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someguy152

What brand new 18650 cells should I get for my 3 yr old battery to replace some 0v cells?

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It is a tough decision when one considers wheels are improving at such a fast rate, the battery technology is far better, and the power is quite a bit more... so the distance, speed, and acceleration is quite improved on newer wheels.

A miniPRO with only 350 miles on it hiccuped during firmware testing. One miniPRO is now super fast, the other is now a parts pile. Ordered an in-circuit programmer to try to save the main board (none available locally). Worst case is order a new board...

I'm still surprised  there's no support for the KS-18S given it is still being sold, that part is upsetting, and I'm not sure what to make of it as related to my future purchase(s). For instance, the KS-18XL is an expense wheel, but it's been out for about three years also, how long will it be continued to be supported? 

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still most of the parts are on ewheels website.  but they're discontinuing the model is what my email from them says.

As i didn't buy my wheel from them, they don't want to be in a position of telling me i can swap 14s batteries into 18s ones as its too nonstandard 

 

 

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Posted (edited)

Swap the 4 cells with new ones, add balance leads, done. Worst case is you need to manually balance every 3-12months. Best case is you monitor once every 6 months and don't need to do anything.

Edited by alcatraz

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(opinion) It could be "balance every few rides," or "every ride," depending...not balancing often enough might be how this all came about.

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On 4/27/2020 at 12:59 PM, alcatraz said:

Swap the 4 cells with new ones, add balance leads, done. Worst case is you need to manually balance every 3-12months. Best case is you monitor once every 6 months and don't need to do anything.

I need a bms that fits too, (i shorted out some component on my bms diagnosing the problem) i think because the kingsong batteries has some extra wires that seem to communicate with the control board

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How bad is the bms? Maybe you just shorted two battery terminals which could leave the bms intact. If you did damage the bms, maybe the overcharge protection still works. Sure you don't want to test it?

On euc's, if the bms doesn't balance it's essentially only an overcharge protection. That can be replaced, but what you can't replace is the communication to the control board (if there is such a connection). A faulty bms with a working connection is still usable.

What about 2nd hand battery packs? What about buying an original bms board from china?

Kingsong 18S are very valuable in China. There are lots of riders that swear by them and ride crazy long distance. I'm sure you can find spares. Ask some kingsong sellers on aliexpress perhaps.

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7 hours ago, alcatraz said:

Ask some kingsong sellers on aliexpress perhaps.

that's a great idea. thanks for the impetus.  ewheels and tina and vicky from kingsong will not sell me a bms.

i dropped a magnet somewhere in the middle of the bms so i don't think its the battery terminals.  Im not sure how to test it.  I imagine i'll probably put balance leads on and try to reuse the bms first. if the device doesn't run with that, then i'll have to consider a new bms.

As far as replacmenet battery packs.

I was able to pickup a $300 840wh ks14s with the hope that one of its 420wh sidepacks could go in the space of the 840wh toppack of the 18s....haven't got around to trying that out yet because i still have hopes of restoring the original bad battery, but if i can't get a bms and need one, its something i will try out.  Im not sure if i asked you if you think this is a viable option.  You might know more with ur experience with other 18s riders in china.  again ewheels and tina and vicky have not said whether that will work or not.  Tina said it will but vicky said it won't.  I don't want to be the first to try out though i can't imagine too much stuff would go wrong assuming the voltages of the battery packs are in line.

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@alcatraz  could you look at my previous comment and let me know  if you've heard of anybody in china has tried putting a 16s or 14s battery in the top pack of the 18s?  i got mixed messages from two kingsong reps. thanks

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Posted (edited)

on this ongoing saga of my bad battery packs, i removed my bad 420 wh one and am in the midst of balancing my remaining 420wh one.

on darknessbot, I got it up to 66.6v and 97%, before it stopped charging.  My crappy HF charger measured 2 of my quick chargers at 66.8 and a crappy basic 2a charger at 66.6V, and i think it's off by .2 to .3V (compared it to some 18650 battery chargers by opus and liitokala).

So that part seems normal, but i've left it on the charger for several (3) hours now, and the voltage has dropped to 65.7v and 92%.   The charger lcd reads    0.66 or 0.67v and 0.00A.

Does that seem normal?

I haven't tried this but I probably will unplug the charger and plug it back in to see if it charges back up to 66.6 or stays at 65.7

Edited by someguy152
added info

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1 hour ago, someguy152 said:

I got it up to 66.6v and 97%, before it stopped charging. 

i've left it on the charger for several (3) hours now, and the (darknessbot) voltage has dropped to 65.7v and 92%. The charger lcd reads 0.00A.

This sounds like your BMS triggered its Charge Stop protection.

To give your pack more opportunity to balance, discharge it by 10% then attempt charging again. It may improve each cycle like this... (or, balance manually).

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4 hours ago, RagingGrandpa said:

It may improve each cycle like this... (

thank you for the feedback.

what does an improvement look like besides not dropping down to 65.7v after a few hrs of balancing on  the charger...

should the charger lcd be reading not 0.00A?

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I don't know about kingsong but gotway bms seem to balance by "discharging" cells. A resistor is switched on to a group with too high voltage so that voltage lowers.

It could explain the lower voltage after a few hours. Try disconnecting the charger and reconnecting after a few minutes. Maybe it will start charging again. 

You're pretty close to 67.2V though so it's probably no problem with the pack.

About the question of 14S battery in a kingsong KS18S that's impossible. You'd end up with 8.4V too low voltage.

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10 hours ago, alcatraz said:

About the question of 14S battery in a kingsong KS18S that's impossible. You'd end up with 8.4V too low voltage.

can u tell me how u got to that?  they're both 67.2v wheels. i use the same charger on all 3  of my S series wheels

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21 hours ago, RagingGrandpa said:

This sounds like your BMS triggered its Charge Stop protection.

To give your pack more opportunity to balance, discharge it by 10% then attempt charging again. It may improve each cycle like this... (or, balance manually).

I used it around 20% yesterday and today went thru the same charging as yesterday. no difference i could really notice. darkness bot reporteed 66.8v and 97%, wheellog 100%

leaving it on the green led balancing for 3 hrs again dipped the voltage and capacity to 94%. and high 65.x V

when i unplugged the charger and waited 20 min and replugged in, darknessbot again reports 97% and 66.6v right away, the charger itself started at around 1A and over 10 to 20 min is steadily decreasing.

 

i think i'll just try to enjoy my remaiing 420wh as much as i can, and then maybe get a new 840wh battery. Spending too much time worrying when the weather rn is amazing

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21 hours ago, someguy152 said:

can u tell me how u got to that?  they're both 67.2v wheels. i use the same charger on all 3  of my S series wheels

16S means 16 cells in series. 14S means 14 cells and so on.

For cells in series you just add(multiply) up all the voltages. Lipo chemistry that we use uses 4.2V per cell. 16 * 4.2 = 67.2V which is the end voltage of a Lipo 16S pack.

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33 minutes ago, alcatraz said:

16S means 16 cells in series. 14S means 14 cells and so on.

Imho here 14S means the wheel KS14S and not a 14s battery configuration. KS wheels never  had a wheel with 14s batteries. They were always 16s, with the newer ones (84V) having 20s.

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3 hours ago, alcatraz said:

It's probably best to write KS14S then. :lol:

oh whooosps sorry for my imprecision

yea ks14s in my ks18s.

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Posted (edited)

news update. 

i carefully unravelled my non charging 420wh battery on the ks18s and measured individual cell voltages.

they ranged from 3.45 and 3.55 to mostly 4.1 all the way to as high as 4.18

so this looks like it could be easily recoverable or usable again once i either attach some balance leads (if theres any room to put any) or do a manual burning of the high voltage cells using some high power resistors

sorry posting from my other acct i use on my phone when i forgot my pw.

Edited by someguy153
added info

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2 hours ago, someguy153 said:

so this looks like it could be easily recoverable or usable again once i either attach some balance leads (if theres any room to put any) or do a manual burning of the high voltage cells using some high power resistors

Or if you have a single cell liion charger, charge the low ones.

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i have 18650 4bay chargers. could probably hook alligator clips to the appropriate terminals

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23 minutes ago, someguy152 said:

i have 18650 4bay chargers. could probably hook alligator clips to the appropriate terminals

But just _one_ cell! Excpect your 4 bay charger having internal connections which wouod shortcircuit the serial cells in the battery back!

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Bingo. Remember that the 4 bays share a common ground terminal. So as Chriull writes you only connect one cell group at a time to it. Otherwise you will shortcircuit the battery pack.

If you had 4 disconnected packs you could balance one group in each of the packs with that same charger but that's usually not needed.

My 18650 charger can do 1A charging I think. That's a bit slow. Your idea is very good though. Use what you have around you. Take care not to short terminals somewhere. To get a more plug'n'play result just attach 20-22awg balance leads and get one or two 2p jst-xh single cell charger with 3A. :thumbup:

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thanks all for the helpful comments again cautioning me from doing something stupid. 

 

yes those chargers are in my cart but with aliexptess theyll take a while to get here.

plus i dont k ow if ill just be wasting time adding balance leads if i end up not being able to put the battery in its already snug location again. im already concerned after cutting the shrink wrap (but not removing it yet) if itll fit after  "resealing" the shrink wrap with packing tape

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Replacement shrinkwrap is super cheap and a hairdryer is all you need. The end result looks very pro and you get a bit better protection against water damage. The hard part is to figure out what size you need. Too big and it won't shrink enough, too small and you can't get the pack into it.

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