Webasto HVH50: Difference between revisions
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Pin 4 and 8 are unused | Pin 4 and 8 are unused | ||
Ground must be connected the the case via a stud. | |||
== Communication & Control == | |||
While there is a document describing the [https://www2.calact.org/assets/4d.%20Heater%20Info%20-%209035422C_II-OI_HVH_50_and_70_EN%2019-01%20PMC.pdf LIN interface] , Webasto seems to have altered the interface for different OEMs. According to the document, LIN bus speed is 19200 but on a unit obtained from ebay it was 9600. So always try both. | |||
The data format seems common as follows | |||
{| class="wikitable" | |||
|+HVH LIN Protocol | |||
!Command | |||
!Possible IDs | |||
!Byte 1 | |||
!2 | |||
!3 | |||
!4 | |||
!5 | |||
!6 | |||
!7 | |||
!8 | |||
|- | |||
|Write power | |||
|35 | |||
|0=Off, 1=On | |||
|Temp setpoint | |||
1 digit=1 degree | |||
Offset -40 | |||
|Power limit | |||
1 digit=40W | |||
| - | |||
| - | |||
| - | |||
| - | |||
| - | |||
|- | |||
|Read Status | |||
|24 or 23 | |||
|various | |||
|status | |||
|info | |||
| | |||
| | |||
| | |||
| | |||
| | |||
|- | |||
|Read Meas | |||
|40 or 22 | |||
|Lin status | |||
0=good, 1=issue | |||
|Outlet temp | |||
Scaling as above | |||
|Inlet temp | |||
|HV value MSB | |||
|HV value LSB | |||
|Power MSB | |||
|Power LSB | |||
1 digit=20W | |||
| | |||
|} | |||
Some units allow control via a simple on off signal on Pin 3 (12V=heat up liquid to 85°C) and some units allow a strange PWM control between 50-100Hz where 25%-81% duty cycles allow setting various power levels. |
Revision as of 09:44, 19 April 2021
The Webasto HVH series are electrical water heaters typically used in popular PHEV.
Connectors
The HV connector is a Tyco HVA280 connector with A-key (might be different on other devices).
The small center pins are for interlock (detect that the connector is seated). The right pin (with tab facing upwards) is HV+, the left one HV-
The LV connector is best found by the VW part number 1J0973714
Pin 1 is permanent 12V
Pin 2 is an analog output
Pin3 is an analog or PWM input
Pin 5 and 7 are interlock (probably must be shorted)
Pin 6 is LIN
Pin 4 and 8 are unused
Ground must be connected the the case via a stud.
Communication & Control
While there is a document describing the LIN interface , Webasto seems to have altered the interface for different OEMs. According to the document, LIN bus speed is 19200 but on a unit obtained from ebay it was 9600. So always try both.
The data format seems common as follows
Command | Possible IDs | Byte 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
---|---|---|---|---|---|---|---|---|---|
Write power | 35 | 0=Off, 1=On | Temp setpoint
1 digit=1 degree Offset -40 |
Power limit
1 digit=40W |
- | - | - | - | - |
Read Status | 24 or 23 | various | status | info | |||||
Read Meas | 40 or 22 | Lin status
0=good, 1=issue |
Outlet temp
Scaling as above |
Inlet temp | HV value MSB | HV value LSB | Power MSB | Power LSB
1 digit=20W |
Some units allow control via a simple on off signal on Pin 3 (12V=heat up liquid to 85°C) and some units allow a strange PWM control between 50-100Hz where 25%-81% duty cycles allow setting various power levels.