Smart Car of America Forum banner

21 - 34 of 34 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter #21
I ran the test again after recharging and got slightly better results (still not great, but still within MB's tolerance for battery life). When I ran the "bms all" test, I got a message on one line that said "NOTICE - cell deviation over 45mV - consider balancing charge." How do I perform a balancing charge? My EVSE is a ClipperCreek and it seems to just shut off after reaching full charge.

Here is my latest battery status report:

-----------------------------------------
--- Battery Status Report ---
-----------------------------------------
Battery VIN: WMEEJ9AA5EK732636
Time [hh:mm]: 08:17, ODO : 51307 km

HV Battery Status: OK

Battery Production [Y/M/D]: 2013/6/26
Battery verified [Y/M/D]: 2013/6/26

realSOC : 97.8 %, SOC: 99.5 %
Charged capacity : 47.4 Ah, min. Cell# 36
BMS estimate : 47.1 Ah, value @25degC
Measurement done : 0 day(s) ago
Estimation factor: 0.849, very good

OCV timer : 1157 s, @32.5degC
OCV state : HV ON, can't meas. OCV

DC isolation : 48922 kOhm, OK

Voltage Distribution (dV= 70 mV):
--------------------------->----[|==]--
4100 00 > [4159; 4161; 4166] < 00 4170
min [p25; median; p75] max
-----------------------------------------
 

·
Premium Member
MY08 cabrio MY09 cabrio Brabus MY15 ED
Joined
·
7,748 Posts
Then charge it to 100% and take your reading. Neither of your cars was charged to 100% when you took your test. Curious why?
Vincent, are you using the Charge and Depart (pre-condition) feature?

Charge and Depart can (and does) alter the charging rate if the system determines it can reduce the need for temperature moderation in the pack and still get the charge done in time.

If you end the charge cycle before the “scheduled” departure time you will be left with less than a FULL charge. During cabin “pre-conditioning” the HV is also topped off (100%) in anticipation of departure.
 

·
Registered
Joined
·
24 Posts
Discussion Starter #24
No, I don’t use the charge and depart feature. I admit that I‘ve never quite understood the purpose of that or how it‘s supposed to work. Guess I need to spend a little more time with the owner’s manual. I typically have been plugging the EVSE into the car when I want to charge it and then unplugging when the charge is 80-90% full. I don’t do that much driving, so it only gets charged every three or four days.
 

·
Registered
Joined
·
150 Posts
IMO, you want to at least every so often charge to 100% and leave the car “charging” even a few hours after 100%. The car’s charger is smart; it won’t hurt anything to do that. Don’t try to always out-smart it (no pun intended).

If you’re able to easily charge it every time you park it with less than 80% charge, I’d just do that. Time of day power rates or inconvenient access to power would be reasons to not do this perhaps, but if I had access to power where I parked, I’d mostly just plug ‘em in as a habit. (I don’t have easy charging at home, so was in the habit of charging every time at the office. That’s not happening right now, so I’ve had to charge at the grocery store, run an extension cord across the city sidewalk a few times, etc.)
 

·
Registered
2017 453 Passion ED/EQ
Joined
·
265 Posts
Charge and depart is only good to use if, because of the weather or season, the car is really hot or really cold. The cabin and the battery is heated up or air conditioned using the mains electricity before you unplug, so all battery energy is initially used to propel the car, and you'll maximize your mileage. If the weather is mild or if you are only going a short distance, you don't need it.
 

·
Registered
Joined
·
1,200 Posts
Vincent, are you using the Charge and Depart (pre-condition) feature?

Charge and Depart can (and does) alter the charging rate if the system determines it can reduce the need for temperature moderation in the pack and still get the charge done in time.

If you end the charge cycle before the “scheduled” departure time you will be left with less than a FULL charge. During cabin “pre-conditioning” the HV is also topped off (100%) in anticipation of departure.
I've never seen charge and depart alter the charging rate on my ED. It will charge to full at the full rate, then, 10 to 15 minutes before, and 5 minutes after the set departure time, it will turn on the heat and pre-warm the car while also turning charging back on so the pre-heating is done on "shore power". I've never used it to pre-cool the car in summer, but I assume it works similarly.
 

·
Registered
Joined
·
1,200 Posts
How do I perform a balancing charge? My EVSE is a ClipperCreek and it seems to just shut off after reaching full charge.
If your EVSE provides an AC amperage reading, you will notice that near the end of charging, the amperage will slowly taper down, with some ups and downs, over maybe 10 minutes before shutting off. That is the balancing mode of charging. It is shunting current past the high cells, while tapering the current until all cell's voltage reached an equal full level (about 4.15 to 4.2 volts).

The closest mechanical analog to charging a lithium cell is filling a bottle with a long thin neck - when the liquid level reached the neck, you have to taper the filling rate to prevent overshooting the top of the bottle.
 

·
Registered
Joined
·
183 Posts
So the smartED top-balances? So maybe 4 times out of 5 when I fail to stop charging @85% and it goes to 100% would be beneficial since it would then go thru the whole top-balancing process.

Nice analogy with the bottle neck !!
--
 

·
Registered
Joined
·
1,200 Posts
So the smartED top-balances? So maybe 4 times out of 5 when I fail to stop charging @85% and it goes to 100% would be beneficial since it would then go thru the whole top-balancing process.

Nice analogy with the bottle neck !!
--
Yeah, it top balances. I used to hear about about "bottom balancing" from EV home-builders but it never made sense to me.

The ED pack probably only needs balancing only every couple dozen charge cycles or so.
 

·
Registered
Joined
·
183 Posts
If your EVSE provides an AC amperage reading . . . [Yinzer]
Never seen one of these yet but I guess you have. However, to clarify it is the charger unit inside the smart that would be doing any balancing, not the EVSE. The EVSE is just a cable, a connection to the power grid.

Originally the 2012 Tesla ModelS featured volts and amps during charging with readouts right on the dash. You could busy yourself at a SuperCharger saving the data as the charge tapered off. The x axis was either rated range or time. I had to plot the curves later at home lacking a laptop setup to plot real time. After a year or so Tesla eliminated the volts and amps instead offering only the product value (kw) taking all the fun out of it, but by then most owners had smartphones to waste time with during those interminable supercharging sessions.
--
 

·
Registered
Joined
·
150 Posts
Chargepoint app will give the charging rate when using a Chargepoint station. Here's a sample from a charging session (on my LEAF).
IMG_2214.jpg
 

·
Registered
Joined
·
24 Posts
Discussion Starter #33
I did another check after depleting the battery to 20%, letting it sit for four hours, and recharging to 100%. The readings were about the same as the first time. The car runs fine and I’m able to get 70+ miles out of a full charge, so I’m just going to enjoy driving it and not worry too much about anything else. I will be a little bummed if the HV battery suddenly bricks like some of the posts I’m reading, but life is too short to worry about something that may never happen.

i wonder if the 453 models have the same bricking issue with the HV battery? I haven’t come across any reports of that happening, but maybe those models are still too new? Or the sample is just too small?
 

·
Registered
Joined
·
183 Posts
if the HV battery suddenly bricks [VSAncona]
'Suddenly' has never been verified as far as I've seen so far. Link here please if someone feels it has been.

HV batt's well being is completely dependent on the continued health of the 12v battery. If the 12v is disconnected then the contactor in the hv batt drops (disconnects) leaving the hv batt sitting alone and unaffected by anything except the sloow sloow voltage decrease due to internal electrical leakage or chemical migration etc. Months go by before you can perceive any differences in voltage: after 5 months the two Chevy Sparks here show the same mileage as when the 12v batt was disconnected. This is how Li-Ion behaves when left alone.

The SmartEV and SparkEV back home have the 12v disconnected under my new plan of hv batt isolation. Both cars still have their old original 12v batteries hence my desire to isolate the car from their fragile state. The Smart's 12v has has been put on a tiny float charger. When I return I will see how they have survived.
--
 
21 - 34 of 34 Posts
Top