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Bonzo Moon

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Posts posted by Bonzo Moon

  1. Thanks Simon it was a good result in the end. To be honest it has taken very little sorting to get it flying well. 1st step was giving the motor a bit of down and right thrust. And a bit of adjustment to the upper wing. I'm well pleased with it now. Very easy and predictable to fly.

    My first 'big' Lidl foamie biplane rc build below took a good few adjustments before it flew ok. Biplanes are funny creatures! 🤔..... 

     

    • Like 1
  2. 13 hours ago, Geoff S said:

    I'm not sure how useful static thrust measurement is.  I did experiments like this when I was trying to get electric models to fly with NiCads and cheap brushed motors, using a spring balance to make the measurements but once the model is moving through the air all the static measurements are moot. 

    Agreed,   airframes are all different and some more efficient than others.   But does give a rough guide of power to weight.  Gives you a chance to see what difference different props make too.

  3. Ah interesting.  And thanks.   I'm glad I'm not the only one who comes up with these ways of amusing myself on rainy days!

     

    The only other scale I have with a hook is the old kind of spring balance.  Very crude. Just a spring that you put under tension and it has a scale on it.  I've got one 1.5kg scale and one that has 3kg scale. the 1.5 kg one shows divisions of 25g but nowhere near sensitive enough to measure say 40g or 45g. A small digital balance like that would have been easier.  I just figured what can you do with what you do have!  A mechanical way to change the thrust direction. It was a bit of fun really but reasonably accurate.

    I might improve it with a better trolley! 

  4. A little idea I came up with on a wet afternoon. Might be useful? It kind of follows on from my '3 maidens 2 fails' video where I had an issue where a small 1s lipo had insufficient power to drive 2 small brushed motors in an experimental model. It's called C rating. 'The capacity of energy the battery can safely discharge, represented as a multiple of its overall capacity.' I hadn't considered it with small 1s lipos I use in small models.
    I'm sure it could be improved, eg I just cut a small V in the front of the trolley to take the fusi!
    Suggestions welcome (polite preferably please. 😉)
    You never stop learning in this hobby!
    • Like 1
  5. A couple of weeks back I asked for suggestions for my next Lidl build after creating 10 big Lidl's and 4 mini Lidl's, including twins, 4 motors and biplane. I had a few suggestions, but in the end decided on something I hadn't tried before, a swept wing design somewhat inspired by the Hawker Hunter! (Hence the attempt at a silver finish (fail) and RAF roundels. She flies! Used a very cheap power train package from Banggood which has a 1104 motor, 5A esc, prop and prop saver. Works ok with a 1s and the FS2A rx. Link in video description.
    Very short and quick build blog and I've just seen these little foamies on Temu at less than £2.
    The question now, what next again? Swept wing BIG Lidl I think?
  6. 19 minutes ago, Phil Green said:

    I know you know, but its apparent that some of your viewers dont 🙂

    Fair comment!  I was a bit surprised just how much discussion the post has created.  I did include a very small diagram in the video of cells in series and tried to explain where the balance lead is connected, but as you say, some confused comments.  

     

    Just wanted to show folk that one dead cell doesn't necessarily mean you need to throw away a lipo.  😉

  7. 3 minutes ago, Phil Green said:

    Balance connectors are wired in parallel.

    Inside the battery, balance neg and power neg both go to cell 1 neg

    and the last balance wire goes to the last cell pos and power pos

     

     

     

    balance.jpg

    I know the way  they are wired in a lipo thanks,   I have built and repaired a good few lipos.  I just didn't know how the ports were wired in my charger. 

    • Like 1
  8. 33 minutes ago, Phil Green said:

    I think you've completely misunderstood Jason. Assuming cell 3 was the faulty one, the disconnected balance lead (one wire) is from the positive of the removed cell 3, and hence this wire is redundant.
    The positive power lead which is floating after removing cell3, is moved to the pos of cell2.  Its very simple, not at all dangerous if done by someone competent, and not 'daft', in fact personally I think its daft binning of perfectly good Lithium  🙂

     

    Edit: I just watched it again and realised that its cell 1 that has gone, so the balance plug does need to be changed after all, sorry Bonzo thats me speed-watching.  If cell 3 has gone then 3 wires of the 4S balance plug can stay, the last wire is redundant and can be snipped or insulated away.

    In Bonzo's case its cell 1 so its easier to replace the whole balance lead than to shuffle them all up one - its only 3 wires so not worth messing about 🙂

    In order of ease of fixing, a bad cell 3 is the easiest. A bad cell 1 is a little bit more faff, a bad cell 2 is double the effort, more so if its a PCB for inter-cell links - I probably wouldnt bother.

    I'm very guilty of speed watching, scrolling through, we all do it!  I actually said in the video that had it been the centre cell of the 3 it would have been more of a pain of a job! Luckily as it was the end one it was easy to peel it off, re-solder the neg wire and put an old scrap 2s balance plug on.  If balance socket leads are commoned to each socket I'll try using the 3 plug next time. 

  9. 16 minutes ago, Ron Gray said:

    As a matter of interest did you try and charge the one ‘dead’ cell. I’ve done that on a number of occasions, true it’s mainly been if I’ve had 1 cell that’s badly out of balance but I’ve also done it on an otherwise ‘dead’ cell. Even having done that the ‘repaired’ battery is consigned to desk duty.

    I saw online that once a lipo has gone as far as zero they cannot be revived. 3.65v is less than 10% but I've done it from the low 3v mark. 

    Worth doing for a little bit of work to have a useable 2s 800mA I reckon.  I don't like chucking stuff away! 

    • Like 1
  10. 7 hours ago, Jason Channing said:

    You never said you opened the pack up and resoldered the pack and bypassing the dead cell, you made it sound like you only removed the balance lead.Sounds like a pain in the arse to save a few pounds.

    You never said you opened the pack up and resoldered the pack and bypassing the dead cell, you made it sound like you only removed the balance lead.Sounds like a pain to save a few pounds.

     

    Did  you actually watch the video?   😉 You can see I rebuilt and rewired the pack after removing the dead cell? 

    Pain in the ass for some, but I enjoy messing with stuff and OK, it saves a couple of quid too.

     

    As I said, people are posting telling me they already do the same thing. 

     

    My video was intended to be educational, but each to their own! 

  11. 18 minutes ago, Jason Channing said:

    Inside the pack the cells are still wired in series whether or not you disconnect the balance lead. Probably the daftest thing Ive read in a long time and the most dangerous.

     

    Of course they're wired in series in the pack. I took the end one off the series, so it was two good ones in series. And the balance lead and power lead attachment points needed changing to suit a 2s not a 3s.  I am a qualified electrical engineer too as it happens 😉

    It's not daft and on other groups people are telling me they already do the same thing if there's one dead cell in a pack.

     

    Please tell me what's dangerous about it? 

    • Like 1
  12. 28 minutes ago, Geoff S said:

    How does the charger 'know' you're plugged into the 3S or the 2S balance connector?  Mine certainly doesn't and it displays individual cell voltages.

    Good question. Mine has 5 slots for balancing leads. It certainly senses the voltage on the power lead to see if it's with acceptable parameters for the settings you have chosen.   I doubt I can plug a 3s into the slot with one dead cell and tell it that it's a 2s. More importantly there was zero volts across the power lead,  so it just said 'low voltage' and wouldn't work.   My charger doesn't display individual voltages either? 

  13. 4 minutes ago, Phil Green said:

    Yep, several of my 2S batteries started out as 3S.   I mostly use a blunt plastic tool rather than a Stanley knife.

    As Geoff says, theres no need to change the balance plug, just remove or insulate the 4th wire if its a 3S to 2S fix.

     

    I was thinking after using the blade a plastic spatula would be safer!  I just went very carefully  😉

  14. 13 minutes ago, Geoff S said:

    There's no real need to change the balance connector.  You just plug it into the 3S socket and the charger will 'know' it's a 2S LiPo as all the balance connectors on a charger are wired together.

    Plugged into my charger and because one cell would not allow current to flow through it the power lead showed zero, charger said low battery, and didn't want to know? 

  15. I was testing an FPV tx the other day and like a fool forgot to disconnect the lipo until a while later. Put a meter on it and it read zero! Quite a recent 3s 800mA. I was not pleased. Checking cells I discovered that in fact it was only one cell that had gone to zero, two others were showing 3v + . I tried unsuccessfully to kick the zero cell into life by charging as NiCad, at NiMh, but it stubbornly stayed at zero. Reluctant to bin it I salvaged the 2 good cells and turned it into a 2s 800mA. Here's how
  16. 13 hours ago, Engine Doctor said:

    Good luck wigh tesf flights Bonzo . EPP  foam isnt harmed with most solvent based paint but do a check first odinary Polystyrene foam just melt with most solvents but takes artist water based acrylics well then a coat of Rpnseal waterbased clear to seal it. 

    As I said I thought mine was a Lidl glider , just plain white. Obviuosly not . Anyway it all a bit of fun.

    Thanks, I'll give it a try sometime!

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