Hi Guys,
Thanks for all your input.
One point I think some may have overlooked is that while my PHEV is in my garage at home while I’m away for about 3 months the Charger Cable will be connected to a live 240V supply and the charge timer set to charge the vehicle Traction Battery once each week.
Now a number of comments on various aspects raised:
Disconnecting the 12V Battery and Loss of Critical Parameters:
Disconnecting the Auxiliary Battery appears to have the deleterious effect of, according to “The Technician Training Guide, PHEV Outlander” (undated) (hereafter the “TTG”), page 28 discussing the counter in the ETACS:
The counter is rest every time the customer adds more than 15 litres of fuel in the tank. Note: The counter will also be reset in case the 12 Volt auxiliary battery is disconnected! This counter function is implemented to keep the fuel in the MPI system, particularly in the fuel rail from deteriorating to the extent of damaging the injectors.
Further, at TTG page 111 is states:
Do not disconnect the 12 volt battery for long period. This is to ensure that the control information for the drive battery is correctly stored in the PHEV ECU and BMU.
There are other auxiliary systems, such as the security alarm system, that also subject the Auxiliary battery to a continue energy drain, and if my PHEV is like other cars I’ve owned, disconnecting or letting the battery run down triggers the vehicle’s alarm, much to the annoyance of my neighbours when I’m not home, because they have no way of cancelling it.
It is also noted that the Auxiliary Battery also operates the electric “parking lock actuator”, controlled by the PHEV-ECU, that locks the front transmission system (TTG pages 58 & 59), and without power from the Auxiliary Battery the vehicle cannot be moved.
2:00 PM Charging of the Auxiliary Battery:
The TTG, page 82, in discussing the “EV remote ECU” and Remote Control function provides the following:
NOTE:
1) Once a device has been connected wirelessly to the vehicle, the onboard DC/DC converter will automatically charge the auxiliary battery at 2.00pm every day. This is to replenish the power consumed by the EV remote ECU.
This implies that the 2:00pm charging routine ONLY occurs while there is a Remote Control device connected wirelessly, and again at TTG page 82:
3) If the vehicle is not driven, charged or had the power switch set to READY for a period of 10 minutes or more within a 36 hour period, the EV remote ECU will turn off the Wireless LAN signal.
This is telling me that the “EV remote ECU” is switched off after the conditions noted are met, and as there will be no Remote Device connected to my PHEV’s “EV remote ECU” once I leave home and my intended charging interval is once per week, this also appears to mean that the 2:00pm charging provided by TTG Note 1 above is also cancelled.
At TTG page 111, we find the following:
Maintenance Precautions for drive battery and auxiliary 12 volt battery
If the vehicle is not used for a long time, check the drive battery meter reading every three months. The battery SOC should be a minimum of 1 segment.
If the reading is zero, charge the battery until at least 1 segment is shown on battery SOC. This is done by putting the electric motor switch in READY then start the engine and press battery charge button. Allow the engine to run for at least 5 minutes. After 5 minutes, stop the petrol engine and keep the vehicle ignition switch in “Ready” status. This allows the OBC to charge the auxiliary 12 volt battery.
Do not disconnect the 12 volt auxiliary battery for long period. This is to ensure that the information for the drive battery is correctly stored in the PHEV ECU ad BMU.
Fortunately I expect to be back before the 3 month period expires, but this again suggests that the Auxiliary Battery will be depleted following a long period of vehicle inactivity.
At TTG page 122 we find the following:
When the PHEV-ECU inputs the operation enable signal into the DC-DC converter with the power switch in the READY condition or under charging conditions (normal charge or quick charge), the DC-DC converter decreases the high voltage of the drive battery down to the auxiliary battery power supply voltage of 14 volt.
This suggests that the Auxiliary Battery is also charged whilst the Traction Battery is being charged. However, as noted above, the “EV remote ECU” is switched off after 36 hours of inactivity, so maybe then the DC-DC converter doesn’t get triggered by the PHEV-ECU to charge the Auxiliary Battery. The interaction of the “EV remote ECU” and the PHEV-ECU under these conditions is unclear to me.
Then we get, also on TTG page 122:
The decreased auxiliary battery power supply voltage is output from the B terminal to the auxiliary battery or to other electrical components. The DC-DC converter monitors the terminal voltage of the auxiliary battery through the S terminal, and adjusts the output voltage so that the terminal voltage of the auxiliary battery can be maintained at approximately 14V.
This appears to imply that the DC-DC converter can charge the Auxiliary Battery from the Traction Battery at any time the Auxiliary Battery drops below 14V, possibly without being triggered by the PHEV-ECU. Again it is unclear how these systems are interacting.
From all of the foregoing I’m still unsure as to what I will find when I arrive home from my overseas trip. Will I, or won’t, I be able to get into my PHEV, immediately start it and drive away. I guess I’ll have to wait and see.
Cheers
Trevor
