# Power Box



## Brian Rupnow (Jan 26, 2014)

Yes, I know, its a rather strange thread title. While I wait for CNC parts to arrive for my Opposed Piston engine, I am thinking of my collection of i.c. engines. I now have the Webster, the Kerzel hit and miss, the Atkinson engine, the Odds and Ends engine by Philip Duclos, the "Rupnow engine" and the newest, my opposed piston engine. On all except for the Rupnow engine, which I used a CDI ignition, the rest of the engines use conventional 12 volt coil and ignition points. The Kerzel engine is in a category of its own because the 12 volt coil is built into the engine base. This still leaves me with four engines which require that every time I want to run them require a complete wiring up before they are runnable. They all have their own point set and condenser, but the coil has to be changed from engine to engine. Coils are not cheap. I pay $50 each for 12 volt coils at my local auto parts store. Fortunately I have a deep cycle 12 volt battery for my fishing boat, which is a ready (if heavy) power supply. I think I may embark on a small woodworking project.-Basically a small wooden box which will hold a 12 volt coil, an on/off switch, an indicator light to show when the power is on, and a permanently installed high tension lead from the coil. I may make the "power in" lead and the ground lead "plug in" style connectors with alligator clips on the ends which attach to the battery and the ignition points. I may even make it a dual compartment box so that all of the electrical leads can be coiled and stored in the second compartment, so that my "power box" doesn't have a gaggle of wires hanging from it. Has anybody else done something similar?---Brian


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## doc1955 (Jan 26, 2014)

I did something similar but with a CDI ignition. I have a small wooden box that house the CDI unit with coil and switch and an LED power indicator along with the battery pack which is only 3 aaa batteries. I have plugins on the box for the wires they all unplug from the box I can hook it up to any of my engines it has provisions for hall effect and a plug for points so it works with either style of ignition. I'm actually thinking of building a second on so that I can run a couple of my engines at once right now only one can run.

     I did another build you might be interested in that is a power test box then you could eliminate the deep cycle battery. If you can get your hands on an old computer and grab the power supply from it they put out a nice steady supply of DC current in various voltages. It would be smaller and much lighter then a deep cycle and you can just plug in to an outlet.


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## goldstar31 (Jan 26, 2014)

The Brits had things in the Royal Air Force called 'trolley ac's' or more correctly Trolley Accumulators which where wheeled 12 and 24 battery sets to start up things like Rolls Royce Merlin engines that were used in Spitfires, Hurricanes, Lancasters and Mosquitos. They were plugged in- engine fired and pulled out of the way whilst the engines were run up with a couple of erks( aircraftsmen) on the chocks. When it was impossible to use them, we used Coffman starters which were essentially cartridges fitted into the Merlin engines. I'm a bit more vague on American types but I do recall a North American Harvard coming in to Hendon and a pool of gasoline/petrol overspilled onto the apron and two stabs of 'lightning' from the trolley acc as some idiot had left the power on whilst pulling the connection. 

 More recently( still a long time ago) the local electricity board headquarters had the basement with enough linked batteries in boxes to make up a reserve battery supply of 240 volts to cover a major fault covering the administration covering  1.3 million customers on the network. 
 I have no idea what the present situation is- my bank account  has been credited with my pension- for the last 28 years.


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## Brian Rupnow (Jan 26, 2014)

Aha!!!---Recycling is good!!! I've had this "partial" box setting around for ages. It was originally going to be a base for my Webster, and was built to hold a 12 volt coil. This entire project just got a boost.


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## Brian Rupnow (Jan 26, 2014)

Oh Yeah!! Now we're rockin'!!! I found a piece of .085" aluminum plate to make a bottom for the box. I also dug  out a piece of 1"plate that is destined to be a coil mounting bracket. That piece (with the purple layout dye on it) used to be part of the Doodlebug.--How many of you remember the Doodlebug???


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## Brian Rupnow (Jan 26, 2014)

So---Nobody remembers the Doodlebug?? Well, it was almost 5 years ago. Anyways---I now have a coil mounting bracket. about half way thru this I was wishing I had set it up in the 4 jaw chuck in my lathe, because I can bore much faster with deeper cuts in my lathe. I opened out the existing hole with a one inch endmill, but then had to take about a thousand passes because the maximum depth of cut I can take on my small mill is about .025". I was originally going to split the one inch thick block into two 1/2" blocks and position one at each end of the coil, but it seems very stable just as it is, so I will find a balance point and epoxy the mount to the coil.


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## Brian Rupnow (Jan 26, 2014)

Goldstar31---I was in the Canadian Air Force in 1963/64 I was stationed at Rivers, Manitoba for 8 months waiting for my course as "Airframe Technician " to start up in Camp Borden, Ontario. While I was at Rivers, they were retiring the Harvard trainers. A whole squadron of Harvards flew in from Comox B.C. (I think) and fueled up then left again. The new trainers were the Tudor jets. I heard later that the entire Harvard squadron flew down to New Brunswick and were sold to a private dealer for $12 each, who then scrapped them. We used to fly the Tudor jets south and see how far we could get into American airspace over North Dakota before the Americans would scramble their fighter jets, then we'd turn tail and run like Hell to get back into Canadian airspace. --- -Can't imagine doing something like that now in this post 9/11 world.---.--Although I was "groundcrew", my duties would be taken care of during the first 3 hours of my 8 hour shift, and then the trainee pilots and instructors would let us ride with them to kill time. One time I asked to go along for a ride and they took me--and then practiced take-offs and landings for 3 hours straight. I was never so sick in my life!!!---Brian


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## Brian Rupnow (Jan 27, 2014)

Ongoing scrounging thru my cupboards and cabinets has yielded a treasure trove of switches, alligator clips, and one real prize--A red light. (I don't know if it works or not yet). The box now has the bottom bolted on and the coil mounting bracket bolted into place. There is a blizzard here today. Highways are shut down, school-busses are all cancelled. I have two public school age grand daughters here for the day--their mom and dad both had to go to work. We have 23" of snow on the ground and another 4 to 6" forecast before the end of today.


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## Brian Rupnow (Jan 27, 2014)

Bummer!!! The red light doesn't work!! oh well, I have enough other stuff to keep me busy for the rest of the day---


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## Philjoe5 (Jan 27, 2014)

Nice project Brian.  Some day I'll need one of these

Cheers,
Phil


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## Brian Rupnow (Jan 27, 2014)

I just took my team of Huskies and mushed down to my nearest auto parts store, and found a red indicator light with two terminals, and an illuminated switch with 3 terminals. I haven't wired anything much since I built my hot-rod ten years ago, but this has got me thinking. If I put the two terminal light in series with the hot wire that goes thru the switch to the coil, the light will only be on when the points are closed and the current is flowing. The light will be constantly blinking on and off as the points open and close.--I don't want that. Plus if its wired in series, the light itself is going to act as a flow restraint to current running to the coil. If I hook the light up in parallel with the coil, it will be almost the same--no current can flow--period--until the points are closed and let the current flow to ground--and when the points are open, it will still be an open circuit, causing the light to blink on and off as the points open and close, but since it is in parallel with the coil it won't act as a current gate. My original thinking was hot wire from battery to switch, to light, to coil, thru wire which leads back to points, thru the points to "ground" and a jumper wire from the engine base back to the negative side of the battery. If I don't want my light flashing on and off as the points open and close, maybe I have to run a relay. This will (I think) make it necessary for a third wire (not counting high tension coil wire) to run from the relay to ground. So--current travels from battery to switch, to light, to pull down relay, then back out this extra wire back to negative side of battery. Hot wire from battery is split before switch and runs to relay--one side of relay is always "hot". So--when switch is turned on, light is lit, relay is "pulled in" and wire runs from other side of relay back to negative side of battery. Then there is a second circuit which basically is a hot wire from relay to coil that is only hot when switch is on and relay is "pulled in". Current travels thru coil, then to points, then to ground, then thru jumper wire from engine back to negative side of battery. Light will be lit constantly as long as switch is on and current is flowing thru relay to keep it "pulled in". Current will flow to coil and engine will run as long as the relay is pulled in. When switch is turned off, current no longer flows so light goes off, relay is no longer "pulled in" so reverts to open circuit---No power gets to coil so engine stops. Have I got this right or am I overthinking it???


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## canadianhorsepower (Jan 27, 2014)

this should help


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## BaronJ (Jan 27, 2014)

Brian Rupnow said:


> Bummer!!! The red light doesn't work!! oh well, I have enough other stuff to keep me busy for the rest of the day---



Stick an LED and resistor in there.  If you choose the resistor to allow 10ma through the LED and don't reverse polarity to it, it will last forever.


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## Brian Rupnow (Jan 27, 2014)

Guys--I was overthinking this one. I can do it without a relay. All I will need is the extra wire to return the hot feed from the light back to the frame of my engine which will be grounded to the negative side of the battery. Crap-o-cad sketch attached----


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## canadianhorsepower (Jan 27, 2014)

thats the picture I sent you
 but in a manual drawing as long as it works for you


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## Brian Rupnow (Jan 27, 2014)

Thanks Luc---Brian


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## Brian Rupnow (Jan 28, 2014)

After gathering up all my parts for the power box, I couldn't decide just how to arrange things. I need room for a coil, a red indicator "power on" light, a switch, and storage for my wires. This morning I woke up at some heathenish hour and couldn't get back to sleep, so I got up and laid it all out on CAD. Haven't decided just what I'm going to do for a latch or a handle, but they shouldn't be a big deal. I think this looks pretty good considering I am working with a recycled "box". I might have to put some insulating rubber between the end of the coil and my light and switch, but then again, I might not.


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## cfellows (Jan 28, 2014)

Brian, just a thought, on my original Odds n Ends engine, I used a standard ignition with points, condenser, and coil. But instead of a car battery, I used a rechargeable RC battery.






The RC battery is about 2" x 4" and maybe 5/8" thick so it would fit inside you power box. Mine is 9.6 volts but you can also get 12v that are about the same size. Mine is NiCad and will power the engine for hours of running between charges.

Chuck


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## Brian Rupnow (Jan 28, 2014)

Thank you very much Chuck. I've gone a bit too far for that change now, but I will certainly file that for future reference.----Brian


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## Brian Rupnow (Jan 30, 2014)

The power box is finished. I have reached a point where I didn't want to cobble some wiring together to try and start the opposed piston engine, so I took today and completely finished the power box. There are two pics of it with all its wires hanging out. I have not shown the one wire with an alligator clip on each end that connects the engine frame to the negative side of the battery.--Mainly because I had one red alligator clip and one black one, and that particular "jumper" should never be hooked to the positive side of the battery---so I painted the red alligator clip black and now its hanging in the furnace room drying. I have also shown a picture of the box closed up with all of the wires tucked away inside of it. The last 2 1/2" of coil wire is glued inside a 0.335" diameter wooden dowel, with bare wires showing at the end which inserts into the coil. That way I can insert it from outside the box and not have to be terribly concerned about it going into the hole in the end of the coil. I tried to find a hardware store handle, but they didn't have anything that would fit, so I made my own handle. I bought a "draw down" latch, and for once I actually got the holes drilled in the right place. If you have ever installed one of those miserable things, its almost a magic trick to get the two halves so that they actually do "cam over" and draw the lid down tight and stay latched. I just picked up 2 or 3 days of engineering work this morning, so the start up of the opposed piston engine might get delayed a day or two.---I hate to turn away work---that's what buys all my machine shop stuff!!!


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## Brian Rupnow (Mar 31, 2021)

An update---Concerning different size wires and sparkplug boots---.---Find a piece of wooden dowel that is a "good" fit into the end of the coil, and long enough to stick out thru the hole in the box about 1" when it is seated in the coil.  Drill a hole lengthwise thru the piece of wood, big enough to run the insulated coil wire completely thru it. The coil wire should be about 18" long between the sparkplug boot and the bare end which fits into the wood. Cut about 3/4" of insulation away from the non sparkplug end of the coil wire. Coat the last 3" or 4 " of the stripped end of the coil wire and coat it with slow setting glue and push it thru the wood until the bared end sticks out of the wood. Fold the wires back over the outside of the wood, coat them with glue and smooth them against the wood. Now, when dry, you can insert the wood thru the hole in the box into the coil.---If you require a different sparkplug boot, make up a second coil wire assembly. the 1" of wood which extends beyond the side of the box lets you grip the wood in your fingers and pull it completely out, then you can push in a different coil wire assembly.


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