The KS 48V-DC constant voltage generator (50–55V version) by German brand Könner & Söhnen is a backup charging device designed for batteries with an operating voltage range that includes 50–55V. Suitable for recharging batteries in independent energy systems for households, solar/wind setups, telecom, camping, etc. The 50–55V range is optimal for common lithium batteries like LiFePo4 (51.2V), and may be used with other types as long as 55V max voltage is acceptable. Charging begins with constant current up to 60A until output voltage reaches 54.5 ± 0.5 V, then switches to constant voltage mode. In AUTO mode, the generator monitors battery voltage and starts if it drops below 50V for over 5 seconds. It warms up for ~1 minute, then activates the DC output. It stops when 54.5–55V is reached and current drops below 20A for 30 seconds. In EXTERNAL CONTROL mode, the generator starts/stops by closing/opening the CONTROL TERMINAL contacts, independently of battery voltage or output current. External programmable control enables integration with modern solar inverters and time-based activation. Equipped with short-circuit, polarity, and battery overvoltage (>59V) protection – shuts down instantly if triggered. No built-in battery – starts from the battery it charges, simplifying maintenance and increasing reliability during infrequent use. Comes with transport wheels and handle for easy relocation and extended application scope. Enables charging in off-grid areas. Reliable Könner & Söhnen engine complies with European quality and environmental standards, including EURO 5. High-quality copper-wound alternator and branded motor ensure long and safe use.