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[DonTom]

Has anybody else here experienced this issue?:

You START a charge at above 80% SOC with above 6.0 KW worth of chargers.

It will only charge at around 2.0 KW or a bit less.

But if we START the charge at 70% or below, we get the full 6KW charge, even when we get to 80% SOC.

I am not 100% sure if  it happens every time as it is not often when I try to top off a charge at 80% SOC or above. But it is very common and happens at least MOST of the time.

I do know it has happened to at least one other person (who  rides a Zero SR/S Premium with a charge tank (uses mostly Tesla Destination chargers with Tesla Tap to get that 12 KW) .

On my 2017 Zero SR, I use two external 2.5 KW Elcon chargers plus the OBC to get my six KW. At first, I thought it was just my setup until it also happened with that Zero SR/S.

At least this issue has an easy fix. Simply ride FAST as possible if you think you will need to top off so you get to the next charge station below 80%  SOC. The idea is to always start the charge below 80% SOC.

Perhaps this issue is only when warm, but I am not sure. It's always been warm and after some hard riding when I have this 2 KW charge issue at 80% SOC.

-Don-  Auburn, CA

[Crissa]

"Yer full, darnit, why are you trying to charge?"

Maybe this is like the issue that Teslas pre-warm their batteries before supercharging:  For certain levels of charging you want certain temperature ranges spread through the battery.

-Crissa

[TheRan]

When starting the charge below 80% how far past 80% does it get before it starts tapering down? If it's something like 85% perhaps it figures that it's not worth starting at 6kW if it's soon going to have to start dropping down.

[DonTom]

When starting the charge below 80% how far past 80% does it get before it starts tapering down? If it's something like 85% perhaps it figures that it's not worth starting at 6kW if it's soon going to have to start dropping down.

IMO, it should let me decide if it's worth it, who is the boss between me and the bike? .

But I never have noticed much reduction in charging power until the high 90's SOC  or so.

It sometimes makes sense to recharge  at 80%. Such as when I leave Genoa, NV  to go to Markleeville, CA  and at Markleeville the next charge station is almost 100 miles away in the direction I am going. So I want every drop possible of charge possible in Markleeville.  Of course, I now know to make sure I only charge to 80% SOC in Genora so I will be well below that in Markleeville.

Am I the only one here who has tried to recharge at above 80% SOC on a Zero?

For now, I mainly want to know if others here have noticed the same issue.

-Don-  In very smokey (AQI=110) Reno, NV

[Shadow]

Charge algorithms are not much more complex than simple Constant Current followed by Constant Voltage. Graph the voltage (and current) against temperature if you want to make a better guess about what it is doing.

Measured voltage of lithium battery chemistry increases with heat. I'd guess without any data that the CV charging phase threshold is met and current flow mellows out because of where pack voltage is against the charge algo.

[DonTom]

Charge algorithms are not much more complex than simple Constant Current followed by Constant Voltage. Graph the voltage (and current) against temperature if you want to make a better guess about what it is doing.

Measured voltage of lithium battery chemistry increases with heat. I'd guess without any data that the CV charging phase threshold is met and current flow mellows out because of where pack voltage is against the charge algo.

So what would explain the difference between 80% SOC starting at 80% and 80% SOC when starting at 70% SOC?

That is a 4KW difference, both at 80% SOC.

BTW, nice to see you're back in the forum!

-Don-  Reno, NV

[Shadow]

So what would explain the difference between 80% SOC starting at 80% and 80% SOC when starting at 70% SOC?

That is a 4KW difference, both at 80% SOC.

There's a lack of data as presented about time/temp/current/voltage. The charging algorithm could be like everything else ever made for lithium battery chemistry that it is CC-CV; above a certain voltage set point it would try a strategy to modulate charging current such that the target voltage is met at the end of the charging parameters. State of Charge is meaningless to us as it is derived from some unknown algorithm and coulomb counting component tolerances via pack BMS and MBB. "4KW difference" doesn't aid to infer anything about the charging behavior either. BMS logs have the required data.

[DonTom]

The charging algorithm could be like everything else ever made for lithium battery chemistry that it is CC-CV; above a certain voltage set point it would try a strategy to modulate charging current such that the target voltage is met at the end of the charging parameters.

I think you have something there. That makes some sense, that I am trying to start a charge where it isn't expected to be attempted, which can confuse things.

But have you (or others) had the same issue?  Have others noticed it also?

-Don-  Reno, NV

[VroomVroomItsElectric]

HI, i have a 2020 dsr, and a few electric vehicles, like scooters, unicycles skateboards, what i think is happening, is a problem with limitations in lithium ion technology, the battery, its about how a battery can be charged depending on soc. like IMHO, in my understanding, ONCE u hit 80 percent, and from using my lvl 2 charger in my house and KNOWING for fact, that power of the charging drops once i hit 85 soc, and this is the same for my fluid free ride mantis scooter, which has a display on the 5 amp charger, once a soc hits around 80 to 85 percent, percent, there is like  a CURVE down, in speed of charge,  so like 0-80 will always charge at  at 6kw, for my dsr using my  my lvl 2, but like around 85 percent its starts going down, and continues till i hit 100 percent  like i have it calculated, that i charge 1 percent in 1 minute till 85, then the last 15 percent. takes about 30 minutes.and then it does a bms balancing for 5 minutes. https://batteryuniversity.com/learn/article/charging_lithium_ion_batteries this website shows the battery charging curve once any lithium ion battery hits 80 percent.

[DonTom]

HI, i have a 2020 dsr, and a few electric vehicles, like scooters, unicycles skateboards, what i think is happening,

Welcome! I see that is your first post here.

But the issue I am talking about has NOTHING to do with hitting 80% SOC. I have NEVER noticed an issue at 80% SOC when I start the charge at 70% SOC or below.

It's ONLY when I START the charge at 80% or above. And Never happens at 80% when I start the charge at 70% and below.

-Don-  Reno, NV

[princec]

Good old software. Honestly I'd love to write the firmware for these things but they probably pay peanuts.

Cas

[DonTom]

Good old software. Honestly I'd love to write the firmware for these things but they probably pay peanuts.

Cas

I see the problem as when you once have it perfected, you're no longer needed. So then you have to convince somebody an important update is necessary.

I sometimes wonder if many software updates and design changes are just to protect somebody's job.

-Don- Reno, NV

[reini]

I see the problem as when you once have it perfected, you're no longer needed. So then you have to convince somebody an important update is necessary.

Haha! I've never had to deliberately make software bad in my entire career 

[princec]

Well, there is a school of thought that says I get paid all day long to fix my own mistakes... 

Cas