Marcum will be coming out with V3 of their software for the LX-7 very soon. This update really makes the unit what it should of been originally, I saw an original one with V1 of the software and one with the V3 last weekend. What a difference, like night and day!!!!
Check the battery terminal connectors, they are not the best design and seem to come loose very easy, this could be the shut down reason. All you need to do is squeeze them with a pliers so they fit tighter or replace them with a tighter fitting set.
Marcum will make it right for you!!!