Search results

Date Relevance Most replies

  1. L

    Good replacement for fried 48V LiFePO4 BMS?

    A few years ago I put together two ebikes, each with 48V 20AH LiFePO4 batteries, from Chinese kits. The Trek 7500 had a rear 48V 1000W hubmotor, tops out at 29MPH with big fat me on it, I'm happy. The Schwinn Cimarron had a front 48V 1000W hubmotor from a different manufacturer, tops out at...
  2. L

    Connectors for balancing cables on e-bike batts, chargers?

    Does anyone knnow where to get the connectors that are commonly found on the ribbon cables for e-bike batteries and chargers? Not the heavier 14ga or 12ga wires that carry the main drive current from the batteries. I'm talking about the ribbon cables that are used for cell balancing by the...
  3. L

    "Lithium" battery explodes in San Diego FedEx warehouse

    There was an explosion in a FedEx office this morning (Wednesday, April 14) here in San Diego, maybe four miles from where I live. Apparently a box with some kind of lithium batteries in it, went bang. No one was hurt. First I heard of it was an announcement on the local station (KOGO 600 AM)...
  4. L

    Rode the Trek 7500 Ebike to work today (12 miles)

    Whizzed all the way here nicely, except for the rear rack pack falling off due to my clumsiness at bungeeing it on. 48V, 1000W rear hubmotor, 20Ah two-piece LiFePO4 battery, top speed 30mph on level ground. Registered with Calif DMV, and even has its own cute little moped plate! At one point...
  5. L

    Trek 7500 conversion, with split battery

    Some pics of the project. I ordered a 48V 20Ah battery from Vpower.hk to be made in two pieces, so I could mount it as shown. They basically made up two 24V 20Ah batteries and wired them in series, with BMS taps as appropriate and a 48V BMS and charger. Works great so far. Bike is somewhat...
  6. L

    How much electric cost to ride an Ebike?

    I just tried to figure out how much electricity it takes, and what that electricity costs, to ride an Ebike. Came out with a VERY low figure, which I'm not sure is right. I rode the Trek 7500 Ebike 22 miles. Some flat, some hills, moderate-to-high speeds (15 to 28 MPH). The WattsUp meter said I...
  7. L

    Can I solder directly to Headway 38120 cells?

    I've seen Headway 38120 LiFePO4 cells (10Ah) that have screw terminals, and other Headway 38120s that appear to have no terminals at all. I know that some cells have flat tabs spot-welded on. But I can't spot-weld! Does anyone know if it's possible to solder some flat tabs directly onto these...
  8. L

    Article on Ebikes in NY Times, Jan 16 2010

    http://www.nytimes.com/2010/01/17/business/17ping.html Gaining a Toehold for the E-Bike by BRAD STONE Published: January 16, 2010 TECHNOLOGY has eliminated many of life’s milder physical demands, like getting off the couch to change the channel, or going to the store to buy a book...
  9. L

    Where can I find Headway 38105 cells?

    I need the shorter 38105 cell (8Ah, slightly more than 4" long) for an ebike application, but so far I haven't found a vendor that has any. Anyone know where to get this particular cell?
  10. L

    How "Express" is "Express" in China, anyway?

    Ordered a battery from vpower.hk, to be shipped by their fastest way, "Air Express". It was shipped on the 13th via DHL, and I got a tracking number. Now, four days later, it has been bouncing around from Shenzhen to Hong Kong. It's still in Hong Kong as nearly as I can tell. By my reckoning...
  11. L

    Any law requiring brakes that cut off power to elect motor?

    I've put together two 48V 1000W ebikes so far. Both kits came with "power-break" brake handles, that have electrical connections to the controller. They work: if you are applying throttle and you squeeze a brake handles, the bike sags abruptly as power is cut off to the hubmotor. That part...
  12. L

    Is this Vpower 48V 5-Amp LiFePO4 charger operating correctly

    My 11-year old son and I took turns driving the new 48V 1000W ebike around this afternoon. According to the WattsUp meter, I used about 1.5 Ah, and he used around 2 Ah. So I'm sure the 48V 20Ah battery was at least partly depleted. I then unplugged the battery from the controller, and plugged...
  13. L

    Can I leave WattsUp meter in circuit when I charge battery?

    Can I leave my WattsUp meter in the circuit when I CHARGE my battery? I have a WattsUp meter I will be installing soon on my 48V 1000W ebike. It will be installed the "usual" way: "Source" side to the battery/BMS, "Load" side to the controller. I expect it will show me amperage, voltage...
  14. L

    Anybody have manual for Vpower 48V 5-amp LiFePO4 charger?

    I got a 48V 20Ah LiFePO4 battery from a chinese company on Ebay, and it came with a Vpower 5-amp 48V charger for LiFePO4. Does anyone have a manual or instruction sheet for this charger? I think the battery had a fairly full charge when it arrrived, it drove my ebike at fairly good speed with...
  15. L

    Is "LiFePO4" the same as "Lithium Ion"?

    I've heard of LiFePO4 batteries (Lithium-Iron-Phosphate), which have good power capacity and discharge rates, and are safe to use. Also heard of LiPo (Lithium-Polymer), which also have good power and discharge, but tend to catch fire or otherwise go boom in the night. Now I occasionally hear...
  16. L

    LiFePO4 batteries with 30C discharge rating???

    Most LiFePO4 batteries I've seen for e-bike applications, usually have discharge rates around 1C. So, a 20Ah battery can put out 20 Amps continuously for one hour, before being exhausted. If you try to discharge it at, say, a 2C rate (40 Amps), it will do it. But instead of lasting 30 minutes as...
  17. L

    Can a model plane brushless controller run an ebike hubmotor

    Can a model airplane brushless speed controller be used with an e-bike direct-drive hub motor? Some of the bigger controllers can provide 100A or more, according to their advertisements. Even a 48V 1000W e-bike hubmotor will seldom go over 20 or 30 amps. One example of a possibly-usable...
  18. L

    Can you wire LiFePO4 cells in parallel in a battery?

    Forgive me for the ignorant-newbie question, but I get the impression this is being done. To give a simple example: A guy has a bunch of 5AH LiFePO4 cells, and wants to build a 10AH battery. So he takes two of the cells, and wires them in parallel - that is, wires positive to positive, and...
  19. L

    How much of the time are ebikes run at full throttle?

    How much of the time are ebikes run at full throttle? It's a serious question, not asked frivolously. Every data sheet I've seen, lists the power, amps, torque, RPM, efficiency etc. only with full throttle applied. And they only list data at the motor's highest RPM range, usually 300-400 RPM...
  20. L

    What waveforms are present on an Ebike brushless hub motor?

    What waveforms are present on a running Ebike direct-drive brushless hub motor? This being the technical forum, I'm hoping there's somebody here who has hung an oscilloscope on the wires that go to (and come from) a hub motor. Anybody got any pictures of what the waveforms look like? Both from...
  21. L

    What size brake disc for an ebike?

    I'm converting a Trek 7500 to an e-bike, 48V, 1000W rear hubmotor. This hubmotor seems to have a mount for a disc brake, and I'd like to take advantage of it. It's a screw-on type, and I understand that adapters are available with a standard 6-bolt patters so that more modern brake discs can be...
  22. L

    48V 1000W rear hubmotor project (now with pictures)

    This may turn into a long, serial thread. I ordered and paid for a 48V, 1000W rear hubmotor from daoji888 of YXM Corp. in China, on Oct. 29. They shipped it on Nov. 5 (700c rims were out of stock, hence the delay), and today (Sat. Nov. 14) I got a call from the post office saying a big box had...
  23. L

    Has anyone here bought from EP-Battery (may273@gmail.com)?

    Has anyone here done business with EP-Battery in China via Ebay? How was their service, communication, products? Any comments/compliments/complaints?
  24. L

    Has anyone bought anything from vpower.hk?

    Has anyone bought anything from vpower.hk? They are an Ebay vendor, selling hubmotor/wheel conversion kits, batteries, and parts. Good things/problems to relate about them? I am considering buying one of their 48V 1000W hubmotor/wheel kits, Ebay # 220497274921. If you've bought a hubmotor kit...
  25. L

    I give up. What are the laws on E-bikes in California?

    Everywhere I go, I get a different story. There's a 20mph limit on ebikes. No, it's 22. No, it's 25. No, those speed limits are only for factory-built, complete bikes that are sold to customers; and that's a Federal law, not a state law.. If you convert your own bike to e-power, there are no...
Back
Top