Renault Master Battery/Charging Problem

Question

I'm having some alternator charging issues with my Master since 1 month, today it got much worse. It is 2016 with 135k km.

Car shows up STOP and Low Battery warning, when it first started happening last month, the warning was going away after 2-3mins. Today it came up every 20-40 seconds while running, it stays on like 20 seconds and goes away, it keeps happening all the time in a loop.

Battery voltage is around 12.2-12.3V while driving. I read the Alternator values with OBD. When the warning light is on Alternator Load is 99.5% Power is 190W. When light is off Power is around 640W max, it doesn't go more than that. Its a 3000W Alternator.

I tried checking connections, it seemed ok but I don't have much exp with this. Right now I'm in a foreign country, 2 official Renault services didn't want to help and sent me away. So I depend on internet. Can I be sure its 100% faulty alternator? If yes, I will try to get a new one installed. What do you think? What would you suggest?

Answer 1

What year? Mileage? Examine battery cables, 12v connection to alternator and one or two main battery ground(s); battery to chassis, chassis to engine block. Powdery residue on battery posts can be dissolved with warm water and baking soda, water rinse. Do not allow this mixture into battery cells. This solution will kill each cell contaminated with baking soda. Be sure the battery is good. Have it tested. Voltage on the 'hot' 12v wire to the alternator terminal should measure the same as battery voltage. If all checks out, your alternator is most likely worn out as alternators output around 14.5vdc; the voltage difference is for recharging the battery after every startup and supplying all the electrical power for the vehicle while recharging the battery.

Answer 2

Has the battery ever been changed? If not, it's time. Most car batteries can only be expected to last 5-6 years, the best ones 7-8 years.