Prototype of my Visforvoltage invention

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colin9876
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Joined: Thursday, October 23, 2008 - 11:37
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Prototype of my Visforvoltage invention

Ive just had first trial run of my new invention, not named yet, (suggestions welcome??)

Anyway working fab in this sunny weather.

Set up is 16 (2.7v 3000F) Ultracaps, each with own 400miliamp 2.5v solar panel (thats one 10cm x 12cm on each capacitor)
250w 24v motor on my bike and 48v controller (with low voltage cut off removed). Throtlle only used at half when caps are full.

Sits on bike charges up, and you can use it for about 7or 8 minutes continuous, seems to take about an hour to charge from flat tho, so I intend to save it for hills etc.

Worked better than I expected. I only use the throttle half way when the caps are full up, so the motors not getting more than 30volts ish, and then full throttle when caps are low.
Needed it like that, to have a more powerful voltage and controller and then limit it by the throttle because of the way capactitors decline their volts when discharging, its not a flat discharge like batteries

Cost of this to make the solar panel units on capacitors was about £400 so not cheep. But no balancing required, or any other issues.

Anybody reckon this is worth 'taking to market'? I wouldnt know where to start - also I need that name lol

Mik
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Joined: Tuesday, December 11, 2007 - 15:27
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Re: Prototype of my Visforvoltage invention

Great idea!

This gets rid of the need to switch from parallel to serial connection!

Can the solar cells ever over-charge the ultracaps? What is the max voltage the cells can produce?

Imbalance could however occur if a few of the panels were shaded - a bird dropping on one of them? Or a solar panel that dies earlier than the others?

What would happen to that ultra-cap that is lower in voltage than the others - will it get destroyed by reverse charging?

This information may be used entirely at your own risk.

There is always a way if there is no other way!

colin9876
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Last seen: 7 years 10 months ago
Joined: Thursday, October 23, 2008 - 11:37
Points: 289
Re: Prototype of my Visforvoltage invention

fortunately both those things are covered, the solar cells produce no more that 2.55v, and when that level is reached in capacitor charge then any sunlight after that would be wasted as if the panel was on an open circuit.

These ultracapacitors can be charged in reverse with no problems, but it hasnt happened in pracice anyway - the pack cant run the motor when its less that 8v and even when this low ive measured individual caps theyve always been in positive charge, but it wouldnt matter if they had gone negative.
By leaving the pack in the sun slightly longer than necessary it ensures all caps are full and therefore balanced even if there was a small shaded area on one of the cells etc.

I think it would be a very useful device for someone doing some long cycle trek over weeks where they cant charge up from mains etc.

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