Former Member Posted June 25, 2018 Share Posted June 25, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Former Member Posted June 25, 2018 Share Posted June 25, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted June 25, 2018 Author Share Posted June 25, 2018 Hi Peter, thanks for explanation, well written, but are you saying plugs can be blown with power panel just because we have adjusted the amps to a high level, and with a single cell the volts and amps are fixed ? Cheers Quote Link to comment Share on other sites More sharing options...
will -0 Posted June 26, 2018 Share Posted June 26, 2018 Of course in this weather, a glow stick, fuel pump and a stick of wood is all you need......... Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 26, 2018 Share Posted June 26, 2018 "plugs can be blown with power panel just because we have adjusted the amps to a high level" Quite so. "You missed the washing up liquid and rags to clean the Merco 35 powered models before fitting them on the back seat of a Vauxhall Viva" You got me there! Quote Link to comment Share on other sites More sharing options...
Don Fry Posted June 26, 2018 Share Posted June 26, 2018 Posted by fly boy3 on 25/06/2018 21:22:05: Hi Peter, thanks for explanation, well written, but are you saying plugs can be blown with power panel just because we have adjusted the amps to a high level, and with a single cell the volts and amps are fixed ? Cheers I am out of my comfort zone, but I believe a panel supplies 12 volts to the plug, but in very short bursts, think high speed switch. There is a school of thought that this is not good for plugs. Might be right, might be wrong. Quote Link to comment Share on other sites More sharing options...
Cuban8 Posted June 26, 2018 Share Posted June 26, 2018 My Turnigy power panel doesn't have an adjustment for current, but automatically drives about 2 to 3A to the plug depending on whether the plug's a bit wet or whatever. Has a useful glowstick charger as well - I do tend to use the glowstick rather than the panel's driver, but I'm rarely left without 'heat' with the choice of two sources. Dumped the old (20 years according to the date I'd written on it) 12V gel battery in my flight box for a 2200 lipo. More than enough. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 26, 2018 Share Posted June 26, 2018 "I am out of my comfort zone, but I believe a panel supplies 12 volts to the plug, but in very short bursts, think high speed switch. There is a school of thought that this is not good for plugs. Might be right, might be wrong." Yes, panels operate a cheap & simple chopper circuit (much like a brushed motor ESC). Key words are normall cheap, cheap, and, er, cheap. They can fail "on", i.e. 12V constant to the plug. Obvious end result. They may or may not enjoy driving a shorted plug, or having the clip attached in such a way as to create a short. If they are in working order, it's not bad for the plug in the slightest, providing the overall energy delivered to the plug is correct. The major problem they seem to suffer is the glow goes south when the starter motor is used. Again, easily compensated with some extra circuitry, but AFAIK most panels simply do the bare minimum necessary to get a variable drive. Edited By Nigel R on 26/06/2018 11:02:12 Quote Link to comment Share on other sites More sharing options...
Don Fry Posted June 26, 2018 Share Posted June 26, 2018 I would suspect Cuban8 has an answer with the lipo. Because, while I think panels are overcomlicated, my main criticism is the lack of power to drive it all with a small lead acid. A lipo would work. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 26, 2018 Share Posted June 26, 2018 Gel cell about 4 or 5lbs, vs the lipo at about 1/2lb, no contest. Gel cells are mainly useful to stop your workbench moving when test running a 20cc+ motor. Quote Link to comment Share on other sites More sharing options...
J D 8 Posted June 26, 2018 Share Posted June 26, 2018 I use a 3s 1300 for my power panel and a 3s 2200 for the starter. Both are old batts but do their new job fine. Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted June 26, 2018 Share Posted June 26, 2018 Posted by Cuban8 on 26/06/2018 10:51:41: My Turnigy power panel doesn't have an adjustment for current, but automatically drives about 2 to 3A to the plug depending on whether the plug's a bit wet or whatever. And this is - potentially - another problem! Different plugs glow at different current levels, depending on the thickness of the wire! An OS 8 or Enya 5 will typically draw around 3 amps when lit correctly. However, some of my older engines use long-reach plugs, which are glowing quite happily at 1.5 amps! Pushing 2 or 3 amps into them will definitely not do them much good! What is important is the VOLTAGE at the plug itself - not the current or the voltage at the power panel! At these sort of currents, a long glow lead will significantly drop the voltage by the time it reached the plug. An ammeter is only useful as an indicator of whether the plug is wet or dry (or blown!) once you have learned how much current your particular plug draws. There is no "one size fits all" current that is suitable for all plugs. A single cell NiMh (or NiCad) and short leads (or a glow stick) will allow the plug to draw whatever current it needs without human intervention and without any risk of over-driving it. Most power panels are pretty crude, with just a big variable resistor in series with the plug. High current rating variable resistors are not noted for their reliability! More sophisticated ones use a variable resistor to drive a transistor, which eliminates the need for a heavy duty variable resistor. The most sophisticated ones use a variable mark-space ratio to deliver 12V to the plugs in short bursts, producing the equivalent of 1.5 or 2 volts *on average*. However, as the peaks are 12V, I can't help but wonder what the ensuing vibration (thermal, if not mechanical) will do to the thin platinum coating. In short, you can't beat a single NiMh cell of adequate capacity as a glow igniter. Its self-regulating regarding current, and makes it almost impossible to overdrive. -- Pete Quote Link to comment Share on other sites More sharing options...
Former Member Posted June 26, 2018 Share Posted June 26, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Nigel R Posted June 26, 2018 Share Posted June 26, 2018 Maybe my experience is a bit limited, but, I've not ever seen a power panel with a large variable resistor. It'd have to be capable of wasting about ~30W of heat and would be pretty large and expensive. A power panel with a transistor wasting that heat would need the transistor to be bolted to a significant chunk of metal to sink the power. Metal cases and heatsinks tend to be a bit expensive compared to a plastic box. A 555 chopper circuit and mosfet transistor on the other hand, costs pennies, and wastes no heat, and can be stuck in a cheap plastic box. The Turnigy panel regulates to 1.5V, according to the Hobbyking web page. Presumably using some voltage sensing arrangement to control a chopper circuit. Quote Link to comment Share on other sites More sharing options...
Bob Cotsford Posted June 26, 2018 Share Posted June 26, 2018 In 50+ years messing with models driven by glow motors I think I'm right in saying that the only time I've had a power panel blow a plug was the time I plugged the glow lead into the 12v starter socket by mistake. That cost me 2 * OS-Fs. I've run glowplugs off cyclon cells, 2v lead acid, NiCad, all manner of on-board glows and the worst, least practical, most dangerous and most likely to let you down were the clip-on glow sticks. I'm sure Pete is correct on the theory side but in practise my plugs last for years and were more likely to be swapped because they'd become gunged from running castor than any other reason. Quote Link to comment Share on other sites More sharing options...
Trevor Crook Posted June 26, 2018 Share Posted June 26, 2018 Can't match your 50 years Bob but I was flying with glow for nearly 40 before my electric conversion. I had a couple of power panels and they worked ok, but I ended up going the simple route with a 12V ex-alarm sealed lead-acid for the starter. You used to be able to get them cheap at model shows. For the glow, a 2V sealed lead-acid with an ammeter in series. Pete is right to caution against too much reliance on the meter, but in my last years of glow operation they were all 4-strokes using O.S. type F plugs, even the Lasers, and these were quite consistent. If I remember correctly, they were quite juicy, around 4-5A primed and ready to start. If the current varied much from that, something was amiss! Regarding LiPo chargers, you can get a mains powered one that will also charge other chemistrys for £30-£40. Quote Link to comment Share on other sites More sharing options...
Former Member Posted June 26, 2018 Share Posted June 26, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Peter Christy Posted June 26, 2018 Share Posted June 26, 2018 Posted by supertigrefan on 26/06/2018 17:45:17: ......so what mods would make a standard panel a decent, plug friendly and reliable panel? The garbage bin? -- Pete Quote Link to comment Share on other sites More sharing options...
trebor Posted June 26, 2018 Share Posted June 26, 2018 I picked up an old MFA power panel for a £5 from a second hand sale, works great Quote Link to comment Share on other sites More sharing options...
gangster Posted June 26, 2018 Share Posted June 26, 2018 Those old Mfa panels were reliable enough. Just a resistor. I used a resistor for years. Sometimes the old ideas were the best Quote Link to comment Share on other sites More sharing options...
Don Fry Posted June 26, 2018 Share Posted June 26, 2018 Tigerman. You have a 12 volt battery. You have a charger. Get a 12 volt B6 type 4 button charger. £20. Run it off what you have. It will charge your plane batteries, transmitter, and anything else you have. For ever. Scrounge a useable but puffed when hot 4s battery from a clubmate. Common as muck. It's good enough for a starter, as you aren't running it to hot. And you need a cheap starter, which you have. That will start a 180 with ease. Get a cheap geared starter, and you are starting a 360. All you need is a tray to mount the battery to the starter. If you are posh, and don't like scrap, a cheap 10, 20 c new one does. Get a sub c, say 300 to 5000 sub C Niamh, £4, and it will do for the plug. So, £24, you are set for life. £28, and a box gives you a nice ammeter. Keep an eye out for future duff(ish) Lipo batteries. So when the gallon of fuel is gone, charge the batteries. Quote Link to comment Share on other sites More sharing options...
Former Member Posted June 26, 2018 Share Posted June 26, 2018 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Martin McIntosh Posted June 26, 2018 Share Posted June 26, 2018 I make my own power panels using a very simple and cheap circuit powered by any voltage you like. PM me if you want a copy of the diagram. No PCB required and anyone should be able to make it. Quote Link to comment Share on other sites More sharing options...
trebor Posted June 26, 2018 Share Posted June 26, 2018 Posted by gangster on 26/06/2018 19:22:04: Those old Mfa panels were reliable enough. Just a resistor. I used a resistor for years. Sometimes the old ideas were the best My low amp switch position is a tad over 2amp and the high amp position is just under 5amp, not sure if they are adjustable but I use a long wire so they are no problem. Quote Link to comment Share on other sites More sharing options...
trebor Posted June 26, 2018 Share Posted June 26, 2018 Id be interested in the wiring diagram for a diy panel Quote Link to comment Share on other sites More sharing options...
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