A car battery that keeps losing charge is draining, failing or not being charged. A simple fault-finding order, what a drain test measures, the dashcams and trackers common in the UAE, and when a new battery won't fix it.
A battery that goes flat overnight has one of three problems: something in the car keeps drawing current while it is parked (a parasitic drain), the battery itself can no longer hold a charge, or the alternator isn't recharging it while you drive. Test them in that order: battery health first, then the charging system, then the drain. In the UAE, hard-wired dashcams and aftermarket trackers are among the most common causes of drain. If the drain or the charging fault is the problem, a new battery will just go flat again.
| Cause | Typical signs |
|---|---|
| Parasitic drain | Flat after a night or a few days parked; starts fine after a jump and drives normally |
| Failing battery | Slow cranking that gets worse, battery over three years old, fails a load test even when charged |
| Charging fault | Battery warning light while driving, dim lights, goes flat even on days you drive a lot |
A technician puts an ammeter in series with the battery and waits for the car to lock and its control units to go to sleep, which can take anywhere from a few minutes to much longer on modern cars. The reading is the standby current, in milliamps (mA). Germany's ADAC motoring club measured 5 to 40 mA on properly locked cars. A reading well above that, or one that never settles, means something is staying awake. Pulling fuses one at a time narrows down which circuit it is on. The acceptable figure for your car is the manufacturer's, so treat these numbers as a guide.
Owners of some models, including the Toyota Camry, report recurring drain problems. The fix is the same: confirm battery and charging first, then measure the drain rather than guess.
Age and heat. Inside every lead-acid battery, the grids corrode and the active material wears out over time, and heat speeds that up. Being left partly flat, as a battery with a drain often is, makes it worse. Eventually the battery can't store enough to start the car after a night parked, even with nothing draining it. In the UAE that often happens around three years. See how long a car battery lasts in the UAE.
That is why we test before we sell. If your car won't start at all, our guide to battery, alternator or starter faults helps narrow it down.
We come to your car in Dubai, Abu Dhabi and Sharjah, jump start it if needed, and test the battery and charging system for free. You get a straight answer on whether you need a battery or something else.
Written by the SayaraBattery team, mobile car battery technicians in Dubai.
Usually a failing alternator, a slipping or broken drive belt, or a loose or corroded connection. A worn-out battery can also refuse to take a charge.
Yes, if it is hard-wired with parking mode and its low-voltage cut-off is set too low or missing. Set the cut-off correctly or switch parking mode off if the car will stand for days.
ADAC measured 5 to 40 milliamps on properly locked cars once their electronics had gone to sleep. The figure for your car is the manufacturer's; much higher means something is staying awake.
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