Solar power a DSLR help?

[southwestsnapper]

Hello guys, please be gentle as i don't understand electronics. I have a problem that needs solving.

I would like to be able to build a rig to capture kingfishers diving underwater and film them. I will be using LED lighting to boast the light levels.

I will be filming with a Canon EOS 550D/T2i Digital SLR camera.

My issue is power, the waiting could be for many many hours and I am not planning to change batteries once the rig is set in the water.

My plan is to utilise the fake battery at the end of a power lead designed so that you are able to power the camera from the mains. I will chop off the transformer and just use the dummy battery, insert into the camera and now i have a couple of wires hanging out of the camera..

running the lead back to the river bank where i will have some sort of rechargeable battery pack, this in turn will be connected to a solar panel so I can run the camera in the field all day long with it being underwater in the river. (i plan to control the camera via a powered USB and laptop back on the bank)

The problem i do not know how to solve is what battery to buy and how to regulate the output, it must be 7.2V the battery it is replacing is a canon LP-E8, however the camera is just as happy running from 6 AA Ni-MH batts also so i dont amps sorry.

So please remember i need this to be very portable as i have lots of equipment to carry maybe a couple of miles across rough ground so a smaller battery ans panel would be better.

Can anyone suggest a solar panel and battery plus explain how i connect it together please, or at least point me in the direction...

I am UK based so Maplins is close by for me..water proof stuff would be good but not really essential...

Many thanks Phil - Bristol UK

 

[ronv]

To give us some idea of capacity required, can you tell us how long the camera will run on the 6 AA batteries?

 

[HarveyH42]

Pretty much every digital camera I own, has a jack for external power (wall adapter). I don't know about yours, but might be worth checking, usually gets overlooked, since nobody ever uses them...

 

[southwestsnapper]

Wall adapter? This is what i said, the camera has an adapter available that uses a dummy battery on one end. The camera is is Canon EOS 550D it has no socket built in for external power you are expected to buy the ac power adapter that i am going to use..however i have no access to an AC supply. im on a river bank in the middle of nowhere..i hope this is clear now?


the spec on the bottom of the canon charger that is for the battery this camera takes is...

Battery Charger LC-E8E
Input: AC100-240V 50/60Hz
14VA-23VA 0.25A

output: DC8.4V --- 0.72A

the battery than canon supplies is a 7.2V 1120mah (i use two in a special battery pack on the camera, however the camera normally just takes one of these)

here is the power spec from the canon website...
POWER SOURCE
Batteries 1 x Rechargeable Li-ion Battery LP-E8
Battery Life Approx. 440 (at 23°C, AE 50%, FE 50%) ¹
Approx. 400 (at 0°C, AE 50%, FE 50%)
Battery Indicator 4 levels
Power Saving Power turns off after 30sec or 1, 2, 4, 8 or 15mins.
Power Supply & Battery Chargers AC Adapter Kit ACK-E8, Battery charger LC-E8, LC-E8E

Regarding the time it will run on AA's i do not know, figures are not produced for that sor of thing...

sorry if im a bit thick, i know photography but i dont know electronics...P

 

[4pyros]

What are the specs of the transformer you chopped off the dummy battery? Thats what you need to replace with batterys. Andy

 

[southwestsnapper]

Thanks for the replys.
Andy, i have not bought the mains adapter yet. I was going to buy everything in one go and build it. Are you saying the only way to do this is to buy the adapter first and look at measure the output. This makes sense...i could measure the output of a camera battey if that helps..??

regards SWS

 

[4pyros]

It seems that all your specs are different, thare may be some circuitry in that dummy battery to change the voltage and or current. So working from the adapter may be the only smart thing to do. Let us know when you get it and then we can help you. Andy

 

[southwestsnapper]

Ok will do. In the mean time is there a place i should be looking regarding solar panels? Im after something small and portable, maybe folding, light, and with a handle possibly?

regards P

 

[southwestsnapper]

Output Voltage: DC8.4V 1.5A this is the sepc on the adapter i was going to get from China on ebay...

 

[ronv]

I'm going to guess a bit that your regular battery will run your camera about an hour. So lets say 7.5 watts. I think if you used a 4 amp hour 12 volt SLA battery and a 15 watt solar panel (15 Watt, 12 Volt Solar Panel) you could then use a little regulator like this to feed your camera.
(**broken link removed**).
This should give you 2 or 3 hours on battery only, all day with sunshine, and somewhere in between with partly cloudy days. Few pounds to carry around though.
Let us know if this sound feasable to you and we can hooker up.

 

[southwestsnapper]

I'm going to guess a bit that your regular battery will run your camera about an hour. So lets say 7.5 watts. I think if you used a 4 amp hour 12 volt SLA battery and a 15 watt solar panel (15 Watt, 12 Volt Solar Panel) you could then use a little regulator like this to feed your camera.
(**broken link removed**).
This should give you 2 or 3 hours on battery only, all day with sunshine, and somewhere in between with partly cloudy days. Few pounds to carry around though.
Let us know if this sound feasable to you and we can hooker up.

thanks, if i still live in Phoenix then clouds would not be an issue!! But im in the UK..sadly now!

Im looking for something more portable really...it needs to all fit in a small rucksack.

I am right in thinking If I were to use a lover voltage battery i would need a lower wattage solar cell to charge it at the same rate?? I do have a basic understanding of electricity just not electronics..so i get ohms law, i think!!

I need to be able to fit this all into a small back pack really, i use a set of NiMH 2900mah AA batts in this camera and in cold weather it will give me a couple of hours use..

 

[southwestsnapper]

I have just found a couple of Li-ion Batts i have spare, they are 7.2V 6000mAh so i guess i could use these if i can charge them from my solar panel faster than my camera can discharge them, right??

Im guess the big question is what load is my camera, i am right?? If i can work out the camera load in Amps/mA then i the man way there right??

Help!! I think this is right isnt it, or am i being stupid again!!

 

[ronv]

No, you have it right. If we know the camera current we can calculate the amp hours required. The batteries never get quite what they are spec'd for so your 2900 mah batteries are probably supplying over an amp but lets say 1.45 amps for 2 hours just so the numbers match. The thing we need to look at is power. So in this case it's 7.5 volts at 1.45 amps or 10.87 watts. Solar panels usually put out about 1/2 of the spec. because the spec is for perfect conditions. (Phoenix at noon on a dry day) The 6000 mah lithium's should work the best. (more power for size/weight) Now you need a little buck/boost regulator set at 8.4 volts to charge the battery. So here we are: 6 amp hour battery / 1.45 a for the camera = 4 hours. If we used the 15 watt solar panel we might get 7.5 watts out of it. Or, about . 9 amp hours at the 8.4 volt charge rate. The little voltage regulator is about 80% efficient so .7 amp hours X 4hours = 2.8 amp hours or another 2 hours of operation. Your best bet might be the 2 batteries for 8 hours.

 

[4pyros]

I have seen small flexible chargers for cell phones. Google "flexible solar panels" Andy

 

[blueroomelectronics]

Much of it will depend on how many photos it's taking, MF or AF, LCD off etc...
How many photos a day would be a good start. Is it stationary?

 

[southwestsnapper]

No, you have it right. If we know the camera current we can calculate the amp hours required. The batteries never get quite what they are spec'd for so your 2900 mah batteries are probably supplying over an amp but lets say 1.45 amps for 2 hours just so the numbers match. The thing we need to look at is power. So in this case it's 7.5 volts at 1.45 amps or 10.87 watts. Solar panels usually put out about 1/2 of the spec. because the spec is for perfect conditions. (Phoenix at noon on a dry day) The 6000 mah lithium's should work the best. (more power for size/weight) Now you need a little buck/boost regulator set at 8.4 volts to charge the battery. So here we are: 6 amp hour battery / 1.45 a for the camera = 4 hours. If we used the 15 watt solar panel we might get 7.5 watts out of it. Or, about . 9 amp hours at the 8.4 volt charge rate. The little voltage regulator is about 80% efficient so .7 amp hours X 4hours = 2.8 amp hours or another 2 hours of operation. Your best bet might be the 2 batteries for 8 hours.

I have a couple of these 6000Mah batts. the camera will be set at MF the LCD is off it may be set in video mode. The camera will be recording in burst of say 10 - 15 mins max when there is some action and just sat in standby for the rest of the time. I may use it one day just for stills and again it is not shooting continuously spend long periods inactive and then needed for busts of action..i would be shocked if i shot over 100 photos in a day...

So can someone explain what is meant by a buckboost regulator please? Im a bit lost at that point...

thanks P

 

[ronv]

A buck/boost regulator will increase the output voltage over the input voltage if the input voltage is lower than the desired output voltage and it will decrease the output voltage to the desired voltage when the input voltage is higher. So for your case it will try to keep the output voltage at 8.4 volts no matter what the sun is doing.

 

[southwestsnapper]

A buck/boost regulator will increase the output voltage over the input voltage if the input voltage is lower than the desired output voltage and it will decrease the output voltage to the desired voltage when the input voltage is higher. So for your case it will try to keep the output voltage at 8.4 volts no matter what the sun is doing.

Oh ok thanks for that explaination, so where could i find one of these regulators please??

P

 

[4pyros]

so where could i find one of these regulators please

Google is your friend!!!

 

[ronv]

This one might be a little marginal but you can get the idea.
**broken link removed**