Solar powered Canon SD500..trouble shooting

[inkblotrobot]

I'm trying to attach a solar film to my canon sd500. I've soldered the positive and negative wires of the solar film to the corresponding contacts on the camera battery with a blocking diode in line with the positive solar film wire to prevent the electrical trickle from battery back to solar film.

When attempting to power up the camera, I hear 6 quick beeps in succession and it shuts off. From my understanding, after researching what the beeps mean on Canon's site, it seems the battery is not holding a charge.

I would like to know if anyone has any solutions to make this system work. I feel like I am close to getting it but am missing some vital info I can't seem to come by to complete this project.

Thanks in advance for any help

 

[HarveyH42]

How large is the solar panel (voltage/current)? Can it both charge the battery and power the camera? Is there enough light for the panel? Don't no the specs, can only guess at this point.

 

[inkblotrobot]

solar film: Output -22mA @ 3V; Open-circuit voltage: 4.1V

Canon battery: 3.7V ; 750mAh

Blocking diode: peak inverse voltage is 200V

I believe i might have answered my own question............the voltage of the solar film need be more than the voltage of the battery i want to charge right?
so i need a larger voltage solar film

Thanks very much for the help, HarveyH42

 

[Nigel Goodwin]

solar film: Output -22mA @ 3V; Open-circuit voltage: 4.1V

Canon battery: 3.7V ; 750mAh

Blocking diode: peak inverse voltage is 200V

I believe i might have answered my own question............the voltage of the solar film need be more than the voltage of the battery i want to charge right?
so i need a larger voltage solar film

You need a MUCH, MUCH larger solar panel - probably 30 or 40 times as large - if you're wanting to take any reasonable regular pictures..

 

[HarveyH42]

True, the voltage is much to low, even if it was in ideal light, but not much current either. Don't know the details about charging lithium batteries, but have read they don't like to trickle charge. Pretty sure the camera needs much more than 22mA to run. How well protected is the camera? Will it handle the higher charger voltage okay? Don't remember Cannon producing cheap cameras...

Usually, you would select a panel that is well above the charge voltage, and regulate it down to what you need. You won't always be getting peak output from the panel the entire day.

 

[Nigel Goodwin]

You won't always be getting peak output from the panel the entire day.

Slight exaggeration

More like you won't ever get it's rated output, and the peak you will get won't be for very long.

 

[inkblotrobot]

forgive me for the rookie questions.....but I have two

Ok........higher voltage from the solar panel....i've got that

1) How does the units milli amp and milli amp hour relate? specifically 22mA given from solar film to 750mAh from the camera battery (a question for google for sure but I feel you guys can really give me a tailored answer to this project)

2) How would I be able to gauge whether or not the camera can hold the higher charge?

There are a variety of solar films that I can get with more juice. The problem of course is space to mount the solar film on the camera.

PowerFilm 4.8V 50mA Flexible Solar Panel MPT4.8-75

PowerFilm 4.8V 100mA Flexible Solar Panel MPT4.8-150

PowerFilm 6V 50mA Flexible Solar Panel MPT6-75

PowerFilm 6V 100mA Flexible Solar Panel MPT6-150

PowerFilm 7.2 volt 100mA Flexible Solar Panel MP7.2-75

PowerFilm 7.2V 200mA Flexible Solar Panel MP7.2-150

This info was gotten from.......... **broken link removed**

THANKS AGAIN, GENTS

 

[Nigel Goodwin]

You use the solar film to charge a rechargable battery, and the battery powers the camera - how big a solar film you need depends on how much power the camera takes, how often it's used, and how bright the sunlight is. Bear in mind the figures quoted are usually unattainable in practice, and will average only a small fraction of it over a complete day (and nothing at night of course).

 

[inkblotrobot]

So a higher voltage and higher current like say .......PowerFilm 7.2 volt 100mA Flexible Solar Panel MP7.2-75.....would do the trick......double the voltage of the camera battery........

would it be wise to add a capacitor to the system to store excess electrons gained from the solar film?

 

[Nigel Goodwin]

You need to find out EXACTLY what the solar panel will provide under what circumstances, and if tthat's enough to keep the battery charged under the proposed useage.

For a start though you need to measure the power the camera takes, and under what conditions.

 

[inkblotrobot]

OK ...i'm getting closer to figuring this thing out with much help here......soooo

I checked the charger that accompanies the Canon NB-3L battery and it reads as follows:

Output: DC 4.2 600mA (separated by a solid line over a dashed line)

If I emulate this with a solar panel or panels that provides a similar charge and current, I should be ok...is that close to being right?

I can't seem to find out what the camera uses under what circumstances though

 

[Sceadwian]

The voltage on a solar cell is going to be pretty constant, unless it's under load, if you pick a solar cell that an exactly meet your needs it will ONLY meet those needs when 100% perfectly aimed at the sun under possible unrealistic conditions.

I'm guessing what's happening is that the current usage on power up is not too high, enough for the camera to turn on, but it knows to start charging the battery as soon as it boots up and it needs it. As soon as it does it starts the charging circuitry which increases the current draw, which causes the voltage to drop like a rock causing the entire system to reset. If you want this system to work you will need to a separate battery to buffer the current from the solar cell, so that the solar cell directly charges a battery whenever it has a higher voltage. Digital camera charging systems were NOT meant to have varying supply current. It expects a hard 4.2 volts when it slams on that 600ma charge current, if it doesn't get it it'll go into a fault mode.

In short if you expect a solar panel to directly charge a digital camera, think again, not gonna work, not properly at least.

 

[HarveyH42]

Any particular reason for wanting the solar panel attached directly to the camera? I know that a spare battery for my Kodak costs $40 at Walmart, about $30 online (plus whatever shipping), almost as much as the camera... My panasonic uses 2xAAs, so many charging options. I'm sure what you want can be done, have seen solar chargers for Cellphones (don't own or use cellphones myself), pretty much the same sort of battery and requirements. Don't think you want to run the camera at the same time you are charging the battery though. I've got a 150 watt inverter, with built in 3AH battery, and can charge anything that plugs into the wall or USB port, anywhere. Not solar charging (yet), but could, since I have panels mounted on my roof...

 

[inkblotrobot]

I'm intrigued by solar power and wanted to just start a project involving solar energy. I realize the easier route would have been to just modify the battery charger itself to charge the battery independent of the camera. But, this seems cooler. I've actually got the battery in the camera so the solar panel wires are attached to the battery contacts while the battery is in place in the camera. I will order a much larger voltage panel with a higher current.

 

[Evalon]

Hi,

I just quickly scanned this thread so might have missed this. But when charging li-ion batteries you need to pay attention to how you do it if you want them to last just a reasonable amount of time. They cannot be charged beyond a certain voltage limit without this being destructive to the battery (won't explode but will quickly cease to work). I don't remember for sure right now but there might also be current limitations. Li-ion batteries are not Lead acid batteries which may be connected more or less directly to an appropriate solar panel.

Might I suggest that you look into charging circuits for Li-ion batteries and then, as mentioned by some of the other posters, aim for a very over-size solar panel (depending on where you want to use it - a rule of thumb here in Denmark where I live, is that 1 watt specified of solar panel generates 0.9 kwatts/YEAR. That is 0,1 watts/hour (Wh) meaning that a 1 watt solar panel - optimally positioned - would take about 28 full-sunlight hours to recharge your battery. Not to mention loses in the batteries, charge electronics etc. which may double this. Not full-sunlight may quadruple this or even more.

So, if you want to charge your battery in e.g. 3 hours - including 50% loses and 25% of max. sunlight - you will need a panel of estimated 7,4 watts. Additionally, to allow the electronics to regulate probably at least 5-6 volts output at ~25% sunlight is needed. In my experience (and estimate) that could mean some 18+ volts peak voltage as the panel's output drops quickly when not in direct sunlight.

But, again, you may find that charging a Li-ion battery requires electronics designed for this.

Regards,

Jesper

 

[Evalon]

A P.S.: If you connect the wires of the solarpanel directly into the camera you may also risk entering a higher voltage in the camera than it may accept without failure ....

Best, Jesper

 

[Sceadwian]

Evalon, if the voltage the solar panel is rated for in direct sunlight under full load is under the normal battery voltage there is no risk of this.

 

[HarveyH42]

Don't know how it all works out for the camera, but the solar panels I use to charge 12 volt batteries, put out over 20 volts (no load), over 16 volts with a load. I use a charge controller, since these are hooked up all the time.

Think what we are trying to point out, is the panel won't be getting optimal light all day, so it needs to exceed the requirements, so it produces what you actually need most of the day. There will be a period, where the output will be much higher than the camera will need, maybe want, and that what could cause damage. There should be some regulation to provide some protection for the camera. Don't know much about lithium batteries, since if handled wrong, some chance of fire. With NimH, you just destroy the battery.

 

[Sceadwian]

Harvey, you can not all willy nilly feed a random voltage to a modern IC device in general, let alone a lithium battery charger. The typical charging port on a NiMH NiCad or lead acid pack is connected nearly directly to the cell with only a few components. Modern Lithium systems are all IC controlled, if you can't feed it the fixed voltage it needs it will not work. Lithium's do not tolerate trickle charging the lithium plates out and the cell becomes useless, so charge control circuitry is required.

Regardless of optimal light, if you can not feed a camera type device with a VERY specific fixed voltage that can source it's needed current, it will not work. For feeding a camera that needs that kind of imput (most of them) via a solar cell you need to charge a seperate battery pack through a regulator to give the camera what it needs, you can not simply tack on a solar cell.

 

[HarveyH42]

Harvey, you can not all willy nilly feed a random voltage to a modern IC device in general, let alone a lithium battery charger. The typical charging port on a NiMH NiCad or lead acid pack is connected nearly directly to the cell with only a few components. Modern Lithium systems are all IC controlled, if you can't feed it the fixed voltage it needs it will not work. Lithium's do not tolerate trickle charging the lithium plates out and the cell becomes useless, so charge control circuitry is required.

Regardless of optimal light, if you can not feed a camera type device with a VERY specific fixed voltage that can source it's needed current, it will not work. For feeding a camera that needs that kind of imput (most of them) via a solar cell you need to charge a seperate battery pack through a regulator to give the camera what it needs, you can not simply tack on a solar cell.

Several people, including myself, have already mentioned the potential of damaging the camera and battery, using the method proposed by the OP, whom seems believe all that's needed is a diode, and a larger panel. My hope, was that he might see that the panel's output isn't going to be steady and constant. If the best he can hope for, from the panel, is just enough for what the camera needs, it'll be useless most of the time. By going bigger, he risks damage at peak production. I wouldn't personally abuse a camera like that (have several cheap ones). Think the majority of lithium battery packs have protection circuits built in, because of the fire hazard. Mostly, because there hasn't been any reports in the news for quite a while, and have seen the circuit on two items I repaired. Adding the protection, is good business, much cheaper than the lawyers need to make right for burned down houses and dead people...