https://alexnld.com/product/dc18rf-replacement-battery-charger-18v-4a-liion-battery-replacement-power-tool-battery-with-lcd-display-for-makita/?hilite="Upgrade Version BL1850 18V 3.0%2F4.0%2F5.0Ah Rechargeable Lithium Li-ion Battery Power Tool Batteries for Makita BL1840 BL1830 BL1850B LXT 400"