MItchell 45xx battery/radio control

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JackBlack
Posts: 131
Joined: Tue Jul 22, 2008 1:25 pm

Re: MItchell 45xx battery/radio control

Postby JackBlack » Tue Nov 12, 2019 8:40 pm

Thanks for the replies, I've actually not seen either of those boost boards, the smallest I could find are the ones I used. Do you get enough current though? The larger adjustable booster outputs 2A.

The 9V Pololu board looks ideal for an RX63 though so I'm going to order a couple to have a play around.

Having said all that, the desire to remove the need for a voltage booster has led me down the route of 4V motors and I'm getting good results with this latest one, the Mabuchi N30. So I'm going to see how it goes. Also for the price of a Mashima motor + Pololu 9v board I could buy 30 Mabuchi N30 motors!

The 45XX is very nearly finished so I'll post some more pics and videos later in the week.

Cheers, Nick

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JackBlack
Posts: 131
Joined: Tue Jul 22, 2008 1:25 pm

Re: MItchell 45xx battery/radio control

Postby JackBlack » Sun Nov 17, 2019 10:33 am

Back in Portugal, 4556 is basically finished. I now need to install the little connection board that allows the battery to be connected and the power to the RX/Motor that are in the chassis to be connected, and then locate the switch and charging socket in the cab. Some cab detailing still to be done. It currently weights 180gms, but it needs some more weight in the coal bunker as it's slightly front-heavy right now, and I think I can get some more weight in the tank sides once everything's put together.

IMG_20191116_212826386.jpg


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More later. Cheers, Nick

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JackBlack
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Re: MItchell 45xx battery/radio control

Postby JackBlack » Fri Nov 22, 2019 5:12 pm

A bit of progress this week...

Chassis with the N30 motor and RX63...

01.jpg


These are the main parts, 14430 battery, switch, charging socket and my connector board.

02.jpg


The battery attaches to the connector board using two 12BA nuts. The same arrangement for the RX. I've ordered some 1.47mm pitch micro connectors for my next project so I can tidy this area up a bit.

03.jpg


The connector board is sandwiched between two pieces of plasticard and glued to a piece of lead which is for now blu-tacked to the underside of the firebox. Charging socket and switch are fed through to the cab.

04.jpg


Undercoated, but I forgot to attach the doors dammit...

05.jpg


Nearly there. Iron Mink 63229 watches with interest, gently reminding me that it's been waiting two years for buffers to be fitted...

06.jpg


07.jpg


All the parts ready for painting, doors attached!

08.jpg


Now to the painting...

Cheers, Nick

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Le Corbusier
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Re: MItchell 45xx battery/radio control

Postby Le Corbusier » Fri Nov 22, 2019 11:06 pm

I know this is meant to be about battery control .... but actually I am loving the loco build itself ;)
Tim Lee

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JackBlack
Posts: 131
Joined: Tue Jul 22, 2008 1:25 pm

Re: MItchell 45xx battery/radio control

Postby JackBlack » Sat Nov 23, 2019 10:29 am

Le Corbusier wrote:I know this is meant to be about battery control .... but actually I am loving the loco build itself ;)


Thanks! It's gone suspiciously smoothly so far, I'm still waiting for something to go wrong...

Last night and this morning basic colours have gone on. Undercoat is Halfords Grey Primer.

09.jpg


Humbrol matt black (which isn't matt)...

IMG_20191122_144935141.jpg


Precision GWR Loco Green and Buffer Beam Red and then Alclad II Copper Laquer for the chimney top.

IMG_20191123_101000634.jpg


IMG_20191123_101036014.jpg


I have a rather domestic weekend ahead of me, but hopefully this will be dry enough to put the decals on tomorrow evening and pick out the whistles and other details. After that weathering with oils on Monday, which takes a week to go off, and should be dry enough to bring back to London on the 1st....


Cheers, Nick

Alan Woodard
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Joined: Tue Sep 26, 2017 3:15 pm

Re: MItchell 45xx battery/radio control

Postby Alan Woodard » Sat Nov 23, 2019 12:42 pm

Enjoying the build also, and how the R/C goes together.

Regarding the Halfords primer paint. They do an Acid etch grey primer which is more expensive, but is better on Brass. It provides a stronger base for the top colour. Less chance of paint chipping off of cause.

Cheers.

Alan.

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JackBlack
Posts: 131
Joined: Tue Jul 22, 2008 1:25 pm

Re: MItchell 45xx battery/radio control

Postby JackBlack » Sun Nov 24, 2019 11:23 am

Thanks Alan. The next time I'm in Halfords I'll pick one up to try. I've had problems before with masking tape lifting off paint and primer back to the brass, which is really annoying! Maybe this will help. Cheers, Nick

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zebedeesknees
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Joined: Mon Jul 12, 2010 5:15 pm

Re: MItchell 45xx battery/radio control

Postby zebedeesknees » Mon Nov 25, 2019 4:26 pm

Dave Long wrote:-
I'd certainly look at the Pololu regulators, I've never seen the point in the adjustable versions or having a step down function, plus they are even smaller.


Many thanks for this info Dave, I/we hadn't discovered those. the RobotShop was out of stock of the 12 volt ones, but I found a source in Germany and they arrived last week. 'Even smaller' is an understatement! They are tiny, I can lay two to just cover one thumbnail.. Which bothered me a little, as looking at the graph of the output, the volts start to drop as the current exceeds 300mA.

On testing one today with a relatively high current old ModelTorque motor, I found that after about ten seconds under full power and maximum load with the clutches stopped, at 380mA the volts dropped, then pulsed, then the output folded back to zero. Power off, then on again, it came up to the original 12.12 volts. So I did it again, and after the output ceased, I touched the chip and burned my pinkie!

I deduce that it was a thermal shutdown, protecting the Pololu, -and the motor if it is stalled and drawing over-current. Thoroughly recommended, with the reservation that it should not be mounted too close to anything that might be damaged or melted by temperature in excess of 60°C.

Ted.

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JackBlack
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Re: MItchell 45xx battery/radio control

Postby JackBlack » Thu Nov 28, 2019 11:36 am

4556 is basically finished now, with a bit of light weathering using oils and powders. I just need to fit the buffers, coupling hooks and add some coal which I'll do over the next couple of days.

It runs nicely, and I was going to make a video to demonstrate, however it seems to have lost a crankpin nut on one of the front wheels. So I'm going to have to wait until I get back to London on Sunday to replace it and figure out why it came off...

IMG_20191127_184356_721.jpg


Cheers, Nick

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JackBlack
Posts: 131
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Re: MItchell 45xx battery/radio control

Postby JackBlack » Sun Dec 01, 2019 10:42 pm

4556 with it crankpin nut fixed, buffers, coupling hooks and coal. I've somehow managed to get the weight up to 232gm. It runs nicely on my tiny test track, but on Saturday we'll hopefully see what it'll pull using Ted's traction testing thingy.

I've also figured out that the videos look better if you turn your phone sideways...



Cheers, Nick

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Le Corbusier
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Re: MItchell 45xx battery/radio control

Postby Le Corbusier » Sun Dec 01, 2019 10:49 pm

JackBlack wrote:4556 with it crankpin nut fixed, buffers, coupling hooks and coal. I've somehow managed to get the weight up to 232gm. It runs nicely on my tiny test track, but on Saturday we'll hopefully see what it'll pull using Ted's traction testing thingy.

I've also figured out that the videos look better if you turn your phone sideways...



Cheers, Nick


Well impressed ..... and that's just the music :thumb
Tim Lee

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Mike Garwood
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Re: MItchell 45xx battery/radio control

Postby Mike Garwood » Mon Dec 02, 2019 4:40 pm

Nice loco and excellent choice of music!

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JackBlack
Posts: 131
Joined: Tue Jul 22, 2008 1:25 pm

Re: MItchell 45xx battery/radio control

Postby JackBlack » Tue Dec 03, 2019 6:47 pm

Can't beat a bit of Floyd on a Sunday evening...


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