MeccAnnoyed

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11 hole Meccano strip and 3×7 bent plate and a velcro cord wrap.  Ooo feel the tech.
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Battery cable with spade connectors

G15 MeccaBattery sucker refit.

What kind of sadistic toy manufacturer … rhetorical?

Relating to the 4 ‘C’ cell butt battery pack.  The G15 is cute and fun in itself.  The build is tedious.  Keeping a ten year old interested for 6 to 11 hours is questionable, and the G15 is the shorter build than the G15 KS.  Then to have the fun cut short by battery.  Sad.  A rechargeable sufficient power battery pack for G15 should have been made available at the beginning.

This article is intended for those who can at least wire and load batteries in flashlight.  It is also for those who find big butted anthropormorphic robots that are not decidedly female are disturbing.

Usual disclaimer:  Don’t do it.  Damage to life, property and unicorns may result.  I’m serious.  Don’t hurt no unicorns.

First thing first go to Meccano.com and download the robot updater:

http://meccano.com/meccanoid-robot-updater

This is essential.   The old rom needs the update if you haven’t already.  It’s a power piggy.  Get the update.  It’s not just for changing the language.

If your an electronics type of people you’ll probably want to know a 6.0V /5 cell 2000mah NiMH pack works well in the G15 Meccanoid without complication.  It’s fused at 2.5A.  A six cell is not recommended due to review of some of the peripherals onboard as well a using a 3V linear regulator which may get hot.  It’s also what is used on the G15 KS.  Which is the same controller as best any one can tell just with 4 extra servos . Look for the leaked schematics from the FCC. 🙂

Yes I am running this minor MODification and have been for many hours now without error or problem other than what was already irritating me whilst running alkaline.

For Instance:  One Noisy servo whining at me and clock which doesn’t hold time which probably means I’ll have to actually crack the brain and pull the defective coin battery.  Yes there is one even though there’s no facility(s) to use it other than to reply to “What time is it?”  Notice that there’s no “What day is it ?” command.  Oh a “wake me at 5 a.m.” clock function would be nice.   But noooooo.  A moving alarm clock would be harder to hit or  smash.

Four ‘C’ cells.  Yaaaa.   Own stock in battery manufacturer do you?  Good quality alkalines will MAYBE get a half hour to 45min. run and those are NOT cheap.  New Meccanoid 2.0 (AKA G16) at least has ‘D’ cells.

Sure,  buy the more expensive KS unit and get some run time.  It uses the 5S NiMH.  Comes with battery charger too.  5S meaning five cell Nickel Metal Hydride.  5C means something different in rechargeable World.  The ‘C’ refers to charge/discharge rate. Which should not be confused with ‘C’ type batteries which refers to physical size.  Stop here if you’re confused.  Intentional.

Using :

5 that’s FIVE commonly available AA size NiMH rated 1200 mAH or better.  I’m using 2200mAH  NiMh.  Charged and ready.  Duh. Could use AA NickelCadmium (NiCd ) but those are usually about half the power rating.  Roundabouts  400-600mAH mostly for NiCd.  Useable.  Rechargeable and more power are the key points.  Work with what is in your possession first.  If NiCd charger and batteries is what you have.  Use them.  I highly suggest NiMH.

NEVER NEVER NEVER

NEVER mix battery types.  Alkaline only with alkaline.  NiCd only with NiCd.  NiMH only with NiMH.   Lead-Acid only with Lead-Acid.  Same size (AA, C, D ) with same size, Try to keep same Amp-Hour(AH or mAh) rating on rechargeables.  Carbon zinc (Zinc chloride/Ammonia Chloride) only with the trash can. They have no place in this.  Ignore this at your own peril/demise.  Burning, exploding, injury, possibly fatality.  Yes I’m laying the scare on thick here and not being unreasonable.    There are other newer cell chemistries which pack more energy per unit but increasingly dangerous as well that I refrain from mention herein.

6 cell AA battery holder with one cell holding jumpered or shorted, or a 4 cell holder with a single cell holder or an eight cell holder with 3 shorted/jumped cell holders.   Getting the idea that 5 cells are needed in series yet?   What’s  ‘series’?  Probably best you not be here or at least type in “series batteries” in your search engine.

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Tamiya mini battery jack.

Tamiya battery connector. mini Female.  Round Ground black.  Square power B+ red. Tamiya on Meccanoid.  Either snagged from battery box or new.  Available at your local Radio Control (RC) hobby shop and online.  For to and so much one could simply get a RC battery and charger from a knowledgeable RC hobbyist working there.  Bring the battery box connector with you.  Saying Tamiya may not be enough.  A 5 cell 6.0v NiMh or NiCd pack that you think u can secure on bot frame.  Not 4 cell.  Not 6 cell.  FIVE. Five Cell.

5.    F-I-V-E  .   5.

Also known as an 5S 6.0v NiMH or NiCd pack having mAH ratings of 1000 and up.  No you don’t need the fancy 20 cell charger and 200amp power supply it needs.   A simple AC wall wart charger and connector with idiot light for on and charged is good ’nuff fer now.  Honestly some of them hobby sellers are worse than used car salesmen.   Yes the cheap chargers suck and are somewhat detrimental to battery life but they work.   Should be able to get out of there around 25-35$USD.

A four cell will work for a bit but on board battery power detection will shut down in a few minutes.   A series four cell pack of 1.2v is nominal 4.8 volts.  That’s a dead set of battery in Alkaline land where 1.5v times 4 is a nominal 6.0v.  Also why jamming four fresh 1.2v rechargeable AA in the C slots of the battery fanny pack  only works for a bit.  Ya sure you didn’t try that.

The disadvantage is being stuck with a battery and charger that may be good for only one thing.  Individual cells are better in my opinion.   They are: configurable, common charger, useable in other devices and projects.  If you and/or others in your dwelling get into this hobby “Robotics” there WILL be other projects needing those batteries and most likely not just in 6.0Vdc.  Then they get bigger and more advanced.  Then the chargers get bigger and more capable,  and then  … well.  Have you seen the Frankentstein movies where there’s huge power arrays, Tesla coils, Jacob’s Ladders,  Townsend gas discharge globes/tubes,  Faraday cages, Van de Graff generators and the like sprawled across the lab floor and an ominous work table on which delicate arranged rats nest of wires in certain spots  with an assortment of slightly smoking soldering irons?  Like that, only more modern and slightly less chance of electrocution.  Slightly.

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Installed.  Plugged in.  Ready.
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Connector with spades for adding or removing items like fuses.

Basically that’s it.  The battery box does have a 2.5A slow blo poly fuse.  That’s a fuse that resets itself assuming the power though it isn’t excessive. It’s up to you if you want to add one in line(series).  An automotive type blade fuse or even an older glass style in the 2A to 3A slow blo range would be good.  Some manufactured battery packs have them in the blister wrap of the battery pack.  I haven’t had my hands on an official K15GS battery pack so I’m without my ball of twine. (no clue).  But, whereas the G15 has one on its’ fanny pack I’ll assume there’s one on the KS as well. At the least the leaked schematics suggest that it is so.  It is a good idea to prevent damage due to shorting on the  the servo outputs which aren’t fused.  Those do have ESD protection on signal line but not fused.  So if ur tinkering in that side please do. Barring stupid  like try to bypass the key way and slamming servo connector in upside down.  I havent fused on my quick rig yet and so picture shows.  When I get to that I will put a fuse.  There is a  mosfet switch and current sense on the v-mot line and v_bat which suggests that there would be a shut off if excessive current was detected by the processor.  Guess there.  Assumption.  The processor , USB, and peripherals have their own fuse and blocking diode.  The servos have their own regulators.

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Polyfuse on G15 4 ‘C’ cell fanny pack.

One could also us a 6v sealed lead acid.  But that’s covered on Youtube by someone else.  The charger and battery can often be bought at department stores and sporting goods where hunting supplies such as deer feeders and camping supplies such as 6v lanterns are sold.  SLA (Sealed Lead Acid) 6v batteries come in several sizes.  4AH being the most available and resembling physically the same size as 6V Alkaline Lantern battery but being able to be recharge a couple hundred times usually less. YMMV. Improper use as in trying to put too many amps out or overcharging usually kills them.  Majority of batteries are rated 20hr rate. Take the 4AH SLA battery divide by 20.  That battery would put out 200ma per hour for 20 hours without harm to battery. That’s less than what your bot wants.  So it’s gonna want more.  The more it sucks the less run time and the less battery life overall.  Same goes for NiCd and NiMH but far less effect on overall life.   Again “cheap charger” can cause issues but with care should be fine.  Most notably some chargers may push the fresh SLA to significantly higher voltages than 6V.  This is temporary effect.  Let the battery sit off charger for ten minutes and is likely to go down to usable voltage less than 7V. SLA are heavy and don’t last as long recharge-wise and cost easily as much as a Five NiMh.  Five times the life or more, and less weight, but only little more than half the power per charge with AA NiMH.  The weight of the SLA may be helpful for traversing rugs.  Helps the wheels from slipping by more friction.  Where it’s put makes a difference.  The robot builders quandary: Power vs. weight vs. run time/ functionality then at cost per unit say WH (watt-hour) and serviceability cost.  That’s just the battery concern for rovers.

Have fun.

There’s a “the the” in there somewhere.  One last butt picture:IMG_20160810_061908.jpg

You been staring at robot but pictures.