2017 FFE Battery degradation

[jghall00]

I have the exact same problem with Cell #25!!

Perhaps the location in the pack is causing some deficiency in the cooling system efficacy, or higher C charge / discharge.

 

[wind_driven]

I have the exact same problem with Cell #25!!

I’d like to learn how to see this cell data—could someone point me to a thread that has more/specific info on the how to, and what equipment is needed? I do have a ScanGauge, which I got “programmed” by Linear Logic to work specifically with our EFF. Thanks!

 

[calvinhc]

Our experience, too. Heater & defroster are noticeable energy draws. We tend to use the heated seats if reasonable, seems like less of an energy draw. Interestingly (and we’re in a very hot & humid summers area) the A/C (on full chilly blast!) does not seem to give nearly the energy hit as heating the car. No hard data here, sorry, just 5 years of constant use. There is a dash (left side) gauge that shows energy draw in some bar graphs, you can see the hit as you turn on the heat.

A major reason that the A/C is not such a hit on the range is that even if you don't feel the need for the compressor to be on, the motor and battery will need some cooling that just running coolant through the radiator will not be enough for. What we've noticed regularly is that when you switch on the A/C initially, the range will initially drop maybe about 15-20 km but will slowly climb as the cabin reaches the cooling setting. It will still be a little lower, perhaps by about 5-10 km than when it was not on, but still better than the hit heating takes. It is definitely less noticeable as the without-A/C warm temperature range is like 170-200 km while the without-heating cold temperature range is only about 130-150 km.

I'm not sure, but I seem to recall somewhere hearing that the heating element for the coolant is rated at something like 5 kW. Someone will likely know more accurately what it actually is. Given that when the FFE is fully charged the GOM's range will drop by about 30 km when the heating is switched on, that is in the right ballpark for losing 5 kWh off of a roughly 30 kWh charge.

I don't know what the power draw of the seat heaters are, but I suspect each is about 50 watts or less, so if you can get by with just using that, you will get back much of the loss of range.

Any pre-conditioning of the cabin you can do while plugged in will save you the range lost to bring up or drop down its temperature before a trip.

 

[Anti_Climax]

The AC compressor will only chill the coolant going into the battery - whenever battery cooling is running above 97F, the diverter has that section looped back on itself. The rest of the components get radiator cooling at most.

The cabin heater is about 5kw, at full tilt it goes just high enough to read "5kw+". The fuses for the heated seats are 15A, so they are less than 180W but more than 100 (otherwise they could use a 10A fuse). My guess is 150W each running full power.

The battery has 3 PTC elements rated for 300W each to heat it. Once the loop is heated (the radiator can also be bypassed), that can be fed into the battery to warm in place of the heaters.

It should also be noted that even when plugged in, remote start conditioning still pulls down the battery, which is strange since L2 charging can push enough to power the heater at full tilt. But summer and winter, I can see the drop on my ScanGauge when I start the car. You've probably also noticed that the average Wh/mi starts off the top of the scale and takes quite a while to come back down because of it.

 

[Anti_Climax]

Checked this morning - we had a freeze overnight, showed 29F on the dash. After running 10min on remote start it had dropped from 95% SoC to 94% SoC. While the defroster and battery heating *might* be just enough to overwhelm the output from my L2, that would not be the case for the AC in the summer.

 

[Heima]

So this got me thinking. Lets say that a battery at 29F has X amount of charge. If that battery was heated to 80F by an external power source, the amount of charge would be X+Y. It would increase. But if it is seen that the SOC drops, then power had to be taken from the battery, or the calculation of SOC takes temperature and current in/out of the battery into consideration, and not just the apparent pack voltage.

Also throw in this. Is the 29F measured in ambient air, at a coolant fitting, deep within the battery mass, or somewhere else? If ambient air, then the battery mass maybe a much higher temperature, maybe 60F. At a coolant fitting, then the stagnant coolant and the plastic wall of the fitting may locally be at that temperature, and the battery mass at 50F Still, raising the temperature of the battery, you would think the SOC would increase.

 

[Anti_Climax]

I mention 29F air temp simply to note that the heater would be running full tilt during the warm up. And the battery conditioning heaters stop at 40F for the inlet temp.

I see similar drops in SoC when I remote start in the summer. The takeaway is simply that the conditioning is not pulled entirely from the L2 during remote start. Not sure if the "go time" behaves differently, but that's not really an option anymore.

Also, I ran the seats at full to calculate from the battery current draw and they actually did come in around 30W each. So good call on that. Kind of surprised they would have such a large fuse.

 

[elec2017]

In Froscan what should I be looking for to check the battery health? I know that HEV_BAT_VAR_V is an important number, and you want it to be as low as possible. What else should I look for? Does Forscan give you the state of health or you have to do a run down test? TIA.

 

[Anti_Climax]

Energy to empty will tell you what a rundown test would.