Hi all,


I’m looking to generate power from the movement of a trolley (see attached picture), and the idea I have for this is to use a motor attached to one of the wheels. Being a trolley I assume it’ll be moving at walking pace (4mph maybe) and as it’s symmetric, it could be moving in either direction. I know the speed is slow, and so the trolley wheel will probably do about 3rpm. The device it’ll be powering required 5W, but it will be attached to a battery. My thinking is that the motor can recharge the battery. What do you think? Would that work even? Are there better ways of charging the battery? I’d really like to avoid solar if I can; the trolley is likely to get thrown around and I wouldn’t want the solar panel to break.

Thanks,

 

Any PM field DC motor will generate DC.
The generated voltage out is the same (roughly) for a given rpm as the applied voltage R.P.M.
Max.

 

Welcome to AAC!
Judging by adverts such as this, 5W is beyond what a typical generator could provide. I doubt 4mph will be enough to generate even 1W .

 

Also the dynamo referenced is AC.
So conversion would be needed.
This could be an asset in this application as moving the trolley in reverse, a DC generator will change polarity.
Although a bridge could be used to correct this.
Max.

 

The bicycle dynamo you linked could probably achieve 0.5W, so 5 is most definitely out of the question. I'll provide some more details. I want to use gsm to track its location. It would have to send its location probably once every 6 hours, maybe once every day is fine. This would require full power for about 1 minute every time it wanted to transmit, otherwise it would be sat in standby (standby power not known at this point, but very small I assume). It would need to be able to survive without a battery replacement for over a year, and because batteries are expensive and heavy I'd prefer a small one that could recharge through some means (like power generated through movement) rather than carting around a huge power bank.

This has been a real head scratcher for me. Of course the obvious questions to ask are: 1) how fast will it be pushed and 2) how far will it be pushed per day

I assume the answer to 1 is walking pace (hence the 4mph) and for question 1 I'm not so sure but I assume 50-100m. It could also go weeks at a time with no movement and so the battery would have to see it through these periods.

I will look into the bridge to convert to DC, thanks for the advice.

If any one could offer a sugestion I'd greatly appreciate it. Maybe a motor isn't the way to go, it's just the only thing I can think of.

Thanks

 

First, my qualifications:

• Purchased and assembled multiple and varied types of utility carts.
• Stenciled and scribed indicia of departmental ownership on every surface of every cart in both obvious and covert locations.
• Searched entire very large facility for missing carts, including suiting up to search clean room service aisles.
• 100% recovery rate except for one cart that was taken to a trade show in Las Vegas, overloaded and crushed then discarded on site. The sociopaths (evil colleagues of other departments) conspired to conceal and deny the facts of the cart's disappearance but I was able to break their cabal and eventually forced a confession out of them.

Practical constraints (wet blankets for the flames of inventiveness):

1. If the wheel you mount to swivels as all on the illustration do, how do you propose to manage the cable from the generator to the rest of the system?
2. If this is intended as a remedy for a cart being stolen, borrowed indefinitely, etc. by sociopaths, the same sociopaths will quickly disable your clever system as that is their nature.
3. Unbalanced drag of a generator on one side only will be annoying enough in use to cause normal cart users to become sociopaths. See point 2 above for consequences.
4. To generate anything more than a few milliwatts would require so much wheel to ground friction that an unloaded or lightly loaded cart would simply skid the generator wheel.

Battery power with periodic charging, perhaps via a magnetic charge pad in a docking corral would seem best to me but it does nothing to mitigate wet blanket point 2 above.