Vehicle Programming Battery Maintainer.

We decided to make our own battery maintainer that was on a par with BMW’s Deutronics £1300 tool.

Vehicle Programming Battery Maintainer.

When doing any software work to modules connected in the vehicle, you really DO need to use a battery maintainer. On some vehicles, you can get away with a half decent battery charger (10a minimum) at 14.x v. On premium vehicle makes you need a 40a minimum maintainer at 14.x v for ANY flashing operations. All battery chargers have no way of regulating the voltage as the vehicle demands current and will suffer from voltage sag. Any fluctuation in voltage could lead to a corrupt flash…and a dead vehicle!

We made some changes in the PSU circuitry to enable OVP protection and to add a way to adjust to V+ output voltage. We set this to 14.9v. The PSU is rated at 120a. We load tested the PSU at 120a and the voltage sag was only down to 14.7v.