Two KS18Ls go out for a ride

[GothamMike]

One was fully charged, the other (me) 83%

We stopped and I topped off my battery (was at 27%) to 40%, the other was still at 70%

I ran out about 5 miles away, the other still had 50% charge.

The other KS18L is a year older.

Mine is less than a year old.

Mine has firmware 2.0, the other does not and still has the high pitch whine

Everything looks fine.  Is it the batteries? BMS? Motherboard?

Tires were both at ~35psi, i'm about 20 lbs lighter.

I took a video with my RYLO 360, you could see the battery drain quickly on DarknessBot.

[UniVehje]

Look at voltage, not percentages, if you want to compare like that. And it doesn’t go down linearly. I usually ride almost 60 kilometers on the first 50 % of battery but I cannot ride 120 km like that (18XL). In some models the app shows 100% at less than 84V. There are many variables. Your experience sounds similar to mine and I don’t think there’s anything wrong with your wheel. The last percentages always seem to go faster. Try again with full battery on both (and remember to balance charge often). 

[GothamMike]

Balance Charge?

[.....]

1 hour ago, UniVehje said:

Look at voltage, not percentages, if you want to compare like that. And it doesn’t go down linearly. I usually ride almost 60 kilometers on the first 50 % of battery but I cannot ride 120 km like that (18XL). In some models the app shows 100% at less than 84V. There are many variables. Your experience sounds similar to mine and I don’t think there’s anything wrong with your wheel. The last percentages always seem to go faster. Try again with full battery on both (and remember to balance charge often). 

Just like my CAR and TRUCK... the last half tank goes twice as fast as the first half, its not linear. Try not to overthink it. I can get 25miles or so at hi speed non-stop rides on my 18L at 130lb rider, 30psi on twisty up and down road(5mo old wheel 500miles), before ANY throttling. One can expect around 30 miles or so. Just go for a 2 hour ride from full and see how far you get. Partially charging it and trying to calculate that into your math, will be a bitch. Just balance charge it and range test it! Mine also shows 100% on the apps, BEFORE its totally full. I had 2 new 18l's, and they reported differently to the app. Neither was accurate reporting, as compared to a calibrated multimeter check.

Balance charge is when you leave it on the charger for a while AFTER it shows to be full. The charger will continue to trickle the batteries. Depending on the bms system, it helps to do this sometimes, as you don't want to stop charging when it says 'full', as there could be a cell or two that is just a tiny bit under charged. Overtime, the undercharged cells can become a problem. There is a HUGE thread on batteries and so much argue over how often to charge and how. I simply use mine and if i ride them under 70% or need to go far, I charge them fully. Every 2-3 charges, I leave the charger going for a couple/three hours AFTER it shows 84.2. The charger is putting out very few milliamps after the light goes green, so its not terrible. Speculation as to wether or not this decreases battery life over time. Again, so subjective. Feel free to look at battery threads and come to your own maintenance terms.  I use ewheels fast charger, I charge at 1amp most times. I only charge when wheel has cooled from riding, and I only ride once wheel has cooled from charging. 5amps gets used ONLY if i have to. I'm not keen on charging on the road, but we gotta do what we gotta do!

Edited July 12, 2020 by ShanesPlanet

[UniVehje]

42 minutes ago, GothamMike said:

Balance Charge?

Leave it on the charger for some hours after it has turned green (standard charger). Some cells are full faster than the others and the charger turns green when one is 84V. With time they will be more and more unbalanced and the pack fails. Leaving it charging will slowly trickle the slower cells to the same voltage. 

[GothamMike]

7 hours ago, UniVehje said:

Leave it on the charger for some hours after it has turned green (standard charger). Some cells are full faster than the others and the charger turns green when one is 84V. With time they will be more and more unbalanced and the pack fails. Leaving it charging will slowly trickle the slower cells to the same voltage. 

Thanks! 

[GothamMike]

22 hours ago, UniVehje said:

Leave it on the charger for some hours after it has turned green (standard charger). Some cells are full faster than the others and the charger turns green when one is 84V. With time they will be more and more unbalanced and the pack fails. Leaving it charging will slowly trickle the slower cells to the same voltage. 

I thought you should not over charge your cells? Wow.

[Alj]

On 7/11/2020 at 7:59 PM, GothamMike said:

One was fully charged, the other (me) 83%

We stopped and I topped off my battery (was at 27%) to 40%, the other was still at 70%

I ran out about 5 miles away, the other still had 50% charge.

The other KS18L is a year older.

Mine is less than a year old.

 

How was battery been used during that 1 year? Did you always charged it to 100%? How many times did you let it to discharge past 20%?

[mrelwood]

5 hours ago, GothamMike said:

I thought you should not over charge your cells? Wow.

Both the charger and the BMS are designed to prevent overcharging. But since the charger relies on the battery pack’s total voltage for said functionality, an unbalanced pack is risking some of the cells to become overcharged.

 So best to leave the charger plugged in in order not to overcharge!

[GothamMike]

I usually charge to 80-90%, often to 100% Got to 5% only twice.

[Alj]

4 hours ago, GothamMike said:

I usually charge to 80-90%, often to 100% Got to 5% only twice.

The thing is that combination of not charging to 100% and discharging too low has a risk of one element getting out of balance and receiving negative charge (that happens when you drain battery low when this element is already discharged but other elements in series still have some charge left). Negative charge destroys lithium cell (creates a short circuit due to copper migration), and the full battery capacity is only as good as the capacity of worst element in it.

The recipe for healthy battery is always charging to 100% and let it continue to charge for some time after it is already fully charged (to balance out elements) and to not discharge it past 20% at least to decrease risk of negative charge.

[UniVehje]

27 minutes ago, Alj said:

and to not discharge it past 20% at least to decrease risk of negative charge.

The thing with this kind of suggestion is that different wheels have different voltage reported as 0 %. On 18XL it’s 60V (3V per cell), Gotways 66 V (3.3V / cell) and V10 68V (3.4V/cell). It’s the voltage that matters, not the percentage the wheel reports. What I’ve heard is that as long as you don’t go below 3V very much, you should already be safe.

So in principle you are correct but usually that 20% is already included on the percentage you see on the app. 

[GothamMike]

DarknessBot won’t display voltage on my Apple Watch

[GothamMike]

9 hours ago, UniVehje said:

The thing with this kind of suggestion is that different wheels have different voltage reported as 0 %. On 18XL it’s 60V (3V per cell), Gotways 66 V (3.3V / cell) and V10 68V (3.4V/cell). It’s the voltage that matters, not the percentage the wheel reports. What I’ve heard is that as long as you don’t go below 3V very much, you should already be safe.

So in principle you are correct but usually that 20% is already included on the percentage you see on the app. 

I don't think I ever got it down to 3V. 

[UniVehje]

1 hour ago, GothamMike said:

I don't think I ever got it down to 3V. 

The wheel won’t let you drain it down to dangerous levels. You don’t need to worry and manage it. Just charge it full and enjoy the ride to 0% if you like. 

[GothamMike]

7 hours ago, UniVehje said:

The wheel won’t let you drain it down to dangerous levels. You don’t need to worry and manage it. Just charge it full and enjoy the ride to 0% if you like. 

Good news. I’m having a blast! 

[GothamMike]

2.9 mile lunch run. KS18L charged overnight. 100% to 83% in 3 miles? 84.45v to 79 volts. Something isn't right?

[UniVehje]

12 minutes ago, GothamMike said:

2.9 mile lunch run. KS18L charged overnight. 100% to 83% in 3 miles? 84.45v to 79 volts. Something isn't right?

If you really went from 100 % to 83% in 3 miles or 5 kilometers, then something isn’t right. I’m not familiar with 18L, only 18XL. But I do not think it should take that much to go 5 km. Maybe if you did all that distance at 50 km/h and checked the app while at speed? Did you check it at rest or at speed? The voltage can dip quite a bit while riding. If that was at rest and you did the 3 miles at normal speed, then I would check the battery. 

A warning: I had a nasty face plant (teeth through upper lip etc.) when riding a Kingsong that had a bad battery. Do not attempt crazy accelerations if you are not sure the battery is fine. 

[GothamMike]

I'm going to write KS support. Still under warranty.

[.....]

29 minutes ago, GothamMike said:

2.9 mile lunch run. KS18L charged overnight. 100% to 83% in 3 miles? 84.45v to 79 volts. Something isn't right?

Wow, that does seem like very low battery miles. Is this the wheel that is less than a year old? Is there anything left on a warranty? Have you opened it to make sure that BOTH packs are connected? Be sure to charge them separately if you notice this. I recall reading about how sometimes one pack could be unhooked and it only results in a seemingly horrid range. If  under warranty, you may want to contact your retailer and ask if you can open it to check. I don't know how finicky they are about that stuff. Perhaps riding it down(carefully) a little more and doing another long slow charge with balance. Ride it again and see if you are still getting the same poor mileage. If you are, there's definitely a problem. My 18L gets me about 20 miles from full until minor throttling. I ride it around 25mph nonstop in the mountains at 130lbs for that range. Hate to hear this man, these batteries are definitely the weakest link and the most expensive. Ah the joys of such expensive yet 'disposable' wheels...

Edited July 16, 2020 by ShanesPlanet

[UniVehje]

@Mike Sacristan had a similar problem with 16X, the other half of the batteries were busted, I think. Sounds a bit similar problem?