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[heroto]

Calling all Battery Experts:

2018 S 7.2

I'm not going to be a slave to things that are theoretically but not practically better, but I will try to avoid stuff that degrades the battery over time.

Until the weather improves my rides are short, just a few % per ride. I don't need a full charge before every ride.
Which is better, or does it not matter:

Multiple short rides without recharging every time, or recharge after every ride?

If I let it run down, how far is OK before I should recharge?

Any long term advantage to recharge to 95% rather than 100%?

Thanks

[Keith]

I'm  not a battery expert, but I know something so I'll try. The real truth is nobody really knows these numbers with any certainty. But a few general principles are known. Don't charge to 100% all the time unless you are going to use it soon, a full charge does stress the battery some, each time. Don't store it with the charge very low because if it gets too low it may die. So I'd say don't charge it between rides, stop short of 100% charge sometimes if you don't need that much, don't let it sit below about 30%, and keep it at 50-60% for storage. All of these will prolong the life, but ignoring all of these won't hurt much except don't let it sit at very low charge. There is a need to charge to 100% occasionally to let the balancing happen, because it is done by discharging some cells while others catch up.

[domingo3]

I'll assume that you've read the stick up top and looked at the Unofficial Manual https://zeromanual.com/index.php/Unofficial_Service_Manual#Charger_Operation

Overall, I wouldn't stress about it too much.  As long as you don't need the full charge, I'd wait to recharge until you get down to between 30 and 50%.  Be aware that you're more likely to run into current limiting when the battery is at a lower state of charge (SOC), especially in colder weather.  This will reduce acceleration and top speed, which can be an unpleasant surprise if you are on the highway.

[T.S. Zarathustra]

There are million (and one) specialists on this subject.
Accelerated cell damage starts to occur:
A. At fast charging. But who has time for slow charge?
B. When the battery voltage goes over 4.4 Volts (fully charged).
C. When the battery voltage goes under 3.0 Volts (empty).
Your battery management system (BMS) should report full battery when the voltage is close to but below 4.4 Volts and empty before the battery is discharged to 3.0 Volts, thereby reducing battery damage. In other words, the fuel meter should show the battery capacity as smaller than it is to keep the battery within "safe" voltages.
Now, close to full and empty there is a slow damage occurring inside the batteries, so it is advisable to to keep storage charge close to the half charged. Since the batteries lose charge over time it is usually recommended that you charge to 60-80% and charge again when 10-30% remain.

Edit. Cells with different chemicals will have slightly different "safe" voltages.

[dennis-NL]

But the capacity will drop over time also.
The charge will keep trying to get like 116V when it's not possible?
I maybe wrong.
But wouldn't it be better to adjust it, or do modern chargers recalibrate: like 100% is now 114V instead of 116V?

[T.S. Zarathustra]

Full charge and empty will still be the same voltage as new. It is just that the distance between full and empty will become shorter.
The charger is set up for the battery pack it is connected to. It will not recalibrate, but a firmware update can change parameters.

[dennis-NL]

I now had 3 times completely run out of battery (meaning BMS did a shutdown because battery was reaching critical low?, was riding like 10km/h in the end).
Is this harmfull for the battery?
Within 1 hour it was recharching again, so at least it was a short time.

A possitive from it:   I now know my 12.5 battery has about 11.2kW actual power in it.

[dukecola]

Most elect vehicle's BMS won't charge till full and empty is not really empty. So full (100%) on the dash might really be 94% and zero might be 6%. The manufacturer does this to preserve battery life.  I don't think anyone knows what high/low parameters Zero has but I'm certain they changed them with the summer 17 recall update.  I'm guessing they learned from prior years about degradation and got tired of replacing packs. If you're riding every day, it ok both to recharge every day and also not recharge until you get to say 10%.  I say 10% only because the GOM (Guess O Meter) is not that accurate.

[dennis-NL]

yup, for me between 3-6% is shutdown.
But also have seen 0% while running 25km/h limping home pace... not accurate.
So below 10% is the level too be home or near a charging station or near any house with electricity and have a coffee with the owners... done it twice

[Scotchman]

I also have a new 2018 S 7.2, and had the same situation and questions.  I read lots of stuff and asked the same questions, and I decided on the following process.  If battery is above 80%, I do not charge.  When battery is below 80%, I charge to 100% (usually overnight).  This is the optimal balance of optimizing battery life and still being convenient for me.  However I am pretty sure that as long as the bike never went below 30% for an extended period, I would probably never notice a difference during my time with the bike treating it one way vs. another.

Keep in mind that if you let your bike get down to 50% before charging it, there will be times you start your day with the bike at, say 52%.  If you need to get the full range out of your bike on that day, you will wish you had charged it.  If your use of the bike is purely recreational it may not matter, for me it is my primary vehicle, so I keep it between 80 and 100%.  My opinion is the juice is not worth the squeeze to keep your bike relatively low, because you assume you won't need more than a couple % tomorrow.

[Richard230]

I kept my 2014 S with PT plugged in at 100% 24-7 for three years. This might have caused its full charge shut-off to fall to 98% at the end those three years, once I started pulling the charging plug after the charger stopped working. The charger eventually stopped at 92% now that my daughter owns the bike.  However, she reports to me that, although it stops charging at 92%, if she leaves it plugged in for another 6 days the battery will show a 98% charge. 

[MrDude_1]

Forget  maximizing battery happiness.... focus on  maximizing YOUR happiness

Just plug it in whenever you either know you will need it, or everytime if you want to make a habit about it and/or always have it ready.

there's a 90% chance you will not own this vehicle by the time any battery degradation becomes noticeable. Dont waste time stressing about it.

[Richard230]

Forget  maximizing battery happiness.... focus on  maximizing YOUR happiness

Just plug it in whenever you either know you will need it, or everytime if you want to make a habit about it and/or always have it ready.

there's a 90% chance you will not own this vehicle by the time any battery degradation becomes noticeable. Dont waste time stressing about it.

That is my thought, too.   

[dennis-NL]

Hmm, the next owner will like it.
But sure, your own fun is more important.
Because I am a long term owner kind of rider I want my Zero to be good too last lots of kilometers.