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[Charlyseabass]

Hi there,
Back in this forum ,
Still own my zero fx 2015  zf 5.7with 21000km on it, after having fixed my first issue with motor bearings few years ago,
I’m now at the point that my range is 50km and top speed 90km/h…
I had my batteries logs checked and they sag a lot under heavy load… diagnosis : battery worn out😫
I’ m looking for some informations to know if someone already tried rebuilding those packs on 15 fx plateform?
I’m in Europe ( France) and tried contacting many e-garages but didn’t find anybody able to rebuilt it yet…
Second hand modular batteries are not available….
I want to keep it alive but definatly won’t spend 7000€ on new 2x3.6kwh brand new power tanks…
I really enjoyed this bike since 2018 and rode it for commuting in the summer… and store it at 60% in winter….
Shame ,with low mileage my bike is about to become useless and dangerous …
Can shut off at 47% suddenly on the road…
I heard that zero company was working on a battery exchange program for early buyers but no news for the moment…

Any help or guidance or second hand link would be appreciated

[Specter]

Shut off at 47 percent suddenly?
WTF is that all about?  Should not shut off suddenly at all unless there is a major issue, that is just dangerous.

Aaron

[MVetter]

Such behavior is not unheard of. Sounds like one or more cells is is weak and way, way out of balance which manifests when the majority of the pack is around the 50% point. I wouldn't be surprised at all if, watching Zero's app while riding, the mV cell balance reading is 300+ mV out of balance. So if the majority of the cells are 3.65vdc and one in really bad shape is now 3.3vdc or lower, the BMS has no choice but to disengage the entire pack. Really no way around it.

And because Zero's packs are thermally potted you can't replace the bad cell(s).

[TheRan]

Yeah, while the battery stats might look okay just sitting there at 47% put it under some load and you expose the weak link, and because it is literally a series chain if that one cell can't keep up then it's taking the rest out with it.

Is it possible to convert from the modular packs to a fixed 7.2 pack? Those should be much easier to find on the second hand market because not only was it probably the more popular option for the FX/S there will also be S/DS models as donors. I'm assuming that the connector is the same and the modular bikes will run with just one pack connected and the jumper in place. It would seem that the main frame is also identical on modular and fixed models, maybe at the least you'd need to source some bracketry to hold the pack in place (AF1 maybe?).

[Charlyseabass]

Here is the quick analysis from someone working for zero..each pack used one after the other alone with the jumping plug:

 both batteries seem to have about the same performance:

14sg1067 sagged to 3.1V on one cell and had around 11kW power lmit
 02513     04/03/2023 11:33:43   Riding                     PackTemp: h 22C, l 22C, PackSOC: 99%, Vpack: 91.907V, MotAmps: 146, BattAmps: 114, Mods: 01, MotTemp:  33C, CtrlTemp:  17C, AmbTemp:  17C, MotRPM:2594, Odo:18691km
 02514     04/03/2023 11:33:43   Batt Dischg Cur Limited    128 A (58%), MinCell: 3111mV, MaxPackTemp: 22C

14sg1061 sagged to 3.3V on one cell and had an 11kW power limit:

 02543     04/03/2023 09:34:57   Riding                     PackTemp: h 21C, l 20C, PackSOC: 98%, Vpack: 95.774V, MotAmps: 211, BattAmps:  92, Mods: 01, MotTemp:  37C, CtrlTemp:  18C, AmbTemp:  14C, MotRPM:1387, Odo:18692km
 02544     04/03/2023 09:34:57   Batt Dischg Cur Limited    111 A (50%), MinCell: 3368mV, MaxPackTemp: 21C


I can't easily tell which BMS log goes with witch battery name listed above, but here is one log, showing that at around 80A out of the battery its output voltage drops to around 90V:
 03400     04/03/2023 10:26:30   Discharge level            002 AH, SOC: 90%, I: 81A, L:3066, l:3557, H:3300, B:234, PT:018C, BT:023C, PV: 90291, M:Bike On
 03401     04/03/2023 10:26:30   Discharge cutback          58%

I don't think that 58% cutback means it was from the 14sg1067 because the MBB and BMS logs don't log the cut-back rate at the same time.
the Balance of that battery under load isn't great it is 234mV imbalance (note the B:234) entry, but when batteries are sagging that much a big imbalance isn't un-expected.

this is from the other battery:
 04430     04/03/2023 09:34:48   Discharge level            000 AH, SOC: 98%, I: 84A, L:3278, l:3718, H:3413, B:135, PT:021C, BT:024C, PV: 94135, M:Bike On
 04431     04/03/2023 09:34:48   Discharge cutback          34%

it is showing similar internal resistance, with around 84A discharge its pack voltage drops to 94V, it has decent balance with 135mV imbalance

So my quick analysis is that your batteries are just worn out, and sag a lot under load, and take action to protect against over discharge

[Charlyseabass]

Here are the informations I got from an enginer about solutions

getting a 7.2kWh battery into your frame would be a bit of a challenge, there is a different power and signal harness and some additional bracket changes.  You can probably modify your harnesses, but it would be a fair amount of work.

With the latest MBB firmware, the 2014 motorcycle is compatible with all 2014 and newer battery modules, so maybe you could keep an eye out and find batteries from crashed motorcycles, and they will just pop in and work.

It is possible to build your own replacement batteries.  If you can manage to use the BMS's then you can still use the MBB and all the other Zero Systems will work, but if you can't use the BMS's then you'll have to remove the MBB's ability to disable the motor controller.  The charger can be put into "always charge" by connecting two wires in the harness, so it will charge whenever it is plugged into AC power.  The dash won't display anything useful about the batteries, but the speedometer and odometer might still work. To remove the MBB's ability to disable the controller you will need the Sevcon programmig tool, which is an IXXAT USB CAN device, and DVT, or the Zero Dealer GUI tool.

Rebuilding the batteries using the aluminum casing that you already have is impossible. The cell's are encapsulated in urethane as one solid brick, you can't disassemble the box without cutting and bending things beyond repair..  you can build your own box out of fiberglass or something, and re-use the electronics that are on the outside of your current batteries, it would be a bit of a challenge to get the BMS wired up with temperature sensors just like we use in the cell box so that the BMS has all the required inputs, but it is possible, I haven't heard of anyone trying to do this before wiith 2013 or newer batteries. Most of the people trying to rebuild old bikes with home-made batteries have 2010 or older bikes where were much simpler.  Now that zero 2013 bikes are more than 10 years old, I suspect there will be more people looking at trying to rebuild bikes using home-made components, maybe there will be more information available online from people doing it.


I am not sure what the value of a motorcycle with weak batteries is. I imagine it is worth at least $1000 to someone, the motor and controller alone might be worth that to the right person

[Specter]

Remember, when lith discharges, towards the end, it falls off a cliff.  so it may go from 3.0 volts to 0.4 volts in almost no time as the individual battery cell is totally driven into the toilet by the other ones.  It's basically a useless resistor at this point, and will immediately dump your arm voltage by that 3 volts, even if the others by their own discharge would have otherwise dropped by 0.003 volts.

Are the batteries completely potted?  can you get to ANY of the connections on them.  While it's a bit of a chore, if you could find the bad battery, you might be able to just charge that ONE battery to bring it's voltage up to the rest of the pack's individual cell's mean voltage, then try a topping charge to get the whole pack to fully charge and balance.  This is all assuming of course, the battery is not just totally destroyed at this point by the excessive dump discharging like that.

For those contemplating rebuilding an entire pack.  Please remember that the reason they are in sturdy aluminum cases etc, is to PROTECT them.  If you get into a wreck, or even a minor fender bender.  Something smacks into your pine box and dents a few of those cells, it's game over, you are a blow torch.  Keep this in mind, as well as waterproofing etc that may no longer be there.    Hot / Cold a few times and get a little condensation ont he bottom of that battery box and you might be in for some problems.  Just be careful if you are going to take on a task like this.

Aaron

[MVetter]

They are fully potted in epoxy as an anti-corrosion measure. You aren't getting in there and finding the bad cell. And again, the cell is brought up and balanced with the rest of the pack during a charge cycle, but it is so weak that it drops way before all the others even with the balance cycle.

And yeah this is more or less exactly what I suspected. The logs speak for themselves:

L:3066, l:3557, H:3300

Low cell voltage value 3.066vdc, high cell value of 3.300vdc. That's an imbalance of 234mV.

[Charlyseabass]

Fantastic EV world….
After 20000km you can put your vehicle to the garbage unless you spend the value of the used bike in new battery….
For me : bought the bike 7000€ rode it for 13000km
Have to spend 7000€ more for 2x3.6 kWh new power packs….
Real cost 50 cents/km
Which compared to gas is 25litres/100km which is a v8 consumption !!!!!
And not even sure to sell the bike 7000€ with new batteries….

I didn’t have luck some bike for sale here in Europe have 50-70000km without too much issues…
I hope that zero will finally roll a program for people like me …
And keep those bikes alive…

[MVetter]

Sorry man. That sucks. I've known owners with over 100,000 miles on their original packs. I've also seen what you're going through. Generally, unless someone abuses the pack, I would say in my experience the battery packs are fairly well-built and reliable. The vast majority of owners with functioning bikes don't come to forums like these and say, "hey just checking in everything is still awesome". And yeah there was a 5 year warranty on the pack, but that was 9 years ago. If this was me I'd just start casually looking out for used or crashed bikes that might have salvageable packs. Good luck.

[Jepe]

I’m afraid that the main problem with the powerpacks in general is this: filling a petroltank can be done by everybody, but it takes some basic knowledge (and some more) to handle a lipo battery in the right way. And if you buy a second hand electric motorcycle the damage can be done by the first owner. It sure helps if an owner did or does some radiocontrolled airplane or helicopter flying as a hobby, you can learn a lot just by looking what an rc-charger does, and with which values it works  .

[Charlyseabass]

Thanks for your support MVetter I’m searching second hand batteries since 1 year already, nothing available in Europe…
I find only salvage auctions in USA….

You’re absolutely right jepe !
It’s chemistry not mechanical….
I bought 2 molicel 21700  p45b batteries for e-cigarette use,6 months ago
Needed 1 per day after 6 month need 2….
This is so representative of the world we leave in….

Everything goes fast… but don’t last…

Everyone goes crazy on the stark varg , surron storm bee…
Spare battery of the stark is 7000$ and 4500$ for surron….
In few years we will see many people realize too late they absolutely didn’t save money in gaz…

Companies should be obliged to have a battery management long term program to keep their customers happy…..
Discount on new packs and obligations to recycle old one….

I didn’t post this topic to criticize zero motorcycle because I love my bike and cruising in silence and don’t scare ,children’, families ,birds ,horses….
But I really hope EV future is not going to be millions of lithium packs low mileage in the dump after 10 years….

[TheRan]

There's currently two batteries on Ebay for around £1k, a 14.4 on its own and a 7.2 with the charger and storage bin (off an S/DS). Both from low mileage bikes too. However they've been on there for quite a while and I highly doubt the sellers have been maintaining them, rather just letting them sit stuffed away in a corner, thus they're most likely junk by now and the sellers make no mention of voltages or how long they've been sitting or even that they might not be any good. Had someone snapped them up when they were first put on they may have got a bargain, but these batteries aren't the sort of thing you can leave sitting around for years until they're needed.

[gt13013]

If you want to analyze in detail your batteries, ZeroSpy (Android application) can be helpful. It records the parameters of your bike every second. And you can further make graphs in order to analyze the records.
Here is an example with my FXS 2016 (with two 3.3 kWh amovible packs).
https://www.dropbox.com/scl/fi/2qwb24m5nykw2qvnrjkwx/ZeroSpy_modele_analyse.des.donnees.xlsx?rlkey=8or6htwb51w8mqc51jzuq7glo&dl=0
I make a correlation between the balance and the battery current.
You can compare your data to mine.

[Doctorbass]

When pack are deffective ( at the cell module level) it can be:

1 - All cell internal resistance are  high = no more usable due to voltage sag too low under load
2 - Magic charge = one or more cell have connection problem in serie ( bad crimp between cells tab) = making voltage sag under load to one or more cells
3 - One or more cell having high internal resistance  = voltage sag anyway which also make the BMS to shut down the power prematurely

for 1, your pack is pretty DEAD
for 2: It is possible to  open the pack and re-crimp or spotweld  the bad cell connection with couple hours labor and patience and care.. but you will have to dig the potting manually without puncturing the cell below. I did it when i reconfigured a ZF2.5 brick into a 51V module for my nefew 's electric ATV. The battery was a situation 1 where all cells were too high internal resistance, but spliting the connection into two seperate groups of 14s in parallel made enough power to get about 2.2kWh out of it and make his mini electric ATV to go 90km

For 3, It is possible to solve the single cell internal resistance problem by paralleling another high C current  low capacity cells to it to rematch to the other cells the internal resistance  and have all internal resistance the same again.  I am making it for a Long brick ZF7.2 that I use as range extender on my 2017 SR. The problem is that the cell group no 17 always charge higher voltage than the rest and always sag lower voltage than the rest under load. My plan is to measure the actual internal resistance of the deffective cell group no 17 and to measure the internal resistance of all other cells and to match the calcualted internal resistance to put in parallel to the problematic  cell. I think that this job really worth if it can save a 7.2kwh battery that already fit in a ZERO if it can cost let say 100$ in material and 4-5 hours of work.. maybe more

So what it involve:
- Measure all the cells internal resistance ( 28 total) by applying a load to the pack direct terminal ( before the contactor), using a 500w or 300W light bulb and measure all the cells voltages with and without the load.
- Find the deffective one that have higher internal resistance than the rest
- Calculate the resistance of the cell to parallel to it to make it having the same internal resistance than the rest ( https://www.allaboutcircuits.com/tools/parallel-resistance-calculator/)
- Open the long brick aluminum sheet that is hardly stick to the putting material inside
- Find the location of the deffective cell  tabs under the semi transparent potting
- Dig with cutter, exacto and grip carefully until you reach the metal tabs
- Unfold the crimped tab
- Solder connections to it and take care to not transfer too much heat to the tabs... or drill a horizontal hole thru the crimped tab and install wires with terminal and screw
- extend these wires outside the pack,
- Connect a permanent high current ( high C rate) NMC chemistry cells
- Redo the load test with the bulb and make sure the voltage sag of all celsl are now the same. If not adjust the cell capacity or C-rate until getting uniform Internal Resistacne on all the channels 

IMPORTANT: YOU MUST HAVE A MINIMUM OF BATTERY DIY SKILL TO MAKE THAT.

I made a video to explain the concept in french but you can use the auto translate as well.
( Dont forget to subscribe to my channel if you like it! there are videos in english and video in Français)

https://youtu.be/5WSYysw-4cM?si=eqSow1lNeui6EjcR

Doc