Shad0z Posted March 29, 2019 Share Posted March 29, 2019 My standard 1.5 amp gotway charger gets really hot after about an hour of charging. And starts to smell like plastic/burnt. og like the same smell as if you open up any electronic device or wheel especially. Just more powerfull. My theory is that it may be due to the heat and that the smell is then just more powerfull cause of the heat. But could it be something else? Link to comment Share on other sites More sharing options...
LanghamP Posted March 29, 2019 Share Posted March 29, 2019 My Gotway chargers also run extremely hot, and that makes me uncomfortable. I think I've lost 3-4 chargers, Gotways and Kingsongs. Pop and done, with the burnt smell. Link to comment Share on other sites More sharing options...
Marty Backe Posted March 29, 2019 Share Posted March 29, 2019 My chargers (not just Gotway) get extremely hot, and smell too. One big advantage to fast chargers (besides the fast charging part) is that they run really cool, because of the fan(s) that they use. I also have a cheapo 67-volt charger that came with a generic wheel, and surprisingly it had a fan. I can use it to charge my KS14S. That charger runs nice and cool. So maybe invest in a fast charger and keep the Gotway as a backup. 31 minutes ago, LanghamP said: My Gotway chargers also run extremely hot, and that makes me uncomfortable. I think I've lost 3-4 chargers, Gotways and Kingsongs. Pop and done, with the burnt smell. Wow, you've had exceptionally bad luck. None of my supplied chargers have failed. Link to comment Share on other sites More sharing options...
RockyTop Posted March 29, 2019 Share Posted March 29, 2019 Same here. They get hot. Before I switched to a charger with a fan I was tempted to make a charging brick cooling box. I was going to mount my two chargers to the inside walls of a 50 cal ammo can complete with a cooling fan. This would not only cool the charger it would protect the charger from starting a fire. Link to comment Share on other sites More sharing options...
esaj Posted March 29, 2019 Share Posted March 29, 2019 The "stock" plastic bricks have the downside that the plastic enclosure traps the heat inside. Before the battery has reached full voltage, the charging amperage is limited by dissipating some of the "extra voltage" inside the charger, which mean a lot of watts being turned into heat. A "smarter" option would be adjusting the output voltage further down to minimize losses through an adjustable SMPS or such, but it would be more complicated and costly, and I doubt at least the cheap basic chargers go that route. I've never really studied those chargers, but I think they simply first regulate the voltage to the maximum voltage of the battery (say, 67.2V or 84V), and then use a basic constant current circuit to keep the maximum current from going into too high numbers by dropping the "extra" over a power transistor. Just as an example, if you use a Charge Doctor to monitor the charging, at no load (not connected to the wheel) the output voltage would show 67.2V (for a 16S wheel). When you plug it in, and the batteries are more empty, it could show 58V and 2A. 67.2 - 58V = 9.2V are going "somewhere". Likely being dropped over some mosfet or similar inside the charger. At 2A, the power dissipation of that is 9.2V * 2A = 18.4W. May not sound like much when the wheel motors are rated at something like 1000+W, but those motors transform most of the energy into motion (which is "power hungry"), not heat. Low power soldering irons can be like 15-30W, they can still reach 450 Celcius (840F) in a matter of minutes. More heat "ages" electronics components faster, especially electrolyte capacitors. I doubt the standard "brick" chargers have a very long lifespan, although I still wouldn't be surprised if "good ones" survive several years, but likely far less than a decade, maybe less than 5 years? EDIT: Come to think of it, maybe they do drop the output voltage before the current limiting even in the cheapo chargers, closer to 20W seems like a lot for a circuit inside closed plastic box with no ventilation holes... I'd have to tear open a charger to take a closer look. Link to comment Share on other sites More sharing options...
RockyTop Posted March 29, 2019 Share Posted March 29, 2019 I can’t remember who but someone simply placed a small 4 inch fan pointed at the brick and it kept the brick cool. It really doesn’t take much. As @esaj said the heat damages the components over time. A fan should help the charger last longer. Link to comment Share on other sites More sharing options...
esaj Posted March 29, 2019 Share Posted March 29, 2019 39 minutes ago, RockyTop said: I can’t remember who but someone simply placed a small 4 inch fan pointed at the brick and it kept the brick cool. It really doesn’t take much. As @esaj said the heat damages the components over time. A fan should help the charger last longer. I have a 67.2V/4A charger that has a fan and ventilation holes, although it probably still runs pretty hot. I opened up one of the "usual" bricks I have, this one came with a used KS16B. There's nothing "smart" here, and it likely just does dissipate all the extra off as heat without much further attempts at minimizing the power dissipation. The board was glued to the bottom of the case, so I didn't tear it down further to see how everything connects up, but from what I can tell, this is a pretty similar set up you see in cheap mobile phone chargers and such (feedback through optocoupler, right below the big transformer coil in the mid left), just scaled up. Something similar to this: Well, that's probably more complex. I didn't see any switching controller IC or such there, not sure how the constant current mode is handled. There's only one potentiometer, likely for adjusting output voltage rather than maximum current. There are aluminum flat bars on both sides of the "walls" as heatsinks, and the components taking the brunt of the dissipation are connected to those. Can't make up the component names as everything's covered in silicone. The "Q" in front of the component number would suggest these are transistors, but based just on this, I can't make up the entire circuit in my mind (plus I don't know much anything about AC/DC SMPS transformer design anyway, just the DC/DC-topologies make my head hurt ). The one on the other side connected to the aluminum bar is a diode (set up looks similar to the "D2" in that random circuit diagram I pulled out of google image search). Bonus: thermal camera picture from a hot charger brick taken last year, unfortunately I don't have the camera anymore: Link to comment Share on other sites More sharing options...
Shad0z Posted March 30, 2019 Author Share Posted March 30, 2019 Im gonna keep using my 5 amp fast charger But it doesnt charge the wheel to 100% though. So for times where i need the 100% in gonna use the gotway just to get it that little extra to top it off Link to comment Share on other sites More sharing options...
Marty Backe Posted March 30, 2019 Share Posted March 30, 2019 1 hour ago, Shad0z said: Im gonna keep using my 5 amp fast charger But it doesnt charge the wheel to 100% though. So for times where i need the 100% in gonna use the gotway just to get it that little extra to top it off Oh yeah, I forgot about the fact that it doesn't fully charge. Most of the time I use the Gotway charger because I"m not in a hurry to charge. But there are times that I want to charge faster. Sometimes I'll use the fast charger and near the end I'll change to the Gotway charger to get the full charge. How have you been? I don't see you much in the Forum (like the old days), but maybe I've been missing your posts? Hope all is well Link to comment Share on other sites More sharing options...
Shad0z Posted April 6, 2019 Author Share Posted April 6, 2019 update my fast charger broke, the end of the charger fell off and was stuck in the charging port of my wheel and almost shorted it, i got it out and now i need a new charger, well. shit happens i guess Link to comment Share on other sites More sharing options...
RockyTop Posted April 7, 2019 Share Posted April 7, 2019 18 hours ago, Shad0z said: update my fast charger broke, the end of the charger fell off and was stuck in the charging port of my wheel and almost shorted it, i got it out and now i need a new charger, well. shit happens i guess If the end coming off is the only problem you could likely get it fixed pretty cheap. If you walked into my shop I would not even charge a fee. Link to comment Share on other sites More sharing options...
Shad0z Posted April 12, 2019 Author Share Posted April 12, 2019 On 4/7/2019 at 4:38 PM, RockyTop said: If the end coming off is the only problem you could likely get it fixed pretty cheap. If you walked into my shop I would not even charge a fee. well the cables insulation was failing other places, seller sent me new charger for half price Link to comment Share on other sites More sharing options...
rinzler Posted April 13, 2019 Share Posted April 13, 2019 On 3/30/2019 at 2:45 PM, Marty Backe said: Oh yeah, I forgot about the fact that it doesn't fully charge. Most of the time I use the Gotway charger because I"m not in a hurry to charge. But there are times that I want to charge faster. Sometimes I'll use the fast charger and near the end I'll change to the Gotway charger to get the full charge. Any particular fast chargers that you can recommend? I saw also the Doctor thingy (charge regulator). Are they worth it? I don't get all the worry with charging to 100%. I know there is the technical reasons but surely these eucs should be designed to charge to 100% and then auto shut off? Link to comment Share on other sites More sharing options...
Chriull Posted April 14, 2019 Share Posted April 14, 2019 On 3/29/2019 at 5:56 PM, esaj said: EDIT: Come to think of it, maybe they do drop the output voltage before the current limiting even in the cheapo chargers, closer to 20W seems like a lot for a circuit inside closed plastic box with no ventilation holes... I'd have to tear open a charger to take a closer look. +1. Step down converters can easily be adopted to act as CC sources - but from my recent investigations i found no "solution" on how to switch inbetween the operation mode from CC to CV, but this should be no real problem. Imho ... My thoughts regarding these cheap chargers would be, that they are just not well designed. In the CC mode they need a voltage range from 3.3 to 4.2V x number of cells. With 16 cells thats ~52V to 67.2V. With 2A charging current that's an output power from ~100W to ~130W. Even with some good efficiency of around 90% that's 10-13W of dissipated power. A switching Mosfet in a TO 220 case with typically ~50K/W thermal resistance from junction to ambient would reach by this some 50°C+10x50=550°C. Theoreticaly... The small heatsinks for TO220 still have some 20K/W which (ignoring the smaller junction to case resistance) would still lead to 250°C melting the mosfet... So there the power has to be partially dissipated in the other components (coil,...). With ~20K/W less than 5W can be dissapeted by the Mosfet But the above thermal resistances are only valid if there is free air convection possible... So these chargers work quite borderline. With component tolerances, not to perfect design and some missing Q&A (heatsink attachment can easily make many K/W difference in thermal resistance) a theoretical working charger can get way to hot in mass production. If one looks at good not too cheap chargers, they have aluminium heatsink profiles at the outside and fans for higher powers... On 3/30/2019 at 2:28 PM, Shad0z said: Im gonna keep using my 5 amp fast charger But it doesnt charge the wheel to 100% though. So for times where i need the 100% in gonna use the gotway just to get it that little extra to top it off Most chargers can be adjusted for max voltage - so most likely you could trim your fast charger to fully charge your wheel @Cranium once wrote a nice detailed tear down of his charger with the three trim potentiometers for max voltage, max current and cutoff current... 2 hours ago, rinzler said: Any particular fast chargers that you can recommend? There is the canadian "cycle saturator" - absolutely recommandable, but also absolutely expensive... Ewheels.com afaik offers a nice fast charger with switchable max current, 90/100% charge and voltage/current display in the US? Mine from 1radwerkstatt.de works fine all the time. Has no gimmicks. The fan is a bit loud (like with most consumer electronics:( )- this reminds me to put some quality fan inside... Or you look around aliexpress/etc... Imo most of the sold chargers cone from China anyhow. Just with a western distributor one has warranty and possible better QA. 2 hours ago, rinzler said: I saw also the Doctor thingy (charge regulator). Are they worth it? I don't get all the worry with charging to 100%. I know there is the technical reasons but surely these eucs should be designed to charge to 100% and then auto shut off? Yes. There is an overvoltage protection in the BMS to shut off and the charger max voltage should be adjusted to charge just to (almost) 100%. The charge doctor is for stopping the charge below 100% to increase battery live and is no charger - it's an addition to a charger. But afaik there are none available by now... Link to comment Share on other sites More sharing options...
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