Time-Lapse Package
Revision E
The most common battery chemistry for long term, remote applications is lead-acid. Unfortunately, lead-acid batteries have a number
of drawbacks. An equivalent capacity lead acid battery would add about 8 pounds to the system, and would be almost as large as the
housing itself. ALL Lead acid batteries (even the sealed ones) can vent gases during charge and discharge, making them inadvisable
to install within a sealed housing. Most other secondary (rechargeable) battery chemistries have high self-discharge, meaning that
they won’t work well in a long term application. LiPoly batteries however, have low self-discharge, are very light-weight, and quite
compact. Good stuff, but not cheap!
The advantages of the LiPoly battery pack for this application outweigh the significantly higher price, and allow the high capacity
battery to reside inside the housing, making the entire unit quite portable.
In order to save some money, one customer
ordered the housing without the internal battery,
for connection to a large, less expensive battery
outside the housing (i.e. motorcycle battery).
We have a report that this worked well, up until
the time that arctic foxes chewed through the
cable! Another time, their external lead-acid
batteries actually froze, while the Li-Poly battery
continued to work.
Actually we’ve heard from a number of
researchers over the years that electrical cables
are a big attraction to a variety of wild animals.
If you really want to hike in a big heavy lead-
acid battery, that’s fine, but you way want to
also bring some armoring for the cable!
Solar Panel
The fully charged LiPoly battery pack has enough capacity for about 2 months of operation between charges, depending on the
details of the application. Most photographers prefer to augment the battery with a solar panel, reducing worry about the battery
status.
A high quality 5 watt solar panel is a
standard feature with the Time-Lapse
Package. This is sufficient to keep the
battery charged in many installations. If
your installation site does not get frequent
full sun exposure, or you have other power
concerns, please contact us. We can
supply long cables to re-locate the solar
panel, or work with you to develop other
options, such as external AC or DC power.
Custom aluminum brackets are used to
mount the solar panel to the housing. The
brackets may be further formed by hand to
suit your particular needs. You may want
to consider a couple of things when
orienting the panel. If the panel is located
over the housing, it can serve as a shade to
the housing, reducing the internal temperature when in the sun. The panel can also serve as a rain shield to minimize drops on the
front window of the housing.
A high quality ‘gland’ is used to pass the solar panel cable into the housing, maintaining the watertight integrity of the housing. The
price for the solar panel assembly (which requires the solar charger circuit) is $167.08.
Please note that the 5W solar panel may not provide enough power to keep the internal battery pack charged under all circumstances.
If your system only takes a few shots a day, and you get a reasonable amount of full sunshine, then it should keep the battery charged.
If on the other hand, you are taking hundreds of shots per day, or do not get frequent sunshine, then the battery voltage will fall, albeit
more slowly than if there were no solar panel. It's very difficult to estimate the maximum number of shots that can be taken while
keeping the battery fully charged!
Harbortronics Inc 10 10/7/2008
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