i bought this crazy thing in the event of an emergency jumpstart. But most of its use is charging phones at the beach and laptops on the road. It does not replace my green battery tender Junior. Love that little thing
https://www.amazon.com/VETOMILE-Starter-Portable-21000mAH-Flashlight/dp/B073FD3NKW/ref=sr_1_1?s=automotive&ie=UTF8&qid=1521756584&sr=1-1&keywords=VETOMILE+800A+Peak+Car+Jump+Starter+Booster+Portable+21000mAH+Auto+Battery+Charger+Power+Bank+with+USB+charge+Port+and+Flashlight%2Cfor+Engines+up+to+6.5L+Gas+and+3.0L+Diesel+or+Pickup+Truck&dpID=41h22g1WhOL&preST=_SY300_QL70_&dpSrc=srch