My great aunt and great uncle live in The Netherlands from ~April to November and here in Phoenix from November until April. So 7 months there and 5 months here. Their car is a 1998 Plymouth Breeze (same thing as a Dodge Stratus) and has the 2.0L. I go over to their place to check on it and run the plumbing, check the mail etc. every couple of weeks. The car has around 113k miles and is like brand new. They have the oil changed every November they come back as well. What can I do to keep the battery on the car charged? They own a condo/townhouse and the car is in covered parking but there's no outlets to plug in a battery charger. The car is also de-insured while they are gone, but I can if need be drive it to my grandparents house (literally 2 blocks away in residential) and charge it there. I usually start it once a month and let it run for 10 minutes or so to keep the battery charged. This last season it may have been 4-6 weeks since I last started it and the battery was just barely too low to start, but I jump started it and it has been fine since. The car has been driven the past 2 weeks that they've been here but due to medical problems they have left back to The Netherlands until March and they may come for another 2 weeks then, and be back in November. So essentially this car will only have 4 weeks of use from the time period of April 2014-November 2015. I'm not worried about fuel dillution since the oil is changed every year so I have no problem idling it. Will idling it for 10-15 minutes once a month keep the battery charged? Any other ideas? Also I would pop the battery out or disconnect the terminals but the battery is behind the front bumper and the tire and fender skirt has to come off to take it out - stupid. I'm not doing that. Thanks for your help. Also I need to drive it this summer in July to get it emissions tested so it'll have about 15 miles or so put on it then and it warmed up.