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Xelvic

My KS-16S (sport) review

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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! ? 

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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)

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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On 2017-03-27 at 10:43 PM, Mono said:

sure, but there is really nothing wrong with 67.2V either. The difference between 67 and 84V is, AFAICS, from a technological perspective really not a decisive one.

Well, not decisive maybe, but there IS a difference.

High wattage from a high voltage pack means lower amps from the batteries. That in turn means lower temps and less risk for catastrophic overheating, battery related cut-outs etcetera. That becomes even more crucial when you're down below 50% and push it. You could easily ask for more than the batteries safely could give you for more than a few seconds.

Also, higher voltage and lower amps means less energy converted to heat. So as long as the components can handle the higher voltage, there's only sunshine. If they can't... that's a different story.

Aaaaand of course, with higher voltage comes higher power motors, and the amp-draw is up there again, but now with even more power going through the board and cabling. :D 

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In this voltage / current game - taking about 84V systems  slightly like the idea of jumping from 400V to 1000V battery voltage in Telsa cars (afaik this is planned)...

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On 2017-5-18 at 11:52 PM, Scatcat said:

Well, not decisive maybe, but there IS a difference.

High wattage from a high voltage pack means lower amps from the batteries. That in turn means lower temps and less risk for catastrophic overheating, battery related cut-outs etcetera. That becomes even more crucial when you're down below 50% and push it. You could easily ask for more than the batteries safely could give you for more than a few seconds.

Also, higher voltage and lower amps means less energy converted to heat. So as long as the components can handle the higher voltage, there's only sunshine. If they can't... that's a different story.

Aaaaand of course, with higher voltage comes higher power motors, and the amp-draw is up there again, but now with even more power going through the board and cabling. :D 

All true (well, almost, higher voltage does of course not always come with higher motor power. Voltage and power are independent specifications. We can well have a 50V 1000W motor and a 100V 400W motor). Nobody in the right mind would deny that there is a difference between 67V and 84V. Yet, this seems neither to explain why this 25% difference may be decisive, nor that any of these consequences cannot be achieved through other means, e.g. 25% thicker wires or...

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Posted (edited)
3 hours ago, Mono said:

All true (well, almost, higher voltage does of course not always come with higher motor power. Voltage and power are independent specifications. We can well have a 50V 1000W motor and a 100V 400W motor). Nobody in the right mind would deny that there is a difference between 67V and 84V. Yet, this seems neither to explain why this 25% difference may be decisive, nor that any of these consequences cannot be achieved through other means, e.g. 25% thicker wires or...

Well. Generally you have less resistive loss with higher voltage, which means less power loss and less temperature. There is a reason why power lines are in the thousands of volts. But the word "generally" is revealing, because as always there are exceptions. For example: the circuits and motor must be designed for the higher voltage, or you can get very interesting problems with high temperatures, low reliability and low efficiency. Arcing is a lot less of a problem with lower voltages.

But overall, having a higher voltage is beneficial.

And of course it doesn't always come with higher motor power, Volts and Watts are not the same. But it comes with the potential for higher motor power, given that what you're looking for is to keep the current from going through the roof. You could work around it with higher gauge wire on and off the board, but simply put: With the same gauge wire, whatever gauge wire, you'll see higher temps with low voltage and high current, than with low current and high voltage. The principle is even used in glow-plugs for diesels and RC-engines, where a switch from high current/low voltage to the opposite just wouldn't work.

Edited by Scatcat
repetitive

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Posted (edited)

As was recently witnessed in the power tool market when the Yellow/Black firm started promoting a higher voltage product with wild claims... then their competitor came out with a product using their standard voltage that crushed the so called superior high-voltage product.  It just depends and the design and the requirements of the design in the application. So don't get sucked into the 84V is better, it's better when it can be shown to be a better design and not before.

Edited by FreeRide
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5 minutes ago, FreeRide said:

As was recently witnessed in the power tool market when the Yellow/Black firm started promoting a higher voltage product with wild claims... then their competitor came out with a product using their standard voltage that crushed the so called superior high-voltage product.  It just depends and the design and the requirements of the design in the application. So don't get sucked into the 84V is better, it's better when it can be shown to be a better design and not before.

Absolutely true. For 84V to be better, the darn thing must have a design that can make use of the higher voltage.

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22 hours ago, Scatcat said:

And of course it doesn't always come with higher motor power, Volts and Watts are not the same.

I was just citing what you said: Aaaaand of course, with higher voltage comes higher power motors...

22 hours ago, Scatcat said:

But it comes with the potential for higher motor power, given that what you're looking for is to keep the current from going through the roof.

If you define an increase of 25% to be going through the roof, right :P 

Just for a rough reference:

EUC: 1kW at 60V -> ~17A

Tesla: 2x200kW at 400V -> ~2x5000A

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1 hour ago, Mono said:

I was just citing what you said: Aaaaand of course, with higher voltage comes higher power motors...

If you define an increase of 25% to be going through the roof, right :P 

Just for a rough reference:

EUC: 1kW at 60V -> ~17A

Tesla: 2x200kW at 400V -> ~2x5000A

Point taken.

But just so you didn't misunderstand me. That quote was a bit sarcastic, because much of the gains in terms of efficiency and temp disappears in the general power increase.

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