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  1. 2

    Looking for a power supply

    I am after some pointers in the right direction for a new power supply that I want to use in a new project. Main specs are: - runs off-line, ideally something like 85-265VAC, 50.60 Hz - constant current output which must be adjustable from 0-5A - maximum output voltage 60V or higher - high...
  2. 2

    Higher quality alternative to HobbyKing cells?

    I've been using HobbyKing cells (http://www.hobbyking.com/hobbyking/store/__18560__Turnigy_5000mAh_1S_20C_Lipoly_Single_Cell_.html)to make custom battery packs and the quality of these has been pretty disappointing. Even though, I qualify them and group them accordingly in packs, discard any...
  3. 2

    BMS for Hobby King bricks?

    Does anyone know of a modular BMS that can be used with the 5 or 6s LiPo bricks that HobbyKing sells? Ideally, it would be modular, so that there is a BMS for each brick and can be daisy chained. Anyone know of anything along those lines?
  4. 2

    Delta vs Wye winding

    Looking at using an outrunner motor for a new project. Size-wise, one of these would fit nicely: Specs (as far as they go) are here: http://www.hobbyking.com/hobbyking/store/__18184__Turnigy_Aerodrive_SK3_6374_149kv_Brushless_Outrunner_Motor.html Now, I'd like a even lower KV than the...
  5. 2

    Looking for controller recommendations

    I'd like to try some different controllers on my hub motor. I am currently using a low-end Kelly controller (KBS4805) and while it works fine, I'd like to get more starting torque. I know the motor is capable of more. So, I am thinking of the following: - sinusoidal commutation - 100A min peak...
  6. 2

    HobbyKing ECO6 chargers - WTF!

    I seem to go through these pretty regularly. Are they just junk? They don't seem to last more than about 4-6 months. It's this one: http://www.hobbyking.com/hobbyking/store/__11060__HobbyKing_ECO6_50W_5A_Balancer_Charger_w_accessories.html What's a more reliable model for a similar spec? Don't...
  7. 2

    Strange LiPo behaviour

    OK, so I got 4 small Zippy LiPo 2s/1100mAh packs from Hobby King. I've wired them up into a 4s/2p configuration, i.e. 14.8V/2200mAh nominally. I've cycled them a few times using my balance charger which I use for all my LiPo and LiFePo4 packs. It charges/balances fine to 4.2V/cell. The strange...
  8. 2

    Yet another BMS!

    Well, this will be my first post to hopefully make a decent contribution to ES. After having looked around pretty exhaustively (at least I hope so) for a suitable BMS, I came across one designed by Walls99. His BMS thread can be found here...
  9. 2

    Calculating the voltage constant Kv

    Is it possible to calculate the voltage constant from a measured phase voltage when rotating the motor by hand? In other words, the known values are: - peak-to-peak voltage - frequency of voltage - number of motor poles - number of slots Is that enough? BTW, it's a standard brushless direct...
  10. 2

    Low current BMS

    I am hoping someone can point me in the right direction. I am trying to build a simple BMS/LVC circuit for a small battery pack for a photo studio flash unit. I am using a 4S LiPo battery with 1500mAh capacity. All it needs to do is deal with maybe 2A of charge current, monitor cell balance, and...
  11. 2

    Upgrading from Kelly controller

    Looking for guidance and advice on replacing my Kelly controller that I am currently using with a direct drive hubmotor commutated with hall effect sensors. Specifically, I would like to improve the startup torque. Clearly, the Kelly controller is a low budget one. Are there better ones? I only...
  12. 2

    Most powerful hub motor?

    Looking for recommendations for a hub motor, preferrably non-geared, i.e. direct drive, that produces the most amount of torque. Not really bothered about speed, mainly low speed torque. Which one?
  13. 2

    Torque at zero speed

    In general, how good are hub motors at producing full or near full torque at zero speed, i.e. setting off from a dead stop? Is the fact that commutation is relatively crude with typically just 3 hall effect sensors a factor that works against it? Is there a combination of hub motor and...
  14. 2

    Torque Constant?

    Having looked at more spec sheets than I care to, there seems to be distinct lack of mention of the motor's torque constant. Everything seems to be focused on speed, i.e. voltage constant as in RPM/Volt. But without the required torque to accelerate the maximum speed is largely theoretical...
  15. 2

    Leaf hub motors any good?

    Hi all, newby here. I am starting another electric bike project, an electric trials bike this time. Was looking to use one of the higher powered hub motors this time, almost certainly a direct drive, as geared ones tend to have longevity problems in serious off-road use. Have been looking at...
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