I bought a KBOX 40W and at a B&M a while ago and they sold me an MXJO 35amp 18650 battery to fire it. It's been working fine but I want a spare battery. I saw on the KBOX description on sweet-vapes.com that you need a 20 amp battery minimum. I got an LG 18650 HE2 20 amp battery. Did I screw up?