https://www.ebay.com/itm/1260361290...customid=4f8001e4a4b311f082fb6ebc803c0ef90INT ECO-WORTHY 3584Wh 12V 280Ah Smart LiFePO4 Battery w/ Bluetooth Monitoring on sale for $399.99 - 20% with coupon code HOLIDAYREADY at checkout = $319.99. Shipping is free.