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danny_galaga

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Everything posted by danny_galaga

  1. danny_galaga
    You're still overthinking it for many ultralights. A switch alone can handle the current I'm talking about. What's the voltage drop across a good switch? It's pretty minimal, way less power loss than any superfluous extra wiring and doohickeys you have to add. More power less and more weight. But if your objection is spade terminals, I present, for your edification 🙂
  2. danny_galaga
    I get that what is good about it is that you have a very low trigger current, which is especially useful if you wanted to trigger it with say a 555 timer or something, or where you have a big boy plane with a panel drawing 25amps and a 170 amp alternator bolted to that Lycoming 0360. But I am talking about ultralights here. The total output of the alternator is 17 amps. That's the total, but all the loads add up to maybe 5 amps through my (described rather than named because I admit I'm guilty of confusing terms) OFF/ON/START switch. But if for some reason I thought that was too heavy a load for that switch (which it isn't), why wouldn't I just use a 35amp automotive relay? That will have a switching current of maybe 200 mA. What is the SSR? 50mA? But it's constantly dumping power. So yes, only 50mA through the switch, but several amps as heat through the heatsink, while the 35amp relay is only losing 200mA total. The original query was about total isolation of the battery. To do that needs something that can handle the cranking current of the starter. Which is either a giant relay (which is why I started the thread since I hated the idea) or a giant switch AKA a battery isolation switch. Gotta keep it simple on an ultralight, especially with only 17 amps to play with 🙂
  3. danny_galaga
    Quick, you only have 15 minutes!
  4. danny_galaga
    Life of Brian? He's not the Messiah, he's just a very naughty boy!
  5. danny_galaga
    I don't care about what 'gay' means to anyone. The one that annoys me the most is AWESOME Having a particularly nice sandwich AND seeing a volcano blowing up and enveloping the town below in ash and lava cannot both be 'awesome'.
  6. danny_galaga
    Geez, how old are you? Gay has meant homosexual since the 1930s 😅
  7. danny_galaga
    I already bought a long tubey one from Clear Prop. But if the plastic pin goes on it I'll either "borrow" the cup I found, else fit a steel pin to my tubey one 🙂
  8. danny_galaga
    Would you believe I just found one in the hangar 😄 But I like the long tubey ones. Doubles as screwdriver for the cowl, and long and tall means it's easier to see water in it. The new one works well. Best would be long tubey one with a steel pin 🙂
  9. danny_galaga
    Yes, and it does that by switching off a big relay/solenoid. I'm very happy to have avoided that by just having a giant switch 🙂 And there can't be any confusion about what the switch does- it's big and red and has a picture of a battery on it 😄
  10. danny_galaga
    Yes, this is great advice. Maybe not today, but before it gets flying 🙂
  11. danny_galaga
    Yeah, I did try to stick a fuel drain in the bung last week thinking "surely that hole means something". But I borrowed someone's fuel drain, with a plastic pin. It's so old it was just bending. But it worked in the gascolator. But now I have a new fuel tester so just for shits and giggles tried it. Waddaya know 🙂 I feel bad for bending the other guys fuel drain so I bought him a new one too.
  12. danny_galaga
    See my post above, I guess I have these flush mounted drains https://www.aircraftspruce.com/catalog/appages/curtisflushmounted_05-04888.php 😄
  13. danny_galaga
    F&$k me. The BUNGS are the drains 😄 Problem solved.
  14. danny_galaga
    Note that the bungs are definitely at the lowest point in the tank, which is good. Gascolator hangs in the breeze.
  15. danny_galaga
    I might quiz the Bushcat crowd to see what they are doing. The kit didn't call for a separate drain so I assumed the gascolator was all you use. This kit comes with everything but prop, engine, instruments BTW. So if it's supposed to have a drain, it would be in the manual. But I'm always open to improvements.
  16. danny_galaga
    Ok, did the experiment. First I drained the gascolator without doing anything else. Got maybe 5mL like before. Then I ran the boost pump for 15 seconds, switched it off and tried again. About the same. Then I tried while the pump was running and sure enough got as much as I needed. I think as long as there isn't a larger volume of water in the tank than the gascolator can hold that method will be ok. There are two threaded bungs in the bottom of the tank so I could put a fuel drain in that. But that adds more complications and it points straight out the bottom. Some tiny chance something flicks up when taking off and knocks the drain off. KISS
  17. danny_galaga
    A lot of this came about for me (I started this thread) because I was being lazy and wanted to know if I had to have an isolation relay/solenoid. People pointed out you really want to be able to fully isolate the battery in case of emergency (starter stuck in mesh, accident where positive cable shorts to airframe/engine, general electrical fire etc) Which it turns out that ssr is not big enough to do. So then it's kinda irrelevant. The starter key (off/on/start) on mine isolates everything but the battery from the cable already and now my battery isolator fulfills the emergency total isolation aspect. It's all interesting info though.And now my plane is much safer than when I started the thread. A good outcome 🙂
  18. danny_galaga
    Technically a relay, not a solenoid. Solenoids are supposed to cause a mechanical movement too, for instance a solenoid attached to a starter moves a fork which pushes a pinion into a ring gear. Some starters don't have that system but a giant relay to just turn the starter on and inertia pushes the pinion into the ring gear (Lucas starters for instance) or it it just has a sprag clutch like our little BMW 650 starter. Because that relay is about as big and boofy as a solenoid (which doubles as a relay on a starter) some of us call them solenoids. So then any giant metal can relay ends up being called a solenoid.It's a bad habit! I mention it because you'll want to get the wording right when you contact them Turbo 🙂
  19. danny_galaga
    Yeah, very rough guide for this sized starter is to allow maybe 500 amps. It's one of the reasons in the end I was happiest with a mechanical isolator over a relay. Pretty much no voltage drop or current draw. Every watt of energy to the starter. Faster starts, and battery recharges as quickly as possible 🙂
  20. danny_galaga
    Actually misremembered that. Cable does go to back of starter. Negative bus bar is fed by a wire straight from the negative battery terminal
  21. danny_galaga
    I have the negative battery lead going to the back of the starter. Because the starter was designed for the BMW 650, it has a couple of superfluous lugs on the back. They bolted to the BMW crankcase but just hang out in the air on the Rotax. Perfect for bolting the cable on. Gets the current right where you need it most, at the brush box of the starter for the shortest run. Then a lead goes from there to the negative bus bar on the instrument panel.
  22. danny_galaga
    My alternator is 204W by the way. Even the regular relay is using more than 10% of the alternators output just being there. Let alone 60W 😲
  23. danny_galaga
    Just when I was thinking I'd consider it 😄 I'm a big fan of every single watt of energy going to the starter when you are starting. That big lump of a battery is basically there just for that. It's also why I wasn't keen on a regular isolator relay/solenoid although that will draw less than the SSR it looks like (maybe 2a X 12v = 24w). In both cases, they are losing power all the time your key is on. 60w reliably (I guess 60w at start, and less otherwise but start is when you want the least loses), or 24w continuous with chance of contacts burning or fusing. Also that particular SSR has rather small terminals. Big cables tend to pull/twist so I wouldn't want them just hanging off those terminals. Maybe there's a bigger one, but then it might be dropping even more watts. Nope, I'm very happy you guys convinced me to put SOMETHING there. And I'm extremely happy with the isolator I went with, even though if I spent more time on it I concede I could have made the cable run a bit shorter. The cable run is still probably less than half what the kit suggested, and maybe a 1/4 or less of what I've seen in planes that have to have the battery rearwards! All in all, pretty pleased with myself 😊
  24. danny_galaga
    Welcome aboard! I used to dream of a Quicksilver and I reckon I would have bought a new kit a few years ago if it weren't for the double whammy if Rotax pulling out of two strokes and Quicksilver having financial difficulties at the time
  25. danny_galaga
    I should point out that if I put an isolator on the firewall, with a mechanical extension into the cabin, that would take about the same amount of cable as installing it in the instrument panel like I did. The battery is inside the plane..in the panel in this is just as good, and one less thing to go wrong (the extension). If the jigger faced the right way, it would be ideal because there's not one centimetre of extra cable used (it bolts directly on the battery terminal) . Facing the right way, I could have run a tube straight from that to the instrument panel
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