Question for best-of-both-worlds users / electronics experts

[whosscruffylookin]

Quick question for anyone running best of both worlds trains, or anyone with the electronics knowledge...

Would it be possible to charge batteries in the 9V (6xAAA) box, or even a PP3 via a PF clip ( http://www.bricklink.com/store.asp?p=bat_chavez&itemID=22828531 ), from a modified 9V motor in a best-of-both-worlds train? I was wondering if running over powered track could trickle-charge the batteries, keeping them topped up for longer, and then the train could be parked on powered track if it neeeded a full charge. I'm particularly keen on the PP3 idea as it would make smaller locomotives possible, although being able to save money on a LiPo would also be nice.

If special circuitry is required (e.g. to prevent over charging) could this be culled from a wall-wart charger, or easily assembled from readily available parts?

Pretend the max draw at 9V is 1A. If the motor was running at half power, then 0.5A would be available to charge the batteries. I guess some circuitry would have detect that power was coming from the track, store the "excess" charge in a capacitor, and then release that in a controlled pulse to the battery. When over non-electrified track, the motor would get power from the battery.

[roamingstop]

There are threads on it - try the advanced search. From memory you will need a diode rectifier bridge - so that the same polarity is producted no matter which way around the 9V motor is on the track. There is a drop of about 0.7V per diode; so expect around 7.6V from a rectified motor; then you would need the charging circuit to be integrated.

If you plug into the connector on the rechargable box it would work... but if you take just a pure PP3 you would need the trickle charge circuit (removes spikes etc). Nothing too difficult.

[whosscruffylookin]

Thanks for the reply! I have searchedabout this and got lots of info on best of both worlds - having first read about it railbricks - but only for using the LiPo pack, which has a charging socket....

I guess what a simpleton like me needs is a picture / circuit diagram / parts list...

Another idea I had - which might be impossible... electroplate some PF train wheels - the O-ring would be a problem - and then use some brushes to pick up power. Then a PF train motor could be used as a pickup, without modification (only the wheels would be modified).

[roamingstop]

Thanks for the reply! I have searchedabout this and got lots of info on best of both worlds - having first read about it railbricks - but only for using the LiPo pack, which has a charging socket....

I guess what a simpleton like me needs is a picture / circuit diagram / parts list...

Another idea I had - which might be impossible... electroplate some PF train wheels - the O-ring would be a problem - and then use some brushes to pick up power. Then a PF train motor could be used as a pickup, without modification (only the wheels would be modified).

Yep... there I even heard of someone on Bricklink selling custom metal wheel sets (similar to those used in 9V motor) - but I never found the link. Within Eurobricks it was discussed some time ago.

I used a search term for recifier...

Search 1,

search 2,

search 3.

Each is in a slightly different thread; which is worth reading up and down.

Edited July 28, 2011 by roamingstudio

[JopieK]

Yep... there I even heard of someone on Bricklink selling custom metal wheel sets (similar to those used in 9V motor) - but I never found the link. Within Eurobricks it was discussed some time ago.

I used a search term for recifier...

Search 1,

search 2,

search 3.

Each is in a slightly different thread; which is worth reading up and down.

A Czech guy is making those wheels. Ludo Soete from BeLUG has some samples from him, he showed them to me!

A bridge rectifier is of course handy to be able to charge such a motor... but... I heard here that TLG might be coming up with a charing station as well!

[Redimp]

I've been thinking of doing something similar with the old 12v system using BB53s, and having only a few 12v track charging sections to act as loco servicing depots. Charging time might be a problem though.

[whosscruffylookin]

Thanks for the replys! After starting the thread I got quite ill for a few days hence my lack of posts...

The bridge rectifier trick I knew about as it's been used in plenty of examples here - BOBWTs and I think also in trains with automatic headlights - it's defnitely the charging circuit that's trickier! It would be wonderful if some enterprising person could figure out a way of getting it all into a 2x2 PF brick...

A charging station would be very interesting, especially if it works with the 6xAAA battery box as well as the lipo. I don't know how lego can do it without the same "safety issues" that casued them to abandon electrified track though. Perhaps induction is possible, or maybe a brick with a 3.5mm socket or similar that you can plug into (and pretend that it's a hose with diesel...)

I've been thinking of doing something similar with the old 12v system using BB53s, and having only a few 12v track charging sections to act as loco servicing depots. Charging time might be a problem though.

I though the issue was that the pickup would foul 9v/PF style points? If you can build a loco with a BB53 pickup and it works fine on 9V/PF points then that would be a great option - you could always hook those 12v centre rails to 9v power to avoid over volting...

Edit: see http://www.eurobricks.com/forum/index.php?showtopic=57025

Edited August 2, 2011 by whosscruffylookin

[Redimp]

A charging station would be very interesting, especially if it works with the 6xAAA battery box as well as the lipo. I don't know how lego can do it without the same "safety issues" that casued them to abandon electrified track though. Perhaps induction is possible, or maybe a brick with a 3.5mm socket or similar that you can plug into (and pretend that it's a hose with diesel...)

I though the issue was that the pickup would foul 9v/PF style points? If you can build a loco with a BB53 pickup and it works fine on 9V/PF points then that would be a great option - you could always hook those 12v centre rails to 9v power to avoid over volting...

Edit: see http://www.eurobrick...showtopic=57025

lol, how annoying is it when someone's not only come up with your idea already but discovered it won't work:) Luckily for me I've been buying 4.5v points from Bricklink pretty cheaply so I should be ok. Before I found the BB53s I was thinking about custom made pickups made from phosphor bronze strips, I have a bit of experience of doing this for my Dad's model railway so that could be an option if you have the newer style points.

Re-reading your opening post were you thinking of using the PF controller/receiver to control the train or come up with a system using the 9v controller?

[whosscruffylookin]

lol, how annoying is it when someone's not only come up with your idea already but discovered it won't work:) Luckily for me I've been buying 4.5v points from Bricklink pretty cheaply so I should be ok. Before I found the BB53s I was thinking about custom made pickups made from phosphor bronze strips, I have a bit of experience of doing this for my Dad's model railway so that could be an option if you have the newer style points.

Re-reading your opening post were you thinking of using the PF controller/receiver to control the train or come up with a system using the 9v controller?

I'd love to see a write up of anything you create for custom pickups!

I've also been buying 4.5V points - they are relatively cheap and very useful for when the 9V/PF points just aren't compact enough. I've found that hacking the ends of flex track makes it a good interface between 9V/PF track and 4.5V track...

What I wanted to do was create a best of both worlds train, as explored in Railbricks and by Toastie, where 9V track (or perhaps 12V middle rails) is used to power a PF controlled train, with these changes: use a 6x AAA box instead of the LiPo (or, preferably, a 9V PP3 battery as they should be good for small shunters), and instead of a modified 9v motor, use a pickup and an unmodified PF motor.

I don't know how expensive electroplating is, but there do seem to be a few services aimed at modelmakers, so if BBB or someone else don't actually come out with some metal/metal-plated wheels, it might be possible to get it done as a bespoke service. Then I guess some kind of brush or low friction sprung metal to pick up the power from the wheels, feed it into the magic circuit which I have no idea how to build but needs to at least have a bridge rectifier in it, which needs to split the power between the battery and the PF IR reciever (which then feeds the motor) when over powered track and otherwise let the battery feed the PF IR reciever when not on powered track.

Not the place to mention it, but I'd also like to see the IR receiver replaced by a 2x4 stud brick that uses some kind of RF, perhaps bluetooth, to allow many more than 8 controlled motors/light sets.

[hoeij]

Can rechargeable batteries be safely charged while sitting in the AAA battery box?

[peterab]

Can rechargeable batteries be safely charged while sitting in the AAA battery box?

I cant see any reason why not apart from heat (I'm pretty sure ventilation shouldn't be an issue since that would imply a loss, and rechargables must be a reversable process), and by limiting the charging current you should be able to limit that to reasonable levels.

An easy solution would be to take a commercial battery charger, remove the electronics, use a modified Lego cable to connect to the battery box, and Bobs your Aunty. This of course requires that you know what your doing re modification of the battery charger so you don't electrocute yourself, so be careful; don't try this at home etc.

Once tested and working hide the circuit inside a refueling depot, with a removable cable as a fuel hose ...

[hoeij]

I cant see any reason why not apart from heat (I'm pretty sure ventilation shouldn't be an issue since that would imply a loss, and rechargables must be a reversable process), and by limiting the charging current you should be able to limit that to reasonable levels.

An easy solution would be to take a commercial battery charger, remove the electronics, use a modified Lego cable to connect to the battery box, and Bobs your Aunty. This of course requires that you know what your doing re modification of the battery charger so you don't electrocute yourself, so be careful; don't try this at home etc.

Once tested and working hide the circuit inside a refueling depot, with a removable cable as a fuel hose ...

The battery box only has a connection for all 6 batteries tied in series. My battery charger, on the other hand, has a spot for each AAA battery separately.

Of course, it is possible to run a current through the 6 batteries in series, charging all 6 at the same time, but then you wouldn't know if some batteries are already fully charged while some others are only half-charged.

What would happen if you overcharge some of the batteries?

[peterab]

The battery box only has a connection for all 6 batteries tied in series. My battery charger, on the other hand, has a spot for each AAA battery separately.

Of course, it is possible to run a current through the 6 batteries in series, charging all 6 at the same time, but then you wouldn't know if some batteries are already fully charged while some others are only half-charged.

What would happen if you overcharge some of the batteries?

I didn't consider that, though it would be more of a problem with NiCd than newer NiMH batteries. Ideally you'd want to charge them individually. Also your charger voltage is not going to be high enough to charge them in series anyway.

I think overcharging is likely to shorten the life of the battery, also NiCd batteries should ideally only be charged when fully flat as they tend not to fully discharge or fully charge after a while if you repeatedly just top them up.

[whosscruffylookin]

hoeij - I thought that 9V PP3s were actually made of 6x 1.5V cells in series. There's some pictures here: http://en.wikipedia.org/wiki/Nine-volt_battery

As such I don't think there'd be a huge issue of charging 6x AAA in series, providing the set of batteries were always kept together. Most of my AA/AAA chargers require two batteries at once for charging and can't charge single batteries, although I'm not sure if this done in series or not.

peterab - if the batteries were trickle charged rather than continously charged, then this would improve battery life and reduce the risk of overcharging. There are also "intelligent" chargers that can monitor the charge level of the batteries rather than just relying on a timer.

I think the trickle charge method would be ideal. It would keep the batteries topped up without over-charging them, and if you needed to do a full charge then you could always take the batteries out and put them in a fast charger.

[vampyre78]

Hi everyone. I've been lurking this forum for a few months now, and as a new AFOL this thread has been of particular interest to me.

I was just curious as to whether people had seen the wireless charging systems that are available for cellphones/cameras etc?

A setup like this would allow you to 'park' a train over the mat for a period to recharge, or possibly several mats under parts of the layout to allow trickle charging. If Lego are considering releasing a charging station, I would suspect this will be how they do it. The cellphone versions i've seen in stores are fine to touch, they only charge when a compatible device is placed down.

It would solve the kid-safe aspect that Lego have to adhere to, but it would require the LiPo batteries to work. I don't think this system could be modified to suit the AA/AAA battery holders due to their current wiring. I haven't looked into these systems in any real depth, but i think it could be worth investigating.

[JopieK]

Hi everyone. I've been lurking this forum for a few months now, and as a new AFOL this thread has been of particular interest to me.

I was just curious as to whether people had seen the wireless charging systems that are available for cellphones/cameras etc?

A setup like this would allow you to 'park' a train over the mat for a period to recharge, or possibly several mats under parts of the layout to allow trickle charging. If Lego are considering releasing a charging station, I would suspect this will be how they do it. The cellphone versions i've seen in stores are fine to touch, they only charge when a compatible device is placed down.

It would solve the kid-safe aspect that Lego have to adhere to, but it would require the LiPo batteries to work. I don't think this system could be modified to suit the AA/AAA battery holders due to their current wiring. I haven't looked into these systems in any real depth, but i think it could be worth investigating.

That would be a very good idea indeed!!! Tesla's idea you mean! http://en.wikipedia....uctive_charging / http://en.wikipedia....energy_transfer (quote: "The electric energy transmitted by means of electrostatic induction can be utilized by a receiving device, such as a wireless lamp. Tesla demonstrated the illumination of wireless lamps by energy that was coupled to them through an alternating electric field.)

See this: http://www.instructables.com/id/Low-Power-Wireless-Charging/

[vampyre78]

Very much Tesla's idea. It's finally getting credence in the 21st century!

This is one company that i've seen their product in stores.

http://www.powermat.com/

I think it's a great concept, and I also think it would solve a lot of the issues that face Lego collectors in particular. :)