Help - Truma Combi 4e

gasman

i know im not in the right part of c/t for tech question but im hoping more people will see it here. i am away with van and my truma combi 4e has packed in. on the control panel i have a message saying battery flat <10v. i know the battery is fully charged
but wondered if anyone has had this prob. and if there is anything that i can do myself to sort.