Hobbywing Quicrun WP 880 on 4S (Newb)

[ferp420]

on 4s the bec thats built in to the esc might have failed thats alot of voltage to drop 14v down to 6v will create alot more heat than a 3s 11v down to 6v will and usaly takes out the bec first if this is the case the reciver is nolonger reciving voltage you can test this by hooking up a 6v power sorce directly to the reciver i just plug a small 2s lipo in for that test but first unplug everything then turn everything on then turn everything off then plug everything back in and turn it on do those simple things before replacing anything

[Voodoobrew]

That makes sense, careful not to touch power to the wrong pins though. Maybe if you saved an old broken servo cut off the plug for that brown/black is neg, center is positive.

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[LincolnofDeath]

You guys are awesome. I’ll let you check my math here:
Ferp’s directions—-

1) plug a “close to 6V” small 2S battery into receiver (Rx) channel 2. This animates the Rx and can now check for continuity with our test servo in Ch 1. (I’m confirming with you guys I have the right idea here and plugging the right gear in the right places).

2) Swap in a known working BEC in a 1080 ESC and if the Rx powers on then the we suspect the 880 BEC died a valiant death to protect the stock Rx.

We’re doing early Thanksgiving out here in the windy desert today so I don’t have the full test options or kit on hand...and since my nieces were waaaay in to the tiny trucks the last time I was here, I’ll get this truck running with a 1080 and check the Rx before swapping a Flysky Rx so they can all drive around together while us old folks pound Doritos and boxed wine.

That good idea (1) bench test has to wait till Tuesday. Which is coincidentally about how long it takes to ship out a BEC. Last question here:

3) if the internal BEC failed, can an external BEC now be added, with a BEC bypass? My guess is it cannot because the internal BEC was a signal conduit. In any event, do ya think this setup, with a BEC bypass, dedicated BEC, and 880 would be the “coolest” setup as we’re continuing down this 4S crawler on the cheap experiment? Like that’s where the smart money’s at? This motor just came in the mail...I’ll maybe order a Holmes bypass and any recommended BEC in the meantime.

Thanks guys. I look forward to hearing what you have to say, as always.

[Voodoobrew]

#3 if the internal bec dies, toss it. Or go for a warranty. I wouldent use half broken electronics.

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[LincolnofDeath]

Copy that. New receiver in and functional. 880 internal BEC happily humming along on 2S/7.4V. Will test with half a dozen packs then adjust accordingly.

[Voodoobrew]

Hopefully just random failure then.

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[fyrstormer]

Small correction: 2S is 8.4v, not 7.4v. 7.4v is the average voltage over the pack's discharge curve; 8.4v is the peak voltage when the pack is fully charged. I have no idea why lithium-ion batteries are rated according to their average voltages when it's peak voltage that burns-out electronics.

I'd like to find the person who came up with that idea, drop a cinderblock on their foot, and then explain to them that the cinderblock shouldn't have broken their foot because the cinderblock's average velocity was much lower than its peak velocity. I'm sure they'd understand and agree with my entirely reasonable explanation, and accept the blame for having a defective foot.

[LincolnofDeath]

Got it, and I’ll drop that with the rest of the latent knowledge accumulating like so much dandruff from my head.

Put in a Crawlmaster Sport 550 12T along with a Flysky Gr8E receiver in The Sendero, did a chill pack and a half on 3S to break things in, along with a fresh front axle to replace one that was broken at the pin when I first got the truck. There was a little drag to control for in that instance. Team Associated took real good care of me on that, and I’m grateful and want to send props. Thanks Rich S. if you’re on here somewhere, thanks for hearing me and sending out the replacement—you made my day. So it’s all buttoned up by late morning tomorrow and just ahead of the rain.

Will give it another try on internal BEC alone, 4S and stock gearing.

And, check out this amazing pile of cinder-block and concrete just out the back door at work! One man’s immovable pile of trash is another man’s Erzberg Enduro...

[LincolnofDeath]

I’ll update the original post to summarize this thread. For now I’d say this looks like a successful upgrade path. Eight packs through without any over-voltage zaps to the receiver. The Crawlmaster Sport 550 pairs exceptionally well with this battery’s voltage and programmed differentials in a Quicrun 880. The heat gun says we’re maintaining low temps, although the ambient temperature while running was quite cool. I tried to stress the system with a variety of variables. Should any more receivers burn through I’ll note that here in the future.

All the best, Lincoln

[upit4x4]

Did you get any where further on this ?

I have got my hands on a 880 to try out on 3S mainly for the internal BEC but would love to throw 4s at it if I get the chance

And thank you for documenting it all.

[Voodoobrew]

They work fine on 4s. I ran one for a while with a 550 crawlmaster pro 10t on 4s.

[cartronicshn]

i am getting one for the clod spare parts build i have been procratinating for so long, i hope it handles 2 servos..