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350matt, Engineer
Category: Hyundai
Satisfied Customers: 21707
Experience:  Mechanical Engineer BEng Hons 22 years experience in car engine industry, 10 years in formula 1
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2007 Hyundai Santa Fe. Battery won't hold a charge. Had it

Customer Question

2007 Hyundai Santa Fe. Battery won't hold a charge. Had it checked and battery is good. Charge battery, car starts. Leave it sit overnight, no start.
Meter shows a drain on power but no obvious reason. Pulled fuses and looked for cause, suspect rear defroster.
Submitted: 9 months ago.
Category: Hyundai
Expert:  350matt replied 9 months ago.


A typical current drain with everything off and un-alarmed should be around 0.05Amp and if its higher than this can you tell me if any of the fuses pulled effected this reading?

Also check that the alternator is actually charging the battery in the car by taking a battery voltage reading with the engine off then another with the engine running. The 2nd reading should be higher than the 1st and climbing steadily. And also check that the alternator is secure to the engine as this provides the ground for the charging circuit and make sure that the engine / gearbox earth strap is secure and the contacts are clean and bright.

if the alternator appears not to be working - take it to a electrical specialist and ask them to test it as sometimes you can replace just the diode pack and this will repair the alternator without requiring replacement

Customer: replied 9 months ago.
My description leaves the alternator out of the equation. If I charge it at night and it starts then leave it sit overnight I can't suffer a power shortage because the alternator is failing. I never ran the car, it just sat there.
Expert:  350matt replied 9 months ago.


fair comment about the alternator

however have you tried the current drain measurement?

if so what have you found?

Expert:  350matt replied 9 months ago.


do you still need help?

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