Carriers have faced a range of industry and economic challenges over the past couple of years, forcing many fleets to operate on razor-thin margins. For these companies, the unforeseen maintenance costs and downtime accompanying dead truck batteries could be enough to jeopardize their profitability. 

The Threat of Parasitic Drain

To safeguard their companies against this risk, fleet leaders should be aware of the parasitic draw or the energy that drains from a truck battery when not in use. This is often the culprit behind dead truck batteries, especially during the colder months or after long periods of idling. 

Many carriers accept the ramifications of this slow drain — including dead batteries — as a hazard of doing business, but it does not have to be that way. Fleets can access options to mitigate this issue. 

“While at first blush, these small amounts of energy might not pose a significant threat to vehicle readiness, over a long enough time, they can prove disastrous for fleet efficiency and costly to your bottom line,” according to a recent PowerFilm Solar blog by Julia Stone. 

Mitigating Risks with Solar Panels

In an economic environment where efficiency and cost-savings are top of mind, this seemingly slow-growing threat warrants action from carriers sooner rather than later. However, pinpointing and solving every source of parasitic drain is difficult. Instead, fleets should focus on mitigating risks by increasing available energy sources. 

“Often, the culprit could be a worn wire that is nearly impossible to isolate amongst the dozens of other cables in your truck’s system,” Stone wrote. “To mitigate this parasitic draw, the simplest and least stressful solution is to pair that draw with the appropriate solar panel to cancel it out.”

Solar Panels Increase Fuel Efficiency

In addition to reducing the risk of dead batteries, solar panels help carriers increase fuel efficiency, further safeguarding themselves against ongoing economic headwinds.

In 2019, a nationwide rail refrigeration fleet — which utilized Carrier Vector hybrid reefers — conducted a one million-gallon study to evaluate the impact of reefer solar panels on overall fuel usage, according to a PowerFilm Solar blog post by Kelly Junge.

During the study, a differential fuel meter was mounted on each truck’s fuel lines, and data was monitored via telematics. Loads were kept at either zero degrees or minus 5 degrees. The study lasted an entire year, ensuring data was collected from warm and cold months.

“The final result of the study was a 0.09 gallon/hour diesel savings with the addition of a 20-30W solar panel,” Junge said. “In addition, it was found that the diesel savings were more significant in the colder months (starting a cold diesel engine to charge a low-voltage battery can be inefficient).”

Ultimately, for every 24 hours a reefer truck runs a solar panel, the carrier stands to save over two gallons of diesel, according to Junge. That statistic suggests that reefer solar panels could pay for themselves within a few months.

Solar Panels Expand The Technology Fleets Can Use

When trucks have an additional energy source, like solar panels, it is also easier to engage other tools and devices to increase productivity and efficiency, further compounding the positive effects.

“Telematics can be a significant parasitic load on your reefer battery, especially for idle trailers that periodically sit over weekends,” Junge noted in a recent blog post. “It won’t be a question of if your reefer battery will be dead; it will be a question of when. A small 24W solar panel counteracts telematics loads and keeps the reefer battery healthy.”

All said the benefits of adding solar panels far outweigh the time and money associated with acquiring and installing the panels. 

“Considering that a refrigeration technician can run $90/hour and losing a load can cost thousands of dollars, an inexpensive solar panel provides an outstanding return on investment for your fleet. The time and cost for a jump-start service call is too high not to have a solar panel on your truck, trailer, or reefer.”
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