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DC to DC 6V -> 2V

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hantto

Member
Hello, I need help with this. I need to turn an old bike lead-acid battery to a model glow plug driver. I think the current must high in order to get the glow plug glowing. Could i use a power transistor and a zener? Any help is welcome!
 

Gene

New Member
I obviously can't speek for anyone else on the forum but to design a circuit it might be helpful if you could tell us the voltage and current requirement of a glo plug. I was thinking they were 1.5 volts. Perhaps you could apply a 'standard' supply to one and measure the current drain to get this project going.
 

john1

Active Member
Yes, i think Gene is right, they are typically 1.5 volts
for models, for motor car diesel engines 12 volt is
normal.
I suppose various trucks or lorries might be 24 volt.

i have never heard or seen of a 6 volt glo-plug.

I will see if a search will bring anything up

John.
 

john1

Active Member
This is taken from here:
http://www.lakelandaero.50megs.com/glo_plugs.htm
***********
Your battery should heat the plug to a nice bright
orange or red orange color; if the plug glows white
hot, it just isn't going to last.
***********

They do them at 3 volts for models.
I didnt know that.
 

hantto

Member
Yes the voltage that a glow plug wants is 1,5V. I just said 2 because my battery (the x-cell 5Ah battery) was 2 volts (the guy from whom I bought it said that it is a 1,5V).

When i measured the resistance of the glow plug it was 1 ohm. So 1,5V/1=1,5A. And i allso measured the voltage of the bike battery and it was 7volts.

In short:
Energy source: 7V 4Ah battery
Glow plug: 1,5V 1,5A

I think it's good idea to make the converter at least capable of supplying 2A @ 1,5V. Or any better ideas? :)
 

Chippie

Member
Easily done with a 555 timer with a variablem-s ratio to give the requisite current......... followed by a power transistor or mosfet
If you struggle with finding a cct let me know I'll dig mine out.........

Glo plugs work at around 15-2v with a current draw of some 4 amps


RC modelling is a hobby of mine 8)
 

hantto

Member
Thanks for the reply, i'm still a n00b in electronics, so if you would show me your shematic, it would be very helpfull! :D
 

Chippie

Member
I'll dig out my circuit for you 8)

just realised I put 15-2 volts, missed the . out

ah well :p
 

Phasor

Member
Careful with the LM317 - I think their lower limit is 1.2V. Try it, but personally, I wouldn't use it below 2V.
 

Sebi

Active Member
In this case the best choice the LM2576 buck converter.
It sucks from 7V battery only about 320mA.
 

bogdanfirst

New Member
yes thats a better solution
and about lm317 i used it for 1.5V @1.3A for quite a lot and no problem if a good heatsink is there.
 

Chippie

Member
Sorry guyz, you seem to be missing the point here.......

Glo plugs need around 1.5-2.0 v at around 3-4 amps........

an LM317 couldnt cope with these demands nor the LM switcher.......hence the 555 astable and series pass device.....
 
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