votage glo

Even a new alkaline battery might read low if you're checking it under a load. If it's less than 1.5v unloaded then Dave's right, get a fresh battery(s). Since I've started using a clip-on sub-c NiCad, I've realized that even fresh alkalines only barely get the job done. If you hook that NiCad to a plug and look at it, you'll be seeing spots for a minute. It's that much brighter. And it stays that strong until it's almost time to recharge.

There is an extensive discussion on the subject, only a couple of months old. Some people prefer Nimh to NiCad. Both are superior to alkys.
Rusty

I have typically seen .80Volts or less at the glowhead under load with a new set of 2 D cells in parallel, (1.5Volts DC), using 2-18guage wires for + and - connections. I don't have any equipment to measure the low resistance of the wires, but the current thru the glowhead must be very high when it is glowing hot.
   Has anyone else ever measured the voltage at the glowhead under load before.
happydad

   

I did away with durrelcells,got Nihm cells,charged them for 5 hrs,to quote somebody (you'll be seeing spots) tks thanks happydad

happydad wrote:I have typically seen .80Volts or less at the glowhead under load with a new set of 2 D cells in parallel, (1.5Volts DC), using 2-18guage wires for + and - connections. I don't have any equipment to measure the low resistance of the wires, but the current thru the glowhead must be very high when it is glowing hot.
   Has anyone else ever measured the voltage at the glowhead under load before.
happydad

   

I haven't checked the voltage under a load, but the drop is not surprising, as the glow plug draws about 3 amps. That's a lot of juice to exploit the internal resistance of the battery.

This subject has fascinated me. It's been a long time since I've used batteries directly.. to light a plug. I've always used the glow-driver circuit in my power-panel. Since it has an ammeter; it tells me if there's continuity or not.. and when there "is".. it shows me the plug's "draw"... which can also be adjusted. This is helpful in diagnosing a blown plug. If there's an "open circuit".. the meter reads "zero".. which tells you immediately. If your glow-plug "clip" is loose and not making contact, the meter reads "zero".. If repositioning the clip still results in a "zero" reading; then the glow-plug is probably blown.. which can be quickly checked with a "spare" glow-plug before removing the suspect plug. If there's still a "zero" reading on the meter when connecting the spare plug.. then it's likely there's an open connection in the "clips" wiring.

I like using a power-panel's glow-driver because of these diagnostic abilities. When it's time to run an engine.. the less there is to fuss with.. the better.

I've learned a LOT from this forum... and never figured that NiCd or NiMh batteries (both of which are 1.2v/cell) would light a plug better than a standard 1.5v cell.. apparently it comes down to internal resistance in the cell(s) between types.

The "old standard" used to be a "hobby battery" which looks very much like a 6v lantern battery.. except it's wired differently "internally".. to deliver 1.5v. Inside it's case, you'd find four 1.5v cells wired in parallel.. whereas inside a 6v "lantern" battery; you'd find four 1.5v cells wired in series. The "capacity" of the 1.5v hobby battery's 4 cells wired in parallel is why they last so long.

Tip: If you have a power-panel.. and your 12v battery is dead (won't take a charge anymore..) instead of spending 20-30 dollars on a new 12v battery.. pick up "two" 6v lantern batteries and connect them in "series" using a short 18ga. jumper-wire with alligator clips, which will yield 12v. The lantern batteries won't last long if you're using an electric starter or fuel pump frequently.. but for the glow-driver circuit; they'll last a VERY long time. Wal-Mart sells a 2pk. of Ray-O-Vac Heavy-Duty (Carbon-Zinc)6v lantern batteries for $4.95 (+tax) That's cheap money to get an old power-panel back into service.. or for use as a back-up.

The large battery latern/phone batteries worked great, after those disappeared from local stores I have gone through a few NiMh ones and they are a bit disappointing...

The problem is that the average voltage from NiCd and NiMh is 1.2V, which is too low. Only around maximum charge will then be around 1.45V. So for the NiMh batteries to work, they have to absolutely fully charged and there cannot be any loss in wires to the glow plug (which is why they are attached directly to the regular plugs).

The best handheld driver I've had so far is the LiPo driven one from Dynamite RC, there you have a regulated 1.5V output throughout the whole discharging cycle of the battery.

I had a setback on lighting plugs,I thought maybe someone wrote back on it-you guys are the best,roddie as always, good info on 1.2 Vs. 1.5v that's one thing I was struggiling with when they wouldn't lite, the Nihms will put out 1.34v fully charged,to get to the point,it was a brand new 2 cell (D) setup, there was a factory splice in the leads and that's where the problem was.I still don't think they lite bright enough but it will fire an engine,these are new plugs.kris I never heard of a handheld driver.Tks. roddie went back and read your post again I'm not sure what a power panel is. if you want to PM me and tell me more about it.mark

rat9000 wrote:kris I never heard of a handheld driver.

The picture glow driver above is from Dynamite RC; Lipo glow driver

Here are two pictures that I have posted before on the forum, the first is a NiMh direct battery one and the second the Lipo with regulated output (both pictures taken with the same exposure times);

For as long I've had Cox engines I've used a Cox battery Pack available from Bernie.  "Too expensive!" you may say but what price would you detractors pay for dependable performance in starting your engines?

Seriously if "cheapness" is your goal you may be "shooting yourself in the foot".  So how much do Dura-Cel's cost per pair?

SD

SuperDave wrote:For as long I've had Cox engines I've used a Cox battery Pack available from Bernie.  "Too expensive!" you may say but what price would you detractors pay for dependable performance in starting your engines?

Seriously if "cheapness" is your goal you may be "shooting yourself in the foot".  So how much do Dura-Cel's cost per pair?

SD

This was a battery pack from Bernie,around 3 months. old, I've used it half a dozen times with alkys,no problem,my failure came at critical time,thats why I came back to forum-when Rusty suggested NiCad or Nihms,I went to Batteries Plus and told them I wanted the best-54. 00 dollars, I'm not cheap. The problem was theres a factory splice on leads coming out of the box it has shrink tubing over it, I soldered in an old lead below splice and that worked

Not sure if this is in line with the subject, as I don't have any idea of the actual voltage getting to the plug or head.  I have been using this little field box for a long time, building it back in the day when I made runs to the S.M.A.L.L. Fly-In in Little Rock.  I needed a way to take the basics with me out to the flight line without packing a monster along with the plane and radio.

It uses a mini-power panel with a small sealed battery, and has allowed me to use the really long leads needed when you're holding combat planes waist high while starting them.  I DO have to remember to stick the thing on the charger the night before, but it has gone through several flying sessions with no previous charge and still cranked up everything just fine.







My only real problem so far is forgetting NOT to plug the glow plug lead into the starter receptacles!  Liquid Platinum !!!

Kim,thats a neat looking field box,like the NRA sticker-I'm just getting into this game,I got one plane into air and crashed it.I went into work and was telling a Toolmaker about it(Harrold) he's 64, he lit up like a Christmas tree,he said I used to mess with them when I was a kid-the next day he brought a swordfish in-.049 engine froze, you'll find this interesting-on one side of crankcase there was an extrusion where its cleared for rod.I said Harrold it threw a rod,being a toolmaker he took it apart and said no the tool was dull when they machined it.. he also told me he found a No. 2 stamped somewhere, he got it free,I had a known good glo plug and knew I could fire it off prime,I just wanted to see the expression on his face,it was sitting for 25 years,thats where I could not get a plug to lite,DISAPPointed,have you ever been there.I think I've got that problem solved.







































pointed