BV-2 can be maintained easily in DMEM high glucose (4.5 g/L), 10% HI-FBS.
In the original culture conditions by the group that cloned it, the cell line was maintained in RPMI (which has 2 g/L glucose according to Invitrogen).
As per my protocol I have to culture the BV2 cels in normal glycemic condition (5.5mM/L of glucose ie; 1g/L). But when I started using this concentration of Glucose the cells started dying and i could it maintain it for more than 4 days. But its growing fine in high glucose media.
To add another thought: the cells will consume the glucose available, and this will depend on the number of cells you have in x-ml of culture. Therefore, low amounts of glucose may be used up after 4 days.