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[JaimeC]

I've only owned Gen2 bikes and long term storage was pretty straight forward: Don't let the battery discharge below 30% and place it in storage at 65% or lower.  However, this doesn't seem to be the case for the Gen3 bikes as a friend of mine kept her SR/F main battery well above 30% only to discover when she wanted to take it out for a ride that the 12V battery went completely dead.

Most of the issues I've seen regarding the Gen3 bikes have been centered around this 12V battery. Since I can no longer get a new Gen2 bike I need to know how to PROPERLY store a Gen3 bike so that I don't get the same kind of unpleasant (and EXPENSIVE) surprise...

Thanks,

[Ingineer]

I'd say charge to 60% and then disconnect the 12v.   Might be worth adding a 12v battery switch if you will be doing it regularly.

When you come out of the storage, maybe plan a ride, and charge to 100% so it ends about an hour before you depart.  This will allow some time for the pack to re-balance if it was out of balance.  I don't recommend a balance charge more than a few times a year, or unless you regularly need the full capacity.   I keep all my ternary packs at or below 80%, most around 70%, for daily use.

(I am an Electrical Engineer with extensive experience with Electric Vehicles and am CTO of an EV company)

[DonTom]

I'd say charge to 60% and then disconnect the 12v.   Might be worth adding a 12v battery switch if you will be doing it regularly.

When you come out of the storage, maybe plan a ride, and charge to 100% so it ends about an hour before you depart.  This will allow some time for the pack to re-balance if it was out of balance.  I don't recommend a balance charge more than a few times a year, or unless you regularly need the full capacity.   I keep all my ternary packs at or below 80%, most around 70%, for daily use.

(I am an Electrical Engineer with extensive experience with Electric Vehicles and am CTO of an EV company)

When the bike is keyed off, what is the 12V battery running?


-Don-  Reno, NV

[KuRi]

I have just returned mine (dsrx 2024) to normal operation after 6 weeks of storage mode on.

I stored it at 67% and after the 6 weeks period I just turned it on, disengaged the storage mode and it was at 60% SoC.

Happy riding again, zero (pun intended) problems: D

[Ingineer]

Probably the clock in the cluster or something similar.  But it's clearly drawing something.   You should be able to go 6 months on a good (not suphated) 12v lead-acid if there's absolutely no external load.   I do it every year.   If it will be below freezing then it's probably worth removing the 12v and storing it inside where it's not exposed to temp deltas.

[JaimeC]

Probably the clock in the cluster or something similar.  But it's clearly drawing something.   You should be able to go 6 months on a good (not suphated) 12v lead-acid if there's absolutely no external load.   I do it every year.   If it will be below freezing then it's probably worth removing the 12v and storing it inside where it's not exposed to temp deltas.

Except the 12v battery is also lithium based on the replacement price. I believe this was also discussed multiple times here in the forum why Zero went with lithium instead of lead/acid or AGM.

[Ingineer]

Then you'll be fine with a disconnect.  Either ternary or LFP shouldn't lose enough charge in 6 months (I'm not sure the chemistry).   It might be worth it to discharge the 12v somewhat, such as leave your lights on for 20 mins before disconnecting.  (No HV)

[Jepe]

(I am an Electrical Engineer with extensive experience with Electric Vehicles and am CTO of an EV company)

In that case, a small question: I learned at this forum that the 3rd gen Zero bike balances the cells every time you charge till a set percentage, after reaching this percentage, and before ending the charge. Would you say this is true?

[Ingineer]

Most BMS can't effectively balance until they detect an imbalance.   The ?V curve (voltage over SoC), is mostly flat in the middle, so the BMS won't detect a voltage imbalance, therefore it won't balance.   Generally you need at least around 80% SoC for most ternary BMS systems to perform a balance (called top balancing).  Some won't attempt balance until charged to 100%.

Balance isn't a big problem, it just means you temporarily lose capacity.  (at least as long as there are no serious problems in the pack)  It can usually be corrected and the lost capacity regained after a balance.  It's only important if you are regularly using most of your battery capacity, so don't worry about it unless you do.

If you do need the full capacity, charge to full and allow at least an hour for it to complete, then ride as soon as possible.  What you don't want is for a pack to sit around for long periods at 100%, especially when it's hot.   This is what most laptops and phones do, so their batteries start to show marked degradation after only a few years.   Ternary cells want to stay away from fully charged, and fully discharged, they will have much longer lives if they do, so if you can, only charge to high SoC when you know you'll need the range, and maybe a few times a year before a long ride allow the balance to complete at full.

[flynnstig82r]

This is a bit of a tangent, but can someone help me understand why you would ever want to design a bike with a 12v aux battery and not just step down the pack voltage? I used to work at Scoot, which was an electric moped sharing company in San Francisco, and we had so many damn problems with the 12v going flat, usually because the DC-DC failed. I got the impression that the small DC-DC’s you would use to charge an aux battery off the main pack battery are way more failure-prone than a bigger DC-DC you would need to step down the pack voltage to run all the 12v accessories. There are also more failure points overall, with 2 batteries with different characteristics you have to care for, and you still need to step down the voltage for charging the 12v so you haven’t eliminated any problems, only potentially caused more.

Despite this, it seems like almost every electric two-wheeler uses an aux battery instead of just a bigger DC-DC. Is it because they’re afraid of parasitic drain that might eventually brick the pack battery? It seems like there would be easier and better ways to prevent that.

[DonTom]

Despite this, it seems like almost every electric two-wheeler uses an aux battery instead of just a bigger DC-DC. Is it because they’re afraid of parasitic drain that might eventually brick the pack battery? It seems like there would be easier and better ways to prevent that.

Perhaps the main reason is because certain functions still need to work when the key is out and they do not want the drain on the HV battery.


I noticed my Zero DSR/X has a setting for "automatic updates". Does the bike get updates when the key is out? I don't know, but there are other issues also, like keeping the clock running.


BTW, the older Zeros also have two batteries, a small one that is NOT (Zero claims) replaceable to run the clock. When mine crapped out, I didn't buy it was not replaceable. So I did this on my 2017 Zero DS.


-Don-  Reno, NV

[flynnstig82r]

Perhaps the main reason is because certain functions still need to work when the key is out and they do not want the drain on the HV battery.

I noticed my Zero DSR/X has a setting for "automatic updates". Does the bike get updates when the key is out? I don't know, but there are other issues also, like keeping the clock running.

That’s the part I still don’t understand. Is it really easier to have a second battery with all the extra weight and failure points? It seems like it would be better to just design a step-down converter with low enough drain that it takes a long time to make a dent in the big battery’s capacity. Then design a failsafe to cut all aux power at ~20% SoC. Something like the Eastern Beaver connectors and relays for 12v gas bikes.

[Ingineer]

The main reason is safety.  If the DC-DC fails while riding, they don't want the contactors to just drop and create a problem, Also your ABS would fail, etc.

The second reason is to keep aux functions alive such as standby power for clocks, alarms, keyless start, etc.

some bikes like the Energicas have 2 DC-DC's instead of a 12v, a small one for standby, and a large one for powering all the normal 12v stuff, including the motor controller.  The problem with this is, if you leave your bike sitting a long time, it will run your expensive pack into the ground rather than just killing a cheap small 12v that can be fixed with a jump.

In addition, the 12v bus can be noisy, so the battery helps stabilize this.

[JaimeC]

This is a bit of a tangent, but can someone help me understand why you would ever want to design a bike with a 12v aux battery and not just step down the pack voltage? I used to work at Scoot, which was an electric moped sharing company in San Francisco, and we had so many damn problems with the 12v going flat, usually because the DC-DC failed. I got the impression that the small DC-DC’s you would use to charge an aux battery off the main pack battery are way more failure-prone than a bigger DC-DC you would need to step down the pack voltage to run all the 12v accessories. There are also more failure points overall, with 2 batteries with different characteristics you have to care for, and you still need to step down the voltage for charging the 12v so you haven’t eliminated any problems, only potentially caused more.

Despite this, it seems like almost every electric two-wheeler uses an aux battery instead of just a bigger DC-DC. Is it because they’re afraid of parasitic drain that might eventually brick the pack battery? It seems like there would be easier and better ways to prevent that.

That's exactly what the Gen2 bikes did. They only had the main battery pack and a step-down DC-to-DC converter to drive the 12v systems. I'd heard there were issues with this but I never experienced any and it sure sounds like adding the 12v battery didn't make it any more reliable.

[JaimeC]

The main reason is safety.  If the DC-DC fails while riding, they don't want the contactors to just drop and create a problem, Also your ABS would fail, etc.

The second reason is to keep aux functions alive such as standby power for clocks, alarms, keyless start, etc.

some bikes like the Energicas have 2 DC-DC's instead of a 12v, a small one for standby, and a large one for powering all the normal 12v stuff, including the motor controller.  The problem with this is, if you leave your bike sitting a long time, it will run your expensive pack into the ground rather than just killing a cheap small 12v that can be fixed with a jump.

In addition, the 12v bus can be noisy, so the battery helps stabilize this.

As I learned here, the clock on the Gen2 bikes were powered by a separate battery inside the dash. That's the main reason the replacement color dash didn't have a clock; no place to mount a battery.  And the 12v drain was so miniscule that it barely dented the battery capacity. The Gen2 bikes didn't have keyless start (and neither does the SR/F currently sitting in my garage). Most alarm systems have a self-contained powersource so they couldn't be overridden by cutting the main vehicle power either...