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Sullivan Dynatron switch failure

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Sullivan Dynatron switch failure

Old 12-01-2020, 12:29 PM
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Default Sullivan Dynatron switch failure

Anyone have their switch contacts tack weld themselves on a Sullivan Dynatron starter using a 6S LiPo?

I did. Sullivan is kindly sending me a new switch under warranty.

just wondering how common this is.

Old 12-01-2020, 03:50 PM
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I have 2 that I have run on 24 volts, both welded themselves together. The motors are up to the higher voltage ,the switches,, not so much.
Old 12-01-2020, 05:32 PM
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It’s very expensive to fail like that, eh?
Old 12-01-2020, 05:34 PM
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I wonder if I were to reduce the 6S to 20 volts, if it would fair better?
Old 12-01-2020, 09:17 PM
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Probably. I'm running mine on a 6S LiFe (~19 volts) and no issues with 4 yrs of use. Welded contacts at 24v has been an issue with them for a very, very long time....
Old 12-02-2020, 04:35 AM
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After all the years Tool Time made fun of "More Power is Better" you would think people would learn. There is a right way to do things (upgrade EVERYTHING) and there is a half-assed way.
Old 12-02-2020, 05:19 AM
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It is rated at 24V.
Old 01-26-2021, 10:46 AM
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I wonder if I were to reduce the 6S to 20 volts, if it would fair better?
Old 01-26-2021, 11:15 AM
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Originally Posted by Bredly
I wonder if I were to reduce the 6S to 20 volts, if it would fair better?
Interesting your response came up today! I just finished communicating with Sullivan to get a second replacement switch today, because the first replacement switch just fused itself again.

I did try discharging my 6S some, and it seemed to work for a while. But it still failed again. Sullivan acknowledges they had some bad switches, and that they are working on an improvement.

Meanwhile, since the largest motor Iím starting is a Saito 125, I just bought a 4S 5000 Mah battery for it to keep nominal volts down to 14.8, and fully charged at 16.8V.

Sullivan has been very nice and helpful with my complaints. But now I am out another $60 for the 4S, and working at lower torque than the advertised maximum. This is disappointing. However, at this point if it starts my planes and doesnít fail I guess Iíll make do.

Let me tell you, when that switch welds itself ďonĒ, itís pretty dangerous to have that large cone spinning away as you try to unplug a stiff EC5! Itís an unsafe situation.
Old 01-27-2021, 04:01 AM
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I built 2 3S A123 packs wired in series to power my starter, 19V and charge lasts a long time. These are pretty safe batteries. Never had a switch weld. Switch is still original. But if it does weld, my design lends itself for a quick disconnect.




Old 01-27-2021, 04:05 AM
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Very nice! Maybe 19V is the magic number... or you have a better switch than mine.

Old 01-27-2021, 04:33 AM
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Default Sullivan starter switch

the lower voltage will make the starter pull even more current and weld the switch even faster.
i modified mine years ago and used the integrated switch to activate a relay that handled the heavy current of the starter motor,
a bit of a pain to hook up but i got tired of fixing the switches
good luck
Old 01-27-2021, 04:36 AM
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That’s an interesting approach. What relay did you use, a car starter relay?
Old 01-29-2021, 12:02 PM
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Try a little dielectric grease. Auto parts stores sell it in a small packet (like ketchup) for less than two bucks. A light coat on the contacts really helps.
Old 01-29-2021, 03:46 PM
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I did. Thanks though.

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