through the ignition key’s positive connection and the low-resistance dynamo’s ground connection.
Reliable Power Supply from NiCd Battery
The NiCd battery functions as a reliable power source for the coil, regardless of the car battery’s condition. Once the engine starts, the dynamo generates voltage, eliminating any potential difference across the relay coil. Consequently, the relay’s contact switches over, and the coil is supplied by either the car battery or the dynamo.
Diode Safeguards and Continuous Engine Operation
Diode D1 plays a crucial role in preventing potential issues. Firstly, it ensures the relay does not interrupt the current to the coil during the contact switch-over, preventing unnecessary sparks when the engine does not require one. The coil is powered via the diode during this change-over period, causing a slight voltage reduction across the coil, which is inconsequential. Secondly, the diode guarantees that the car can still be started even when the car battery is fully charged, and the NiCd cells are either depleted or removed for charging.
Relay Requirements and Sourcing
To ensure reliable operation, the relay should possess a contact rating of at least 8 A. While spare parts for car relays with change-over contacts might not be readily available, you can often find them in auto salvage yards, particularly in Citroen CX models. In place of the Type FR606 diode, a Type BYW29-100 can be used as a substitute. Both diodes are capable of handling currents up to 6 A, and their reverse voltage is sufficiently high to withstand the inductive surges generated by the coil.
Optimal Circuit Placement and Battery Charging
It is advisable to construct the circuit behind the dashboard. However, it’s recommended to house the NiCd cells in a removable holder to allow for external charging. Alternatively, you can charge them using the car battery via a suitable resistor. The D+ connection associated with the charging indicator lamp is the one at ground potential when the engine is not running but the ignition is switched on. At the ignition switch, there is a cable leading to the coil; this cable should be connected to the circuit’s output. The circuit’s ® terminal needs to be linked to the available contact at the ignition switch, while the circuit’s -ve line should be connected to the car chassis.