Search results

Date Relevance Most replies

  1. I

    Which BMS for lead acid battery replacement in I.C.E. motorcycle application?

    I recently had one of the cells on my lifepo4 motorcycle battery go poof, and when I opened the thing up I noticed that the shunt resistors on the BMS seemed somewhat less than impressive. I know these things are only built to take 3 or 4 amps, but we're talking gnat's ass surface mount...
  2. I

    BMS for motorcycle battery?

    Yeah, that's what I'm thinking. I mean, why NOT balance the cells every time you drive if you can? The problem I have at this point is finding a 4 channel bms that is rated for that short 150 to 200amp discharge peak. Charging should be good, since bms modules with a 30amp charge rate are...
  3. I

    BMS for motorcycle battery?

    No BMS, eh? So you're saying I should just manually top balance the cells and have something to disconnect the pack at low voltage? Still seems like I should have some over-charge protection for each of the cells since they're basically charging every time I get on the bike.
  4. I

    BMS for motorcycle battery?

    Anyone know of a BMS that would be suitable for use in a vehicle starter battery? They want about $170 for a 4ah motorcycle battery and I just can't bring myself to shell out that kind of cash for a battery with so little capacity. I was thinking maybe 4 15ah headway cells in series would do...
  5. I

    Choosing a power supply for paralell charging...

    I have about a dozen 40ah lifep04 batteries (split into 3 packs, of 4 parallel cells each) that I want to charge, and I was hoping somebody might be able to give me some advice on which power supply I should go with. The two that best seem to fit my needs are the meanwell rsp-500-3.3 (or...
  6. I

    EMC-2000 charger from ecity (1500 to 2000W)

    Mega: Not all that much really, the transformer is obviously your major stumbling block when it comes to weight. I suppose you could make it work with a coreless or aluminum wire transformer if you could find a way to cool it fast enough and were willing to trade volume for weight. Kepler: My...
  7. I

    EMC-2000 charger from ecity (1500 to 2000W)

    I don't know about the 900w units, but the "2kw" units are pretty heavy. I dare say that you wouldn't want one tagging along for the ride on anything built for performance, even something in the motorcycle or scooter weight class. I suppose it might be worth the sacrifice for the right combo of...
  8. I

    EMC-2000 charger from ecity (1500 to 2000W)

    So I bought one of these bad boys about a year ago (EMC 2000) and at the time I was using a 68.5v pack, but recently decided to down size to a 24v pack (3.6v * 7 thundersky 40a) to run a geared RC motor system. I've never had any trouble with the charger at the original 68.5v setting, but the...
  9. I

    DIY AC TIG Welder using an e-bike controller?

    So, apparently an ebike controller wouldn't really make sense as the inverter drive for a welding machine, but what about an induction heater? It seems to me that if you could target the ideal frequency for heating the filler metal instead of the base metal you could braze something like...
  10. I

    Pneumatic Transmission?

    Hah! Excellent, so I'm not entirely crazy after all. I was afraid I might have to couple a pair of them to get true torque reduction though, and this does seem to confirm that such is the case. Perhaps it could be done in such a way that the differential housing would serve as the sun gear for...
  11. I

    Pneumatic Transmission?

    Yeah, looks like my main problem was that I was simply failing to scale my mental model correctly. I was thinking we were talking coffee cup hot, when its looking a lot more like we're talking espresso machine hot, or hotter. If you visualize it in this range the whole thing goes to shit in no...
  12. I

    Pneumatic Transmission?

    I appreciate that you're taking the time to explain where I'm going wrong, because that's how my ideas improve, but there is obviously some sort of disconnect, because all I'm seeing here is a reiteration of the basic reasoning behind my argument, only with a contradicting conclusion. What I'm...
  13. I

    Pneumatic Transmission?

    I get that conventional wisdom says that compressed gas is inefficient, which is all well and good because most people don't stop to think about the fact that the majority of the kinetic energy being pumped into your system is going into thermal excitation of the gas molecules, but it is not the...
  14. I

    Pneumatic Transmission?

    I've been farting around with the idea of using a high speed rc motor for my next build, simply because the little buggers are cheap as frak, crazy efficient, and weigh a fraction of what a comprably rated hub would weigh. The only problem is that no matter how I slice it, I keep coming back to...
  15. I

    DIY AC TIG Welder using an e-bike controller?

    I don't know, it seems to me like people have glued aluminum to great effect in the past with bikes, and it is certainly common practice among the DIY aircraft folks (not to mention the aircraft industry for that mater). Either way, it won't cost me much to try, so I'll let you know if it turns...
  16. I

    Dr.Bass Steveo found 7s3p Module! Awesome Price!!

    I think you have to honestly ask yourself just how much your time and energy is really worth in the grand scheme of things before weighing the value of these cells. If you're not in a position like Oatnet to stockpile modules, it may very well be more profitable to pay a little more for...
  17. I

    DIY AC TIG Welder using an e-bike controller?

    Well, I'm an idea man, always have been really, so theory is a good place for me to be, but sometimes when you've got a dozen different ideas all pulling you in different directions, there is a very real danger of either stalling out somewhere in the middle, or just plain biting off more than...
  18. I

    Dr.Bass Steveo found 7s3p Module! Awesome Price!!

    Yeah, pretty much the only way to make something like this work is to have enough buying power to subsidize the loss. If you can consistently buy the cells at $15 with 30% bad on average, but you can sell the cells for $30 a pop, you will come out of the deal smelling like roses. If you sink...
  19. I

    DIY AC TIG Welder using an e-bike controller?

    Well, its not so much about building battery cases as wanting to learn how to do tig on aluminum. Granted, it would definitely prove usefull on my bike projects, and that is one of my major motivators for choosing aluminum tig in particular, but welding is a valuable skill in its own right. At...
  20. I

    DIY AC TIG Welder using an e-bike controller?

    Yeah, money is something of an issue, but then money is always going to be an issue, and I was figuring on consumables cutting into my budget either way. AC tig is where I would prefer to invest my practice time, because aluminum is the material I really want to work with, but perhaps a used oxy...
  21. I

    DIY AC TIG Welder using an e-bike controller?

    http://www.ebay.com/itm/JASIC-Inverter-PCB-welder-Repair-WSE-200P-TIG200P-AC-DC-/170658597127 How does this look? It seems to be the primary inverter module from one of those cheap Chinese welding machines. They also sell a board with a bunch of pots and resisters all over it that I'm guessing...
  22. I

    DIY AC TIG Welder using an e-bike controller?

    Well, I wasn't thinking you would feed them into the same two wires, I was thinking you'd have multiple electrodes. My thinking was that the problem with multiple electrodes would be that the power might want to arc between the electrodes rather than the weld, but then I suppose that produces...
  23. I

    DIY AC TIG Welder using an e-bike controller?

    I was thinking about the phase issue, and it occurred to me that induction should cause a time delay proportional to the amount of power stored in the field, which does seem to be the case after all, but apparently it is more complicated than that. To be honest, I don't really get what all is...
  24. I

    DIY AC TIG Welder using an e-bike controller?

    I'm also wondering why the phase issue is a problem. Don't most controllers have an option to set the phase angle between each output? Shouldn't we be able to paralell the outputs if we set the phase angle to zero (or n*360 for that matter)?
  25. I

    DIY AC TIG Welder using an e-bike controller?

    So are you saying that the back emf sort of fills in the gaps between the pulses, and that this more or less makes the wave look smooth? I suppose I can see how that would work, provided that the back EMF was out of phase by an integer multiple of pi, otherwise you'd more or less just get...
Back
Top