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[enaef]

Let's say, I want to charge up to 80% SoC as I'm on my way and therefore do not want to loose thime with a slowing charging towards charge target: I set the charge target to 95 (or deactivate the charge target at all). At the time the SoC reaches 80% I turn the key on and stop the charging manually. Then I have no slowing down the charging.
Now: Is this problematic for the battery?

[Crissa]

The battery ought to slow down based upon things like capacity, temperature not charge target.

It shouldn't care if you interrupt it.

-Crissa

[MVetter]

Yeah, you appear to be describing a problem that doesn't exist.

[Crissa]

If it is ramping at a different place via changing charge target, that's probably a bug.

-Crissa

[enaef]

Yeah, you appear to be describing a problem that doesn't exist.

I just can say what I observed several times.

Yesterday for example: charge target 80%. At about 70% SoC the power goes down from 11.5 to less than 10 kW. From experience I know, that the power would be reduced gradually to ~ 1.6 kW. Therefore I stop the charging, disable the charge target at the dashboard, restart the charging, and get my 11.5 kW again. When SoC reaches 80% (still with 11.5 kW pumping in) I interrupted the charging again manually.

That my SR/F reduces the charging power when SoC gets nearer to the charge target I have observed several times. It doesn't bother me at home, but it does if I'm on my way.
So - I'm asking me, why that reduction is and if I do the battery some harm if I prevent it.
So - The problem exists (if my procedure is harmfull, otherwise yes, there is no problem).

[Crissa]

I guess someone needs to do some comparisons between charge target 80% and 100% and see if their ramping curves are different.

There's no reason, on average, why they should be, other than temperature.

-Crissa

[Gains]

Could it  be that at the end of the charging , the BMS balances just like it would at 100% in a full charge cycle.

[enaef]

Could it  be that at the end of the charging , the BMS balances just like it would at 100% in a full charge cycle.

That's what I assumed so far but was not sure of.
And - if so - again - does it harm the battery when I circumvent this?

[DonTom]

And - if so - again - does it harm the battery when I circumvent this?

You should charge to 100% once in a while to help keep the battery cells balanced, but every time is not necessary.

-Don-  Reno, NV

[DonTom]

Could it  be that at the end of the charging , the BMS balances just like it would at 100% in a full charge cycle.

I doubt it. I assume it simply charges the bike until the SOC is where set at and has nothing to do with the balancing--which happens near a real full charge, not where you have it stop.

-Don-  Reno, NV

[TheRan]

First off I'm pretty sure there's no harm to be done by manually stopping the charge. Secondly if it was balancing (no reason it can't be done below 100%) it would do it after it has reached the charge target, not when it has 10% left to go, and it wouldn't need 10kW to do it. Thirdly, how much time are you really saving over that final 10%? If you're really going to be that short on time and need as much range as you can possibly get then it would make sense to just cancel the charge target and just let it charge until the last moment as you're getting on the bike to leave, stopping it specifically at 80% isn't needed.

[Crissa]

It's possible it would lose a few watts just from approaching the temperature or time limit.  Hard to say, without lots of experimenting, that it was different between the two charge targets.

-Crissa

[Auriga]

Maybe it slows down so as not to overshoot the charge  target? I guess that would depend on the SOC algorithm.  I'm not sure there's an issue here either

[enaef]

This as an example of a charge at home (preparation for a ride tomorrow)

I started with 81% SoC, set the charge target to 95%, the dashboard showed 25 Celcius (77 F) at the beginning.
I started to take pictures (no picture before the start of the charging as I decided a vew seconds after starting and had to fetch my phone first).
With SoC 86 I started to take a picture as soon as the SoC gained 1%.

When the charge was shut down automatically I disabled the charge target and let the bike charge again.
It started with 7.4 kW

As written above: This is of course no problem at home. If I'm on my way and waiting to continue my ride, possibly already tired, these lost minutes count.

If I'm at a 22 kW station or above I even loose more time.

A similar dropping of charging power towards the end I have observed at all charge targets, which were at least 70%.

So - as all of you think that it won't hurt the battery to circumvent this power drop by disabling the charge target and manually interrupt the charge under full power I will continue to do so.

By the way: It is very usual that the charge goes 1% over the set charge target.

[Crissa]

I do see it ramping down, but what matters if when you started from the same charge but a different charge target if there was a different curve.

You'd expect if you plugged it back in for it to start at some point higher and them ramp back down quickly as it realized where the charge was at.

-Crissa