Decreased performance with battery charge <80%?

[nmope]

I’m seeing posts here advising to keep battery charged between 20-80% range. Any reasoning for this?
On my GTPE I notice one of these bars if it’s 78% or less and the number increases the lower my battery charge is. I want to maximize my performance but still maintain good battery health. Any advice?

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[AKgrampy]

I’m seeing posts here advising to keep battery charged between 20-80% range. Any reasoning for this?
On my GTPE I notice one of these bars if it’s 78% or less and the number increases the lower my battery charge is. I want to maximize my performance but still maintain good battery health. Any advice?

Two different concepts here. First 20 - 80% was the rule but now Ford recommends 90% for day to day driving and overall HVBJB health. The bars are the current power limitations for energy draw. The more bars the less power available from the batteries. By that I mean a smaller hose. You still have all the kWh available but you can’t get it out as fast.

 

[AKgrampy]

If you are asking if the charge level of the HVB affects the number of bars then I am not 100% sure but I think it will add bars as the SOC decreases; however, temp is the main issue for me.

 

[HuntingPudel]

Temperature is a greater factor in the jail bars showing up than SoC. As an example, I have had 3 bars show up at 83% indicated SoC on a cool day. On a warm day, I don’t get bars at anywhere near that SoC. ?‍?

 

[ebeponyan]

Two different concepts here. First 20 - 80% was the rule but now Ford recommends 90% for day to day driving and overall HVBJB health. The bars are the current power limitations for energy draw. The more bars the less power available from the batteries. By that I mean a smaller hose. You still have all the kWh available but you can’t get it out as fast.

To add to this:

• While it is true that 90% is the recommended daily charge, due to the buffer of unusable capacity at the, 90% of the 91kWh usable is pretty close to 80% of the 99kWh total. The 20-80% guideline still applies.
• Gray bars represent power limiting (smaller hose, as said above) and are less about state of charge and more about thermal conditions. Power may also be limited due to heat building up after heavy use to protect components like the HVBJB, or due to cold ambient temperatures for battery health.
• That said, as state of charge decreases, so will pack voltage (non-linearly). The same current at lower voltage will result in lower power output. This will be noticeable at low states of charge compared to fully charged, but certainly not between 78 and 80%.

 

[nmope]

To add to this:

• While it is true that 90% is the recommended daily charge, due to the buffer of unusable capacity at the, 90% of the 91kWh usable is pretty close to 80% of the 99kWh total. The 20-80% guideline still applies.
• Gray bars represent power limiting (smaller hose, as said above) and are less about state of charge and more about thermal conditions. Power may also be limited due to heat building up after heavy use to protect components like the HVBJB, or due to cold ambient temperatures for battery health.
• That said, as state of charge decreases, so will pack voltage (non-linearly). The same current at lower voltage will result in lower power output. This will be noticeable at low states of charge compared to fully charged, but certainly not between 78 and 80%.

Sir you speak with knowledge but I did not understand your post of 80 vs 90. So Should I charge to 80 or 90?
And regarding the pack voltage will it be higher at 100% instead of 80%? Meaning I should have better acceleration?
I’m just trying to get the advertised 634 torque!!

 

[ARK]

90% is not the recommended daily charge, 90% is Ford's 'do not exceed' number for optimal battery health - from a purely battery health perspective, it would not be a good idea to see you are at 50% charge and decide you need to take it up to 90% - maybe you want to do that for performance or for range, but not for the sake of battery health.

On my Standard Range AWD, I have not noticed a drop in performance with lower charge rates (I typically go down to about 20%). But I understand from this forum that that is definitely not the case with the GTs.

I don't know at what state of charge you might start to notice a drop in performance for the GTs, but if that transition happens around the 85% mark or higher (I'm factoring in the buffer), there is going to be a trade off between optimal battery health versus max performance.

 

[SnBGC]

Sir you speak with knowledge but I did not understand your post of 80 vs 90. So Should I charge to 80 or 90?
And regarding the pack voltage will it be higher at 100% instead of 80%? Meaning I should have better acceleration?
I’m just trying to get the advertised 634 torque!!

Max power at 100% charge which is max voltage. As charge decreases then voltage decreases and thus reduced power.

All else being equal, line up three identical vehicles. One with 100% battery, one with 60% and the last at 10%. Drag race the cars and the 100% charged car will be quickest and the 10% car will be slowest.

 

[AKgrampy]

Sir you speak with knowledge but I did not understand your post of 80 vs 90. So Should I charge to 80 or 90?
And regarding the pack voltage will it be higher at 100% instead of 80%? Meaning I should have better acceleration?
I’m just trying to get the advertised 634 torque!!

Charge to 90% if you wish. I go to 85 but may bump it up for winter. The actual battery is larger than available use. There is 91 kW available. So what he meant was that 90% of the available 91 kW is just about 80% of the total battery in the car. Ford built in some buffer. Also not a big deal to go to 100% when heading on a long drive.

 

[mkhuffman]

Sir you speak with knowledge but I did not understand your post of 80 vs 90. So Should I charge to 80 or 90?
And regarding the pack voltage will it be higher at 100% instead of 80%? Meaning I should have better acceleration?
I’m just trying to get the advertised 634 torque!!

Charge to 90% if you wish. I go to 85 but may bump it up for winter. The actual battery is larger than available use. There is 91 kW available. So what he meant was that 90% of the available 91 kW is just about 80% of the total battery in the car. Ford built in some buffer. Also not a big deal to go to 100% when heading on a long drive.

Just to clarify, 90% charge (on the display) is approximately 85% total battery charge, not 80%. It is only 5%, but it matters. The available capacity has approximately the same buffer on the top and bottom of the battery. That means 91 kWh sits in the middle, with 4.5 kWh on the top, and 4.5 kWh on the bottom.

What does this mean? If you want to charge to 80% SoC, you need to charge to about 85% SoCD. Personally I follow Ford's recommendation and charge to 90% SoCD. I trust the BMS to manage the health of the battery and, more importantly, I want to be close to fully charged in case I need to leave town unexpectedly. Which has happened to me several times this year.

 

[MellowJohnny]

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