HI ZOMGVTEK and zombiess,
Thanks for providing so many details and advice. You have given much more feedback than I expected when posting, and it is a great learning curve for me. Thanks again!
Just let me get some assumptions straight.
I am a MD with a PhD in neurosurgery
. That means that I am perfectly comfortable around highly complicated technologies of which I know nothing about, trusting other people’s skills in making things work that I don’t know anything about, and learning new things everyday. I am very comfortable working manually in a small operation space.
With regards to electronics, I am reasonable comfortable soldering small parts (resistors, caps, fets, even ICs) onto a PCB, but I usually do not understand an electronic circuit even when engineers explain it to me in baby talk. Therefore, generally speaking, I don’t know sh!t about electronics, but I can identify and replace a smoked MOSFET. Furthermore, I have an affinity for flowing things. Flowing body fluids, oil flow, water flow, flowing electrons....etc.
Last but not least, I am reasonably uncomfortable around high voltage setups like my 126V 30S pack. That means that I will protect myself when working on it, will use multiple layers of shrink wrap, and so far managed to get KFF twice. Once from connecting a parallel pack in series (resulting in molten 5mm gold connectors), and once from inverting the two 5S tabs on my 10S packs to the balancing board (resulting in molten JST connectors).
I do not NEED a high power setup (who does?). I “need” an E-bike to do my commute (which will be increasing from 6 to 15km in 2 months due to a move). I “prefer” to tinker with my bike and see how far I can push it, because it is fun. I always try to combine need and fun, so I tried 2WD first. That’s why I have a front 9C 2810 lying around in my garage and a rear HT3525 on my bike. Both were controlled with a Lyen MKII 124115 controller. I did not like it, and continued with the rear motor only.
Now I am trying to push the single motor setup as far as I can. In case I fry the motor, I will continue with another. If I fry the controller, I can continue with the other Lyen MKII. Note that I am not against buying a bigger motor and/or a bigger controller, and I agree that from reliability point of view, that is the best way forward. However, I feel it is kind of a waste (not to mention fun) not to try and tease my current components to their highest performance levels. And that is the reason for this thread. How can I optimize my current setup (rear HT + Lyen MKII 12 Fet + 30S) before having to buy a bigger controller?
“sorry if ZOMGVTEK and I are getting a bit techy and off topic on you, but it's related to your initial question.”
- see above. You both have given much more feedback than I expected when posting, and it is a great learning curve for me. Thanks!
“what is your comfort level with working with electronics? Think you could attempt the same mods I've done (I copied markcycle so it's not my mod idea, I'm just impressed with the results from it)?”
- maybe I could do something similar with my 12 fet controller. I have been reading your threads avidly, and I am very impressed. First thing now is to install a temp probe and record temps in a CA analogger that I just ordered from Grin.
“Why not run an 18 or 24 FET and not have to worry so much?”
- because the “worrying” is my learning curve, and I like it.
“be careful with that pack voltage, treat it with respect.”
- I will. I do.
“if you try running 80A it will probably work for a while, but if it fails don’t be surprised.”
- I won’t. Actually, I am surprised it worked up to now. And I am looking into ways of cooling the controller with oil in order to keep temps low. If there is anything I learned from you guys, it is that I need to keep temps around 25oC to get the most current through my IRFB4115 MOSFETs.
“IRFB4110PBF’s are just better for power”
- One day I may replace all my 4115 fets with 4110 fets, decrease voltage to 100V and increase battery current to 120A. But I would like to try cooling my 4115 fets first.
“that is why having a high block time is bad.”
- I understand, and changed block time to 0.1s using the hexedited software.
“18 FET is the minimum for the 4115’s” / “go for the 18 FET controller IRFB4115 controller and set it for 60A battery and probably 140A phase and you'll probably be OK”
- Now I am in doubt with regards to the next controller. However, I would like to postpone that discussion until after I have destroyed my current controllers….
“I'm going to have more high power high voltage controllers than I know what to do with soon LOL, going to have to sell some off on here.”
- one prospective buyer is right here….
“Honestly, the only real logical step forward from where you are, is 36 FET 4110 / 20AH+ 24S LiPo / 'speed' wind hubzilla (which I think is available). Toss the motor in a 20" wheel with an ML75 tire and call it a day.”
- Yeah, you are probably right, and it looks like that in the future I will go that way. However, then I also want a high quality downhill FS frame with a super-duper dual crown 203 fork and the works. So I do not see that coming within the next 6 months….
“I probably should mount some FET's onto a snazzy liquid cooling setup and see what they can take. I have much snazzier equipment now, so I might be able to make really meaningful conclusions as to the absolute power handling, and thermal limits.”
- Now I would like to do something like that but in real life conditions, aka climb a nearby 10-20% hill, record the currents and temps using a CA analogger, and compare the stock controller versus oil cooled controller with a fixed max speed (e.g. 30km/h) on that same hill. That should give me a baseline current/temp curve upon which I can look at the respective changes from baseline from the different mods I plan. The way I see it, my controller needs to be modded first, then the motor. Heat is my biggest enemy, and that will be the main focus of my efforts…
- I was hoping I could copy some ideas from Tomshardware here and from this mineral oil cooled pc site… http://www.pugetsystems.com/submerged.php I should be able to submerge the complete controller into a slightly larger case filled with ATF oil. The shear amount of oil should transfer heat and delay temp increases for quite some time. Otherwise, the addition of a small radiator with a 12V fan would also require a pump to move oil around, but would definitely be more effective in transferring heat. Only one way to find out….
Thanks again for your feedback!