DIY Hybrid 9v / Power Functions Train Motor

[SteveB]

Hi All

I posted three videos on Flickr showing a DIY hybrid 9v / Power Functions train motor modification I made this weekend.

Thanks,

SteveB

[Stefaneris]

This is a great idea. I see this might be somewhere in the future or maybe even now an alternative for aging 9v Motors.

Thanks for sharing your videos so that others can profit from your ideas.

[Paperballpark]

Call me ignorant, but what does it actually do? Does it allow 9V motors to run on plastic track, or allow PF motors to run on 9V track, or allow charging of PF battery boxes through 9V track and motors?

[kieran]

Very nice job

Edited January 4, 2016 by kieran

[SteveB]

What does it do.... great question. :-) Since there are no more 9v motors being made it helps solve that issue. It modifies a Power Functions (Pf) train motor to pick up power from 9v track. It routes that power up the Pf cable to supply power to the Pf receiver so no battery is required. So you might say its the best of both worlds, remote control track powered train motors.

BTY once there is a constant 9v's is on the rails any track side accessory can pull power from the rails.

Steve

[garethjellis]

This is GREAT,

i wish NWSL would make Lego compatible wheels. I had the same issue with the wheel centers not being dead and wobbling a bit.

[LEGO Train 12 Volts]

Amazing experiment! You've done an epic work ...just one question about the grip of the wheels: are they slipping?

[bricks n bolts]

Ow, wow, that is beautiful, congrats. Great how you've found the positions to put the brushes and utilised the 2 PF outputs that were free.

Might be worth building up the brush contacts with alainnekes' bushels and springs (http://www.eurobricks.com/forum/index.php?showtopic=79145&hl=pickups) for smoother running wheels but that will have it's own issues as the axel there is the standard RC train wheel one (metal - insulated by the bushels) and too narrow.

Then next problem, now you've solved the 9v motor and track issues...., is we need a smaller rechargeable battery to act as an UPS, so we can run on both powered and RC track.

This also impacts back onto the motor, because if we had that solution we would need only one pair of 9v pickup wheels, which in turn would help with any slippage issues.

And ultimately we need a 'universal pickup' that can get power from either 9v outer or 12v inner rails in a mixed 12v/9v/RC layout.

[SteveB]

I'm getting bids on wheels and wipers... Some homework before a doing a KickStarter for altBricks. If I can get 250 replacement motors pre-sold via KS, I'll do it.

I think I'll tackle the 9v motor replacement first by removing the Pf wire and internally hard wiring it. All the same new components as the Hybrid but a bit less labor intensive.

Udo (a German LEGO Rail fan) showed me a Pf train motor as a 9v replacement motor using external wipers. Great work, I love the idea of a simple 9v replacement train motor as a second SKU to the Hybrid. Unfortunately for Udo I had to reload my Flickr video and lost his comments. :-( Udo... Please comment and link your videos!

On LiPo's: I fly quad copters (my other hobby) and I know that 7.4v 2000mAh batteries are ~$10 ea. vs. LEGO $50ea. They need to be ran through a PCB (protection circuit board ~$1.50) but "should" run fine. I'll be testing that in a week or two. :-) I already have the batteries... waiting for the PCB's to arrive. This solution would require charging out side the MOC.

It would be nice to get a recharging solution in a small package and charge from the rails using the Batts as a UPS (Uninterrupted Power Supply), mentioned above by Bricks & Bolts. This would be so cool... power and recharge from the rail and still run on plastic rail if needed. Unfortunately the 2S (two cell) 7.4 LiPo recharging circuit is harder to implement then the 1S. Any pointers to a low cost single chip solution would be awesome. I'm sure the Arduino community is working on this so its only a matter of time. :-) LEGO tackled this in their LiPo pack... but this design is several years old (kudos to LEGO to release a "new" technology), but lot's of components in there!

Steve

[bricks n bolts]

Udo... Please comment and link your videos!

Udo's pickup solution / video is here : http://www.eurobricks.com/forum/index.php?showtopic=63596

Another 9v pickup solution from way back that may also interest : http://www.brickshelf.com/cgi-bin/gallery.cgi?f=461894

And my 12v pickup solution is here : http://www.eurobricks.com/forum/index.php?showtopic=63535&hl=pickup

Howard

[garethjellis]

Instead of a battery can you not use a capacitor that will discharge when power is lost and recharge in an instant?

[bricks n bolts]

Instead of a battery can you not use a capacitor that will discharge when power is lost and recharge in an instant?

Yes! Definetly worth testing, may fit as a better use case in this situation than a Lipo.

Not sure normal electrolytic capacitors would give you enough run time though, could try super capacitors. It all needs testing!

To reach the correct voltage for a super capacitor solution you need to run three in series (as each super cap is rated either 2.5v, three gives you 7.5v, exactly the same as the Lego Lipo). However, then it's hard to find the right ones without size becoming an issue again as it's very hard to find a prebuilt series with 3, they nearly always come in 2s or 6s, so might have to build the series manually which could lead to balancing issues without the right protection circuit. Have to start somewhere however, so have ordered these - http://www.ebay.com/itm/1Pc-7-5V-3-3F-Farad-Electric-Double-Layer-Capacitor-Super-Ultra-Capacitor-/371172857388?hash=item566ba0562c:g:UpcAAOSwI-BWJ8CL - the only 3 series I could find pre built with the amps output at about the right level but we're still talking 4 studs wide...

So worth investigating alongside looking at smaller Lipos.

[kieran]

Just watched this again, this is a really neat solution. what did you use for the wipers? is it just thin copper?

[legoman666]

My locomotives I make use the Lego AA pack as a UPS. Works well. I also use NWSL train wheels that I modify with a dremel. With a UPS, the battery voltage and the track voltage either need to be the same, or you need a DC regulator to supply a steady voltage to the motor controller. Otherwise, every time you switched from plastic track to 9v track and vice versa, the speed would change.

A couple of my locos also have a .4F capacitor to smooth out the voltage from the rails. They are rather large in size, and if their capacity was any larger, I would probably need to use a current inrush limiter. Even with .4F, by my calculations it only powers my loco for about 1/8th of a second. So if you wanted enough juice to roll through an entire unpowered R104 90 degree turn, you'd need several farads of capacity, which would take up an enormous amount of space.

I only put caps in 2 of my locos due to how little they help and how much space they consume.

[bricks n bolts]

I make use the Lego AA pack as a UPS

Which brand/model batteries do you use? Good to know which you can trickle charge safely.

A couple of my locos also have a .4F capacitor to smooth out the voltage from the rails. They are rather large in size, and if their capacity was any larger, I would probably need to use a current inrush limiter. Even with .4F, by my calculations it only powers my loco for about 1/8th of a second. So if you wanted enough juice to roll through an entire unpowered R104 90 degree turn, you'd need several farads of capacity, which would take up an enormous amount of space.

Will be interesting to find out what 3.3F does, I'll keep you updated. Hoping to at least make it through switch points, although an R104 90 degree turn would be awesome..

[SteveB]

It seems that super capacitors have a decreasing linear charge v. voltage slope, where batteries, esp LiPo's, have a nice flat voltage until the tail end of the charge. Also the super capacitors have about 1/10th the charge density. But of course you can charge a super capacitors very quickly... interesting trade offs.

Steve

[legoman666]

Which brand/model batteries do you use? Good to know which you can trickle charge safely.

Will be interesting to find out what 3.3F does, I'll keep you updated. Hoping to at least make it through switch points, although an R104 90 degree turn would be awesome..

NiMh are not able to be trickle charged. LiPos can be trickle charged, however, 14500 LiPos (about the size of a AA) are 3.7V each which would yield about 23V, and they are about 1.5mm longer than a real AA. They do not fit in Lego's battery pack, believe me, I tried. What I ended up doing in my Big Boy is putting using 6 LiPos 14500s in a 3S2P setup in some non-lego battery boxes that only required slight modification to hold the 14500s. I run my track at 24V and each locomotive has a DC-DC converter. When there is track power higher than the battery pack, the track power is used, when track power is lower than the battery pack, the batteries are used.

It works really well.

With 3.3F, you will need a current inrush limiter, unless you want to kill your power supply or melt your wires.

Edited January 5, 2016 by legoman666

[SteveB]

Hi All,

I'm thinking about a doing a Kickstarter project for this. If I can get 250 motors pre-sold via KS I'll do it. In the mean time I'm getting bids on wheels and wipers and I'm not getting very affordable results. If anyone has a favorite machine-shop that they work with I'd like to get bids from them. Please LMK the name and contact info.

Thanks,

Steve

[kieran]

Will there be an option to operate with out the ref receiver as Well? I guess you just make a plug tha connects the power wires back to the control wires?

[supertruper1988]

How much for each motor? And any chance to have it as a power pickup for other PF motors? I would love to use them on some steam locos with M and XL motors in the boiler but not have to try to build around a battery pack.

[bricks n bolts]

How much for each motor? And any chance to have it as a power pickup for other PF motors? I would love to use them on some steam locos with M and XL motors in the boiler but not have to try to build around a battery pack.

Just for 9v power pickups you could try to PM Alain for one of his packs if he's still making them (see http://www.eurobricks.com/forum/index.php?showtopic=79145). Although noticed his BL store is closed.

[bricks n bolts]

Hi All,

I'm thinking about a doing a Kickstarter project for this. If I can get 250 motors pre-sold via KS I'll do it. In the mean time I'm getting bids on wheels and wipers and I'm not getting very affordable results. If anyone has a favorite machine-shop that they work with I'd like to get bids from them. Please LMK the name and contact info.

Thanks,

Steve

That's great Steve. I'll buy some! Have you done any more on the prototype? e.g testing for slippage / grip