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[ScootCoupe]

So after 3 months of back and forth with my local dealer I finally got my 2014 Zero SR back with a new battery. The problem now is that the bike is significantly slower before I dropped it off.

A little back story.

I took a road trip with my girlfriend to the next town over and was nearly stranded on my way home because the bike began to lose speed while reading 20% of the battery remaining on the dash. Fortunately I made a J1772 adapter so I could plug into a nearby charger and add some electricity to the bike. After I got home, I was absolutely convinced that the bike should have made the trip, there and back, without supplemental charging. I charged the bike up when I got home, drove it around town until it would no longer move and then charged it up throug a Kill-A-Watt ez meter. Confirming my suspicion that I had a severely degraded battery, I got ahold of my local dealer and after lots of back and forth with Zero, a new ZF 14.4 battery was installed in my bike.

Prior to replacing the battery, the dealer had to update the firmware on the bike to see if that helped at all. It didn't increase the available kWh of the battery but it did succeed in making the bike much, much slower. I merely chocked this up to the bms accurately determining the state of health and internal resistance of my old battery.

Fast forward a month later after the new battery was installed. I received my bike back from the dealer yesterday, 9/21/18, and immediately I noticed that it was just as slow as before. Well I took it back and Zero promptly pulled the logs from the back and says that they don't see anything wrong.

I decided to do some testing on the bike today, hoping that with a 100% charged battery that it would perform better. In short it did not.

Some specs on the bike and conditions

2014 Zero SR
ZF 14.4 primary battery W/ ZF 2.8 Powertank
My weight with gear: 190 lbs
Outside temp: 83°F
Wind:light 0-5 mph

I used a screen recorder on my phone to record the Zero app to show what the bike is reporting.

The first video is of a 0-60 run on a flat road. The bike maxes out at 37kW and does 0-60 in about 8 seconds. The run starts at about 9 seconds


The second test is about 35-76 mph and is uphill, so don't pay attention to the acceleration on this test. Zero rates their max power as 50kW at 4000 rpm, which is approximately 66mph. Again, the bike never exceeded 36kW and at no point was temperature derating of the motor, controller, or battery an issue.


More of the same for the third run


Honestly this bike feels like an S and not an SR. So my question is, does anyone know what max kW and battery amps they see on their screen and could the firmware update have changed some values in the sevcon controller?

[MostlyBonkers]

Ooh, very interesting and thanks for posting. I'm having exactly the same issue with my battery as you had. I've got a 2014DS.

However, even though my battery hasn't been replaced yet, I still get maximum amps - albeit for a very short time when the battery is at a high SoC.  On an SR, you should be getting much more amps than your videos show though and I wouldn't be at all surprised if that power tank has something to do with it.  The first thing I'd try is disconnecting it to see what performance you get just with the new battery.  That's something Zero will have to do of course.

If the powertank came with the bike, I wouldn't be surprised if the cells have degraded in that too and it just isn't capable of supplying a decent current. Either that or the firmware or BMS can't cope with the mix of old powertank and new main battery. Different cell specifications etc...

Just some thoughts there. Hope it goes well with support. It sounds like you just need a new powertank now.

[AutoE]

It could be motor encoder calibration, sevcon or mbb programming.

Sent from my SM-G935F using Tapatalk

[domingo3]

Have you pulled your logs and looked at them using the log parser?  Among other things, look at the header information to see if it has your model correctly listed.  It sounds like you probably have more going on that that, but you can also take a look at the line entries during one of the runs to see what the bike is reporting. 

[ScootCoupe]

I have pulled the logs and fortunately I have an old log before the firmware update when the bike started performing poorly.

Before update:
Serial number      2014_mbb_0386e1_00144
VIN                538SM5Z34ECG*****
Firmware rev.      52
Board rev.         1
Model              SR

After Update:

Serial number      2014_mbb_0386e1_00144
VIN                538SM5Z34ECG*****
Firmware rev.      54
Board rev.         3
Model              SR

Do you know why the board rev would change just from a firmware update?

I have a zero specific OBDII dongle coming this week where I will try and get a log of the target motor current because it feels more so like the motor current is being limited than the battery current. I have experiend cutbacks before the battery was changed and the bike would hustle right up to where the battery current limit was reached and then acceleration would taper off linearly as speed built.