hymer BMC 550, Instruction Manual

Page: 124 / 252

8 Electrical system
124
B-MC - 12/18-2 - EHG-0016-01EN
8.5.1 Battery cut-off switch
The battery cut-off switch switches off all the appliances in the living area,
even inactive ones. Even appliances such as the entrance step, basic light-
ing or the refrigerator will stop working. This prevents the living area battery
from slowly discharging if the vehicle is not used for a longer period of time
(e.g. temporary lay-up).
If the vehicle is connected to the 230 V power supply via the CEE socket
outlet, the batteries are charged, even if the battery cut-off switch is
switched off.
8.5.2 Battery selector switch

If the battery selector switch is set incorrectly, there is a risk of gener-
ating oxyhydrogen gas. Danger of explosion!

Incorrect setting of the battery selector switch damages the living area
battery.

The factory settings of the battery selector switch must not be changed.
8.5.3 Battery monitor

You must fully recharge a discharged living area battery as soon as pos-
sible.
The battery monitor in the transformer/rectifier monitors the voltage in the
living area battery.
If the voltage of the batteries falls below 10.5 V, the battery monitor in the
transformer/rectifier switches off all the 12 V appliances.

Switch off all electrical appliances that are not absolutely essential at the
corresponding switch.

If necessary, use the 12 V main switch to switch the 12 V power supply
back on for a short while. This is only possible, however, when the bat-
tery voltage is above 11 V. If the voltage is below this level, the 12 V
power supply cannot be switched on again until the living area battery
has been recharged.
8.5.4 Charging the battery
When the vehicle engine is running, a relay in the transformer/rectifier alter-
nator switches on the living area battery and the starter battery together and
recharges them with the vehicle generator. When the vehicle engine is
switched off, the batteries are automatically disconnected from one another
again by the transformer/rectifier. This prevents the starter battery from be-
ing run down by electrical appliances in the living area. The starting capabil-
ity of the vehicle is thus preserved. The terminal voltage of the living area
battery or the starter battery can be read on the panel.
Measures: