edit: posted without seeing the other replies
PS having now looked at the Bestek device..It only supplies about 0.9 amp ! ?
Looking at the voltage input of your charger it states input voltage 195 V - 265 V so personally I would not risk damaging it on 110V but perhaps someone more knowledgable will post with more advice.
I didn't check the output of the Bestek, sorry about that but it was just to show you there are options
Technical specifications
Power supply AC voltage 230 V / 50 Hz, single phasePower supply AC voltage 230 V / 50 Hz, single-phase Range approx. 195 V - 265 V / 50 - 60 Hz.Range approx. 195V - 265V / 50 - 60Hz. Output current: Output current: (Charging current
battery II) (Charging current
battery II) Charging current max.Charging current max. 20A, 20A, arithmetic mean, electronically controlled according to the charging characteristic IUoU.according to the charging characteristic IUoU. Output current: Output current: (Charging current
battery I) (Charging current
battery I) From 14.3 V
battery voltage of the
battery II is the 14.3 V
battery voltage of the
battery II is the Parallel connection with
battery I. Equalization current according to parallel connection with
battery I. Equalization current depending on State of charge of
battery I (starter
battery) .State of charge of the
battery I (starter
battery). Does theDoes that fall? Voltage of the
battery II below 13.2 V, the voltage of the
battery II below 13.2 V, the Parallel connection automatically canceled. Output voltage: DC voltage 12 VOutput voltage: DC 12V Charging: Charging: AutomatischAutomatically Automatic switching: Automatic switching: (Main charge phase) (bulk phase) OFF at
battery voltage 14.4 V Charging current <18 A, OFF at
battery voltage 14.4 V charging current <18 A, Automatic switching: Automatic switching: (Recharging phase) (absorption phase) Ten hours constant 14.4 V with gel batteries.Ten hours constant 14.4 V for gel batteries. Four hours constant 14.4 V for liquid batteries. Four hours constant 14.4 V for liquid batteries. Automatic switching: Automatic switching: (Maintenance charge phase) (charge phase) Trickle charge constant 13.8 V.Trickle charge constant 13.8 V. Switching capacity: Switching capacity: Tremat isolating relay 50 ATremat isolating relay 50 A Fridge relay 20 ARefrigerator relay 20 A Consumer relay 35 AConsumer relay 35 A