Dual Hobbywing WP880's for MOA

[TheLetterJ]

I had this thought...

I finally picked up a Bully2 (rtr, minus radio) so I could start mating the axles to my Dahu chassis I've had stashed away. I bought it "used" but it had never been run. While the dig function works, it kinda lags, and the esc is not smooth at all. I'd like to run dual esc's (not just dual outputs on 1 esc) and have the ability to run 4s. I've heard of people running dual 1080's, but those can't run 4s. Hobbywing released the dual output, 4s capable version of the 1080 a few months back, called the WP880, and it got me thinking. What do you guys think about a pair of these 880's, de-cased/stripped of unnecessary leads & switches, only running 1 motor from each?

I'm not opposed to spending more if I absolutely need to, but I don't think I'd really benefit from higher end esc's at my level of use. Dual 880's sounds reasonable in my pea brain since they're cheaper than 1080's ($33 each vs $42, and I already have the necessary programmer) and have the same programmable features, which have been adequate for me. I know they're going to be physically larger than BRmini's, FXR's, or even 1080's, but by de-casing them, and ditching RC4WD's dig unit I'll still be far ahead of where I'm at as far as size/weight. The lower voltage bec (6v compared to a 1080's 7.4v) won't be a concern as I'll either throw a CC bec or possibly a 2s rx pack in the car to power the servo (90% sure I'll go with a Futaba A700) anyway. If I'm out of my mind, I'd like to hear why this is a bad idea?

 

[Voodoobrew]

I don't know much about the ESC you're talking about but if it's cheaper you might want to make sure it has all of the same functionality as the 1080 they probably sacrificed something somewhere

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[TheLetterJ]

It has all the same programmable features EXCEPT bec voltage (bec is non-selectable, but is pretty good at 6v/4a.) It's cheaper because it does not include the program card, simpler BEC, and has a crappier power switch without the program button. None of which are issues considering that I have the programmer (several of them actually), will be running the servo from separate power, and will be lopping off the power switches anyway.

I was leaning towards the 880's mostly because they're supposed to be just as smooth as the 1080's, but accept 4s, not really due to cost. I know there are a few good options from Tekin and Holmes, but if the 880 is as smooth as the 1080, I think I could be happy with this idea. I also like the simplicity/ease of use of the Hobbywing program card. The fact that they'd only cost $66 for the pair is just a bonus.

The 880 has dual outputs, but I figured I'd just desolder a set of leads off of each esc once I've pulled the cases and heatsinks off. Ironic, I know.

 

[Voodoobrew]

If what you say is correct I don't see an issue. I run dual 1080's and love them. yea, looks like a good deal to me. Still 80 amps with freewheeling hope its not some kind of 40A per motor though, probably isn't.

 

[svt923]

I know they're going to be physically larger than BRmini's, FXR's, or even 1080's, but by de-casing them, and ditching RC4WD's dig unit I'll still be far ahead of where I'm at as far as size/weight.

I don't know how much will really be gained by de-casing because HW's brushed ESCs are usually buried in a block of epoxy that is only a bit smaller than the outer case. Also makes desoldering anything from the board a huge pain.

 

[TheLetterJ]

Good point on the epoxy, I may have to settle for some clipped wires. I looked up the dimensions:

Hobbywing 880:
length: 45.9
width: 34.7
height: 26.5
weight: 75g

Hobbywing 1080:
length: 36.5
width: 32
height: 18
weight: 58.5g

I test fit a couple 1080's in the "cab" section of my Dahu chassis (which is directly over the front axle/motor) and they fit very comfortably. I may/may not be able to get the length down, but I'm pretty confident that I can get the height, width, and weight of the 880's equal or less than the 1080's just by removing the plastic case and heat sinks. The car is currently sitting at exactly 3.5lbs with no servo, rx, esc's, or battery on board. I'll be adding Dlux knuckles (most likely with tungsten slugs and extra rings) but even with the added +/-10oz, I should be able to stay fairly near 4.5lbs rtr. I mention that mostly to say that I don't think I'll have heat issues after removing the heat sinks.

RPP is having a 15% off sale, so the pair of 880's is only $57.73, I think I'm gonna go for it!

On the same theme, I'll put my money where my mouth is and buy a pair of Yeah Racing Hackmoto "Just Climb" 16t 5 slot motors too. I know they say "7.4v max" but I'll take that risk. I know this car is probably still going to touch on that $1k mark by the time it's truly ready to run, but I think this inexpensive electronics package should perform very well and won't be throwing good money after bad. I'm rapidly realizing how people end up spending $2k+ on a well setup MOA!

 

[Minoa]

I run dual 1080s in a bully 2 also. Very happy with them. No comps for me so I wasn't worried about weight or getting the most LCG possible. Have one on the chassis "tongue" where it's supposed to be and 1 one the rear axle. Paired them with HH trainmasters and a cheap dual stick fly-sky. Having differential throttle is sweet. Took a little getting used to but the control is unreal, plus I can just use it like a regular dig if I want. Win-win.

 

[TheLetterJ]

ESC's (and lots of other goodies) arrived today. I popped off the top half of the case then removed the heat sink and already dropped 17g from the 71g (though they're advertised as 75g) each esc started at, so they're already lighter than 1080's, but still slightly bulkier. SVT was right about that epoxy, they're not shy about putting it on! I don't want to risk cracking the board trying to remove it, so I may leave the bottom half of the case intact (other than shaving the ears off the sides.) I can now just barely squeeze the 2 esc's side by side under my hood, in fact, if I mount them upside down, the bottom cases will become my hood! That hides most of the wires and uglyness of the esc and gives easy access (from underneath) to the program port. I've still got to lop some wires off, but I bet I'll loose another 10g each from just that. I'm honestly not too concerned with counting grams, mostly just trying to reduce clutter.

I'm going to run black Deans "wet noodle" 16g wire on both sides of the motors to help keep things clean. 16g is what is on the esc's and what came in the box with my new motors, so I'd assume the wire size is adequate? It sure looks small, but I guess I'm just used to 12g or so on my brushless stuff.

When I go to solder a battery connector on, should I just run both positives and both negatives all the way to the connector (it's a pretty short run), or is there a better method of wiring 2 esc's to one battery plug?

I've got 3 or 4 different Hobbywing program cards, but luckily the one that came with the 1080 is the correct one for these 880's.

I've got a little work in front of me, and I'm waiting on a few crucial parts (servo and knuckles) but I'll report back once I get 'er up & running.

 

[TheLetterJ]

Final weight after stripping most (not all) of the unnecesarry crap is 81g for the pair, totally worthwhile. I'm waiting for a response from Futaba about max/stall amp draw of the A700, then I'll order an appropriately sized BEC... even though they specifically state "no bec use!" I've got the rest of the car just about buttoned up, so hopefully I'll have this up and running relatively soon (I'm generally a sloooow builder.)

 

[Voodoobrew]

I don't usualy watch my weight that much so I appreciate the find.

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