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Thread ID: 146488	2018-08-15 07:00:00	POST problem - Nissan Leaf	BBCmicro (15761)	PC World Chat

Post ID	Timestamp	Content	User
1452722	2018-08-15 07:00:00	I turned it on yesterday and it wouldn't POST. Called the AA and he diagnosed a flat 12V battery, which he jumpered like a regular car and it POSTed fine. (The book was insistent about connecting the -ve to the engine block rather than the battery terminal) So, I've been reading on-line about it. Apparently the car uses a smallish 12V battery to run the equivalent of BIOS. Such things as determining the hardware environment (charging cable connected?) POST checks and managing the charging of the 400V traction battery. The traction battery remains isolated until the rest of the car is deemed safe. However, the 12V battery does not get charged at the same time as the traction battery. So if one leaves the charger cable connected for a lengthy period, the 12V battery can go flat, possibly in 1 day depending on the battery's health. I presume this is because of current drain due to handshaking and general monitoring of the charging process. And that's what happened to me while looking after the car for a month while the owner is overseas. The advice on line is either to carry a small jumper battery in the car or install a solar charger or connect a regular battery charger every now and then or make sure you replace the 12V battery every 5 years. After the AA guy got it going and the traction battery connected, I simply left the "ignition" on for a few hours while parked. That's how the 12V battery is normally charged - from the traction battery	BBCmicro (15761)
1452723	2018-08-15 17:15:00	Don'cha love it? That the Keep Alive 12v battery is not in the normal charging circuit when you're plugged in - that's incredible. I've gotta go see a Leaf for a buddy. It's stuck about 200 miles from here, deep into Idaho --- and he is giving the same story - No Post. I told him that I don't want to work on it --- what with 30 foot in diameter craters in the ground where a Leaf once stood --- and perhaps a pair of shoes where the mechanic once stood --- is scary enough to keep me at bay.	SurferJoe46 (51)
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