Thursday 8 October 2009

Silva SC44 Solar Battery Charger

I tend to find most technology amazing, but one area that I’m really excited about is portable solar power.

On the one hand I hate all the battery powered gadgets I find myself schlepping around – GPS, MP3 players, cameras, computers, video cameras, radios, illumination, etc., etc. And yet I love all that stuff, and the possibilities they open up. I may not like the bulk and the weight they add to my set up, but I sure do like the ability to record the imagery I see, process and back up the pictures I took, have a library of data at my fingertips, navigate to a pin point location, communicate with my partners, light my way, oh and listening to some tuneage while I do it is pretty sweet as well.

The batteries that power all that amazing technology add weight, cost money, and then there is also the aspect of the long tail they drag behind them once they’ve performed their magic.

Solar power opens up the possibility of reducing some of that weight, reducing some of that cost, and reducing some of the nasty garbage.

One thing that really drains the life out of batteries is a camera. While placing an order with MoonTrail I saw that they had a Silva Tech4O SC44, and I got it. (Moontrail no longer offers it, and the Silva site only shows the SC22, which charges two rather than four – which strikes me as a step backwards) but it is still offered by some online retailers. (I’ve spoken a little bit about the modifications I made to it here, but I figured I should delve a little more into the actual charger itself.)
In its entirety it’s 60 cm (24") long, and the part that actually matters is about 30 cm to 33 cm (12" to 13") long, and it folds to 8.6 cm x 14.25 cm x 3.5 cm  (3 3/8" x 5 5/8" x 1 3/8").
The SC44 also incorporates LED lights that let you know the charge status of your batteries
The SC44 will charge 2 AA batteries in only 5 hours, and 4AA in 10 hours.
Even with the bits of webbing and two tri-glides I added to it the whole unit weighs less than 100 grams (31⁄2 ounces).
If I have a quibble about it, it’s that it only came with 2 of the AAA to AA adapters. I’m appreciative of the fact that they provided any at all, but for me having only 2 poses a problem. The Petzl TactikkaXP and Tikka that I have run on 3 AAA batteries. I really don’t think it’s a good idea to charge 2 batteries, and then a 3rd. The likelihood that they will all be at the same charge level is really dubious, and trying to run them on different charge level batteries would likely cause all sorts of problems. I’d rather charge 4 at the same time and have the 4th one for use in my Fenix L0D or E0. I wrote to them and suggested that they should provide four if they’re going to provide any at all. I was told to send them my address and they would send me another pair. Which I did, but never heard from them again. I know they’re available, but I haven’t had any luck in finding any locally yet. In the mean time I’ve continued to use regular AAA in my Petzl head lamps.
When hiking I have it strapped to the top of my pack to try and catch as many of the suns rays as possible. Doing that makes bushwhacking a bit problematic as branches can either damage it or get caught between the top lid and the charger itself.
On canoe trips I strap it to the top of my pack.
This is shortly after I got the unit and you can see the para cord I used to tie it to the thwarts so that the wind didn’t blow it away. Having to tie them on in the morning and then untie them when I got to a portage and tie them back on and then untie them again at the next portage and then tie them on again and then untie them when I made camp – that all got a bit long in the tooth after a week of it. Hence why I made the modifications I did.
With straps added to the charger, I can weave them through the PALS webbing on my packs, it’ll stay put in the wind and I don’t even have to take it off when I get to a portage.
After a year and half of use some of the solar panels appear to have become delaminated in a couple of spots, but I don’t know if that is affecting performance at all.
When the sun is blazing and the panel is perpendicular to the sun, it’s charging at 100%.  Same conditions when they are at a 45° angle, it’s charging at 71%. When it’s lightly overcast the unit is charging at approximately 60-90%. When it’s heavily overcast it’s still charging, but at only 20-30%. Still better than nothing though. Even indoors under artificial lights, it still charges, but at such low levels (0.2% in an average home) it’s hardly worth it.
When laid out on the ground, I have to keep in mind to check it every hour or two so that it’s getting the maximum exposure to sunlight. Not a big deal, just something to keep in mind and get into the habit of doing. And also to get and either bring inside, or put in a clear plastic bag when it begins to rain. It’s water resistant, not water proof. It could handle a bit of rain, but it’s best not to risk it.

I’m sure in years to come I’ll laugh about how big and slow and heavy this thing was, but for now I think it does a very good job of addressing a need. If I had to take the quantity of non-rechargeable batteries required for my camera on a week long trip, I’d likely need a pound of them. This saves me a lot of weight, a lot of money, and hopefully cuts down a tiny amount on the number of batteries going into landfill.

1 comment:

  1. Regarding Charging 3 batteries, it is a complcated thing. Practically you need to enforce a charging regiment of letting 3 batts depleted, then another 3. You charge 4 and then 2. But you have to ahve a 3rd set for your headlamp to be ready all times.

    But more seriously charging abtteries in pairs is doen by using the wrong method....all the se 2-4 chargers charge the batts of each pair in series. Which is a No-No for NiMh batteries. Luckily what is compromised is the battery longevity.

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