On occasion, I work on my X5 on flat driveway. A friend mine passed away two years ago. I go visit his widow often. I try to be there around lunch time. I go out for or take her lunch. She's 90 years old. After my friend passed away, she told me I could work on my cars there anytime. Not wanting to bother her too much during a thermostat change, I took my 18V converter. It's rated for 1.25 amps. The 4 amp charger uses less than the inverter rating. The inverter was connected for almost two hours. It did a good job of maintaining the battery charged up. In a fix, I could use it temporarily charge up the battery. After a battery reaches 80% charge, charging amps do drop down. Mostly to maintain. My X5 has 850 mA in draw. A new DME should reduce it 500 mA. F60 will drop it 200 mA. Once those are fixed, the X5 can sit for months with a good battery. The experiment was mostly for a boat battery test. Warm weather is coming soon. If I can find a stock hitch, it will be used as a boat tow vehicle. It's good to have a good boat battery in the middle of a lake!

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'06 X5 3.0i - bought @143,123 miles (12/26/20)