Can the battery for the JTV be used in the Standard Variax? A local store (UK) has 1 battery which they say is L6 genuine for the JTV and which is stated to have a rated battery life of 12 hours. The Standard Variax battery seems to only have a 4 hour life. Can the JTV battery be safely used in the Standard? They certainly look outwardly identical. The store “advisor” seemed unsure.