The correct way to reset your vehicles BMS…

During the Covid 19 lock down cars & vans are being used on a very limited basis as such vehicles are not being driven as much as they would do normally. This will have a massive effect on the vehicles battery, even more so on vehicles with stop / start fitted as standard. You might ask why? Stop / Start vehicle batteries charge alot slower than a normal / older car battery to protect the internal cells. These stop / start batterys are normally labled as AGM. This means the car will need to be driven for longer to charge the battery. Keeping the vehicles battery in a discharged state is never a good idea because it will damage the internal battery cells.

Many cars after 2011 use start / stop technology however the first vehicle manufature to introduce this was BMW back in 2007 on the 1 series. Since then many vehicle brands have added this to cut emissions and add fuel economy. The only time this causes a problem for many owners is when they want to replace the vehicles battery. The first issue is cost! these batteries for stop / start vehicles cost a small fortune. And they can no longer be swapped on a DIY basis.

Why can’t the battery be swapped DIY? car batteries are ” normally ” not to bad to access and remove ( basic tools will normally be enough ). however the problem comes when it needs to be correctly programmed into the vehicles BMS ecu. It doesn’t make sense for the average DIY’er to buy an expensive diagnostic tool to fit a car battery. DB Vehicle Electrics can fully program your vehicles battery into the vehicles BMS ecu via our Auto Diagnostic service.

You might ask what happens if you fit a new battery and no dash lights appear warning you of a problem? you might think it’s fine however unless the stop / start fails to funtion you wouldn’t notice any effects straight away, the BMS won’t know any different if it hasn’t been told the battery has been changed. As such it could be under charging the battery meaning you could break down due to not enough power being stored in the battery or the major issue would be over charging the new battery you have just installed damaging the cells inside. If this happens your new battery won’t last long.