Hi All:
I want top drop a 2 vdc source to 1.5 vdc for glow plug use. I have had many suggestions that were strange and not desireable.
One suggested an .016 ohm resistor, One suggested a .5 ohm resistor, a length of lamp cord etc I think the resistor would have to be about a 5 amp capicity ?
I am looking for a small device that may carried in hand or pocket. Perhaps I should just purchase one of those recharable head lock type of batteries or purchase Fireball Plugs that take up to 3 vdc. Wdhere does on purchase on of the rechageable head lock type of starting batteries?
A substantial silicon diode will drop about .6 volts, something like a 10A05, should be about a nickel at the electronics supply house. A resistor will work, you need about about .1 ohm, but long zip cord leads will get you about right. I don't like that solution because the voltage changes with current and it gets moderately hot.
But, if you aren't stuck with 2v lead-acid cells, I have used the McDaniel Ni-Starters for years, and the new Li-Ion versions are quite excellent, long-lasting (if you don't overcharge them repeatedly) and reasonably cheap.
Brett
p.s. resistors aren't rated in amps, they are rated in watts. In this case, if you are drawing 4 amps (about what you get on a moderate rich setting) you will be dissipating about 1.6 watts which will get pretty hot pretty quick. A 5 watt resistor would do the job, but you would not want to touch it after about a minute. The long zip cord will dissipate the same power, but over 2-3 feet of wire, so the temperature would not be too high.
They used to make radios that way, the cord had a logn resistor element in it, along with the regular power, and they dropped maybe 30 watts. When it worked, and the cord was not all coiled up, it was *accceptable*. But they were called "curtain burner" radios for a very good reason.