Xelvic

My KS-16S (sport) review

63 posts in this topic

4 hours ago, houseofjob said:

That ending plug doesn't look correct. You need it to be GX16-3 for the KS-16S, but the picture looks awfully like GX12 (16 and 12 are the diameters in mm I believe)

Fingers crossed that it works! Can't really return it back to China too easily! ūüėā¬†

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5 minutes ago, Jason McNeil said:

Hey, I recognize that line! The information from a 16S Customer was that initially the Wheel charged, then stopped on the subsequent attempt; this evidence led to the incontrovertible (& erroneous) conclusion that it was a fault with the Wheel, possibly associated to the higher charging rate.  

Based on what we now know (one of the wires was on pin 2 instead of pin 3), it's not known what, if any, risk is associated with 4A charging with the 16S. Because there are four parallel packs, there should be ample margin for this load to be shared among the packs, so this could very well be a CYA move to limit warranty claims for poorly assembled battery packs or something else.

I'm pretty sure that charging the pack at 4A won't hurt them one bit.

In the R/C plane and offroad R/C vehicle world,  charging at the rate of the capacity of the battery is considered a very safe rate of charge and the batteries are usually in series in the pack.  (i.e. - battery rated at 6A power is charged at 6A charge rate and considered totally safe.)

 

Allen

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1 hour ago, Jason McNeil said:

....this evidence led to the incontrovertible (& erroneous) conclusion....

Ha ha ha.  Good one! :lol:

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Posted (edited)

On 30.3.2017 at 7:18 PM, abinder3 said:

I'm pretty sure that charging the pack at 4A won't hurt them one bit.

In the R/C plane and offroad R/C vehicle world,  charging at the rate of the capacity of the battery is considered a very safe rate of charge and the batteries are usually in series in the pack.  (i.e. - battery rated at 6A power is charged at 6A charge rate and considered totally safe.)

 

Allen

Standard charging rate for most of the 10A cells used in EUC battery packs (in 18650 format) is 0.5C, maximum charging current is usually 1C. Since the KS16S uses 3500mAh cells, 0.5C would be 1.75A per cell = 7A for the entire pack. Actually, since the capacity to use for this calculation is the minimum and not the nominal capacity, it's more like 3400mAh x 0.5 x 4 = 6.8A

I don't know which cells they actually use, but it could be an LG MJ1 for example:

https://eu.nkon.nl/sk/k/Specification INR18650MJ1 22.08.2014.pdf

So for the KS16S or the KS18, 4A is still well below a standard charge, but for smaller models using only 2 parallel rows of cells and maybe lower capacity (3000mAh), 4A would be more than a standard charge, although still within limits for a 1C charge. I guess they just wanted to keep it simple and define one standard charging method which is OK for their entire product line, or there is a limit imposed by cables or circuits between the charging port and the battery pack.

I wonder what Chris from 1RadWerkstatt thinks about it, he would know for sure if the KS16S can handle 4A chargers.

Edited by Christoph Zens
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Posted (edited)

With the amount of cells the big (parallel) packs have, the amperage shouldn't be a problem, but the GX16-3 is rated for something like 5A max. Going above, you might risk the connector overheating and the plastics might begin to melt :P  1RadWerkstatt has 8A chargers for the largest packs, but they come with different connectors or multiple GX16's in parallel (don't remember which), because the current is too high for the single GX16.

Also, didn't older (not S) KS16's have packs (2 x 16S2P?) that were daisy-chained? If only the first pack in chain is charged directly by the charger current, then the amount of parallel cells there (16S2P?) is the limiting factor, although if it's two in parallel, I think it should still be ok for 4A...

Edited by esaj
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Posted (edited)

28 minutes ago, esaj said:

With the amount of cells the big (parallel) packs have, the amperage shouldn't be a problem, but the GX16-3 is rated for something like 5A max. Going above, you might risk the connector overheating and the plastics might begin to melt :P  1RadWerkstatt has 8A chargers for the largest packs, but they come with different connectors or multiple GX16's in parallel (don't remember which), because the current is too high for the single GX16.

Also, didn't older (not S) KS16's have packs (2 x 16S2P?) that were daisy-chained? If only the first pack in chain is charged directly by the charger current, then the amount of parallel cells there (16S2P?) is the limiting factor, although if it's two in parallel, I think it should still be ok for 4A...

To the daisy chained question:

ALL KS wheels -except Ks16S- have "daisy chained" Batterie packs, BUT:

I have to learn (from Chris-1Radwerkstatt) that this is also a parallel connection, so 4 Amp charging is no Problem, the 4 amps are shared by all packs, and not only that:

This Daisy chain Connection is the only Connection that makes the BMS work in all Kind of conditions and situation!!! If you parallel Batterie packs like for example GW did earlier...you have a Kind of dangerous Situation for the Batterie packs, as because of the true paralleling you Bypass some of the BMS protections, as the packs are now directly connected!

Like said, this is a Statement from Chris, who trully knows what he is saying!

On newer wheels like the ACM and V3 GW implemented because of that another direct Connection between the paralleled Batterie packs, which, in case of BMS Alarm, Transfer this to the other pack, also.......

On the KS16s the packs are not paralled by Y-Cable, they are paralleled on the board in a specific Management, so that this BMS "Bypass" is not going to happen....

Edited by KingSong69
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Posted (edited)

1 hour ago, KingSong69 said:

This Daisy chain Connection is the only Connection that makes the BMS work in all Kind of conditions and situation!!! If you parallel Batterie packs like for example GW did earlier...you have a Kind of dangerous Situation for the Batterie packs, as because of the true paralleling you Bypass some of the BMS protections, as the packs are now directly connected!

Is this also true when my parallel packs each have their own separate BMS, ie. each having their own protection circuitry? My understanding would be that each BMS works independently from the others, so no daisy chaining is necessary (and actually it would be detrimental in this case for the maximum discharge and charging current).

Edited by esaj
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1 hour ago, esaj said:

Is this also true when my parallel packs each have their own separate BMS, ie. each having their own protection circuitry? My understanding would be that each BMS works independently from the others, so no daisy chaining is necessary (and actually it would be detrimental in this case for the maximum discharge and charging current).

With what i am saying here i am only quoting what Chris told me in some conversations....i can not perfect technically describe the reasons behind that.

 

As I understand it, yes - each BMS works seperatly, but because of paralleling the packs if one pack Fails, the Connection by parallel would overgo this protection. That is what i get from the conversation with Chris.....I won't give to much Details of this discussion, as i dont know if he is good with that!

 

My -personal- thinking would be: let there for example be 2 dead batteries in one pack, so that the voltage of this one pack is 7,4 Volt lower.....A dead cell does not always lead to a shutdown of the pack.

Now guess what happens if this pack is not shut down and paralled then to a higher voltage pack....

I dont know if this example is even possible or if that example is what is "not good" on paralleling........but: Chris also stated something like that real parallel packs could be a "Kind of danger".....

 

i always will follow his tips, as he has a very deep knowledge and is building Batterie packs on his own

 

To my own wheel:

I personal own a Msuper V3 , upgraded it from 820wh to 1160wh, partially with the help of Chris....

I was pretty stunned at first when i saw that those 2 x 410wh packs on each side not only been parallel connected by the powercables, but also had a second seperate parallelConnection from pack to pack(4 extra cables!), which is totally missing on older GW models. So there is some Kind of protection on the newer models just because of that paraleling!

What was done i my upgrading case: Because not enough room for the 2 of 410wh packs on one side of the shell, it had to be unpacked and packed again to a big 820wh pack....This was done by Chris and is documented in my V3 Review:

 

On this Photo you can see that the V3 BMS PCB gives out 8 cables! 2 for power, 2 for charging, and even 4!! for the mentioned extra Connecting of a eventually paralleled pack!

So now in my V3(+) on the left side a (old)340wh pack sits and on the other side the "changed" 820wh bigpack...the Chargeport runs into the 340wh pack, and the 340wh goes into the 820wh big pack.

I could (and on advise of Chris should NOT) "real" parallel the 340 and 820wh as the 340BMS has had no "communication ports/cable", as this 340wh pack was from a further bought time....

 

 

What i definitly know is: "daisy chained" is not bad in any way!  ......and charging with high amps is the same possible as on "real" paralled.....

 

 

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Jason, did KS ever get back to you as to why mine wouldn't charge? Curious minds want to know.

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14 minutes ago, Xelvic said:

Jason, did KS ever get back to you as to why mine wouldn't charge? Curious minds want to know.

Yeah, mentioned above, the chargers were wired wrong.

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Ahhhh...well good that it's a charger problem and not a wheel problem.

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