Assembling spark arrestors!

[Eodman]

A couple of questions :

1.) When assembling, what gauge wire would be optimum for the auxillary conductor wire?

2.) What size auxililary connectors would be optimum?

3.) What would be the correct size resistor to use or is it driven by the battery size? If so can someone put together a chart showing size recommendations?

4.) All of the illustrations I have seen show the resistor unwrapped - should the resistor and its connections be shrink wrapped to prevent mishaps?

Thanks for the input guys!

[Flying Scotsman]

It is interesting that some ESC maufacturers do not recommend spark arrestors. A better design?

Douggie

[domwilson]

A couple of questions :

1.) When assembling, what gauge wire would be optimum for the auxillary conductor wire?

2.) What size auxililary connectors would be optimum?

3.) What would be the correct size resistor to use or is it driven by the battery size? If so can someone put together a chart showing size recommendations?

4.) All of the illustrations I have seen show the resistor unwrapped - should the resistor and its connections be shrink wrapped to prevent mishaps?

Thanks for the input guys!

http://scriptasylum.com/rc_speed/_nospark.html

[AntronX]

I've been using 1 Ohm resistor as recommended by Castle with my controllers. That online calculator gave me 67 Ohms to charge 1500 uF of caps to 8S voltage in 0.5 seconds. So I was waay in the safe zone with my setup - charging my caps in 7.5 milliseconds. Most likely before MCU could even boot up.

[mickvk]

http://scriptasylum.com/rc_speed/_nospark.html

Wow is that a great resource (for a hundred other things too). Thanks a million.

[Gary]

It is interesting that some ESC maufacturers do not recommend spark arrestors. A better design?

Douggie

Douggie it is interesting. Whats really interesting is i called CC and was told you do not need capacitors installed to cut down the spark. That spark is telling you that the unit is powerd up correctly and that should happen. Who really knows.

[Ub Hauled]

Douggie it is interesting. Whats really interesting is i called CC and was told you do not need capacitors installed to cut down the spark. That spark is telling you that the unit is powerd up correctly and that should happen. Who really knows.

Not sure about this... I get sparks sometimes and other times nothing at all, it's more like a little fart... that is with one of my "old faithful" ESCs. The key I think is using the spark arrest, so the system is not jolted every time we hook up...

IMO of course.

[Joe Ford]

That is true Gary. The caps sparking lets you know that they are functioning properly. Unfortunately, the higher the voltage you are using the bigger the spark. My 12s setups spark pretty good. The 20s setups we have been testing for airplanes will arc and melt the part of the connector where it arcs. Crazy to see.

For an arrestor circuit use a 1 ohm 5W resistor. Wire gauge can be as little as 22ga...can be larger if you prefer. Most times when a manufacturer does not recommend them it usually has to do with the cutoff voltage on the speed controller. With our ESCs it causes issues with problems with auto-lipo cutoff (which we will be adding to the Hydra software). The resistor value is the most important thing here. Too high of a resistance and the ESC will not properly detect the cell count of your lipo pack. Bad news. Yes, shrink the exposed electronics. You don't want them to short on anything they may touch while powered.

[domwilson]

That is true Gary. The caps sparking lets you know that they are functioning properly. Unfortunately, the higher the voltage you are using the bigger the spark. My 12s setups spark pretty good. The 20s setups we have been testing for airplanes will arc and melt the part of the connector where it arcs. Crazy to see.

For an arrestor circuit use a 1 ohm 5W resistor. Wire gauge can be as little as 22ga...can be larger if you prefer. Most times when a manufacturer does not recommend them it usually has to do with the cutoff voltage on the speed controller. With our ESCs it causes issues with problems with auto-lipo cutoff (which we will be adding to the Hydra software). The resistor value is the most important thing here. Too high of a resistance and the ESC will not properly detect the cell count of your lipo pack. Bad news. Yes, shrink the exposed electronics. You don't want them to short on anything they may touch while powered.

Will this new software apply to the current hydra controllers?

[Joe Ford]

It will. :) Across the board.

[domwilson]

It will. :) Across the board.

I know I'm bombarding you with questions...Do you have a release date for the new software?

[Joe Ford]

Don't mind the questions at all. No release date for the software. I will keep you all posted though.

I do have a question for you though. Would you want auto-lipo as the default setting or optional? We'll be changing manual, etc too so we want to make this what YOU guys want. Let me know.

[domwilson]

For me, Auto lipo as the default would be fine as most people use lipos I would say. Will it allow for manual adjustment of the cutoff voltage? What is the proposed cutoff voltage for auto-lipo?

[Ub Hauled]

I am for Auto Lipo as well, but just for the record, like most other options, it's not fool proof...
if one uses older cells that do not hold charge as well (or discharged), there may be a miss read and a cutoff that may lead to dead cells and/or "smelly returns". I don't think that most of the experienced guys would go w/o redoing/rechecking the settings anyway but the more inexperienced guys would just plug and go... and they are more likely to have older cells as well. Aside of that, I think it's a good plan.

[DISAR]

Auto lipo detection, yes.

Eodman,

Every ESC manufacturer recommends their own resistors. For Hydras 1Ω-5W, for MGM 20-50Ω - 5W for the rest I don't know.
That calculator gives too high values and then the ESC does not arm properly (I tried it).