Chriull Posted February 2, 2017 Share Posted February 2, 2017 10 hours ago, KingSong69 said: ... Also KS did for a example not use all of the packs in parallel....the packs (on the actual wheels) are just "daisy chained"... ... The KS daisy chained packes are in parallel! They only have to look that every pack but the first one from the charger is not allowed to have an inverse polarity protection at the input - or this protection has to withstand the partial "driving" current from the packs between the charger and himself. Link to comment Share on other sites More sharing options...
US69 Posted February 2, 2017 Share Posted February 2, 2017 2 hours ago, Chriull said: The KS daisy chained packes are in parallel! They only have to look that every pack but the first one from the charger is not allowed to have an inverse polarity protection at the input - or this protection has to withstand the partial "driving" current from the packs between the charger and himself. I had an KS14 680wh....and also i have a KS18 with 1360wh. I can assure you that they are NOT parallel and i even have that assured with 1radwerkstatt. On the KS14 chargeport goes into one 340wh, which is loading the next pack, which then goes to the board. On the KS18 chargeport goes into the 2 x 340wh packs on the side, which then load the giant 680wh pack above, which then goes into the board. i can even tell you that on earlier Versions of high Watthour KS there have been Problems, as if you dont do this daisy chaining correct, there are Problems, as on braking only the pack connected to the board will be reloaded and so packs could get unbalanced. Fortunatly these Problems are not longer existing... (All this knowledge from KS Seller/Repairshop 1radwerkstatt, working on a daily Basis with KS wheels) KS itself is making Promotion for it's new KS16S....Saying that is from now "real" parallel, and not anymore one pack charging the other.....and so now has more power. Look here into there improvement letter for the KS16S: KS-16S improvements based on KS-16 (1).pdf Link to comment Share on other sites More sharing options...
Chriull Posted February 2, 2017 Author Share Posted February 2, 2017 1 hour ago, KingSong69 said: I had an KS14 680wh....and also i have a KS18 with 1360wh. I can assure you that they are NOT parallel and i even have that assured with 1radwerkstatt. On the KS14 chargeport goes into one 340wh, which is loading the next pack, which then goes to the board. On the KS18 chargeport goes into the 2 x 340wh packs on the side, which then load the giant 680wh pack above, which then goes into the board. i can even tell you that on earlier Versions of high Watthour KS there have been Problems, as if you dont do this daisy chaining correct, there are Problems, as on braking only the pack connected to the board will be reloaded and so packs could get unbalanced. Fortunatly these Problems are not longer existing... This prob "only" exists if there is an reverse polarity input protection on any pack but the first after the charger. (And the "overvoltage protection" Mosfet on the input side has to be designed so he can disspate enough power) As Chris stated: Quote KS itself is making Promotion for it's new KS16S....Saying that is from now "real" parallel, and not anymore one pack charging the other.....and so now has more power. Look here into there improvement letter for the KS16S: KS-16S improvements based on KS-16 (1).pdf New "improvements" have to be marketed With the KS16B BMS delivered from @1RadWerkstatt (in daisy chain configuration) Point 8 is as written there not correct. Both packs charge and discharge together. The only difference is the (low resistance) MOSFET on the input side. So with the new "battery pack" system the overall internal resistance of the battery packs should/could be a bit lower and so a bit lower voltage sag happens under load. But for sure not much more powerfull (if they did not change to more powerfull cells or increased the capacity ) If KS delivered their daisy chained packs with reverse voltage input protection for every pack it was a design fault and now its easy to improve... (It's a pity that @hobby16's schematics are no longer available by the links in http://forum.electricunicycle.org/topic/459-electric-unicycles-bms-problem-and-solution/ - the differences between the different packs paralleling systems could be easily seen.) I like very much the other points/improvements of this new motherboard design! Link to comment Share on other sites More sharing options...
US69 Posted February 2, 2017 Share Posted February 2, 2017 3 hours ago, Chriull said: like very much the other points/improvements of this new motherboard design! Me to....waiting from day to day to day now as Chinese new Year! Link to comment Share on other sites More sharing options...
US69 Posted February 2, 2017 Share Posted February 2, 2017 What the daisy chaining belongs: I am pretty sure you got something wrong....?! or it is me :-) Yes: Chris is using a different and much better BMS Diode Solution! But this is still a daisy chaining and not real parallel. One pack Charges the other??? 6 weeks ago we just done an upgrade of my V3 from 820 to 1160wh where we discussed this Problems......where he advised me to do it the "Kingsong way"-daisy chaining- where the 340wh pack then charging the 820wh. I am also in a actual Conversation with Chris about repairing my V3 flat tire and some KS18 upgrades. .... So i just asked him again today and will honestly report about it as soon as he answers! Will i be wrong? Nice, something learnt then :-) That an "normal" Y-parallel Connection of packs is dangerous and daisy chaining is the only professional way : That's pretty clear. But the game has stepped up since the linked conversation.... for example GW:in the ACM and V3 the packs are not just Y-parallel....they are also connected by some extra wires, which get that danger of different pack voltage out of the way. To the board improvements: I am eagerly waiting, but not only for the KS16S...i hope to see the rumored new KS18 2000Watt in the middle of the year, KS said it is in tests at the Moment :-) Link to comment Share on other sites More sharing options...
US69 Posted February 2, 2017 Share Posted February 2, 2017 So .... Ok, Chris had answered me..... And you were totally correct!!! Unfortunatly we talked with "speach-answers" over Whats app, so that i am not able to give it a translated Quote.... To get it together in short: They are charged and discharged in parallel, the BMS's makes it look as daisy chained....he called it german "quasi-parallel"......translates to"virtually parallel"! @Chriull ...like i said: I Allways like to get more and correct Information! Point 8 in the KS list totally got me on the wrong path then......but Ok, now i got it! Link to comment Share on other sites More sharing options...
Chriull Posted February 2, 2017 Author Share Posted February 2, 2017 26 minutes ago, KingSong69 said: ... @Chriull ...like i said: I Allways like to get more and correct Information! ... I just tried to get some (very rough) schematics of the BMS/Battery Pack together - since i am finished it (a bit too late) just by now i'll post it anyways (as you like more infos ): Between the two batteries one has to imagine some "..." or the missing 13-14 cells (depending on the modell). Also most packs have two of this 15-16 cells in series in parallel... Diode D1 is the reverse voltage protection diode (which can be better implemented with a Mosfet (1) - no forward voltage which can cause massive power dissipation...) which is also only needed for the pack directly connected to the charger anyhow. Q2 ( overcurrent protection) are normaly ~3 Mosfets in parallel. But here is seen, that daisy chaining/?cascading? brings the LiIon cells in parallel as paralleling the corresponding charge inputs and discharge outputs does. (with some minor differences regarding D1, Q1 and Q2). As already discussed before the "pitfalls" of daisy chaining is the Diode (which is only allowed in the first pack) and the overvoltage protection Mosfet Q1 which has to handle the "discharge" output current of all the packs "before him". Edit: (1) maybe by Q1 itself with some additional logic and sensing... Link to comment Share on other sites More sharing options...
Xima Lhotz Posted March 9, 2017 Share Posted March 9, 2017 On 2/2/2017 at 11:17 AM, KingSong69 said: KS-16S improvements based on KS-16 (1).pdf 4. 2 pcs 30A fuse instead of one Now, this is a bit strange to me. How is this an improvement? So each pack has a separate fuse of 30A then the board is able to handle 67v*60A=4020W? That seems like a lot before the fuse should blow. (Fuses also have some headroom so it will handle more before it blows) Are the fuses for the board or the pack? Link to comment Share on other sites More sharing options...
Slaughthammer Posted March 9, 2017 Share Posted March 9, 2017 someone once told me: A semiconductor, protected by a fast acting fuse, will allways protect the fuse from blowing by dying faster. The Fuses are not to protect the control board, they are there to prevent a battery fire in case of a short circuit. If each batterypack has it's own fuse, there is a chance, that in the really rare case that one pack but not the other gets shortet, the unicycle will not shut off. further, the doubled amperage of the fuses prevent false alerts--->faceplant Link to comment Share on other sites More sharing options...
esaj Posted March 9, 2017 Share Posted March 9, 2017 22 hours ago, Xima Lhotz said: 4. 2 pcs 30A fuse instead of one Now, this is a bit strange to me. How is this an improvement? So each pack has a separate fuse of 30A then the board is able to handle 67v*60A=4020W? That seems like a lot before the fuse should blow. (Fuses also have some headroom so it will handle more before it blows) I seem to remember some reports of the fuse blowing under heavy load (or maybe it was KS18?) on older models, ie. even when there's nothing electronically wrong, just sudden burst of current needed. Two fuses in parallel would (theoretically) allow double the current before blowing, but that's taking a lot of assumptions (exactly same resistance and thus exactly same current running through both etc). And it's hard to tell from the picture if they even are paralleled or if there's actually two separate battery positive wires and each have their own fuse. 22 hours ago, Xima Lhotz said: Are the fuses for the board or the pack? I'd say both In the event of too much current, the circuit will be broken, so as to save both the circuit board as well as the battery (both will be damaged by excessive current overheating things if the short circuit isn't stopped, the batteries being the more dangerous part if they catch fire). But IMHO, the fuses should be rated high enough not to blow unless there's something REALLY wrong (like a real short-circuit). Guess they at least use slow fuses... There's always something, I'm thinking I should pull the trigger on an older KS16 (assuming the price comes down after 16S gets out), but then there's the fuses, daisy-chained packs, suspiciously thin wiring... If the battery compartments would a centimeter or two wider, I could fit my custom packs to get 4 x "real-parallel" configuration in there, but nope. Link to comment Share on other sites More sharing options...
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