JLG X20JP - X600AJ Service Manual - Manual (Page 148)

SECTION 3 - CHASSIS & TURNTABLE
3-124 – JLG Lift – 3121623
DC – DC TRANSFORMER
BMS is powered by a 12V auxiliary battery, to ensure the
proper functioning even when the battery pack is com-
pletely flat. It also powers the other ECMs of the platform.
The charging process of this lead 12V battery is per-
formed by a board (DC-DC) which transforms the DC 48-
72 Volt of the battery pack into DC 12V to keep the auxil-
iary battery charged.
DC-DC transformer is active every time the BMS is on; for
example when the machine is off but the battery pack is
under charge, the DC-DC is on too.
The output voltage is around 13,5 Volt, so when DC-DC is
ON all the boards and the devices of the platform are fed
by it and not by the lead battery.
Figure 3-55. 48 Volt Battery Pack DC-DC
More details about the electric DC-DC connexions are
available on the wiring diagrams.
Figure 3-56. 72 Volt Battery Pack DC-DC