Charging habits and frequency?

[Chucka Wheelie]

Hey fellow V11 owners (or any EUC nutters for that fact),

  Just out of curiosity in your experience that you've put into practice,  what are all your thoughts in terms of charging frequency, maintaining battery health and battery usage.  How low do you guys ride your battery to till you plug it in for charging?  Do you fully discharge your battery from time to time?  I'm curious about your real world experiences!  I know the best policy is to just ride, use and enjoy the wheel and not obsess about battery statistics but I feel a little healthy dash of regard for battery health and maintenance helps with enjoying our passion longer.     

I've put this in the inMotion section as I'm particularly interested in experiences of other V11 owners but definitely open to hearing from other EUC model owners... well, except for Sherman owners, you guys can just keep riding along with your infinite batteries!   (Jokes)  

Thoughts?  Opinions?  Look forward to hearing from everyone! 

  

[Rawnei]

De ja vu, there was a thread like this in general the other day. 😉

Ride, charge it to 100%, don't overthink things. You don't really need to manage your battery, just make sure it charges to 100% for balancing to occur.

If you are going to long term store it like weeks or months of no use then you can leave it below 100% but in normal use cases just ride and charge.

[mrelwood]

Exactly as @Rawnei said above. The absolute best charging behavior for increasing battery life, is to charge to full + 2 hours plugged in just before a ride, and store at 40-80% for the winter (or other longer-than-a-week breaks).

 The absolute worst would be to always charge to only 80% immediately after a ride, and store it at empty or full.

 Tips for prolonging the lifetime of a li-ion cell are irrelevant if they don’t consider the specific “top-balancing” method that all EUCs utilize.

[Chucka Wheelie]

18 minutes ago, Rawnei said:

De ja vu, there was a thread like this in general the other day. 😉

Ah bugger... apologies if I’ve rehashed a subject that has been done over and over already.  Should’ve used the search feature more vigorously! 
 

For me I’ve always charged my wheel to 100%.  I don’t plug it in after every ride however.  I’ll just use it over a few rides till around 50% then I’d charge it to 100%.   Was curious about what other riders have gotten into the habit of doing is all.  

[Chucka Wheelie]

2 hours ago, mrelwood said:

Exactly as @Rawnei said above. The absolute best charging behavior for increasing battery life, is to charge to full + 2 hours plugged in just before a ride, and store at 40-80% for the winter (or other longer-than-a-week breaks).

 The absolute worst would be to always charge to only 80% immediately after a ride, and store it at empty or full.

 Tips for prolonging the lifetime of a li-ion cell are irrelevant if they don’t consider the specific “top-balancing” method that all EUCs utilize.

Yeah pretty much do similar things to you guys.  I try to time it so when I plug it in to charge to 100%, I leave it with enough time to balance, enough time for the cool down, then go on my commute without leaving it the battery state @100% for too long.   I'm not too regimental about it all 'cause it's easy to get OCD about battery do's and don'ts and before you know it, you're more stressed than actually enjoying the wheel! 

[Zopper]

On 2/10/2021 at 3:01 AM, Kamikaze_K said:

Do you fully discharge your battery from time to time?

NO! Avoid going under 10 % if you can, for two main reasons:

1) The max output of bateries goes down with charge level, so under 30%, you should be way more careful about how you ride and under 10% even more so. (Exact percents vary between EUCs.)

2) Li-ion cells get damaged by undervoltage. Unlike NiMH cells (like those in AA size) which do need to get really empty or they will lose capacity. But if you did that to Li-ion, you are permanently  damaging it.

Two cycles just down to 50% are probably a bit better for the battery than one to 0% (despite the same total power), plus you will have more fun as you don’t have to ride the last leg at snail pace. But it’s not like it would kill the machine. The wheels won’t let you discharge the battery to a dangerous level (they stop riding), so if you need to get somewhere, do it and just don’t let it sit there empty, but recharge it at least a bit.  

 

And I 100% agree with what others wrote. Don’t obsess. It’s supposed to be fun and as long as you are charging it fully, with balancing, the battery should be good for many thousands of kilometers.

[Chucka Wheelie]

3 hours ago, Zopper said:

NO! Avoid going under 10 % if you can, for two main reasons:

Two cycles just down to 50% are probably a bit better for the battery than one to 0% (despite the same total power), plus you will have more fun as you don’t have to ride the last leg at snail pace.

And I 100% agree with what others wrote. Don’t obsess. It’s supposed to be fun and as long as you are charging it fully, with balancing, the battery should be good for many thousands of kilometers.

Great!  Thanks for that.  Luckily I've never gone down anymore than 45% before I plugged it back in for charging but always wondered if there was a need to ride the wheel till shut down once in a blue moon.  I didn't think there were since Li-ion batteries would risk damage if discharged too much.  

100% with all of you on not getting obsessed with it.  I know I got a little OCD in the past with my eScooter (when I first got into PEVs) and realized how much it over took my enjoyment.  Just a dash of awareness is all that's required.  

Thanks for your input fellow riders!  Always happy to hear more of everyone's thoughts on this! 

[FinRider]

4 hours ago, Zopper said:

NO! Avoid going under 10 % if you can, for two main reasons:

1) The max output of bateries goes down with charge level, so under 30%, you should be way more careful about how you ride and under 10% even more so. (Exact percents vary between EUCs.)

2) Li-ion cells get damaged by undervoltage. Unlike NiMH cells (like those in AA size) which do need to get really empty or they will lose capacity. But if you did that to Li-ion, you are permanently  damaging it.

Two cycles just down to 50% are probably a bit better for the battery than one to 0% (despite the same total power), plus you will have more fun as you don’t have to ride the last leg at snail pace. But it’s not like it would kill the machine. The wheels won’t let you discharge the battery to a dangerous level (they stop riding), so if you need to get somewhere, do it and just don’t let it sit there empty, but recharge it at least a bit.  

 

And I 100% agree with what others wrote. Don’t obsess. It’s supposed to be fun and as long as you are charging it fully, with balancing, the battery should be good for many thousands of kilometers.

 

Taking the battery down to 0% is nothing to be afraid of. When the EUC (app) shows 0% it does not mean that the battery is empty, it is just as empty as you are allowed to bring it.

I have plugin hybrid (Mitsubishi Outlander) that has a 12 kWH battery. When the car has an empty battery indicates as 0% charge left by the car it actually still has about 3.5 kWH left of juice. I know this because charging the car from empty to full uses uses 8.55 KWH per my charger.

I have not measured my EUC's to see what the total charge capacity is but I will do so in the spring when I start riding again. It will require me to pull the wheel to 0% and then charge to 100% --> this will indicate how much of a charge there is left. I guess this could be done by looking at the voltage that is left and dividing it by the amount of cells your packs have... but it is easier to just plug a watt meter to the charger and see what the real world numbers are...

 

[mrelwood]

3 hours ago, FinRider said:

plug a watt meter to the charger and see what the real world numbers are...

At least you’ll get thereabouts. I don’t know how good the chargers’ efficacy values generally are, but I do know that the usable Wh of an EUC battery would surely come as a surprise to most riders...

[Zopper]

3 hours ago, FinRider said:

Taking the battery down to 0% is nothing to be afraid of. When the EUC (app) shows 0% it does not mean that the battery is empty, it is just as empty as you are allowed to bring it.

TLDR, yes if it is just about the battery life and if you charge it afterwards (phantom drain on an EUC that was stored over winter with just a few percents could mess it quite a lot). Warning, some charts and numbers ahead.

V11 has the first tiltback at 3.35V/cell (which is a pretty common value in EUCs AFAIK), and with go home mode, it becomes unrideable at 3.1V/cell (source is here). Which is shortening the lifespan if done regularly. E.g. here is this chart. 100% = 4.2V, 0% = 3.0V, so the 25% in the chart bellow is about equal to 3.3V.

We have to charge to 100% for balancing, but discharge is in our hands. If you regularly go down to 3.3V/cell (0% reported by an EUC, 66V with 20p/84V packs) versus 3.6V/cell (72V, ~30% for EUC), the max capacity drops to 80% a bit earlier, although not by much (a few percents of total mileage), so it's not that big issue. They didn't discharge deeper, so I have to guess - the 3.1V line might cross 80% capacity retention at about 2.5-3k cycles.

 

Now, how many cycles one can get? Using @mrelwood V11 data for heavier riders (60km until the end of go home mode at 25km/h avg) and my guess for the number of cycles (2.5k), that gives us 150k km. For a car, this is not that much, but for an EUC, thats... 10 times what a really enthusiastic rider will use it, before it gets obsolete or it breaks?

Now, those numbers doesn't count in the loss from storage and ageing, but even so, it shows that it really is not necessary to stress out.

Edited February 11, 2021 by Zopper

[mrelwood]

@Zopper, good data! Furthermore, any chart that refers to the state of charge only as percent without mentioning the 0% level is redundant. For all we know, the 0% in the above chart could mean 2.5V which is a common manufacturer specified hard limit not to exceed. That would already make the deepest diving 18XL’s 0% (3.0V) into actually being 29%.

Not that I’d recommend to do so, back in the day I commonly rode my Lhotz into under 0%. No idea what the 0% voltage even was. The pack served for the lifetime of the wheel, and now serves in another PEV.

Edited February 11, 2021 by mrelwood

[Zopper]

9 hours ago, mrelwood said:

@Zopper, good data! Furthermore, any chart that refers to the state of charge only as percent without mentioning the 0% level is redundant. For all we know, the 0% in the above chart could mean 2.5V which is a common manufacturer specified hard limit not to exceed. That would already make the deepest diving 18XL’s 0% (3.0V) into actually being 29%.

Not that I’d recommend to do so, back in the day I commonly rode my Lhotz into under 0%. No idea what the 0% voltage even was. The pack served for the lifetime of the wheel, and now serves in another PEV.

They mention it in the article (they are using the percents across multiple charts), but it it’s well hidden.