TOPIC:

Hi
I've recently bought a second hand Bullhead as I fancied something a bit bigger to have play with. I've only had a couple of goes with it and am a bit disappointed so far. It's been set up with 2x Ansmann Clash motors (believed to be 21T?) and an ansmann autosport tuned 20 ESC. I'm powering it with 7.2V nimhs 2300mAh, and it's moderate on forwards and very slow on reverse. It's been set up with the power/economy switch wired up but there's not a great deal of difference with that changed. Do you think I need a much better battery, or is the ESC setup wrong/underpowered? Any advice would be appreciated as I really don't know much about different electrical setups as my other cars all work much better. Cheers...

First thing I'd do is have a go at is some different motors.
That seems to be the weakest link as they don't have a reputation of being all too strong.
What you would replace them with, depends mostly on the terrain you'd like to drive.

Edit - but what kind of battery (brand) do you have and how old is it?
And I'm wondering how it's wired up because that doesn't seem to be a dual ESC.

Welcome on board, bullhead69

Lots of things could be wrong there ...

For a start, a Bullhead or Clod is not particularly fast - they're brilliant in snow, or in big puddles (or lakes), or for drving straight over titchy little cars like Lunchboxes ... but without erious power & modifications, they're not fast - 50 to 60% of a "regular" car with a single same motor - so maybe it's partly your perception?

2ndly, Ansmann "Clash" motors are well known for being a bit pants - the main problem I've found is a complete absence of torque, so unless you have a _very_ light car, and manage to get the gearing absolutely perfect (difficult with Tamiya cars), regadless of the number of turns, a Clash motor is going to be slower than a standard "silvercan" 27T motor. There may also be an issue with motor timing - I know the motor timing is fixed on a clash (i.e. you can't loosen the endbell to change it, but it may be a fixed advance - so more power forwards, but less backwards - this is an issue in a Bullhead/Clod as the motors are spinning in different directions (one forward, one backwards - so one is advanced, the other retarded) - so one end is dragging/pushing the other.

You can test motor timing by removing it from the truck, and running it directly off the battery - if it spins faster one way than the other, then the timing has been fiddled with.


Next, the battery ... there are some sold on ebay that look a real bargain, but have really inadequate current delivery capabilities & lower capacities than claimed - some are even much smaller cells, bulked up to look like sub-C cells... from memory they're a light green (or possibly blue, I can't tell the difference between green & blue) with a red & white label - so what brand are your cells? And are they properly charged?

The ESC ... I have no experience with that model - but it looks very similar to an Mtroniks unit. At a 20T rating it's completely inadeqate for two motors - take the rating of one motor, divide by two - that's what you need for two motors wired in parrallel (aka "power" mode), e.g. for two 27T motors, you need a 13.5T rated ESC, in practice though you'd probably find a 12T is the next lowest match. I'm thinking the previous owner has wired the motors up in permanent serial (aka Economy mode) to stop the ESC frying. A sketch or pics of the wiring would help diagnosis ...



Sorry if that's too much information ... if it is let us know & we'll try & work through it - I have a Bullhead with an ESC & the power switch still wired in - we can compare and contrast to see if your switch is wired correctly

TBH though the motors are crap & the ESC is not man enough, I think any fix is going to involve some replacements as well as some rewiring

And yes, welcome of course! I had seen you on line before and didn't realise that was your first post.

The second you said "Annsmann motors & ESC" I thought "Well there's your problem", but Jonny beat me to it! I'm not a fan of NimH batteries either (I find they have poor power output & a short useful lifespan), but I'll leave that subject alone as most will disagree with anything I have to say on the subject!

A standard Clodbuster, with standard motors, standard manual speed control & a Tamiya 1400mAH NiCd battery will wheelie off the stick in forward or reverse, with the switch set to power OR economy. They're not hugely fast, as Jonny said, but will keep up with most Tamiya cars in standard trim on smooth flat ground (If you can keep it in a straight line). It should also climb kerbs/doorsteps without any issues. Basically, I'm saying they work ok out of the box, so if you've still got the original bits, put them on & start from there.

If you haven't got the original bits, I'd personally go for an original manual speed control, as it'll be cheap, was made for the job, & will handle the power of 2x uprated motors, if you ever decide to go that route. An ESC to do the job will be expensive (More expensive per the more powerful motors you go for) & will need to be a dual output type. Motor-wise if you want something more powerful than the standard motors, look for motors with uprated torque NOT higher revving, otherwise you'll end up making the batteries hot (Which will kill NimH) with no gain in speed (Or may even be slower too). Normally, to get around this, a change of motor pinion would fix this, but from memory there's no adjustment on the Clod to allow for this, so torquey motors is the way to go (27+ turns)

I see there's only the option of a 13T motor pinion so that limits things.
Easiest thing you could probably do is make it a RWD with a better motor.
Not the biggest fan of a mechanical speed control (MSC) instead of an ESC myself because I've seen too many runaways.

If you want to go for a Tamiya setup, you'd need a TEU-103BK or TEU-106BK ESC and two silvercans for example.
The max you can put on these is two Sport Tuned motors so I feel that is a bit limited.
But then again the Bullhead doesn't lend itself for high revving (high current) motors.
There aren't that many dual ESCs around but I know some other brands have controllers that can handle a bit more...

NiMHs shouldn't be all too bad in itself but cheap packs mean short lifespan...
This sort of battery definitely needs maintenance in the form of a regular charging otherwise they just fade away.
I'd recommend buying a proven brand - Vapex for example, they can be had at a good price in the UK.

Do Tamiya recommend the TEU series ESCs for Clod/Bull? - I would've thought with the weight & huge wheels they wouldn't be up to it? MTronics used to do a dual motor rated ESC called truckzilla or something - it was a relatively large blue metal box thing that was supposed to be good, & sometimes come up on Ebay.

Has anyone ever tried rigging up 2x ESCs in parallel? Off the top of my head I can't think of any reason why it wouldn't work.... (Probably have to ditch the speed/econ switch though)

Yep, runaways can be a downside to MSCs if your radio is dodgy or there's a mechanical failure (eg linkages, dead servo, loose fasteners), but with good maintenance it shouldn't be a problem (Only runaways I've ever had have all been SRBs due to radio interference).

I'm gonna throw an idea in the pot now - it stands to reason that if you're cheapskate enough to be buying Annsmann electrics, chances are the batteries will be cheap poor quality ones too, & even if they weren't, chances are the high current draw of the Annsmann motors would've wrecked them through heat build-up anyway.

I'm totting up cost-to-fix in my head (Habit), & I can see posh motors, batteries, & posh ESCs easily costing more than the truck. I'll go back to my original suggestion of MSC, standard 27t motors & a Tamiya NiCd battery, all cheap off Ebay, (I reckon 2x

By the way, I notice you're a Londoner, your Bullhead wasn't covered in oil when you bought it, was it, perchance?

He could go for a dual ESC dig setup, aka get a FlySky GT3B, do the software hack and put two ESC (throtle and 3rd channel) in the car et voila now you can mix your rear and front wheel speed. Had that setup in mind for a mates dualhunter.

Can the bullhead do front and rear steer, than with 6 channel, even more fun make him do the crab crawl.

Okay, posting simultaneously with waterbok made the first bit I wrote out of context...
It would really be an improvement I think if the forum software detects this and gives the option to alter the text.

...

I wouldn't go for the TEU-103BK in any case. The 106 offers much more.
Comes with the 58535 Bullhead also, so I guess they're okay with the big wheels.

Trying to remember where I saw those (Tamiya?) motors that had reverse directions...