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  1. dawrench

    Magnesium rims for ebikes

    Cars need massive rims and spokes because of the side loads on the wheels. Motorcycle wheels are built the way they are because of the way they are used. Look closely at them. Then look at the wheels on a sidecar rig. Chalo is in a perfect position to know what works for heavily loaded bike...
  2. dawrench

    Active pre-charge/inrush control

    I have been using this circuit (fechter's #3 with a switch) since early June on a 48 volt system and had zero problems. Same circuit since the first of August on 18s and nary a problem. The FETs came from Mouser, I used a heat sink with thermal compound and all wiring was point-to-point.
  3. dawrench

    KABOOM!

    1 can of soda, 3 very cold nights. I'm just glad I found it before the 4th night.
  4. dawrench

    Active pre-charge/inrush control

    Sorry Izeman, still not over my foot-in-mouth problem. Yes, you're 100% right and that's why I have them with a key switch as well. What I meant to say was "stop charger sparking". I can leave the pack connected all the time now with secure On-Off and have a tap on the pack for the charger...
  5. dawrench

    Active pre-charge/inrush control

    Photos of a 3 x 4110 build good for 60 amps.
  6. dawrench

    Active pre-charge/inrush control

    Can one of these be used to stop controller sparking as well ? Would only need 1 FET to handle the charging current. I want to build one of these for use with 30s LiPo using 4115 FETs for my Cromotor build. 200 amps means 20 FETs. Other component values don't change? Would a piece of aluminum...
  7. dawrench

    Active pre-charge/inrush control

    Hum, I seem to find my foot in my mouth. The circuit has been working fine since last fall on 48v. I use it as my main On/Off switch. Wanting to use it on my 18s pack, I had to change some connectors. Simple enough. I still put them on wrong - swapped B- pack and B- controller. I changed them...
  8. dawrench

    Opening a LiPo cell

    I have a LiPo cell I'm curious to open. Gloves and face shield are a given as is working outside on a plastic table. Voltage is flat so I don't expect any sparks but is there anything else to beware of. Will the electrolyte melt the table or gloves? Can the remains be put in the recycling bin...
  9. dawrench

    Recovering puffed cells

    I de-puffed and compressed 6 candidate cells last night. The cell that was at 1.29 volts had dropped to 0.03v so I did that one for practice. 20 minutes on a charger and the voltage didn't budge so it"s out back in the ammo can till I can carve it up. I thought that one a goner anyway. The 2 the...
  10. dawrench

    Active pre-charge/inrush control

    Yes, it is the version that brings the gates down to B-
  11. dawrench

    Active pre-charge/inrush control

    I will check. Does the voltage rating of the switch matter?
  12. dawrench

    Recovering puffed cells

    Thanks for the de-puffing thread. I now have 3 cells that won't be going back in the pack I can experiment with. If they show any kid of capacity I'll keep them for starting the lawn mower.
  13. dawrench

    Active pre-charge/inrush control

    I built Fechter`s Automatic precharge 3 circuit using 5x 4110 fets. Been using it on a 48volt pack - 54volts HOC with no problem. When I tried to use this with my 18S pack - 75.2 volts - It did not work as normal. Sparks on connection of pack to controller. With the key ON I got full voltage...
  14. dawrench

    Recovering puffed cells

    Here's a pic.
  15. dawrench

    Recovering puffed cells

    Went to the Post Office today to pick up a new CellLog. Lost mine 3 weeks ago. I verified the cell voltages of my pack once home because the voltage felt saggy. Found one cell at 1.29 volts. Not Good. Opened the box to find the bricks puffed as in the photos. I don’t use a BMS and monitor cell...
  16. dawrench

    Filament Taped Compression of Aged Zippy 8AH Packs

    What did you use to reseal the pouches? I have some puffed NanoTech bricks that have lost capacity.
  17. dawrench

    Starter Question

    Starter motors are meant for intermittent use only. You really need something rated “continuous use”. Here is a bike built with a mobility scooter motor that has a gearbox incorporated and uses the rear wheel gears for extra hill climbing ability. Brushed motors are not as efficient as...
  18. dawrench

    Who runs a 20" rear hub?

    Standard bicycle cranks are 170mm long. Look for SINZ cranks in lengths of 120-135mm. Other manufacturers as well. Sometimes marked as BMX cranks. Get ones to match your BB - square taper or ISIS. Find them on ebay or the Used Parts Page (that's where I found mine).
  19. dawrench

    55V charger safe for 13s 54.6v operation?

    If the charger is not adjustable, is this a case where a half dozen 1N5401 diodes in series added to the end of the charge wire would trim the final voltage down to 4.2 or below?
  20. dawrench

    Throttle signal is higher than the supply

    OK, Measuring from the battery + and – lines to the motor phases I got between 8 and 10 kohms for all combinations. No continuity between the + wire and signal input. I unsoldered the throttle signal wire from its pad and measured the throttle voltages again. Using a different multimeter from...
  21. dawrench

    Has anyone got an Ursus Jumbo centre stand?

    It may be heavy but it's strong and stable. Your ebike won't fall over with this one. Legs are not intended to be length adjustable - they are what give the stability.
  22. dawrench

    Throttle signal is higher than the supply

    Voltages measured used the throttle ground pad on the board. I borrowed a more expensive voltmeter and will verify the numbers with that.
  23. dawrench

    Throttle signal is higher than the supply

    All voltages specified are with the throttle closed and changing throttle position did not change output signal.
  24. dawrench

    Throttle signal is higher than the supply

    Power On without throttle and the LED board status light does not blink. With no throttle connected, supply is 4.22v and signal is 4.24v. There is no connection between supply and signal wires. If I connect the throttle with power on, led does not change. Power on with throttle and the led...
  25. dawrench

    Throttle signal is higher than the supply

    The throttle has been tested with another controller and works fine.
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