For one last day, use the AliExpress promo code “AFFUS20” to knock the price of this Humsienk LiFePO4 battery to just $85. That’s another $13 drop since we listed it three weeks ago and the best deal we’ve seen for this model. (Depending on your account status, the price may be slightly less or slightly more.) Shipping is free from a local US warehouse, too. Buy Now at AliExpress