ETpilot

Now that I am active flying again it is time to mod my DynaTron Starter. I have been using a lawn mower battery for my starting needs. After seeing what some of the other pilots were using, I decided a mod was in order. First I made a cardboard pattern to determine size and shape. Then I cut a sheet of aluminum flat to size. I decided to rivet it together. Trial fit of batteries. Fit battery box to starter. So far so good. I thought I might have to move the starter to another location in my flight box. A trial fit in the flight box showed it could still fit where I keep it. No interference with my transmitter. This mod is coming along good for my needs.

OldScaleGuy

My Feedback: (2)

Perfect!

T.W.

That looks great - and by coincidence my 12v flight-box battery seems to be running out of steam at the moment, so your idea is very interesting to me. But before I do anything: Most of us drive cars to the flying field which have a perfectly good 12v batteries on-board, so why don't we just use an extension cable from our car battery to our model's starter motor (assuming we can park our car close to the pits, of course) - do you think would this work? If so then I can do-without a seperate flight-box battery, yes? Tony

ETpilot

Tony, your idea will work only if you can always get close to your pit area. If you can't you will need a long extension cord or hand prop. Still you have the problem of those cables. Trip hazard for others. Plus cables that may get entangled in that prop. I want to eliminate the cable altogether. Today I made a glow plug igniter holder. I will attach it to the box. So everything for starting is close at hand. BTW, this mod only adds 1 pound to my starter motor. Good luck.

ETpilot

Thanks. It sure will be nice once it's finished.

GREG DOE

Your work looks great, but personally I wouldn't have a metal battery box for my starter power supply. Too dangerous for me! Sullivan makes a neat molded plastic battery box, and metal attachment straps. It was designed for Nicads, or NIMS, but can be used with Lipo's. I bought the straps from Sullivan, and made my own plywood battery box. I use two 7.2volt (6 cell) RC car battery packs. I won't go back to a starter with a power cord. Self contained is the only way to go. When this pack dies, I'll probably change over to lipo's. Good luck with your aluminum battery box, and be sure to use some good insulation.

ETpilot

Greg you are correct. A metal battery box is not for everyone. Your safety concern is noted. I don't have a problem with this battery box. Giving it its due respect and following safe handling techniques is necessary. Sort of like starting a glow engine. Rest assured there will be no electrical fault with this box. I fear the 3 ft. cord attached to the starter more than I fear my battery box. Thanks.

moparbarn

I use a 4s lipo/5000 mah/50c on a dynatron to start my boats. Lasts just fine for a race weekend. Fri. test & tune, then 2 days with 3-5 boats @ 4 heats each = 15 to 25 starts. Battery is attached to the starter with Velcro & straps. Added a Sullivan handle, compact & light set up. Works great even on HIGH compression 2 stroke gas race engines. Since there is no ESC with a low voltage cutoff, I use a volt monitor that plugs into the balance lead.

LarsL

I think it is neat (and can be fun) to make your own battery box. Cool to see folks making their own stuff.

For those of you that want Lithium power and want option beyond building your own box or buying Sullivan's, check out:

http://www.afineredgemfg.com

It is a great solution in that it is a Lithium solution with all those advantages, it is compact, and elegant when it comes time to charge. The downside is that you do need to buy the Makita charger, but you can get them on eBay or Amazon pretty cheaply, same as batteries.

Lars

GREG DOE

ETpilot. I can see by your tools that you know what you are doing. That might not be true for the next guy who decides to make a metal battery box. Over the last 40 years I've known of two metal flight box incidents. One involved a metal glow fuel can explosion, the other was completed, and then abandoned. We agree that self contained is safer, and more convenient.

T.W.

My starter doesn't have enough power when I use long leads from my car battery (lack of power) so I guess I'll be following your lead and building something similar to what you're making, Cheers, Tony

ETpilot

Insulation, insulation, insulation. Key to help keep things safe. Battery packs are insulated. So double insulation. This helps keep the operator safe. But, mishandling by the operator still can cause problems. A metal battery box is safe but, like all things, mishandling can cause unsafe situations.

Now I have to decide whether to paint the rest or clean up and leave it aluminum.

GREG DOE

Leave it aluminum. In time the paint will just get scratched. Although you might shoot it with a clear epoxy like KlasKote?

ETpilot

Thanks, aluminum it will stay. The clear coat is a good idea.

kmeyers

ET pilot
When I see clecos I wonder if you ever built a full scale.

ETpilot

I have given thought toward building an RV-10. The time involved was too much for me. I have done some metal work on full scale aircraft. I am slowly weaning myself from general aviation. That is why I am back to flying RC.

ETpilot

Well the last few pictures. I finally got around to building my battery packs. This was a new and interesting project for me. Since I have an inexpensive charger, I had to make two battery packs. The charger can only charge one 3S pack at a time and requires a power connection and a balance tap. I didn't have shrink wrap so I used reinforced packing tape for the final cover. So the battery case is insulated. I added a coroplast insulator strip between the case and the batteries. It also provides a nice tight fit of the batteries. And the battery pack has 2 layers of insulation. Should be pretty safe. The packs can be removed without removing the starter. A Coro top cover will be added.

The two packs are wired in series with a Y harness. Because of this the wiring is a bit unruly. I will try to pretty it up as best I can. If I ever get a decent charger I will change it all to a 6S pack. Less wiring and neater. I added a Deans connector to the cut off power cord. If I ever have a fault I can go back to regular batteries. I also made a balance tap extension for easy connection for charging.


Power, Power, Power 20.2 volts. It took me by surprise first time testing it.