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Thread: Team Death - New Heavyweight

  1. #81
    Very nice Build Thread and cool Project!

  2. #82
    Christmas- its time to hang up your stocking and disharge your Lipo's.
    It's advised that Lipo and some other batteries are discharged if not in
    use for a while. so with the winter holiday period approaching I chatted
    to Adam about doing this.
    I suggested we could run our batteries flat on one of our motors so we
    tried this method-the battery easily run the unloaded motor for 8 minutes
    and there was only a 0.3 drop in voltage after this so we connected the
    turnigy charger and set it to discharge-this method was very slow but it
    let us free to do other tasks.
    We worked on the castor suspension first by cutting two angle brackets
    to support the castor hinge at a higher level, I estimate 70% of the weight
    of our Robot is at the front and the castors should make the front more
    balanced and responsive to steering.
    After welding the castors to thier base plates we looked to the scoop.
    Originaly the return springs were set inside the scoop jaws but proved
    unreliable and kept breaking so now the springs will be external and run along
    the back -this will make them more vunerable to axes but it will be real bad luck
    if we manged to lose all return capability.
    Each modification comes with a consequence it seems, so the external springs
    will lift the jaws off the Arena floor so we have made a beefy spike at the front
    of the jaws as first inpact zone-to lift the enemy bot into the scoop-In Theory.
    We are hoping to sand down the bodywork in our next session and give it
    a lovely two tone paint job.
    Here's some pitures
    DSCN1977.jpgDSCN1982.jpgDSCN1985.jpgDSCN1986.jpgDSCN1993 (2).JPGDSCN1994.jpg

  3. #83

    The O'Neill (BW), X-301 (BW), Bald Unicorn (FW), X-303 (FW)
    Careful there, for storage you're supposed to discharge LiPos down to around 40% capacity, not fully. Most chargers have a storage mode which gets the batteries to around 3.8V per cell for that.

  4. #84
    Thank's for the heads up Cosmin-our intention was not to fully discharge the
    batteries and Adam mentioned a similar % rate as yourself but for Lipo battery
    novices like myself that storage mode is usefull info-I have only ever used gell
    type batteries in the past which were heavy and quite short lived in a battle,
    while comparing the two I was Amazed at the power of Lipos compared to Gells.

  5. #85
    Redirect Left's Avatar

    Hyperion (BW)
    Wakefield, West Yorkshire
    I was always taught to bring them down to around 25%, and definitely not over 60% when expected to be unused for more than 1-3 weeks.
    I've never experienced LiPos degrading (capacity/ max voltage wise) when brought down to 25% for storage, but perhaps 40% also offers the same sort of protection, and a little quicker to bring them back to life too if they don't need to charge so much when brought back into use.

    When I joined to help, I was quite eager to introduce Colin to the LiPos, as he has been out of the robot combat scene for most of the LiPo introduction and rise phase, I managed to impress even myself with the weight difference, as i'd never really used or even held the old style batteries before, so didn't realise how large and heavy they were in person.
    Last edited by Redirect Left; 6th December 2017 at 21:47.

  6. #86
    Last update before Christmas and the new year...........
    This week was designated as a painting weekend but I got slightly side
    tracked and Adam was attending a Christmas do so I thought I would
    tweak the mechanics of the jaws instead.
    It had been bothering me that the winch jaw puller did not have a
    clear path to the chains it pulled upon-namely its own drive motor
    got in the way so despite it being a working system there's allways
    room for improvement.
    The original system was driven via a two sprocket chain to cut down
    on the length of the single chain as detailed previousley and the winch
    was set well back in the robot to pull the full length of chain.
    I decided that if the winch was placed where the two sprocket roller
    was I could negate the need for that roller sprocket and keep the chain
    nice and short.
    The covering polycarbonate lid didnt fit so I had to modify it and added
    a curved plate to the front as a finishing touch.
    Although the springs pull back the jaws after each bite, there is need of
    a physical stop on the winch to stop it unwinding itself because it is also
    powered return via the motor and has been troublesome.
    At the moment I have put two short springs on top of the jaws-these need
    rather too much energy to close the jaws so I think one much longer chest
    expander spring at the side will work much better as in the previous jaws video
    but not accross the front of the jaws.
    I have added a long tooth to the middle of the jaws-made from 10mm steel
    which sits on top of the spike and should help the enemy into the jaws.
    Heres some pictures
    Merry Christmas

  7. #87
    Holiday break over and we returned this Sunday to progress
    with our heavyweight Robot-which Adam will detail shortly.

    Over the Christmas break I was tempted to tweak a few outstanding
    bits on the Robot and I had previousley described moving the winch
    around for optimum operation.
    My attempt at modifiying the position turned out to be a failure,-the
    torque was much less and it still interfered with the drive motor, so it
    was returned to the original position and a longer pull chain was fitted
    which goes right round the drive motor and the end result is near perfect.

    This Sunday was set aside for painting and electrical work so in preperation
    I sanded down the Robot a little and used primer on any bare metal areas

  8. #88
    Redirect Left's Avatar

    Hyperion (BW)
    Wakefield, West Yorkshire
    and now for my input on the day!
    As noted above, the majority of the day was spent purchasing and applying the first layer of paint, with some electrical work later on.
    We started off by buying the paint, whilst possibly not the cheapest option, we decided to go to B&Q as they have a wide range of colours, and an on-site mixing suite for anything not in a tin already. We decided on a color, waited on it mixing, then set off back. As soon as we got back, we wasted no time and started applying the first coat. It's now pretty much a solid red everywhere, an image of which is below, later on we'll get some black for the chassis pieces, to add some contrast. It didn't take us very long to get a coat on the bot, although we expect we'll need to go over it again and touch up areas covering up brighter colors, or just missed spots. We also may need to do some extra work to cover up a few logos and text on the components we used, as certain hosts may not approve of a 'Calor Gas' logo visible behind the paint, so that might need grinding off or more layers coating over.

    Afterwards, we got on with the electric work. We're still having very little luck with the speed controller, so as a work around, we've put together a simple relay system that'll allow us to get the bot moving, and test what we need to with it. It isn't the ideal solution, but it gets us to where we want to be with the progress of the bot, and will get the bot as a whole into a working order, and certainly allow us to do some needed human related tests to figure out who is going to be the driver of the bot, and may also be fine for competitive use should we not resolve aforementioned issues with the speed controller.

    Colin & I would much appreciate any input on getting a speed controller working, or repaired, or even anyone local to pop by one day and offer advice or even repair in person.

    Some images for today,
    1) Some colour comparing at the local B&Q
    2) The first layer of paint is on!


  9. #89
    Sunday update-After last weeks painting session I thought I would
    take a few pictures while the Robot was on it's wheels and I'm very pleased
    with the look considering it's very much an undercoat and the final coat will
    be applied a week before our first event to allow time to dry.
    Adam was unavailable this week so I set to on my own.
    I picked up a seedling planter from a rubbish pile and thought it may be quite
    effective set into the air intake vents/wheel gaurds on either side of the Robot-
    so I cut it to shape with the grinder and inserted a piece at one side, I may
    run with the idea, but the other side would have to be a half section due to
    removable link being located at that side.
    I told Adam I would check out the temporary relay system to see how it coped
    with with driving the motors at 24 volts via 2 gell batteries (static test).
    This worked really well and even when the wheel was suddenly reversed there
    was no arc on the relay and the chain did not break-so we may be able to have a
    run around with this set up if we conciousley be kind to the circuit and don't suddenly
    reverse the Robot like in the static test.
    We are still unsure what to do about a permament speed controller after getting
    our fingers burnt with the last one and it may be the batteries we have may not
    suit all speed controller types-it would be a shame to spoil all the good work by
    not having a control system as least as good as the competition has.
    After testing the relay I worked on the external return spring for the jaws
    and although this meant grinding off a little paint to weld, it was interesting to
    see how well it scrubbed back and I was pleased that it was almost like grinding
    on old bodywork.
    Lastly I painted over any bare metal with a primer.
    We have stuck with the agricultural/industrial paint scheme and overhall look and
    I think the Robot woulden't look out of place in a country agriculture showroom
    even if it leaves you perplexed about it's application

  10. #90
    Wintery weather Today but the build must go on- unfortunatley due
    to the bad weather Adam was unavailable this week.
    I had planned to use most of today on the electrical side of things
    but due to me working on my own I thought I would do outstanding
    fabrication first.
    Early last week I ordered a couple of things of e bay and they arrived
    in time for this weekends build.
    I bought 2 cheap speed controllers at £8 each -they are rated at 7-16 volts
    and 300 amps and I bought 2 weightlifting bars to complete the fabrication
    of the jaws.
    Fitting of the weights bar to the front of the jaws was quite straight
    forward, it just needed slight shaping and welding in place.
    I then needed to cut a false tooth out of a car disc brake which I had used
    on previous occassions for various things and I welded that to the bar.
    Now I turned my attention to the never ending saga of the electrics
    and namely the speed controller-I could be green with envy at other roboteers
    who say " controller arrived and five minutes later it was running around "-
    this hasn't been my experience-the Ragebridge blew with a massive spark
    as soon as it was plugged in, so before we commit to another I'm doing some
    So my thoughts were-how would a £8 speed controller designed for small RC
    cope with driving a heavyweight ?.
    Bearing in mind my motors are 24 volt and the max current of the speed controller
    is 16 volt I wasn't expecting great performance.
    I tried running it at 12 volts on a gell battery to begin with and it worked well
    (wheels off ground ) and then I tried our 14.5 volt lipo battery and it was slightly
    better going forward and backwards no problem.
    Whether or not the ESC will blow when the Robot is on the ground remains
    to be seen-I have heard that the ampage rating is not the true rating ?-
    What I do know is that I can wire them up and why the Ragebridge blew
    is still a mystery (possible overvolts) but Adam thinks not.

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