Charging the High Voltage Battery in Energi?

[NaplesGeezer]

I have read over the Owners Manual and I have looked online and I haven't been able to find an answer.  When charging the High Voltage Battery, do you have to wait until the battery is completely drained to start a charge or can you start a charge with the battery at any level of charge.  I would assume the battery doesn't have a memory like older lithium batteries.

[Russael]

The memory effect of batteries went out with the NiCad ones.  You can charge your car at any time, at any charge level.  Think of it as the worlds largest cell phone. :)

[HotLap]

Cool, I was just about to post a similar question about the best way to charge the HVB and if you could actually damage it's capacity with poor charging habits.  I sometimes remove the level 2 charger before the HBV is full (run a quick errand or two) and then plug it back in frequently before it is empty.  I wanted to confirm this charging behavior had no detrimental effect on the HBV over time?  I there a "best" way to charge our HBV's...to attain a higher level of charge or for quickest charging (using a Level 2 charger)?  The OM is particularly vague around HBV battery maintenance.

[larryh]

The main factors determining the lifespan of the HVB are average temperature, the average SOC, and the charging/discharging cycles.  Undesirable chemical reactions that degrade the HVB (i.e. reduce its capacity) occur all the time, whether the battery is used or not.  The rate of degradation increases significantly with temperature.  You want to maintain a low average HVB battery temperature.  To do that, keep the power being used from the HVB relatively low, maybe at most two bars on the Empower screen.  Also, park the car in the shade.  People who live in the southern states will experience significantly faster HVB degradation than people in the northern states. 

 

If you are not going to use the car for some period of time, it is better not to leave the HVB fully charged.  The higher the average SOC, the faster the degradation.  I usually don't charge my HVB until just before I am planning to leave. 

 

Finally, the lifespan is determined by the number of charge/discharge cycles and the depth of discharge.   Fortunately, the car does not allow you to charge the HVB to its maximum capacity nor drain it to 0% SOC.  When the car states it is at 100% SOC, the HVB contains about 7.2 kWh of energy vs. its capacity of 7.6 kWh.  The minimum amount of energy of the HVB, before the ICE will start to charge it, is 1.0 kWh. 

 

Note that the SOC shown on the MFT screen and MFM is not the true SOC of the HVB.  It is called the displayed SOC.  When the displayed SOC of the HVB is 100%, the true SOC of the HVB is 96% or greater.  If you want to get the true SOC to 100%, you will have to charge the HVB while the car is running.  It normally charges the HVB to just over 98% SOC.  To get it to 100%, you need to turn the car on with the car plugged in.  But it won't start charging the HVB unless the true SOC is below 98%.  Turn on the heater or AC or reduce the SOC below 98%.  Turn off the AC/heater and allow it to charge the HVB.

 

Since you cannot see the true SOC (unless you have a OBD II scanner), watch the arrows above and below the HVB icon on the left display.  With the AC/heater on, the arrow below the HVB will indicate the HVB is discharging.  Turn the AC/heater off for a few seconds and observe the arrows.  If the arrow below the HVB remains, it means the HVB SOC is still above 98%.  Once it is below 98%, the arrow above the HVB icon will indicate the HVB is charging.  Wait until the arrow above the HVB goes away.  The HVB is now fully charged. 

Edited September 1, 2014 at 05:08 PM by larryh

[Hybridbear]

The main factors determining the lifespan of the HVB are average temperature, the average SOC, and the charging/discharging cycles.  Undesirable chemical reactions that degrade the HVB (i.e. reduce its capacity) occur all the time, whether the battery is used or not.  The rate of degradation increases significantly with temperature.  You want to maintain a low average HVB battery temperature.  To do that, keep the power being used from the HVB relatively low, maybe at most two bars on the Empower screen.  Also, park the car in the shade.  People who live in the southern states will experience significantly faster HVB degradation than people in the northern states. 

 

If you are not going to use the car for some period of time, it is better not to leave the HVB fully charged.  The higher the average SOC, the faster the degradation.  I usually don't charge my HVB until just before I am planning to leave. 

 

Finally, the lifespan is determined by the number of charge/discharge cycles and the depth of discharge.   Fortunately, the car does not allow you to charge the HVB to its maximum capacity nor drain it to 0% SOC.  When the car states it is at 100% SOC, the HVB contains about 7.2 kWh of energy vs. its capacity of 7.6 kWh.  The minimum amount of energy of the HVB, before the ICE will start to charge it, is 1.0 kWh. 

 

Note that the SOC shown on the MFT screen and MFM is not the true SOC of the HVB.  It is called the displayed SOC.  When the displayed SOC of the HVB is 100%, the true SOC of the HVB is 96% or greater.  If you want to get the true SOC to 100%, you will have to charge the HVB while the car is running.  It normally charges the HVB to just over 98% SOC.  To get it to 100%, you need to turn the car on with the car plugged in.  But it won't start charging the HVB unless the true SOC is below 98%.  Turn on the heater or AC or reduce the SOC below 98%.  Turn off the AC/heater and allow it to charge the HVB.

 

Since you cannot see the true SOC (unless you have a OBD II scanner), watch the arrows above and below the HVB icon on the left display.  With the AC/heater on, the arrow below the HVB will indicate the HVB is discharging.  Turn the AC/heater off for a few seconds and observe the arrows.  If the arrow below the HVB remains, it means the HVB SOC is still above 98%.  Once it is below 98%, the arrow above the HVB icon will indicate the HVB is charging.  Wait until the arrow above the HVB goes away.  The HVB is now fully charged. 

Is this the "supercharging" that was described & hotly debated on the C-Max Energi Forum last year?

[larryh]

I'm not sure what they are talking about when they say "supercharging".  No one can provide concrete proof that such a thing exists or even define it clearly.  Their claims are highly suspect.  Running the AC has little impact on the HVB temperature. 

 

If you charge the car when the car is turned on, it will charge to a higher actual SOC than when the car is turned off.  Normally, when the car is off, it charges to around 98.5% SOC.  When the car is turned on, it charges to 99.5% SOC or higher.  You can only see this using a scanner.  The car will report 100% SOC when the actual SOC is anywhere between 96% and 100%.  So you may get 1-2% more SOC simply by charging the car when it is on.

 

In addition, if you charge the car when it is on, you confuse the algorithms for determining estimated range for the HVB, lifetime MPGe, and the current trip MPGe's.  It thinks you are getting regen.  So if you want 255 miles in range to show up on the car's display and in MFM, simply charge a depleted battery with the car running.  I can easily get 999.9 MPGe to show on the trip odometers by charging the car while it is running after a trip.  When the trip odometer decrements down to 0 kWh of plug-in energy used, MPGe stops at 999.9.  You can't get it to show negative plug-in energy. 

Edited September 8, 2014 at 11:46 PM by larryh

[Hybridbear]

I'm not sure what they are talking about when they say "supercharging". No one can provide concrete proof that such a thing exists or even define it clearly. Their claims are highly suspect. Running the AC has little impact on the HVB temperature.

 

If you charge the car when the car is turned on, it will charge to a higher actual SOC than when the car is turned off. Normally, when the car is off, it charges to around 98.5% SOC. When the car is turned on, it charges to 99.5% SOC or higher. You can only see this using a scanner. The car will report 100% SOC when the actual SOC is anywhere between 96% and 100%. So you may get 1-2% more SOC simply by charging the car when it is on.

 

In addition, if you charge the car when it is on, you confuse the algorithms for determining estimated range for the HVB, lifetime MPGe, and the current trip MPGe's. It thinks you are getting regen. So if you want 255 miles in range to show up on the car's display and in MFM, simply charge a depleted battery with the car running. I can easily get 999.9 MPGe to show on the trip odometers by charging the car while it is running after a trip. When the trip odometer decrements down to 0 kWh of plug-in energy used, MPGe stops at 999.9. You can't get it to show negative plug-in energy.

 

I think the poster was claiming that supercharging happened from using AC while charging but likely what he was doing was getting the HVB to charge to 99.5% instead of 96% by turning the car on to run the AC during charging. Edited September 9, 2014 at 11:05 AM by Hybridbear

[HotLap]

Interesting fact, thank you gentlemen for sharing.  I noticed something recently on a 200 mile trip.  Appears the EV side of the HBV wont recharge through regen if it hits 0 miles and switches into Hybrid mode?  I had it in "EV Now" mode and when it hit 0, it switched into Hybrid mode.  I expected that after regen braking it would start to charge the EV portion of the HBV, but it would not allow me to go back into EV Mode and kept displaying "EV Unavailable"...is this normal?  Once I plugged in all was fine and I don't think this is an issue as during my trip (after the EV Now mode was unavailable) it did show the Hybrid battery icon being charged as normal.

 

Also, this AM I had 23 miles of range (was left on the Level 2 charger overnight).  I had never seen above 21 before...

[murphy]

It takes a lot of regen to get back into EV Now mode.  There is at least one report on the forum of someone coming down from the top of Pikes Peak (over 14000 feet) and fully charging his battery from regen.

 

My range is currently between 27 and 28.  It has cooled off here in the morning (it's 68 degrees at 11 AM today) so I am not using A/C or heat.  The highest I have ever seen is 31.

[Russael]

Interesting fact, thank you gentlemen for sharing.  I noticed something recently on a 200 mile trip.  Appears the EV side of the HBV wont recharge through regen if it hits 0 miles and switches into Hybrid mode?  I had it in "EV Now" mode and when it hit 0, it switched into Hybrid mode.  I expected that after regen braking it would start to charge the EV portion of the HBV, but it would not allow me to go back into EV Mode and kept displaying "EV Unavailable"...is this normal?  Once I plugged in all was fine and I don't think this is an issue as during my trip (after the EV Now mode was unavailable) it did show the Hybrid battery icon being charged as normal.

 

Also, this AM I had 23 miles of range (was left on the Level 2 charger overnight).  I had never seen above 21 before...

 

On level ground, you won't be able to regenerate enough energy to bring yourself back out of hybrid mode, but it IS possible if you're going down a long stretch of decline highway (down a mountain, down a pretty big hill, etc).  There's someone here on the forum who completely recharged his battery coming down from Pikes Peak.

 

In Hybrid mode, the only mode available is 'EV Auto', unless you put miles back on the battery.

 

And Murphy beat me to it. :)

Edited September 9, 2014 at 03:16 PM by Russael

[jeff_h]

It takes a lot of regen to get back into EV Now mode.  There is at least one report on the forum of someone coming down from the top of Pikes Peak (over 14000 feet) and fully charging his battery from regen.

 

Correct - I didn't come down Pikes Peak, but came down one side of the Appalachians and got from hybrid mode up to 9 miles - http://www.fordfusionenergiforum.com/topic/1179-once-the-charged-hvb-is-drained-its-stuck-in-hybrid-mode-not-really/