Golf Alternator or Battery

We have a 1999 VW Golf, that had a dead battery the day before yesterday and required a jump. I put it on a charger all night and it still was dead in the morning. The battery (Interstate) is 16 months old. We jumped the battery & I put a Volt Meter on it and it read ~ 14.25 volts. We then took it to the Interstate Store and they put their "Wizard" on it. It was showing 12 volts with the car off.

They put in a new "loaner" battery, as their policy is to charge the existing one to try to find out if it is the battery. Then they measured the voltage with the car running with the new battery in and it was ~14.5 volts. I measured it with mine at home and it was 14.62 volts. The technician said the old battery showed signs of venting...acid from the vent on the battery case, and suggested that the alternator was possibly running too much voltage and could have "cooked" the battery. Incidentally or coincidentally, the right brake light bulb was burned out, something that happened in the last two days or so. This car has had a history of weird electrical problems.

The question is: is 14-5 - 14-6 Volts too high? My 2001 Jeep Wrangler reads 14.23 volts running, measured across the battery terminals.

Thanks for any advice,

Campbell Freeman South Carolina

I see 14.5V all the time. If it tickles 15 I get worried about problems. I think they were just looking for answers as to why a 16 month old battery went bad. It happens. Maybe you are running a lot of extra loads with lights and stereo and so on and sometimes with the engine off. With a HD alternator you can lay a quick charge on a low battery that can cause some bubbling. And perhaps the level was too high to begin with.

You should be fine at at 14.5 or .6. If it goes over 15 for extended timeframes then you could have problems. At this point I would guess that you just got a bum battery.

Steve B.

Thanks to all for the useful information.