AeroVee 5 ohm Ignition Coils (Less Amp Draw)

[sonex1374]

Speaking with Pete Smith of the SDS AeroVee project, he mentioned that he was running coils in his AeroVee that draw less current than the standard coils. Digging around turned up a coil with a 5 ohm winding. This compares to the standard 3 ohm coil, and will result in nearly half the current draw. Now 3 ohms drawing 8 amps will give you a fast coil field recharge, and a hot spark, but the 5 ohm should be more than sufficient to do the job. In fact, Pete reports that he's very happy with his coils, and the extra power he has available to run his panel (and EFI system).

Anyone who finds their power budget a bit thin might consider trying these out as a means of freeing up several amps for electro-goodies.
https://www.2fastmoto.com/2FastMoto-12- ... _1162.html

Note: the coils above are copies of the Dynatek DC8-1 5-Ohm Coil. DC8-1's are commonly available as well, although I have no experience as to the differences between these units. https://www.amazon.com/Dynatek-TRTC13924-Ignition-Coils-DC8-1/dp/B000GRW9LU

Jeff

[n307tw]

This is a great find Jeff. Do you know approximately the amp draw for the 5 ohm system or a formula to figure it out? It may be worth it to switch to these - it also looks like a similar size to the standard Sonex coils. Thanks for sharing with the group Jeff.

[sonex1374]

The coils follow a simple version of ohms law: V = I * R. Calculating for amp draw I, it works out to V / R or 12 volts / 3 ohms = 4 amps. For 5 ohm coils it works to 12 v / 5 ohms = 2.4 amps (a savings of 1.6 A per coil). at a slightly higher bus voltage say 14 V it would be 4.7 A vs 2.8 A, or 1.9 A per coil. In any case, you'll get back 3-4 amps with the 5 ohm coils.

If you don't need to free up more electricity in your plane, then there's no real reason to entertain these. However, if you have a complex system this is a lot easier than trying to add on a second or a larger alternator system.

Jeff

[n307tw]

Jeff,

Thanks again for sharing. Took your and Pete’s advice and bought the new coils Monday since I’m starting on the electrical system now and they arrived today with free shipping. I need every single amp I can get out of this Aerovee Turbo so saving system load will help. If you buy more than one from them they currently are $41.34 a piece. Also if anyone is skeptical about fitment it is exactly the same as the current or older coils Sonex provided no modifications needed to holes or wiring. If anyone needs a set of the older red 3.0 ohm coils I’ll give them away for free just pay shipping. Here is a pic of the new coils installed. Hope this helps anyone on the fence.

-Tim




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[MichaelFarley56]

The coils follow a simple version of ohms law: V = I * R. Calculating for amp draw I, it works out to V / R or 12 volts / 3 ohms = 4 amps. For 5 ohm coils it works to 12 v / 5 ohms = 2.4 amps (a savings of 1.6 A per coil). at a slightly higher bus voltage say 14 V it would be 4.7 A vs 2.8 A, or 1.9 A per coil. In any case, you'll get back 3-4 amps with the 5 ohm coils.

If you don't need to free up more electricity in your plane, then there's no real reason to entertain these. However, if you have a complex system this is a lot easier than trying to add on a second or a larger alternator system.

Jeff

This is good to know Jeff. Thank you for finding these. Personally, I have noticed my secondary ignition system pulls a decent amount of amps at idle power; it's normal to see volts in the 11.8-12.4 range until power is increased for takeoff. I can't help but wonder if lower amperage secondary coils would help reduce the electrical draw at low power settings. If I loose one of the coils I have now, I may have to replace it with one of these!

[rdsafe]

OK, OK --
Looks and sounds great. The wide spacing on the bolt holes (102 mm per their web site) - Is that the same as the coils supplied by Sonex?

The reason I ask, I used nut plates to install my coils - wouldn't have it any other way - What happens down the road when you need to change the coils -
the reason I didn't use bolts.

I'll keep these coils in mind for the future.

That's my story, and I'm sticking to it.

Richard Stauffer

[n307tw]

Richard,

See my post with picture above. These are a direct plug and play to the original coils supplied by Sonex. Same spacing, even same thread on the screws for the wiring as well. Swapped mine in less than 15 minutes. I hope this helps.

-Tim


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[Outlaw6]

Swapped mine out this weekend after the 1-3 coil failed. That's the second time that one has failed. So I figured I would try these, I didn't notice any difference, but I probably wasn't paying close enough attention before and after.