stunthanger.com

General control line discussion => Open Forum => Topic started by: frank mccune on March 21, 2021, 04:12:52 PM

Title: How to drop 2v to 1.5v?
Post by: frank mccune on March 21, 2021, 04:12:52 PM
     Hi All:

     Is there a way that I may drop 2v to 1.5v to drive my glow plugs?

      Tia,

      Frank McCune
Title: Re: How to drop 2v to 1.5v?
Post by: John Rist on March 21, 2021, 04:56:42 PM
     Hi All:

     Is there a way that I may drop 2v to 1.5v to drive my glow plugs?

      Tia,

      Frank McCune
I think if you put a diode in series you may be close.  Although a diode drops around .7 volts so you would be a little low. 
Title: Re: How to drop 2v to 1.5v?
Post by: Dan McEntee on March 21, 2021, 05:36:16 PM
  Do a test. Pick a know, 2 volt glow plug that still works. Put it in an engine. Make sure the battery is freshly charged. Make up a set of glow plug leads that are about 4 to 5 feet long. Hook them up and apply to the engine/glow plug. Measure your voltage at that point, and just for giggles and grins, measure it at the battery so you can see what the difference in the voltage drop from the battery to the glow plug. You should get a voltage drop, and you HAVE to do this testing with every thing connected. Just checking the voltage at the plug connector won't tell you what you want to know.

  Another option is to find some one with an old Glow Bee Fire Plug ignitor battery that has a bad battery in it. Put your new 2 volt battery in there. Unless the rheostat is bad, you should have safe voltage for a 1.5 volt plug.

   Another option is to contact Bill Bischoff and ask if he is still making his glow driver he advertised here in the classifieds;

    https://stunthanger.com/smf/classifieds-92/for-sale-custom-built-globee-type-glow-plug-batteries/
   
    If I understand him correctly, it is basically the same thing as a Glow Bee Fire Plug, it just uses Nickle metal hydride batters You can build your own box to hold the mechanism, and just eliminate his batteries.

   Type at you later,
    Dan McEntee
 
Title: Re: How to drop 2v to 1.5v?
Post by: Air Ministry . on March 21, 2021, 05:39:30 PM
Wear Steel Capped Boots ! .  S?P LL~

Six foot of telephone wire *, or strip some out of your car . Though if its Japanese its probably a bit light ! . ( * Blame the Poms, thier nomenclature . )

As in TWO five or six foot lengths of wire . Building Supplies - Tri Cor . Stripped . Leaves an extra for stripping to core for copper ( or steel ) wire binding / soldering, of things .

(https://thumbs.worthpoint.com/zoom/images1/1/0413/05/triumph-motocycle-dealer-tri-cor_1_760ccdd4090e7fd4a3c54febe7f3fc3e.jpg)

Gen u wine Tri - Cor .
Title: Re: How to drop 2v to 1.5v?
Post by: Dave_Trible on March 21, 2021, 06:08:05 PM
Back in 'the day' many of us used 2 volt military surplus wet cell  telephone batteries.  They wouldn't generally burn out plugs but in most cases we had four to six foot wire leads from the battery to the clip for the engine (or alligator clips).  I think that's all that is necessary .  The wet cells were sort of heavy and had to stay upright so they most always stayed mounted in the tool box, hence the long leads. 

Dave
Title: Re: How to drop 2v to 1.5v?
Post by: Peter in Fairfax, VA on March 21, 2021, 10:14:31 PM
A fixed resistor or variable resistor (potentiometer) would work. Or, as others say, a lot of wire.  Sorry that I do not know the exact value for the required resistance. Many flight boxes have pots to drop 12V to 1.5V.
Title: Re: How to drop 2v to 1.5v?
Post by: Paul Wescott on March 22, 2021, 12:10:22 AM
These gizmos are all over FeeBay.  They take anything from 6vdc to 24vdc input and drop it to 1.2-1.25vdc.  It doesn’t answer the exact original question of dropping a 2vdc source, but it might solve the bigger problem:

https://www.ebay.com/itm/Glow-Plug-Starter-Igniter-Upgraded-6V-24V-Electronic-for-HSP-Nitro-RC-/254837802342?_trksid=p2349624.m46890.l49292

Paul W.
Title: Re: How to drop 2v to 1.5v?
Post by: GregArdill on March 22, 2021, 03:55:21 AM
In the days when I was using a 2v Gates cell, I used 6' of speaker wire. That setup never blew a plug and worked for months between recharges.
Title: Re: How to drop 2v to 1.5v?
Post by: Brett Buck on March 22, 2021, 01:50:19 PM
4-5 feet of 18 gauge zip cord should about do it, that's 8 feet at .021 ohms/ft, .168 ohms, figure 3 amps for a dry glow plug, so that's .504 volts.

 As mentioned, a sufficiently beefy silicon diode like a 10A10 and a short cable would also work. Might get away with a 1N5408 given it is only connected for 10 seconds/start.

     Brett
Title: Re: How to drop 2v to 1.5v?
Post by: Fred Quedenfeld jr on March 22, 2021, 02:00:51 PM
Frank
Follow what Dan wrote  " contact Bill Bischoff and ask if he is still making his glow driver he advertised here in the classifieds;

    https://stunthanger.com/smf/classifieds-92/for-sale-custom-built-globee-type-glow-plug-batteries/"
   
Title: Re: How to drop 2v to 1.5v?
Post by: Dennis Toth on March 22, 2021, 04:31:07 PM
MM,
It sounds like you are using 2v wet cells. If your going to use a 6' or so of wire why not just use a power panel that could set any voltage you want.

Has anyone figured out how may amps our plugs draw and what size resistor could be put on the lead to drop the voltage/amp to usable levels?

Best,   DennisT
Title: Re: How to drop 2v to 1.5v?
Post by: Brett Buck on March 22, 2021, 04:38:52 PM
MM,
It sounds like you are using 2v wet cells. If your going to use a 6' or so of wire why not just use a power panel that could set any voltage you want.

Has anyone figured out how may amps our plugs draw and what size resistor could be put on the lead to drop the voltage/amp to usable levels?

Best,   DennisT

   I calculated it for 3 amps above, which is about what a Glo-Devil #300 draws when it's dry.


    Brett
Title: Re: How to drop 2v to 1.5v?
Post by: Dan McEntee on March 22, 2021, 05:18:03 PM
  I'm gonna ask the obvious question now. What plug are you using, Frank ??  Is it really a 1.5 volt plug??
  Type at you later,
  Dan McEntee