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  1. dave9

    Laptop battery fix

    Those should work, though I might see if I could find some cells with tabs already welded on, unless you have a spot welder to DIY as you're not really supposed to solder directly to the cells themselves. I mean I am assuming that is how the original pack was set up, don't see any battery...
  2. dave9

    Portable Battery Charging Pod for E-Bike Trailer

    If you have 20" trailer tires and are going 15MPH (which you won't be, as already stated due to more energy used for alternator drag than forward propulsion) that is only 252 RPM. You need to increase that tenfold for a typical generator's sweet zone. Next, if your alternator is an automotive...
  3. dave9

    Portable Battery Charging Pod for E-Bike Trailer

    1/3rd HP is about 250W. If he is peddling this contraption around, on top of already peddling around gear, he has to have bicycle legs. Even so, it would take most of the enjoyment out of it, how slow he was going to get an RPM drive ratio for an efficient charge off such a big alternator...
  4. dave9

    Portable Battery Charging Pod for E-Bike Trailer

    Your linked 63A alternator is far too large for peddle power. Recognize that an alternator like that, does not respond linearly to RPM increase, rather falls off a cliff at low RPM so you would have to spin this heavier than necessary alternator, that much faster to get it to produce decent...
  5. dave9

    Portable Battery Charging Pod for E-Bike Trailer

    It still makes no sense, to expend your energy to recharge it, in order to get it back so you don't have to expend your energy. It is a losing proposition unless your battery is only used to power something at your destination like a flashlight or radio, charge your phone etc, not power the...
  6. dave9

    Laptop battery fix

    6 cells, nominal 3.7V each, so 11.1V/3.7= 3 in series 6 cells / 3 in series = 2 parallel runs of 3 in series 2 parallel to reach 5200mAh = 5200mAh/2 = 2600mAh per cell. You do not need to get 2600mAh rated cells, could use a bit higher or lower, and remember that was only their original rating...
  7. dave9

    Designing a soldering iron for limited dexterity

    Then you are not necessarily solving that problem with a new iron design. This is more about learned technique using a standard, but decent quality iron including the right tip shape, size, keeping it clean yet wetted with solder. However, larger through-hole components are particularly easy...
  8. dave9

    ribbon cable connection repair

    The surest way towards a good, long term solution, is desolder the old broken connector and replace with one suited to the existing plastic sheet connector. It would be good to have precision calipers to measure the FFC cable thickness, then go to your preferred electronics supplier and search...
  9. dave9

    Malibu Landscape Lighting Parasitic Draw

    Had a chance to tear into it today. First, it's Twilight brand, not sure why I thought Malibu, except that I'm sure Malibu made something similar back in the day and was a very popular brand in the US for a while. There is a 0.22uF film cap across the relay but it is not leaking. Removed it...
  10. dave9

    ribbon cable connection repair

    I do not think you (or anyone else) can solder to that plastic ribbon cable, would probably destroy it. Conductive epoxy "might" work, or might just fall off as the carbon coating could be a bit slippery. I have not tried using conductive paint or pens for something like this, have no idea...
  11. dave9

    ribbon cable connection repair

    I'm not clear on what these lockable tabs are, do you feel that you can harvest this off a new connector and transplant onto the old existing one, or are you planning on desoldering and removing the old connector and soldering a new one on? Look on the sides of the connector to see if you can...
  12. dave9

    Which computer power supplies produce clean power?

    You aren't making any sense. A trifield device measures noise from the input and has nothing to do with the "produces clean power" which is about the output. Further, what does it matter? What is the application where you are forced to have sensitive equipment located nearby, that don't have...
  13. dave9

    Malibu Landscape Lighting Parasitic Draw

    I'm going to have to open it up... probably due to be cleaned out anyway. I've been waiting for the snow to melt then mud to subside before disturbing the lighting set. Seems that if you move any of the cables much, they may need redone at the nearest lights due to the now non-air-tight...
  14. dave9

    Malibu Landscape Lighting Parasitic Draw

    I'm tasked with repairing a Malibu Landscape Lighting set that is exhibiting parasitic draw. It's a 12VAC setup, old (20+ years?) unregulated linear transformer design with optical sensor, multi-position switch for hours runtime, and a relay to switch power on and off. Originally had ~10W...
  15. dave9

    3.3mm PCB stereo socket

    The most problems with 3.5mm sockets are had using old stock (tarnished contacts) or generic chinese (weak spring metal), though personally I hate any of them when surface mount, as it is just too easy for a headphone cable to yank too hard, or be bumped, and tear a solder pad off so I prefer to...
  16. dave9

    replacing two D cells with pair of 18650 batteries but need voltage drop

    Tenergy makes a LSD 9V so that's what I'd get if you want to go that route, but personally, my only 9V devices are some hardwired smoke detectors and a couple clock memory backups, so I just use alkalines because their 10 year shelf life is near what I get out of them. In that case I buy the...
  17. dave9

    LED Forward Current vs Forward Voltage

    Different LED bins don't matter near as much as the token graph provided, because the human eye isn't that sensitive to small % changes. Yes, there will be differences in output. If that is important to you, change the design. For most people, it isn't important enough to change the design...
  18. dave9

    Trying to reconfigure this jump start/peripheral connector cable thing

    Could be two factors, maybe three. 1) Jump starter packs marketed in recent years are often notoriously overrated, sometimes by a factor of 10X or more. 2) A 650cc motorcycle probably only needs 40CA or so, depending on temperature and a few other variables. 40A for a few seconds is no...
  19. dave9

    replacing two D cells with pair of 18650 batteries but need voltage drop

    ^ I've never had a single NiMH cell leak in use, though one time I bought some old stock no-name NiMH for dirt cheap from an electronics surplus site that were already leaking in the blister pack... so it is possible, but pretty unlikely. I do mark my cells so I keep them in groups of same age...
  20. dave9

    replacing two D cells with pair of 18650 batteries but need voltage drop

    The EBL you linked in the post after this one quoted, have very high self discharge rate. I'd only use them for things you plan to need the most capacity out of possible, within a week of charging and even then, I've never had good luck with EBL batteries as far as # of recharge cycles before...
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