massivly reduce canbus speed

Software/MainBoard/rust/src/hal/v4_hal.rs

@@ -33,7 +33,13 @@ use measurements::{Current, Voltage};
 use pca9535::{GPIOBank, Pca9535Immediate, StandardExpanderInterface};
 
 const MPPT_CURRENT_SHUNT_OHMS: f64 = 0.05_f64;
-const TWAI_BAUDRATE: twai::BaudRate = twai::BaudRate::B125K;
+const TWAI_BAUDRATE: twai::BaudRate = twai::BaudRate::Custom(twai::TimingConfig {
+    baud_rate_prescaler: 200, // 40MHz / 200 * 2 = 100 on C6, 100 * 20 = 2000 divisor, 40MHz / 2000 = 20kHz
+    sync_jump_width: 3,       // 4 TQ
+    tseg_1: 15,
+    tseg_2: 4,
+    triple_sample: true,
+});
 
 pub enum Charger<'a> {
     SolarMpptV1 {