What is load dump, and how does it affect tractor electronics?
Load dump is the highest-energy transient voltage event in a vehicle electrical system, occurring when the battery connection is suddenly broken while the alternator is charging the battery. Since the current produced by the alternator has nowhere to go, the line voltage briefly rises far above nominal. The immunity of vehicle electronics to transient events is assessed under ISO 7637-2 and ISO 16750-2.
The most typical causes of load dump are: the battery terminal post working loose or being disconnected while the engine is running, loss of contact at an oxidised or corroded terminal connection, and the battery being disconnected with the engine running.
Protection practice:
- Never disconnect the battery terminal while the engine is running. This single rule prevents the great majority of load dump cases.
- Tighten and clean the terminal posts. A terminal post loosened by vibration creates momentary disconnections during operation.
- For jump-starting and welding operations, disconnect the battery first and take the electronic units out of circuit.
- Make the chassis connection to a clean bare metal surface with a serrated washer.
Like every electronic unit added to a tractor afterwards, lift retrofit kits operate in this environment. When the charging system and battery connections are kept healthy, the likelihood of such transient events occurring drops noticeably.
Full topic: Converting a tractor hydraulic lever to electronic control