When working with Lithium cells, they are very sensitive to charging characteristics and may explode if mishandled. Protective PCB circuit board is required & installed on all packs sold by Winona Garden Railway. Never leave batteries unattended when charging. Do not put batteries on wood surfaces or carpet when charging. Never charge your lithium battery with a NiCad or Nimh charger. Always charge your lithium battery with a per cell dedicated lithium charger (IE: 14.8V – 4 cell Lithium, 18.5V – 5 cell Lithium, 22.2V – 6 cell lithium). Winona Garden Railway and/or Winona Power is not responsible for damage or injury caused by misuse, misunderstanding, abuse,or modification to the battery-pack in any form, shape, cell configuration, or electrical wiring. Users of batteries supplied by us are required to have sufficient Lithium charging experience and technical knowledge to operate this battery-pack. Please contact us for charging instructions before operating this battery. Warranty is void if pack has been modified in any way including cutting of wire leads.