Category Archives: trail cam

Solar powered trail camera

Storms Ciara, Dennis and now Jorge have rather interrupted my early spring tasks and I’ve been trapped indoors as the wind howls and the rain hammers down. In between the weather I’ve been tree planting and rhododendron bashing but I’ve also had ample time to complete a solar powered supply for my trail cameras.

These trail cameras require a 12V supply. Standard alkaline batteries – eight 1.5V AA cells – are drained very quickly. It is strongly recommended that you use 1.5V lithium batteries. These deliver the higher power necessary to drive the LED flash and IR detector for much longer – for 9-12 months in my experience. Not only do these last a lot longer, they also work much better at low temperatures. However, this is not an inexpensive option. Non-rechargeable AA lithium cells cost a little under £1.50 each when purchased in reasonable numbers.

Which, at about £12.00 per camera, soon adds up.

And they still run out 🙁

Here comes the sun

I’m a big fan of solar power. It heats most of the hot water in the house and I use it on my ‘bee shed‘ for trickle-charging a 100Ah ‘leisure’ battery, providing power for the lighting.

Solar panels are improving all the time and prices are dropping significantly. It seemed logical that the combination of a small sealed lead acid battery coupled with a small solar panel would be able to provide year-round power for my trail cameras (which have an AUX port for a power supply).

I needed a solution that would be reasonably portable, waterproof and with sufficient power to drive the camera(s) even if the sun doesn’t appear for days.

If the sun doesn’t appear for days …

My amateur back-of-an-envelope calculations suggested a 7Ah battery would be sufficient, coupled with a 5W or 10W panel. These calculations were based on the measured power consumption of my trail cameras.

All of my trail cams are made by Browning, and any details provided below e.g. the size/type of connectors used, may be specific to these models (Recon Force Advantage, Spec Ops Advantage and the new Recon Force Edge). In particular note that these Browning models are 12V cameras, whereas many other makes need only a 6V supply.

Parts list

See notes section at the end of the page for an update to the parts list

Solar panel kit – 10W 12V monocrystalline solar panel, charge controller and connectors from Photonic Universe. They also sell through Amazon 1. You can buy the parts individually for about the same price.

Charge controller

Sealed lead acid rechargeable battery – 7Ah 12V. These are readily available new but you might be able to scrounge one from a defunct computer uninterruptible power supply, a mobility scooter or kid’s electric toy car.

MTM waterproof ‘ammo’ storage box – I used what I had available (50 calibre model), but the smaller model 30 calibre model would have been sufficient. Any waterproof box would do, but these have a convenient carry handle and are pretty robust.

Cable glands – these are available in a variety of sizes and most are too large for the relatively thin cables that connect the solar panel and the trail cam. I used PG7’s which are about the smallest I could easily find on Amazon.

Waterproof cable glands

Trail cam power supply cable – for Browning cameras you need a 2.1mm x 5.5mm male connector. Other cameras may well be different. You can buy the connectors separately for a few pence from electronic component shops, or pre-wired with male/female ends as extension leads in various lengths from eBay for a couple of pounds.

Male (top) and female (bottom) 2.1 mm x 5.5 mm DC connectors, pre-wired

Miscellaneous items – a few bits of scrounged closed cell foam, a couple of spade end connectors and some small zip ties.

Tools – soldering iron (not strictly necessary, but it helps to secure the spade end connectors and to tidy up the ends of wires), pliers, small screwdriver and a sharp knife. You may also need a multimeter to be certain of not frying your camera – see below.

Cable glands fitted and tightened down

In addition, you will need a drill bit of a size suitable for the cable glands. For the PG7’s I used this was a 12mm bit and a small amount of widening with a fine file. 


  • Securely fit the battery in the box. I used closed cell foam to pack it in tightly, preventing any lateral movement, but still leaving ample space above the battery for the wiring and charge controller.
  • Drill the side or end wall of the box for the cable glands. You’ll need at least two – one for the solar panel wire and one for the trail cam power cable. Make sure the fitted cable glands do not prevent securely locating the battery. Also ensure that the lid of the box does not foul the cable glands when opening/closing.
  • Make up a short battery cable with spade end connectors at one end and bare wire tails at the other. Connect the battery to the charge controller using the labelled connections (and consult the instructions if necessary). Positive to positive and negative to negative. It is important to connect the battery to the charge controller before you connect the solar panel. The battery should be protected with an inline fuse (1.25 – 2 times the rated current of the charge controller). The Photonic Universe kits include this.
  • Run the solar panel cable through a cable gland and connect to the input connectors on the charge controller. Ensure there’s sufficient slack cable inside the box to pack everything down neatly in due course. Tighten up the cable gland.
  • Run the power cable through a cable gland and attach to the power output connectors on the charge controller. Note carefully the positive and negative connections – see below. Tighten up the cable gland.
  • Check all connections are secure, tidy away the wiring – using zip ties where necessary – and place the solar panel outdoors in the sun. The PV (photovoltaic) charging and load (the battery in this case) lights should illuminate.
  • Close the lid, connect the camera and enjoy years of savings on battery replacements 🙂

All ready to go

As the photo above shows, there’s ample space in the 50 calibre MTM box and a smaller box would have been sufficient.

Be positive

The Browning cameras need the centre pin of the power cable to be positively charged.

Browning trail cam AUX power input showing positive centre pin.

Don’t mess this up or there’s a chance of frying the camera. If there’s any doubt, hook the ends of the power cable up to a small multimeter and confirm that the centre pin is positive. This is what I did. Better safe than sorry 🙁

When the camera is running from the internal batteries the remaining charge is shown in the bottom left of the screen.

Battery power – £12 of AA’s installed

When you plug in the external power cable this changes to indicate the presence of an AUX power supply.

External battery

The camera does not need any internal batteries to run, so these can be removed and used for a camera in heavy woodland or deep shade.

Batteries and battery cage

Replace the empty battery cage to help ensure the camera remains watertight.

In use

I built the first of these external solar powered batteries with long cables for both the solar panel and the camera power supply. In practice I usually co-locate the battery box and the solar panel a metre or two away from the camera in a location that gets a reasonable amount of light.

The solar panel needs to have a good ‘view’ of the sky, ideally directly south facing. With a sufficiently long power cable it is usually possible to secure the camera facing north (to avoid glare) to a tree with the power supply tucked away out of sight (to anything but the sky) nearby 2.

Solar powered trail camera in use

The panel’s aluminium frame could perhaps be usefully camouflaged but it’s surprising how quickly the passing wildlife learn to ignore it.

After just a few days in the field – in pretty terrible weather – the charge controller showed that the battery was fully topped up and the system has continued to work flawlessly ever since.

Safety notes

There are several posts online describing solar powered trail cameras which do not use a charge controller. These are generally 6V systems and smaller panels. Whatever the voltage, if a charge controller is not used it is important that there is a diode preventing battery drain at night when the panel is not working. Inexpensive charge controllers are about a tenner. They stop overcharging of the battery.

The charge controllers I use have one or more USB outputs which sometimes come in handy … but that’s for a future post.

Here’s something I found earlier … and a solar powered trail cam (top right).


After several months of faultless operation of the first of these battery boxes I’ve now built more and they now power all my trailcams. I’ve made several minor changes to the design …

5W solar panel and MTM Mini AC15 waterproof box

  1. I now use a 5W 12V solar panel. It’s half the size of the 10W panel but appears more than sufficient to charge a 7Ah battery on a camera taking up to 40 x 20 second videos per night. Note that I’ve yet to have one of these smaller panels running over a full winter.
  2. I’ve switched to a MTM Case-Gard Ammo Can Mini AC15 box. This is a much smaller waterproof case but still has room to house the battery and charge controller. You need to be careful in choosing the position for the cable gland.
  3. I now use a single cable gland to take all the wiring bundled together. It needs to be larger than the PG7 specified above. I use PG11 cable glands. To avoid water ingress I wrap the bundled cables with Nescofilm or parafilm before tightening it closed. There are probably better ways to achieve this.
  4. I now use a very short cable from the solar panel to the battery box and a 5m power cable to the camera. I zip-tie the solar panel loosely to the handle of the battery box which keeps it in place. There is now only one trailing cable to coil up and it’s rare I cannot find a sky-exposed location within 5 metres of the camera.

Small but perfectly formed

These work very well and power three different Browning trailcams includinghe new Recon Force Edge which has the useful ability to be set on a timer e.g. to only run from 8pm to 7am.

Trail cameras

There is a lot of wildlife on Ardnamurchan. It is one of the reasons I returned here time and again … and came back more permanently in 2018.

Some of the wildlife is obvious.

Siskin (male)

Siskin (male)

The never-ending parties of tits, siskins and finches on the bird feeders.

A white tailed eagle effortlessly gliding along the scarp slope of Beinn Bhuidhe.

The stag ghosting away in your peripheral vision as you drive back late along the B8007. Did you really see it at all?

An otter rolling amongst the bladder wrack exposed at low tide as it searches for crabs.

Otter, Loch Sunart, Glenborrodale, October 2018

Otter, Loch Sunart, Glenborrodale, October 2018

But most of the wildlife you never see because it is about when you’re not.

Either the wildlife makes itself scarce when we’re blundering about … or because it’s the middle of the night.

Smile, you’re on candid camera

But with a bit of technology, some patience, a bit of trial and error and a little luck you can see what you’re missing.

Trail cameras (also know as trailcams or camera traps) are movement-activated cameras that record still images or short videos any time of the day or night. During daylight hours they record colour images. At night they use infra-red LED lighting and record in black and white.

I’m using camera traps to detect the wildlife I don’t see because I’m chainsawing out the rhododendron and making a mighty ruckus.

And I’m using them in the vain hope that they’ll help identify the gaps the undesirable wildlife get through to eat the native flowers and trees I’m planting in the newly rhododendron-free areas 🙁

Red deer hind scouting out a rhododendron-cleared area for newly planted trees

There are dozens of makes to choose from at prices ranging from £25 to at least 20 times that, depending upon the features required. The more expensive models have 4G or wifi built in (and I’ve no experience of these).

Optically – at least from the technical specifications provided by the manufacturers – trail cameras above £150-175 don’t improve very much. Less expensive models tend to offer lower resolution and longer trigger times (I’ll discuss the significance of both of these shortly).

It’s worth noting that none of these ‘hobbyist’ camera traps are going to produce stills or video to compete with the sort of stuff you see on Seven planets, One world 1.

However, they can produce perfectly acceptable results.

Roe deer buck

I’ve used the Browning Recon Force Advantage and Browning Spec Ops Advantage cameras.

Yes … the names are totally ridiculous 😉

I felt like I should spend the weekends disguised as a bush, or at least be wearing a camouflage hat and jacket, when I ordered them over the phone 2.


Both these trail camera models deliver still images of 4 – 20 MP (megapixels).

This is nothing like as good as it sounds I’m afraid. This is because the larger images are interpolated when they’re scaled up – effectively adding pixels as the image is expanded.

I’ve only tested the still camera function during daylight and can see no significant quality differences between 4 MP and much larger images.

Do not expect images comparable to your digital SLR … they’re not even vaguely close.

Video is better being up to 60fps 1920 x 1080p HD 3. This is perfectly acceptable and I usually use them at 30fps to save SD card space.

Less expensive models usually offer lower video resolution and/or a lower frame rate. Both reduce the quality of the resulting video, though perhaps not so much it actually matters.

Lights, camera, action

Well, lights, battery life and action.

To work at night the camera needs to illuminate whatever it has picked up using the motion-sensitive sensor. It does this using infra-red LEDs. The two cameras (embarrassingly) named above use different types of LEDs.

The Recon Force Advantage has ‘low glow’ IR LEDs. These are visible to the human eye and they are certainly visible to animals (as I regularly capture video of them reacting adversely to the light).

Badger – note the surprise when this poorly-sighted fellow sees the ‘low-glow’ LEDs

The Spec Ops Advantage has ‘no glow’ IR LEDs. These are essentially invisible to humans 4, but are effective over a shorter range (~70% the distance of the low glow LEDs).

The other significant feature to look for in a trail camera is the trigger speed i.e. the time it takes from detecting motion to capturing video (or a still  image).

0.4 seconds might not sound very long, but a small animal – like a stoat – moving fast across the field of view will feature for a further half second on the video before you get 10 – 20 seconds of just herbage waving in the breeze.

Mouse … one of several hundred I have videos of 🙁

Both cameras use eight AA batteries. Unfortunately, not just any old AA batteries. You’re strongly recommended to use lithium AA batteries which are appreciably more expensive 5.

Why lithium? You need batteries capable of delivering high current – at least 2500mAh – and they often need to work at low temperatures. Standard rechargeables or Duracell simply cannot do this.

I get 9-12 months use out of a set of lithium batteries in a well-placed camera (i.e. not too many false triggering events) set to take short videos, about 50% of which are recorded at night. So, although the batteries are not inexpensive, they also last well.

I’m also dabbling with building a solar-powered rechargeable battery pack, though this will only be suitable for areas which receive full sunlight at least some of the time. It will make it less portable, but might be worthwhile for a really good location (or a very remote one).

Irrespective of the technical details of the camera trap, the biggest influence I’ve seen on actually capturing useful and usable images is due to the positioning of the camera.

Location, location, location

Firstly, things to avoid …

  • Glare from the sun. Try and position the camera facing north. Or at least somewhere in the arc between north-east and north-west. Not an issue at night of course, but why compromise daytime images beings spoilt by glare and dazzle? 6
  • Herbage moving close to the lens. This will repeatedly trigger the camera during windy weather. There’s only one thing less interesting than screening 89 short videos containing the same small branch being blown intermittently in and out of the field of view.
  • Mounting the camera on something that moves. This almost always ensures lots of false triggering. Even 8-10″ tree trunks sway perceptibly in strong wind. A fencepost is good, as is a tree-stump 7.
  • Mice. This is what’s less interesting. That infuriating branch I just mentioned is insignificant when compared with a couple of hundred ten second videos of mice scurrying around in the foreground 🙁

Red deer stag and glare from poorly positioned camera

Obvious places to try …

  • Game trails. Large animals usually leave a track or trail, particularly if the ground is soft. I usually point the camera along the trail to get a head-on (or tail-on!) video, rather than a fleeting glimpse as they cross the field of view.
  • Paths. Many animals will follow man-made tracks rather than making their own way through the undergrowth. This is where I’ve had most success in filming a wide range of wildlife – from badgers to woodcock.

Roe deer hind on manmade ‘path’ hacked through the bracken

  • Bait. I’ve not tried this but you’ll see many camera traps set up pointing at bait of some sort. Some people use an egg, others use cat food or – for pine martens – a digestive biscuit with jam.
  • A waterhole. Don’t expect hippos and gazelle, but you might well get an otter or animals coming to drink. I don’t have anywhere really suitable so can’t comment on how effective this is.

The camera should almost always be mounted 30-60cm above the ground. Most trail cameras have a small screen you can use to check the positioning. If the camera is only 30cm from the ground this can be tricky to view 8.

Try to position the camera vertical and avoid too much sky in the field of view. The former makes the resulting videos/photos look a bit better quality and the latter avoids lots of ‘blown out’ highlights in the images.

Trail camera firmly strapped to the lower trunk of a tree

The great thing about these cameras is they’re pretty much ‘set and forget’. You can leave them for a week or a month. You certainly don’t need to check them on a daily basis. They just sit there, quietly grabbing images when triggered.

SD cards

Camera on game trail

All of the images are recorded onto full-size SD cards. I only use 16 or 32 Gb cards and have only ever run out of space when I setup the camera incorrectly and recorded very long video clips.

With 16 or 32 Gb SD cards now costing only £6-8 it’s easy to carry spares and swap them with the SD card in the camera. I’ve also built a portable, battery powered, Raspberry Pi Zero backup device which copies the card in situ. However, this gets press-ganged into other roles and, frankly, it’s faster to just swap cards over.

Absence of evidence is not evidence of absence

The two most obvious signs that badgers are in an area are their extensive latrines and their corpses at the side of the road 🙁 The badger (above) was the first I’d seen on Ardnamurchan and I had no reason to suspect they were there.

The camera never lies.

Pine marten, Ardnamurchan, May 2018

In contrast, it’s not uncommon to see pine martens lolloping across the road and their scats (faeces) are often left in prominent places 9.

Pine marten scat

Of course, the ‘biggy’ in terms of mammals on Ardnamurchan, is the Scottish wildcat. Although this area was designated as a wildcat ‘haven’ about 5 years ago, things have gone a little quiet since then.

Scottish Wildcat Action are now concentrating on Morvern which, although not far away, is across Loch Sunart and likely forms an isolated population.

Nevertheless, over the next year or so I’ll continue to leave at least one or two trail cameras well away from areas of human disturbance in the hope of capturing one on video.


Deer and reforestation

The moist and mild climate of Ardnamurchan provides almost ideal conditions for the germination of plants and trees. Wherever you walk, if you look carefully, you can find miniature birch, diminutive rowans or little oak trees.

Birch seedling

Parts of the peninsula have extensive broadleaved woodland and the area is famous for its oakwoods around Salen and Ariundle. We have hazel copses, a large amount of willow and alder carr, some grand old oaks and lots of birch.

Or lots of rhododendron, depending where you look, though it is gradually being cut back.

Mixed established deciduous woodland has excellent biodiversity and oak trees are famed for having more associated species of wildlife – including bacteria and fungi, lichens, free algae, mosses, vascular plants, invertebrate animals, birds and mammals – than any other tree in the UK.

Oak, late November

However, unfortunately, it’s true to say that on Ardnamurchan – and in lots of other places in the Highlands – mighty oaks from little acorns do not grow 1.

The missing generation

It’s easy to find seedlings a few inches high and the mature trees are obvious. What’s missing, or at least significantly under-represented, are saplings and small bushes.

For example, we have two or three rowans (mountain ash) close by the house. All are mature trees (~15+ feet tall) laden with berries from late summer onwards. All spring and summer I’ve been finding 3-5″ tall (short?) rowan seedlings, perfect in everything but stature.

But there are no rowans on the plot that are waist or head height.

It’s all, or almost nothing.

Well, not quite. You can find these missing generation(s) of spindly saplings growing from cracks in steep rock faces or other inaccessible spots.

You can also find a few shin-high, multiply-branched, twiggy, de-leaved, stunted specimens. These often have fat little trunks and extensive root systems, out of proportion to the tree height, like a poor quality bonsai.

Browsed rowan

The grim reaper

The inaccessible saplings and the thick-limbed but dwarfed individuals give an obvious clue as to the fate of the missing generation.

They are being, or have been, browsed to extinction.

There’s no regeneration of native woodland because as soon as a tree is tall enough to be noticed it’s a midnight snack for deer.

On very steep slopes the deer cannot graze so the saplings escape. However, there’s often little soil present, or the ground is unstable, or it dries out too much, so the tree never reaches maturity.

Accessible saplings get grazed and grazed again. The new juicy growing tips are nibbled away, leaving ever-thickening twiggy branches. Year after year this results in a stunted, distorted little bush, with lots of woody growth but few leaves.

Too much of a good thing

There are six species of deer in the UK – red, roe, fallow, sika, muntjac and Chinese water deer. Of these, the first two are native to the UK with the rest being imported. However, fallow deer were here before the last ice age and were re-introduced after the Norman Conquest (11th Century).

Red and (particularly) roe deer are widespread and, in places, common.

Deer … they’re everywhere

Too common.

In Scotland, red deer densities (PDF) can be greater than 30 per km2 in places, with very high levels in the Grampians and north and west of the Great Glen.

It is estimated that the current red deer population in Scotland is in excess of 450,000 head. This number has increased at least three-fold since 1959 when The Deer (Scotland) Act was introduced in response to a growing awareness of the damage to agricultural crops and native woodland.

In 1959 the recommendation was that an optimum number of red deer in Scotland was ~60,000. ‘Optimum’ in terms of reducing crop damage and allowing natural reforestation without ugly and expensive fencing.

Presumably not ‘optimum’ in terms of animals available for stalking. Which is a significant part of the problem …

Simon Pepper (ex-WWF Director for Scotland and Deer Commission) has written a brief account of “the deer problem” in Scotland and Reforesting Scotland nicely describe the impact and management of deer. I won’t rehash the case they make here but I think it’s compelling.

The camera never lies

Our plot is not fenced and deer regularly come down off the hill or out of the surrounding woodland. I occasionally spook them when I’m wandering about clearing rhododendron or birdwatching. At night their visits become more frequent … we might not see or hear them but the dog detects them with her ultra-sensitive radar and growls quietly.

They trample regular ‘game trails’ across parts of the plot, moving from one block of woodland to another during the night, or going down to the shore.

I’ve positioned a trail cam in likely looking spots and regularly ‘see’ red deer and, about 10-fold less frequently, roe deer. Whether this reflects the population density of the two species or is a consequence of the locations used for the camera is unclear.

It’s very common to ‘see’ a red deer hind with a calf in tow. Stags are a lot less frequent.

At times they descend from the hill mob-handed, late in the evening, intent on the destruction of almost everything except rhododendron (which unfortunately they don’t eat due to the grayanotoxins in the leaves).

Reforestation and stalking

It’s ironic that deer are woodland animals, yet their presence in large numbers prevents the regeneration of the forests in which they should flourish. Red deer from open moorland are smaller, less well conditioned and have higher winter mortality than woodland deer.

Inevitably, large scale culls have been unpopular with the general public and the landowners who provide stalking.

Importantly though they have been effective. They have reduced the numbers of deer on the land and have allowed the natural regeneration of forest without the need for fencing (which brings its own problems).

Richard Baynes has written about the consequences of the deer cull in Glen Feshie, both in terms of the uproar in the shooting community and in the resulting improvement in reforestation. The income from stalking is the same now as before the cull; clients are “prepared to pay more to hunt a scarcer, wilder animal”.

For a more extensive discussion of reforestation and biodiversity, accompanied by outstanding photographs, I recommend you have a look at Alan Watson Featherstone’s blog.


I love deer.

Particularly braised slowly with a good quality, full-bodied red and winter vegetables 😉

However, I don’t like venison so much I could make a serious dent in the local population of deer.

Therefore, other measures are needed to deter deer and to encourage the regeneration of trees. In turn this will decrease the triffid-like invasion by rhododendron and increase the native wildflowers and understory vegetation.

Deer fencing remains an option but is unsightly, expensive and – because of access issues  – would require gates and/or cattle grids. Properly maintained it is the only certain way to exclude deer.

Lion dung has proved tricky to source, but may not be effective anyway.

I’ve planted a few tree seedlings ‘rescued’ from inaccessible areas, together with a dozen or so willow ‘sticks’ to provide early season pollen for bees. Several of these have already been decimated by the deer.

Transplanted rowan seedling

I’ve therefore protected some with mesh tree guards to help them get well-established.

I’m intending to plant another hundred or so bareroot native trees this autumn. Rather than littering the plot with dozens of unsightly corrugated tubes I’m hoping to exploit the topography to barricade access points, only putting tree guards around the saplings on the periphery. Additional temporary fencing will be added where needed if the barricades alone prove to be ineffective.

Willow cutting with tree guard

Or when … 🙁


Laga Farm on Ardnamurchan has a large fenced area of hillside overlooking Laga Bay in which native trees have been planted. The sparse woodland is only six years old but is already developing really well and is wildlife-rich … and will undoubtedly get better. In addition to the planted trees there is also a large amount of natural tree regeneration now that the deer are excluded.

Laga Farm Native Woodland