https://www.ebay.com/itm/126036129048?toolid=10001&customid=c538a9288ed211f09c14e2dac73a89da0INT ECO-WORTHY 3584Wh 12V/280Ah Smart LiFePO4 Battery w/ Bluetooth Monitoring on sale for $376.45 - $56.47 (15%) off when you apply coupon code FRESHPICKS on the checkout page = $319.98. Shipping is free.