cyberfish2

I had to jump start it again this morning to get it to the repair shop, after 8 hours on the charger @ 12amps. I removed the ground strap from the battery to charge it. There was a small spark when I reconnected the ground strap. This is the second new Interstate battery since 12/2020. This is my wife's 2008 Lexus ES350. Help. She loves this car.

Wilson2000

Some battery chargers don't do well with problem batteries. I couldn't charge my SC Interstate battery with two different chargers I had on hand. Then I bought a $200 Optima charger because I read about how its electronics customize and modulate the amps and voltage to fit the need of the battery being charged. Even if the battery has "sulfated," the charger has a "repair cycle" which works to dissolve the sulfate crystals. After about 10 hrs on the Optima charger, the battery is back to 100%.

Hayk

iTrader: (1)

You need a professional diagnosis of the charging system.

1. Make sure battery connections are clean of any corrosion and tight on the terminals
2. Check alternator charging voltage at idle
3. Charge the battery to 100% and load test it
4. Search for a parasitic draw in the system

Do you have any aftermarket accessories i.e.: car charger adapters, a GPS, a dash cam, a radar detector, a remote start, an alarm system? Remove them.

Make sure every light goes off when the car is locked, including the trunk. Make sure there is no car keys nearby - the smart access system will keep waking up the car and draining the battery.

Good luck.

Wilson2000

Or, you need a volt/ohm meter.

With the engine idling, your battery should measure over 14 volts, and about 12.5 volts with the engine and key off. If it doesn't measure over 14V with the engine running, you have a charging system issue. If the battery measures under 12V after charging, you have a bad battery.

If the battery isn't maintenance free, before charging, you should add distilled water to bring the levels up to the normal mark.

chuyrobles

You likely have a bad alternator or a short. There are different tests to check an alternator, the simplest of which is to check the voltage output at idle. It doesn't have to be exactly 14 volts. Also, overcharging can be a bad thing. The voltage at idle varies due to ambient temperature, load on the engine, and wear/tear. For most vehicles 13.5 to 14.5 volts is normal. Outside that, check if the readings are normal for that particular model and engine configuration. A short is also relatively easy to fix; it's just so time consuming that it's easier to take the vehicle to a mechanic.