It is some time since we corresponded about my 1997 Mercedes-Benz C 250 Turbodiesel with 255,000 miles on the clock. Unfortunately I have since had to replace it, as it was requiring quite a lot of replacement parts and my family were getting worried about the reliability of it. I have replaced it with a Kia ceeíd EcoDynamics 1.6 CRDi diesel which still has three more years on its seven year warranty and is proving to save me about £1,000 a year on running and maintenance costs. (It was your Diesel Car report on the Kia ceeíd EcoDynamics in issue 303, or thereabouts, that prompted me to buy one, as did your advice way back in issue 99 when I bought the Mercedes-Benz! I still have that copy!) With only 24,000 miles on the clock currently, it is also proving to be incredibly reliable. 

Now to the question. The Kia has stop-start which only works when the battery is well charged. With much of my current motoring being small mileages, the stop-start will only work properly after a good long run. During the coming winter, the battery will be taking even more usage which will be keeping it at a low charge level. The battery is an AGM type (Absorbent Glass Mat) instead of a more conventional lead acid battery, and the handbook for the car states that it should be removed from the car for re-charging. I have got a heavy-duty Battery Charger that is AGM compliant, so I could keep the battery topped up when at home and not in use; but to take the battery out of the car each time would be quite a nuisance as, when it is replaced, the radio, clock, electric windows and ISG (intelligent stop and go) will all have to be re-installed each time, although I believe that the Kia garage can do all this through the diagnostic connector. Why cannot the battery be trickle-charged without disconnecting it from the car? Will this instruction apply to all cars fitted with AGM batteries? Your advice on this will, no doubt, be welcomed by many. 

Terry Raynor, Maidstone

I had my own opinions on this subject, but to be doubly sure of my facts, I approached the Kia press office, who then advised me that a technical man would be in touch. A very satisfying telephone conversation that I have just had with a man called Bob from the technical department at Kia UK has clarified everything for us both. What a pleasant change! The generic advice given in the owner handbook errs on the safe side, and at Kia UK they are aware of this. There is no problem with using an “intelligent” compact battery conditioning trickle charger designed for this sort of purpose, as long as you connect the black earth lead to a good visible earthing point on the chassis, not the battery negative terminal. Apparently some systems have a sensor for earth drainage, and any possible interference with this is avoided by earthing the charging unit directly to a true body earth, as you will find on many cars now. Otherwise, there are no problems.

I think that I would avoid using your big heavy charger though, and buy one of these compact “conditioner” units, which “the man” said should be well capable of keeping the battery in good health. Kia is certainly not the only manufacturer with stop-start system problems, and I have certainly heard about plenty of problems with recent stop-start facilitated Renaults, for example. The problem really is the safety factor they feel they need to build into the system. Were you to drive home in the fog, maybe in heavy traffic, on a cold night, with all lights blazing and the wipers going, as well as the air conditioning, there is a chance that the next morning after a sub-zero night, and the battery below 70 per cent capacity, you might struggle to start, and they have to build such a “worst case scenario” into the stop-start programming. So towards the end of that night’s journey you might have seen the stop-start system failing to operate.

I hope this clarifies everything for you, and maybe other readers with similar problems. It was certainly a good result for me getting through to the right man, who actually volunteered to call me. Well done Kia UK! Best regards, and happy motoring.

The Doc