Benefits of Solar Charging when Combined with a Diesel APU

April 02, 2018

• Increasing demands on APU charging systems have increased, causing excessive runtime just to keep electronics powered up when no one is around - sometimes for days

• Without 100% daily re-charging, batteries incur “walk down effect” where, after time, a portion of battery will become increasingly useless

• Alternator charging is only effective at bulk charging, with reduced output as battery gets near full

APU runtime can be reduced while extending tractor battery life

ThermoLite® Solar Panels paired with diesel APUs like the TriPac® Evolution can be an effective solution for situations where the tractor is stationary and must support small power loads during active or off-duty periods. Many fleets rely on the APU to keep the tractor batteries charged up enough to start the tractor or while in monitor or heat mode during the day.  In fact, the average TriPac Evolution spends approximately 20-35% of its runtime just maintaining the tractor batteries.

Effective Solar +APU Applications: Off-duty weekends, driver vacations or at loading docks

For numerous customer trials across the country, dealers have paired solar with the TriPac Evolution to reduce APU runtime. An average 20-30% APU runtime reduction has been verified when used during the applications listed above. 

Customers reporting 20-30% APU runtime reduction:

• Cypress Truck Lines - 36W panel with TriPac Evolution since late 2015

• Rinaudo Heavy Haulers - 36W panel with TriPac Evolution since 2016 - such success they now install with every new APU

• CDT, Inc. - 36W panel with TriPac Evolution & 72W on trucks with no APU (Flatbed application)

• Custom Pine Straw – 36W panel with TriPac Evolution since early 2017

Aligning APU & Tractor Maintenance

With the TriPac Evolution’s industry-leading 2000 hour maintenance interval, you can pair APU maintenance with the ever increasing tractor PM intervals. Reducing APU runtime can possibly align your APU PM with your tractor PMs, which creates operational costs savings.

TriPac Evolution + Solar Runtime Reduction Trial Example

Test Conditions:

• 3 tractors parked side by side (1 with no solar, 1 with 110W, 1 with 220W)

• 3 tractors run for 7 days each with different electrical loads present

• TriPac Evolution restart settings with solar: 12.2V & 20A shutoff (12.5V & 12.5A w/o solar)

• Panels temporarily installed on top of tractor cab to simulate real world

• Tractors parked facing West

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