Bombardier SeaDoo 2000 factory shop manual volume 2, Page 235Get this manual
Section 09 ELECTRICAL SYSTEM Subsection 03 (CHARGING SYSTEM)
Charging Used Battery WARNING
Never charge battery while installed in watercraftFor best results, battery should be charged when the electrolyte and the plates are at room temperatureA battery that is cold may not accept current for several hours after charging begunDo not charge frozen batteryIf the battery charge is very low, the battery may freezeIf it is suspected to be frozen, keep it in heated area for about hours before charging