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  1. M

    50 cal ammo can batteries

    I will definitely try that vice trick. I have been taking a big pair of cutter pliers I guess is the political correct term for them these days. Almost got fired from one job for calling them the old name.. Anyway I cut in just a little right at the split, holding the pack in one hand as twist...
  2. M

    50 cal ammo can batteries

    Thanks for the good review. I am targeting 20kwh for my tractor project so have ordered 1800 of these cells to finish the project. I have already collected about 350 of the green Panasonic cells in these packs from the medical cells i was ordering. They where in some cubes that where...
  3. M

    50 cal ammo can batteries

    Just a quick update. I have been buying the used medical cells from battery hookup as the price seemed good. The last few days I finally did the testing for self discharging cells and sorted out about 1350 good cells that can be used in my peoject. I didn't keep great records of the shrinkage...
  4. M

    If a gas engine produces 9.9 hp what motor size would be the equivalent

    A gas motor is going to peak at torque somewhere around 1600 -2500 rpm. It will change some based on the compression ratio the higher the compression the higher the peak torque rpm rating. But at 5000 rpm the gas motor will probably have less than half the peak torque. Using a quick internet...
  5. M

    Buck converter 12v to adjustable 3.6V to 4.2V? high current

    For that application I would definitely look at designing for 14S 48 volts. That is the standard for most commercial inverters you would want to power. You could make standard packs of x cells and then put mutual of those in parallel later to upgrade the system. But the power you are talking...
  6. M

    Buck converter 12v to adjustable 3.6V to 4.2V? high current

    What are you going to do with 1000 cells all in parallel? The current draw will be much higher than if you put then in serries groups to increase the voltage. Just wondering because you are looking at either some crazy long run time or some very high current and high current means bigger heat...
  7. M

    If a gas engine produces 9.9 hp what motor size would be the equivalent

    Diesel engines usually have a higher torque but an even more narrow torque band than a gas motor. So their sizing is still very different than an electric motor. That is why an 18 wheeler has so many gears to match the ground speed to the torque curve of the motor. Electric motors typically...
  8. M

    If a gas engine produces 9.9 hp what motor size would be the equivalent

    The issue is you actually need to know the torque and rpm requirements for the load. Often gas motors are oversized to provide the torque at lower rpms. An electric motor has close to full torque at zero rpm so often you can reduce the motor size when sizing for the torque curve of an electric...
  9. M

    Re-wire a house to use 24v LEDs ?

    Unfortunately I can completely relate to your situation. I have an off grid system to install here this summer because if I stay on the gird I solar won't pay for itself in 20 years but if I leave the grid I can buy batteries and it will pay for itself in 9 years. More than half my electric...
  10. M

    Re-wire a house to use 24v LEDs ?

    I don't think you understood my point. I was saying mass production of things like 110vac lights and appliances makes it more cost effective to have an inverter in your off grid home that is running at grid voltage. It will be very expensive to get a DC dishwasher or refrigerator compared to...
  11. M

    KWeld battery

    Keith sorry I forgot his last name is the US distributor for KWeld. His contact is 18650shrink@gmail.com he was really nice about answering all my silly questions. I highly recommend working with him to order one. He involved my PayPal account for the order it was really easy
  12. M

    KWeld battery

    Thanks. I am sure my figures will be the weak point I don't like burns.. lol
  13. M

    KWeld battery

    So you don't worry about over discharging the battery? I was worried I might get too excited spot welding and draw the battery too low. Oh and I better add a good charger to my list if things I need to get...
  14. M

    KWeld battery

    I purchased a KWeld unit recently and bought the Turnigy graphene 6000Ah 3S 75C discharge battery to power it. I am just looking at setting it up today as I am collecting and testing enough batteries to start assembling a pack. I was just wondering looking at the battery what BMS would work in...
  15. M

    Re-wire a house to use 24v LEDs ?

    AC has less line losses than DC by a huge factor. Also the world is designed based on standard grid voltage. Simple mass production makes it cheaper to use the grid voltage and absorb the energy costs.
  16. M

    Have to say it...

    I think the point was simply that the cheap charger testers are not accurate enough to be useful. I have seen this myself I was going to toss a cell for testing > 600 on internal resistance only to have the cell slip out of my finger and the holder reseat to read below 100. Such a test is...
  17. M

    Re-wire a house to use 24v LEDs ?

    Something seems odd about your calculations but the best thing would be to try it out. I was just wondering how long a dewalt battery will run their led lights? I have a led lantern which isn't anything near that type of runtime I would say if it was fully charged a single day would kill it...
  18. M

    dammit JWINYAP(Just What I Need Yet Another Project)

    The biggest thing to watch for with over voltage on an electric motor would probably be arcing out for insulation failure. Which wil probably happen first with the internal air gaps. Higher voltage will mean lower current to provide the same power to the load. Of course if you put a heavier...
  19. M

    Re-wire a house to use 24v LEDs ?

    I wouldn't be surprised if the application you speak of uses AC power and simple rectifiers at the lights to get their 24vdc or the lights are depending on the LEDs to be the rectifier as that circuit is basically just diodes. I installed a manufacturing production line once that someone else...
  20. M

    voltage showing between inverter's earth and neutral

    You have to get to the earth with grounding the roof won't help it will infact just make the risk more as your entire roof will rise the the floating voltage. You need to get a discharge path into the earth people get killed by floating voltage over 40 volts if I remember the OSHA safety...
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