Power Storage

Carmanah has chosen to use a lead-acid technology, specifically a pure lead-tin acid electrochemistry utilizing a patented starved electrolyte. Through careful consideration of the worldwide use of its products, Carmanah has chosen to use this battery technology for a number of compelling reasons:

Performance Benefits of Pure Lead-Tin Acid Batteries

• In terms of performance, there is no comparison: pure lead-tin acid batteries are the right choice for outdoor applications, primarily because they offer the widest performance range of -65°C to +80°C. (-85°F to +176°F).

• The pure lead-tin acid batteries used by Carmanah have been specifically designed to survive in harsh outdoor environments. NiCd and NiMH batteries were never intended for outdoor use. In fact, NiCd batteries have almost no recharging ability below the freezing point (0°C, 32°F) and NiMH are not much better (-10°C, 14°F).

• A pure lead-tin grid inhibits corrosion and acid vapor venting. Combine this with its low internal resistance, and the battery is able to provide longer service life under a wider range of conditions than any other battery of comparable size.

• Unlike NiCd or NiMH batteries, pure lead-tin acid batteries offer a long shelf life - up to 2 years at 25°C (77°F).

• Carmanah's electronics make every attempt to charge their batteries with a constant voltage, however when solar conditions are not adequate for this process, the pure lead-tin acid batteries will tolerate trickle charging much better than NiCd or NiMH.

• It is also important to note that while some other lead-acid technologies may experience freezing problems at low temperatures when they are greater than 50% discharged, tests show the pure lead-tin acid technology utilized by Carmanah is not affected in the same way.

• Pure lead-tin batteries have a much longer operating life that NiCd or NiMH batteries. In fact, pure lead acid batteries are rated to last three times as long as NiCad and twice as long as NiMH. In addition, pure lead batteries do not develop a memory like both NiCd and NiMH. Although all batteries are impacted by high temperatures, the lifespans of NiCd and NiMH are also more dramatically reduced as temperatures increase.

Carmanah Battery System Enhancements

Carmanah's lighting products have been further engineered to improve the performance and endurance of its pure lead-tin battery systems. Key enhancements include:

1. Carmanah's products incorporate intelligent electronics that compensate the charge voltage based on prevailing temperatures. The lights automatically increase their charge voltage during lower temperatures and decrease the charge voltage during higher temperatures, ensuring the charge conditions are optimal for a long lifespan.

2. Carmanah has properly matched the configuration of its batteries to meet each product's unique powering requirements. The systems are designed so that they never discharge beyond 80% depth of discharge. In fact, typical discharges are maintained in a range of 25% depth of discharge or less.

3. Carmanah's products incorporate a low voltage cutoff to prevent over-discharge of the battery system.

Environmental Benefits of Lead-Acid Batteries

Lead-acid batteries are the environmental success story of our time. Approximately 93 percent of all battery lead is recycled - compared to 59% of newspapers, 65% of aluminum soft drink and beer cans, and 40% of plastic and glass soft drink bottles. In fact, lead-acid batteries top the list as the most highly recycled consumer product in the world today.

Due to their widespread use in the transportation industry and strict legislation, lead-acid batteries have huge, successful recycling programs in all advanced countries. Nearly every town has a lead-acid battery recycling facility that accepts old batteries at no cost. The lead-acid battery gains its environmental edge from its closed loop lifecycle. The typical new lead-acid battery contains 60 to 80 percent recycled lead and plastic. When a spent battery is collected, it is sent to a permitted recycler where, under strict environmental regulations, the lead and plastic are reclaimed and sent to a new battery manufacturer. The recycling cycle goes on indefinitely. That means the lead and plastic in the lead-acid battery have been - and will continue to be -- recycled many, many times.

The Environmental Disadvantages of NiCd and NiMH Batteries

Nickel Cadmium

Although both Lead and Cadmium are toxic, Cadmium is also carcinogenic. In fact, there have been strong movements to have NiCd batteries banned entirely in the EU and the nordic countries. Through political lobbying, manufacturers have fought back with the promise of setting up recycling arrangements. So far, these recycling efforts are in their early stages and have been largely unsuccessful.

The NiCd battery is one of the more hazardous batteries in terms of disposal. Cadmium can accumulate in the environment by leaching into ground water and surface water from landfills, and it can enter the atmosphere through incinerator smokestack emissions. Effective air pollution control equipment at incinerators traps cadmium, which ends up in the ash, causing problems of cadmium in ashfill leachate. Our oceans are already beginning to show new traces of cadmium. Cadmium is toxic to fish and wildlife and can pass to humans through the food chain. It has been associated with numerous human illnesses particularly lung and kidney damage. Once absorbed in the body, cadmium can remain for decades.

Nickel Metal Hydride

Although NiMH batteries are considered a more "environmentally friendly" technology than both NiCd and lead-acid, the main derivative is nickel - which is considered semi-toxic. NiMH also contains an electrolyte that, in large amounts, is hazardous to the environment. NiMH battery recycling programs are nowhere near as widespread or as successful as lead-acid battery recycling programs; therefore, in practise, most NiMH batteries are disposed of in local landfills.

So... Why Would Some Manufacturers Still Choose to Use NiCd or NiMH Batteries?

NiCd and NiMH technologies are still selected by many manufacturers because they are readily available, relatively cheap and very compact/lightweight compared with lead-acid. However, it is Carmanah's belief that the overall long-term performance of products using these technologies is in jeapardy. Adequate consideration has not been given to the range of environmental conditions in the world today and the effects these conditions will have on their battery systems. Carmanah's lighting products are typically used in areas where reliability is the primary concern, and the extra cost and weight of using the right battery technology far outweighs the disadvantages.