Yes, have done many times. Connect the power pack and leave it for five minutes before starting is best. My 4.6 goes straight away but, when I can, I leave it connected for a minute or two to help the alternator. It has never failed to start my car. You know what Range Rovers are like: example very early 5am start loading the car for a weekend away with all the doors open for fifteen minutes, jump in and try to start - click, click, click but have trusty Sealey and a minute later on the way!
The one I have is: RoadStart 12v 1600 Peak Amps - there are several different models and shop around for price as some places charge (no pun) a lot.
Code: RS102 Sealey RoadStart® Emergency Power Pack 12V 1600 Peak AmpsComposite case with integral battery clip storage hoods and carry handle. LED battery condition and charge indicators. Test cycle button gives true battery indication. 230V Charger with automatic power cut-off prevents damage to battery whilst charging from the mains. Fitted with 12V power socket that will accept any 12V device with a cigarette lighter type plug. Supplied with mains charger and double plug adaptor for in-car charging.• Cable & Clamp Length: 1mtr.
• Produces in excess of 1600 Peak Amps.
• Composite case with integral battery clip storage and carry handle.
• LED battery condition and charge indicators.
• Fitted with 12V power socket that will accept any 12V device with a cigarette lighter type plug.
• Supplied with mains charger and double plug adaptor for in-car charging.
• Model No. RS102• Composite case with integral battery clip storage and carry handle.
• LED battery condition and charge indicators.
• Test cycle button gives true battery indication.
• 230V Charger with automatic power cut off prevents damage to battery whilst mains charging.
• Fitted with 12V power socket that will accept any 12V device with a cigarette lighter type plug.
• Supplied with mains charger and double plug adaptor for in-car charging.12V RoadStart® Emergency Power Pack 1600 Peak Amps