VW Tiguan battery charging

Bill,
It does sound like you hve a dodgy charger. Either faulty or a "look-alike" that does not have all the functions.
I'd send it back for a refund and buy elsewhere.

On the Berlingo, and any vehile with a Stop-Start or smart alternator, you MUST read the vehicle manual and follow what thay say about charging the battery. These vehicles actively monitor the charge history of the battery. A "sensor", typically a small plastic lump on one of the battery connections is in fact a complete system with a microprocessor, memory and a communications interface. If the battery is charged or discharged without this monitoring it can mess up the history and result in mis-charging on the vehicle or false indication of a fault.
Some have a quick release on on cable and you disconnect thi and connect the charger to the post it came off, but follow what the manual for the specfic vehicle says.

Robert G8RPI.

You could try hooking the charger up to a known good battery (the new one in the Tiguan?) and see if you can get any sense out of the charger controls. If not, send it back.

Beware of trying to use it on a very flat battery. As others have said, it can fool the "smart" charger into thinking it is not connected to anything and so it will not respond to input etc.

With two sheds full of motorbikes that get occasionally used and sit for long periods between, batteries and chargers are the bane of my existence! Seems like modern batteries are getting worse by the year. Catastrophic failure without warning is becoming common. And even with a smart charger hooked on permanently, they still can die in two years or so. The cheaper brands within 13 months - a month after the warranty expires!

I have got to the stage where I bought a cheap battery load tester off t'internet and use it every time I give a bike a service or oil change or any kind of looking at. Easier to change the battery at home than on the side of the road somewhere. The old method of simply doing a voltage reading does not seem to predict failure for these batteries. It must be load tested to get the true story. The tester only cost about $25 so well worth it.

Leaving any battery on permanent charge will shorten it's life even with a "smart" charger. Lead acid batteries will last longest if charged to a constant voltage end point (votage depends on exact chemistry and temperature), disconnected complety, and kept somewhere cool and dry. Ideally on a insulting (electrically and thermally) surface. Then a top up charge annually or if the voltage drops to 12V off load.

For in-service testing a load tester is required. A lot of modern batteries seem to fail with high resistance and you need to load the battery to detect this. One cause of this type of failure is cracks in the internal interconnections. My personal theory on this is that in striving for low weight and manufacturing cost they are using the absolute minimum amount of metal in the interconnections.

My favorite lead acid battery is the Hawker SBS range. I have one of these that is over twentyfive years old. It was absolutely hammered in it's first application but is still going strong.

Robert G8RPI.

Yes after the death of many batteries I now leave them on a battery tender (smart charger type thing) with at timer to switch it on for a few hours a day, or I hook the tender up to it once a month or so when I think of it. I have found leaving them for months uncharged kills them or at best will not crank the electric starter over without a recharge first.

Yes I would say the cause of many of today's battery problems are increasingly thinner internal connections and plates etc as a cost saving measure.