meepmeepmayer Posted April 11, 2017 Share Posted April 11, 2017 Thanks you two! I got it now, 1radwerkstatt says you have to use the standard charger for the last few %, because the fast one is assumed to be limited. I thought somehow doing the last 10% on 5A could be bad and they want you to use the weak one, but it's just assumed to be impossible to use the fast one. I just made stuff more complicated than it is Apparently it's even the same speed for the last 10% (funny that the "low current phase" starts so early). Do the batteries balance themselves without chargers? While the wheel is in use, or just off? They're connected after all. Or does it only make sense to speak of balancing when they are nearly full because it refers to the last detailed fine tuning (aka what the BMSs do, instead of the current by itself)? Link to comment Share on other sites More sharing options...
US69 Posted April 11, 2017 Share Posted April 11, 2017 5 minutes ago, meepmeepmayer said: Thanks you two! I got it now, 1radwerkstatt says you have to use the standard charger for the last few %, because the fast one is assumed to be limited. I thought somehow doing the last 10% on 5A could be bad and they want you to use the weak one, but it's just assumed to be impossible to use the fast one. I just made stuff more complicated than it is Apparently it's even the same speed for the last 10% (funny that the "low current phase" starts so early). Do the batteries balance themselves without chargers? While the wheel is in use, or just off? They're connected after all. Or does it only make sense to speak of balancing when they are nearly full because it refers to the last detailed fine tuning (aka what the BMSs do, instead of the current by itself)? Thats why its not recommended to bring some peaces of batteries together in a parallel or seriell setting when they have different voltage... Because then they will "balance" themself in a microsecond and try to get to the same level.... When the difference is to high it goes "bumm" ... So "normally" all batteries in a parallel setting "should" have same voltage, because of the self balancing....(their are other factors, like resistance and son, but thats the principle) Sorry, can not describe it better in english! Link to comment Share on other sites More sharing options...
meepmeepmayer Posted April 11, 2017 Share Posted April 11, 2017 Yep it's clear! I just didn't know the BMS plays a part in the final intricacies of getting the batteries to the same voltage, I thought they do it automatically all by themselves. But makes sense when individual cells have subtle differences, to deal with that somehow. Link to comment Share on other sites More sharing options...
esaj Posted April 11, 2017 Share Posted April 11, 2017 2 hours ago, meepmeepmayer said: Thanks you two! I got it now, 1radwerkstatt says you have to use the standard charger for the last few %, because the fast one is assumed to be limited. I thought somehow doing the last 10% on 5A could be bad and they want you to use the weak one, but it's just assumed to be impossible to use the fast one. I just made stuff more complicated than it is Apparently it's even the same speed for the last 10% (funny that the "low current phase" starts so early). EDIT: shortened version of a long winded example using (partially wrong) calculations Mostly this is due to the "constant current/constant voltage" -stuff... Here, I'll skip most of the details, but the general idea is that the charger will use a circuit called constant current sink (or source, depending if it's "before or after" the load) to drop it's output voltage. So, it's actually controlling it's (output) voltage to control the current flowing. The charger will internally (typically over a mosfet) drop enough voltage to keep the current from rising above the set maximum (thus, constant current). As the pack voltage rises while the cells charge, the constant current -circuit inside the charger will keep the voltage difference steady to keep the current flowing at a constant rate. The reason that higher current chargers heat up more (and need to be more robustly built with better components than the lower current ones, and thus cost more, or if you got one "too" cheap, is probably low quality ) is that the internal voltage dropping of the charger and the constant current causes a power loss of P = U * I (power equals voltage times current) The charger is "wasting" a certain amount of the power as it needs to drop the "excess" voltage to keep the current in check, which goes into heating up the charger. As the pack voltage gets higher, the constant current sink needs to drop less and less voltage, so it won't heat up as much towards the end. Once the voltage difference between the charger "constant voltage" (say, 67.2V for 16S pack or 84V for 20S pack) and the pack voltage get close enough to each other, the current starts to drop; the charger is now acting as a constant voltage source (instead of a constant current). And this is where the higher and lower current chargers will act the same: to keep pushing the maximum amount of current the constant current -part allows into the pack would require the voltage of the charger to go above the 67.2V -value (in this example). It won't do that. Instead, the charger output voltage will stay at the same value of 67.2V, and since the resistance of the pack stays the same (pretty much, disregarding small effects of temperature etc), the charging current will drop towards the end. Somewhere around there the balancing will also start to happen. Higher maximum output current allowed by the constant current -part of the charger won't help towards the end, once the voltages are close enough together, and thus the "last part" of the charging will take as long as it needs independent of the maximum charger current. 2 hours ago, meepmeepmayer said: Do the batteries balance themselves without chargers? While the wheel is in use, or just off? They're connected after all. They're in series, two components in parallel must have the same voltage (or "voltage drop") over each other, but in series, they must have the same current flowing through each other (or no current flowing, if the circuit is "open").... This would require another long-winded more in-depth explanation, but I won't get into it at least now So, no, the cells won't balance by themselves (not the ones that are in series which each other), unless there's some really clever circuitry in the BMS. Quote Or does it only make sense to speak of balancing when they are nearly full because it refers to the last detailed fine tuning (aka what the BMSs do, instead of the current by itself)? AFAIK, "balancing" in general just refers to the cells in a battery having the same voltage. Link to comment Share on other sites More sharing options...
Hunka Hunka Burning Love Posted April 12, 2017 Share Posted April 12, 2017 At about 20:20 you can see them demonstrating the use of two 5A chargers to reduce charging times... Link to comment Share on other sites More sharing options...
Marty Backe Posted April 12, 2017 Share Posted April 12, 2017 1 hour ago, Hunka Hunka Burning Love said: At about 20:20 you can see them demonstrating the use of two 5A chargers to reduce charging times... These guys are always a riot to watch. Even as they destroy their wheels they have fun Link to comment Share on other sites More sharing options...
meepmeepmayer Posted April 12, 2017 Share Posted April 12, 2017 13 hours ago, esaj said: ... Now THAT is an amazing explanation! Thank you very much Explains very clearly the two phases of charging, and why you need a BMS for the second phase (that means, without BMS the charger might overload/destroy an unlucky serial cell that gets too much voltage because of a slacking neighboring cell?). And the battery longevity tip is to stay in the first phase mostly, with occasional full charging. Link to comment Share on other sites More sharing options...
Scully Posted April 12, 2017 Share Posted April 12, 2017 The fast charger does what it says on the tin. 50%-100% in 2 hours. # Link to comment Share on other sites More sharing options...
steve454 Posted April 12, 2017 Share Posted April 12, 2017 2 hours ago, Scully said: The fast charger does what it says on the tin. 50%-100% in 2 hours. # And the temperature did not go up on the motherboard. 2 hours is fast indeed. Link to comment Share on other sites More sharing options...
Marty Backe Posted April 13, 2017 Share Posted April 13, 2017 3 hours ago, Scully said: The fast charger does what it says on the tin. 50%-100% in 2 hours. # So this is proof that there are people who use Soft Mode Link to comment Share on other sites More sharing options...
Jrkline "Wheel Whisperer" Posted April 13, 2017 Share Posted April 13, 2017 1 hour ago, Marty Backe said: So this is proof that there are people who use Soft Mode A.K.A. Elton John @ the Playboy mansion mode. Link to comment Share on other sites More sharing options...
Scully Posted April 13, 2017 Share Posted April 13, 2017 6 hours ago, Marty Backe said: So this is proof that there are people who use Soft Mode Hahah.... its not true.... I changed the mode, but logged back and it seems to have defaulted back. Ive only had the wheel a few days. I promise it won't happen again. Link to comment Share on other sites More sharing options...
US69 Posted April 13, 2017 Share Posted April 13, 2017 1 hour ago, Scully said: Hahah.... its not true.... I changed the mode, but logged back and it seems to have defaulted back. Ive only had the wheel a few days. I promise it won't happen again. Are you using IOS? It is a fault of the new App...it Forgets your ridemode Settings and always Switches back!....Attention: May also happen to tiltback and Speed warnings.....(that they reset) Link to comment Share on other sites More sharing options...
Scully Posted April 13, 2017 Share Posted April 13, 2017 2 minutes ago, KingSong69 said: Are you using IOS? It is a fault of the new App...it Forgets your ridemode Settings and always Switches back!....Attention: May also happen to tiltback and Speed warnings.....(that they reset) Yes, Ios, Last time i'm sure I just used the old app in the end. Link to comment Share on other sites More sharing options...
Chriull Posted April 18, 2017 Share Posted April 18, 2017 On 11.4.2017 at 6:44 PM, esaj said: ... The charger will internally (typically over a mosfet) drop enough voltage to keep the current from rising above the set maximum (thus, constant current). Or a dc/dc converter is used to produce just this needed voltage for the constant current to prevent this power waste by voltage dropping over the mosfet. Link to comment Share on other sites More sharing options...
xiiijojjo Posted May 10, 2017 Share Posted May 10, 2017 So from what i gather in this thread there should be no problem with me buying 2x 4Amp chargers for my Charger Doctor V2 (dual charger) As my gotway Msuper v3 is a 820Wh version (4 parallel packs) To do the math: 820Wh are 4p = 8Amp/4packs =2Amps per pack Does anyone here have experience with the Gotway musper v3 and the charge doctor (beyond 5Amps total)? Link to comment Share on other sites More sharing options...
meepmeepmayer Posted May 10, 2017 Share Posted May 10, 2017 @xiiijojjo I'm pretty sure 8 amps will melt your charge port wires. They say 5A is what the port can take, between 5 and 6 it gets critical, and above 6 = brzzz [ask someone who knows for sure!]. You'd need to build in a better charge port (in that case, some other part may not like the high current) or a second charge port for using higher currents (Ian from speedyfeet built 2 extra ports into his monster so he can charge with 3 5A chargers at the same time, see his charger video, so it can be done). Using one 4A charger and your original 1.5A charger together might also be possible (5.5A), it's the maximum I would do. One 4A or 5A charger is probably safer (you could probably get a custom 67.2V, 5A charger from 1radwerkstatt (use drop down to select "Ladegerät nach Wunsch" = custom charger). No experience with stronger chargers. But it's not just what the battery cells can take, you have to consider the rest of the wheel too. Link to comment Share on other sites More sharing options...
xiiijojjo Posted May 10, 2017 Share Posted May 10, 2017 18 minutes ago, meepmeepmayer said: No experience with stronger chargers. But it's not just what the battery cells can take, you have to consider the rest of the wheel too. I see. So should i just get a second 1.75Amp Gotway charger and run those two into the charge doctor to get 3Amps total (to stay safe) or should i buy a 4Amp charger and run that alongside the original 1.75Amp charger? Safety is important but if the msuper v3 can handle 4Amp+1.75Amp I'd of course perfer that. Link to comment Share on other sites More sharing options...
Marty Backe Posted May 10, 2017 Share Posted May 10, 2017 18 minutes ago, xiiijojjo said: I see. So should i just get a second 1.75Amp Gotway charger and run those two into the charge doctor to get 3Amps total (to stay safe) or should i buy a 4Amp charger and run that alongside the original 1.75Amp charger? Safety is important but if the msuper v3 can handle 4Amp+1.75Amp I'd of course perfer that. Jason (Ewheels) sells a fast charger. When I bought my KS14C from him he included a faster charger at no charge (he does this with a lot of his wheels). The KS uses the same connector and voltage, so this fast charger also works great on my MSuper V3. I would rather use a fast charge then a charge doctor requiring two chargers. If you really want to fast charge, look at what Ian (Speedyfeet) did with his Monster. The Monster has three battery packs. He added two new charging ports. So each 800wh battery pack has a dedicated charging port. Then he connects a charge doctor to each port. In this way he can connect 6 chargers to the Monster and completely charge it in 2-3 hours. Insane. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted May 10, 2017 Share Posted May 10, 2017 The standard is 1.75A? Mine (84V) is 1.5. I'd personally not try anything over 5, 5.5 in emergencies, 5.75 not. So either 2x1.5 (you only need one extra "cheap" standard charger) or 4A (60€ + free shipping in EU from 1rad) or 5A alone is what I would do. I'm really no expert what the charge ports can take, maybe ask your dealer or so for a definitive answer. Also make sure all the other parts will take it, even if you burn a charge port that's no big deal, but you don't want to fry the board or whatever (I think that applies more to wheels where the charging goes through the board, unlike the Gotways where it's directly to the batteries). Link to comment Share on other sites More sharing options...
Marty Backe Posted May 10, 2017 Share Posted May 10, 2017 1 minute ago, meepmeepmayer said: The standard is 1.75A? Mine (84V) is 1.5. I'd personally not try anything over 5, 5.5 in emergencies, 5.75 not. So either 2x1.5 (you only need one extra "cheap" standard charger) or 4A or 5A alone is what I would do. I'm really no expert what the charge ports can take, maybe ask your dealer or so for a definitive answer. Also make sure all the other parts will take it, even if you burn a charge port that's no big deal, but you don't want to fry the board or whatever. Agreed. I think the consensus (supported by Ian) is that ~5 amps is the max for one charging connector (the internal wires really). If you're willing to replace the wires with heavier gauge wire you could go with a higher current charger. Fortunately for me, when I've depleted the batteries on one of my wheels I won't be riding it again for at least a day, usually many days. So I don't care if my wheel takes 5 hours or 15 hours to charge. Link to comment Share on other sites More sharing options...
meepmeepmayer Posted May 10, 2017 Share Posted May 10, 2017 I think the 60€+free shipping 4A is a good deal, not sure if the standard charger is much cheaper. The 84V 5A costs 100€, so a 67.2V 5A might be the same price range - you can ask, 1radwerkstatt@gmx.de seems to be the standard contact. Link to comment Share on other sites More sharing options...
xiiijojjo Posted May 10, 2017 Share Posted May 10, 2017 Just now, meepmeepmayer said: The standard is 1.75A? Mine (84V) is 1.5. Yeah the Msuper V3 820Wh is 67V and it came with a 1.75Amp charger. You know i think i'll just settle on a 5Amp charger and run that alone into the charge doctor until i upgrade my charge port to be able to handle the full 10Amps that the charge doctor is limited to and then add another 5Amp charger. Thanks guys ! Link to comment Share on other sites More sharing options...
Marty Backe Posted May 10, 2017 Share Posted May 10, 2017 Just now, xiiijojjo said: Yeah the Msuper V3 820Wh is 67V and it came with a 1.75Amp charger. You know i think i'll just settle on a 5Amp charger and run that alone into the charge doctor until i upgrade my charge port to be able to handle the full 10Amps that the charge doctor is limited to and then add another 5Amp charger. Thanks guys ! Good luck. Let the community know your experience if you do ever upgrade the charge port. It would be interesting to see what's involved and how well it works. Link to comment Share on other sites More sharing options...
xiiijojjo Posted May 10, 2017 Share Posted May 10, 2017 Just now, Marty Backe said: Good luck. Let the community know your experience if you do ever upgrade the charge port. It would be interesting to see what's involved and how well it works. For sure i will. I'm like a blind child when it comes to modding so i'd have to get some help from you guys Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.