I own another Fluke product that came with a 12 V automotive ("cigarette lighter") adapter that fits the DC input jack on my Impulse 6000D/7000DP. Can I use this adapter to operate or charge the Impulse 6000D/7000DP from a 12 V vehicle battery?
No. For safe and reliable operation, the battery charger MUST have a good earth ground when connected to the Impulse 6000D/7000DP, and vehicle electrical systems inherently lack an earth ground. For battery charging only (with the Impulse 6000D/7000DP turned off, and no other connections to the Impulse 6000D/7000DP unit other than at the charger input jack), attempting to charge from a 12 V vehicle gives inconsistent results and therefore cannot be recommended.