ElectricMotorcycleForum.com
Makes And Models => Zero Motorcycles Forum | 2013+ => Topic started by: enaef on October 07, 2020, 02:04:38 AM
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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?
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The battery ought to slow down based upon things like capacity, temperature not charge target.
It shouldn't care if you interrupt it.
-Crissa
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Yeah, you appear to be describing a problem that doesn't exist.
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If it is ramping at a different place via changing charge target, that's probably a bug.
-Crissa
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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).
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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
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Could it be that at the end of the charging , the BMS balances just like it would at 100% in a full charge cycle.
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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?
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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
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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
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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.
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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
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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
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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.
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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
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I started with 81% SoC, s
Me as well as a guy I know with a Zero SR/S have discovered that if you START a charge at 80% it will charge at a MUCH lower rate than when it gets to 80% when started at 70% or below.
So now I never start a charge at 80% or above. I will usually only get a 2 KW charge with 6.3 KW of chargers. I get the exact same rate if I remove 2.5KW worth of charging. Makes no change at all when I start the charge at 80% or above.
But I will get close to around 6KW at 80% SOC if I start the charge at less than 70%.
Why? I have no idea. But I have seen it happen several times. It can be very confusing at first, until realizing it only happens when starting the charge at above 80% SOC or so (I cannot give an exact SOC, but AFAIK, it will NOT happen if you start the charge at least 10 SOC below the 80%).
-Don- Reno, NV
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Attached a new recording of charging behaviour this evening.
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Well, that's pretty definitive. It doesn't pop back to the original curve quickly, it starts a new arc down to the charge target.
That's totally not how it should work.
-Crissa
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For me the question remains, if this behaviour is intended and if so, for what reason.
Also, the estimated remaining charging time seems not to include the curve in its calculation.
The estimated remaining charging time seems to be calculated only by the kW which work right at the moment and uses this linearly until the target - instead of including the coming curve.
If you look at time stamp 18:10:05 the estimation is 2 minutes. Actually it took 12 minute until the shut down. And this was with 7.1 kW going in.
At a 22 kW station with ~11.5 kW going in, the difference will be even bigger.
Of course, with a SR/F or /S standard with only one 3 kW charging module the difference will be smaller and less obvious.
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I don't understand why Zero would change the charging curve for the SF/S models, compared with what they use for the legacy S models. ??? On my 2018 S with PT, it charges at 120V without any tapering, according to my Kill-A-Watt meter. The charger/BMS goes full-bore at 12 amps until it shuts off without any reduction. When I check the cell balance using the Zero app, balancing shows 2-3 mV. Also the estimated charging time when checked shortly after first plugging the OBC in is right on the button. So no complaints here. :)
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I don't understand why Zero would change the charging curve for the SF/S models, compared with what they use for the legacy S models. ??? On my 2018 S with PT, it charges at 120V without any tapering, according to my Kill-A-Watt meter.
At a 1.3 KW charge, it's not all that much of an issue. Not much there to taper off.
-Don- Auburn, CA
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ma voi in america avete il caricatore da 9 kw ??'!!!!! che ...fortuna
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ehi don ton hai avuto anche tu una stelvio ' la mia però era del 95
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ma voi in america avete il caricatore da 9 kw ??'!!!!! che ...fortuna
(but you in america have the 9 kw charger ?? '!!!!! so lucky)
On some Zeros, 12 KW charging is available.
12 KW AC is sometimes available from Tesla Destination charge stations using a 50 amp Tesla-Tap.
-Don- Auburn, CA USA
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ehi don ton hai avuto anche tu una stelvio ' la mia però era del 95
(hey Don you too had a stelvio 'but mine was 95).
I still have my 2016 Stelvio. I ride it fairly often, but not nearly as much as my Zeros.
-Don- Auburn, CA USA
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So - out of interest I asked my dealer if he would enquire Zero about the reason of this chargin behaviour. I assumed I would get an answer quicker than if I contacted Zero myself.
According to Zero cell balancing is indeed (also) done at the end for all charging targets under 100%
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That's not a good behavior :P Cell balancing at a target needs to be optional. Especially when you're on the road!
I can see why you might want it say, if you were charging to 80% every night.
-Crissa
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Therefore I'm going to deactivate the charge target when I'm on the road. Balancing then will start to kick in earliest at ~85% SoC I guess. Up to 90% I will still have quite a decent rate. At that point I will have to decide how much I'm in a hurry (or bored) and how much SoC I'm really going to need until the next charging opportunity.
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Perhaps I'm mistaken but I always thought balancing happens after the battery has finished charging (whether it's to 100% or 80%), and that it has nothing to do with the charge rate tapering off at the end. On the older models with no charge target they will get to 100%, tapering off as they approach that, and then once they're at 100% the charge light will stay lit for like 10-15 minutes as it's balancing and the bike will be drawing much less from the mains, like in the hundreds of watts instead of thousands (maybe in the tens, it's been a while since I monitored it).
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Perhaps I'm mistaken but I always thought balancing happens after the battery has finished charging (whether it's to 100% or 80%), and that it has nothing to do with the charge rate tapering off at the end. On the older models with no charge target they will get to 100%, tapering off as they approach that, and then once they're at 100% the charge light will stay lit for like 10-15 minutes as it's balancing and the bike will be drawing much less from the mains, like in the hundreds of watts instead of thousands (maybe in the tens, it's been a while since I monitored it).
Using a Kill-A-Watt meter, I have seen different patterns in charging between my old 2014 S and my 2018 S. The 2014 model would seem to slow its charging occasionally like it was taking time out to balance the battery cells and before it would shut off charging would slow to about 250 watts for several minutes. However, my 2018 S just charges at 12 amps until it shuts off, without tapering the charge, which happens about 15 minutes after SOC shows 100%. I don't know what is going on, other to say that both bikes seem to do a good job keeping the battery cells balanced, with 2-4 mV showing on the Zero app after the charger turns off. It would seem to me that Zero's thoughts regarding how to recharge their battery packs is constantly evolving. ???
My daughter owns my old 2014 S (with PT) and yesterday she rode it to my home along the same route that I take to visit her on my Zero. She used 32% SOC to travel the 37 miles to my home. When I take the same trip riding my newer Zero with a slightly larger battery pack, it usually takes 30% SOC. So I would have to say that her batteries haven't degraded very much during the past 6.5 years that the bike has been in use. I might add that on the 2014 model, the charger remained plugged in all of the time for about three years. before Zero's revised recommendations were published.