Hi Jim,
Maybe you've seen this item at Harbor Freight. It's the first time I've noticed it. Thought you might find it of interest ;-)
=== Viking Only: $79.99 Here's a powerful compact jump starter that can fit in your glove box. The lithium iron phosphate battery in this power pack is designed to maintain a charge for extended periods - 70% over 2 years. Safer than lead acid and Li-ion batteries, this power pack has a higher power density for more efficient power transfer. Built-in USB and 12VDC power ports charge your electronics and 12V appliances.
-Ultra-long life - holds 70% charge after 2 years, 5x more cycle life and 4x more cranks than lead acid batteries -Jump starter -USB/12V power bank -Flashlight -Automatic power-off to preserve battery life -Compatible with all smart phones and tablets" ===