Ansmann 9164016/01, 2-24V Lead Acid Battery Charger, Wall Plug, 900mAh, 2-24Ah

With this battery charger, you can't go wrong as far as voltage is concerned. Rechargeable battery type recognition adjusts the charging voltage automatically according to the capacity of the lead-acid rechargeable battery being charged. No settings are required at the charger at all, just connect it, and the process starts.

Price: 40.99 from Conrad Electronic