panne rc 400 raymarine

Comment est il rechargé ? Branché directement au tableau électrique du bateau ? Un pb de fusible ? Si besoin j'ai la notice en anglais qui précise :
Unit does not function :
1. Make sure that the power supply cable is
undamaged and that all connections are tight
and free from corrosion.
2. Check polarity of the DC power cables for
proper connection.
Reconnect cables if necessary.
3. Check in-line fuse. Replace if necessary.
4. Check vessel’s power (battery) for correct
voltage readings (10.0–18.0 VDC).
5. Make sure batteries are charged.
6. Make sure batteries are properly oriented.
7. Check batteries for corrosion.
8. Make sure battery tray is properly seated