solar battery charger?

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mc

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I am doing a high altiture shoot at the end of the month and may be without electricity for up to 2 full days. I have 6 5600mah batteries, but don't know how long they will last in the cold.

anyone have any experience with a solar blanket to do emergency charging of batteries? i don't want to get stuck lugging a useless HVX like a boat anchor up a mountainside...


thanks

mc
 
Not sure where you're going in the high altitude, but if it's the Himalayas, a lot of people have solar there. If you can connect an inverter it might work well. Best for only 2 days though is to have lots of batteries, keep them warm and keep rolling. 6 5600 batteries should do you well. If you're rolling a lot I'd probably get 3 more in case and not bother with anything else. If you use a portable solar unit check out the watts and do tests. I have a 24 watt unit and it works okay.
 
I would buy or construct a glove of some sort for the camera to insulate it from the cold. Stick a air-activated chemical hand warmer in there to keep the camera and battery warm, along with a silica gel pack to deal with the moisture.
 
Portabrace makes winter covers for most cameras, i used to have one for XL1 cams, it even had little pockets inside for those hand warmer packets to keep the cam toasty..
 
mc said:
a solar blanket to do emergency charging of batteries?
Click to expand...

Jaysus... pluging the batteries into the wall takes 5 hours and thats through MAINS powers, surely its going to take like 'months' to do it via solar!

Indy....
 
mc said:
I am doing a high altiture shoot at the end of the month and may be without electricity for up to 2 full days. I have 6 5600mah batteries, but don't know how long they will last in the cold.

anyone have any experience with a solar blanket to do emergency charging of batteries? i don't want to get stuck lugging a useless HVX like a boat anchor up a mountainside...


thanks

mc
Click to expand...
I think batteries last longer in the cold? Am I right... I don't think they will give you extra record time, but I believe the cold will not negatively effect/drain your battery life unless it freezes your HVX :)

My grandfather used to put unused batteries in the refrigerator. He told me they preserve longer... I don't know if he was just crazy or smart. Either way I have never heard of batteries in the cold being a negative.

Also, you should probably just buy more batteries. Come on man! They are not that expensive! I agree with the last post above me, solar blanket would probably take a very long time. If you are only up there for two days, I would suggest just buying more batteries. Rent some, or borrow some.
 
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I don't know that is why I asked if I was right. I bet room temp is the best but all these old folks like my grandfather keep unused batteries cold. NOT freezing, but cold.

Then again those were alkaline batteries not NiCad
 
Wikipedia says NiCad batteries have "Temperature range: Standard application -20°C / +45°C In charge 0°C / +45°C"

which is what? -5 degrees fahrenheit to 95 degrees for standard application?

Jester,
the one that is NOT the backpack would be the best out of the two. But remember that these stats are for the optimal performance. One overcast cloud can shoot you in the foot. It is a very nice eco-friendly idea, but I would not rely on the weather to provide my power. I would first be certain to buy enough battery power to last what I need and carry this solar panel ONLY as backup, if I would even buy it.
 
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mc said:
I am doing a high altiture shoot at the end of the month and may be without electricity for up to 2 full days. I have 6 5600mah batteries, but don't know how long they will last in the cold.

anyone have any experience with a solar blanket to do emergency charging of batteries? i don't want to get stuck lugging a useless HVX like a boat anchor up a mountainside...


thanks

mc
Click to expand...

I did some simple and quick calculations to see if solar would work, but the numbers aren't good...

It would take about 8aH of solar power to charge one battery. Assuming that you were in the correct location with no overcast and full (100%) sunlight the whole day, you might get 5 peak solar hours of charge. That meant you'll need 2 amps of current during the peak solar hours; that would be about a 26 watt panel or higher. IF the day is overcast, you are screwed.

Assuming that 6 batteries is enough to do your shooting for 2 days, why not just keep them warm by putting the batteries you want to use next, inside your overcoat next to your body. You body will keep the batteries warm enough.


Bob Diaz
 
Some of the problems with solar recharging you might encounter:

-- You're on the move and can only recharge batteries during the time you're camped, and that's mostly when there's little or no daylight.

-- Winds pick up and makes it difficult to keep the solar panel properly oriented for maximum performance.

-- The total weight of having enough solar panel to charge batteries is as much as or greater than having enough batteries to last the two-day trip. Not to mention how bulky a panel or series of panels might be.

Regarding temperatures and battery performance, keeping batteries cold reduce their chemical activity and they're less likely to lose their charge over a long period of time.

Along that same line, reducing their chemical activity also reduces the amount of power they can provide, and cut down their usable capacity. It's important to keep the batteries warm enough for optimum performance.
 
I hope the solar-powered shoot went well in Nepal.

I have successfully used small solar panels as the power source for a DV camera in both cold mountain environments and in the humid tropics. For extended projects a solar panel liberates you from the logistics of finding the nearest power point or generator.

While it is useful to calculate the time needed to fully recharge a battery with a particular panel, the more relevant concern is that the system can replace the battery energy at the rate that it is being consumed. It may not be necessary to fully recharge a battery in one day of sunshine, as long as the charge accumulated over a period of days is equal to the demand. Depending on how the camera is being used, this means that even a small 5 or 10Watt panel may be sufficient - along with a supply of charged batteries as a buffer for overcast days.

In some circumstances the issue of travel/hiking time overlapping with the best charging period of the day can be worked around by charging enroute. During a 21 day expedition I charged batteries on the move using a 5Watt rigid panel lashed to the top of my pack and wired to a cheap Hama baseplate and NiMh battery inside the lid. Two packs were set up like this. The Hama baseplates have an LED indicator and a charging circuit designed to protect the battery, these appeared to work as normal.

At times I have also used bare wires into the battery. I expect that a small capacity solar panel is unlikely to cause any damage, if plugging into a larger solar system it may be wise to regulate the input to the battery.

My 5Watt glass panel weighs 900g (2lbs) and costs US$80. Purpose built trekking/military panels weigh less, are easier to pack and cost more. It is worth carrying a small multimeter to check the output of the panel.

A solar panel is not a replacement for a good stock of batteries, but at around the same weight as 2 or 3 camera batteries they offer great security in remote areas.

Below are a few options for portable solar panels,

Russell
p.s NiMh should read Li-ion...


Folding panels:

10.4W Backpack Panel Folded
http://www.ctsolar.com/Backpacking%20Solar%20Panels.htmUni-Solar UNI-PAC folding solar modules
http://www.ctsolar.com/UNI-PAC%20Folding%20Solar%20Panels.htm

[FONT=arial, helvetica]Brunton Solaris 25Watt folding solar panel
[/FONT]www.solardyne.com/brunfolsolpa.html


Rollable panels:

Power film Rollable Solar Panel (5Watt - 10Watt - 20Watt)
www.sailgb.com/p/powerfilm_rollable_solar_panels/#Product_Options


Rigid Panels:

BP Solar 5Watt 12Volt - SX5M 5
www.renewablestore.com.au/catalog/index.php?main_page=product_info&products_id=7
 
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>During a 21 day expedition I charged batteries on the move using a 5Watt rigid panel lashed to the top of my pack and wired to a cheap Hama baseplate and NiMh battery inside the lid. Two packs were set up like this. The Hama baseplates have an LED indicator and a charging circuit designed to protect the battery, these appeared to work as normal.

At times I have also used bare wires into the battery. I expect that a small capacity solar panel is unlikely to cause any damage, if plugging into a larger solar system it may be wise to regulate the input to the battery.>
Russell, using NiMh batteries is not the same as using Li-Ion. If you connect uncontrolled power source directly to the NiMh battery, there is a possibility it will get charged OK, as long as you do not allow it to get hot, as a result of overcharging.
You absolutely can not do it to the LI-Ion battery, used by all the new 7.2V DV cameras. This chemistry is very particular when it comes to charging, which is tightly controlled to .5% tolerance. Applying wrong voltage will kill the pack in no time.
Alex
 
Hi Alex,

My reference to NiMh batteries was a mistake, they are actually Sony Li-ion. Most of the time I use a regulated battery plate that is correct for that battery. In an emergency I have used a direct input from an unregulated solar panel, and it worked, but as you suggest it is likely to have damaged the battery.

I just looked up your regulated DC power convertor for the HVX batteries, it looks great. I assume this is designed to power the camera from DC sources such as gel cell batteries or motor vehicles. Will it also regulate the charging of a HVX Li-ion battery from a DC source (eg. solar panel or car battery).

http://www.dolgin.net/DCConverterPan.htm

Thanks for your good advice.

Russell
 
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Russell, the converter can power the camera only, it can not be used to charge the batteries, two different animals. Our battery charger TC400 will charge the batteries, and it can also provide camera DC power (it is a separate module inside the charger).
The charger can also take its power from any 12-16V power source, instead of AC. The DC source has to be able to provide at least 20W DC power (more if you would insert all 4 batteries)
HTH
Alex
 
Regarding the tempature issue... yes, you want to keep the batteries warm out there. The reason you store batteries in the fridge is for LONG TERM storage. This slows down the chemical reaction inside and prolongs its life. But when you are actually using the batteries, you want them WARM, so that the chemical reaction is sped up, producing more voltage.

A cold battery in the field will die much faster than a warm one.
 
thanks a lot for all the feedback on this. heading to rainier, so it won't be as burly as the himalaya, but i just don't want to miss the summit shots.
 
Good luck on your climb. This is a true story: my friend went to the summit of Rainier and he slipped on a banana peel.
 
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