An electric truck is only as clean as the electrons that charge it. For operators in weak-grid or remote sites, a solar-powered depot turns the EV truck into a genuinely off-grid asset. This guide covers PV sizing, battery buffering, and hybrid genset fallback so your Dongfeng fleet charges reliably whether or not the national grid cooperates, and so your energy cost and carbon profile both improve at once rather than trading one problem for another.
Mines, quarries, and agricultural hubs often sit far from stable power. Running a diesel generator just to charge an EV truck defeats the purpose. A solar array plus storage lets a dump or cargo EV truck draw from the sun by day and from buffered energy by night. In the Ghana electric truck market, where solar irradiance is strong year-round, off-grid depots routinely cover 60 to 80 percent of charging energy from PV, cutting both operating cost and diesel dependence in a single investment that pays back faster than most operators expect.
A practical rule: size 60 to 90 kWp of solar per truck if you must meet a daily demand near 300 kWh. That range accounts for system losses, seasonal dip, and the fact that a CATL LFP pack of 282 to 600 kWh still only needs a fraction of its capacity topped daily in most duty cycles. The Dongfeng TZ5E electric dump truck consuming around 1.1 to 1.8 kWh/km in haulage fits comfortably inside this envelope on a single-shift site, and a two-shift site simply scales the array linearly with the second shift's added demand.
| Fleet Size | Daily Demand | PV Size (kWp) | Battery Buffer |
|---|---|---|---|
| 1 truck | 300 kWh | 60-90 | 200 kWh |
| 5 trucks | 1,500 kWh | 300-450 | 800 kWh |
| 10 trucks | 3,000 kWh | 600-900 | 1.5 MWh |
| 20 trucks | 6,000 kWh | 1.2-1.8 MW | 3 MWh |
Solar is intermittent, so you need a stationary buffer between panels and trucks. A 200 kWh to multi-MWh lithium buffer absorbs midday surplus and releases it during evening charging. Size the buffer to cover at least one full low-sun day plus the evening charge window. The same LFP chemistry philosophy used in the EV truck packs works well stationary, with simpler thermal demands because the buffer does not move or vibrate and can be housed in a ventilated, shaded container.
A hybrid genset should be the last resort, not the primary source. Size it to cover peak charge rate when solar and buffer are depleted, then let it idle once PV returns. This keeps fuel use minimal while guaranteeing the EV truck never sits idle. For a 360 kW DC charger serving two trucks, a 300 to 400 kVA genset with solar priority controller is typical, and the controller logic should always prefer PV and buffer before starting the generator, which can cut diesel run hours by more than half.
Prioritise DC fast charging at 120 to 360 kW so trucks turn around in 1.5 to 2 hours for a 20-80 percent window. Where battery swap (5-6 min) is available on the model, pair it with solar for ultra-high uptime that rivals a conventional fuel bowser. Payback on a solar depot usually comes from avoided diesel generation and from time-of-use grid arbitrage where the grid exists. A well-designed off-grid depot pays for itself in 3 to 6 years while delivering the lowest-carbon EV truck operation possible, and it also insulates the fleet from future electricity price shocks that would otherwise erode the economic case for electrification.
When you scope the project, bring the depot design and the truck duty cycle into the same conversation rather than designing them separately. A site that charges ten trucks overnight from a single 200 kWh buffer needs very different PV than a site that fast-charges two trucks between shifts from a 3 MWh buffer, and mismatches are the most common cause of disappointed payback. Model a typical week of energy draw, including seasonal lows, and size the array to cover the worst month rather than the annual average, because a fleet that runs out of solar in the wet season will quietly fall back to diesel and lose the story. Engage an installer who has commissioned LFP stationary storage before, and specify remote monitoring from day one so a failing inverter is flagged by email rather than by a stranded truck at 6 am. With the design, the buffer, and the genset fallback working together, the off-grid depot becomes not a compromise but a genuine advantage: lower operating cost, lower carbon, and independence from a grid that may never reach the site at all.
Two financial points decide whether the depot gets built. The first is the incentive landscape: many utilities and development banks offer capital grants or soft loans for solar and storage that cut the payback from six years toward three, and a buyer who stacks these correctly can make the depot cheaper than grid reliance even where the grid is present. The second is the energy arbitrage case, where charging the buffer from cheap night solar or off-peak grid and discharging during expensive daytime hours smooths a volatile tariff into a predictable cost. Neither requires exotic technology; both require disciplined metering from day one so the savings are visible and bankable. Operationally, train a single depot operator to read the state-of-charge dashboard and to sequence trucks so the buffer is never drained below its design floor, because a flat buffer at the start of a shift is the one failure mode that brings the whole advantage crashing down. Get the metering, the incentives, and the operator discipline right, and the solar depot stops being a green prestige project and becomes the most rationally run fuelling station on the site, with a cost per kilometre that a diesel bowser simply cannot match.
There is also a sustainability story worth telling to customers and regulators, because an off-grid solar depot is the rare case where the cleanest option is also the cheapest over time. A Dongfeng EV truck charged from PV rather than a coal-heavy grid can cut the well-to-wheel emissions of a delivery or haul by the large majority, and that reduction is increasingly monetisable through carbon markets, green tender scoring, or simply the marketing value of a verified low-carbon logistics service. Keep the generation and consumption metered separately so you can certify the share of solar in each vehicle's energy, and the claim becomes auditable rather than aspirational. For mining and port operators facing Scope 3 pressure from downstream customers, an on-site solar depot is therefore not just an energy decision but a commercial one that protects contracts and opens preferential freight lanes. The depot that pays for itself in diesel savings thus pays a second dividend in credibility, and the two together make off-grid solar the most strategic infrastructure an EV truck fleet can build.
Ready to electrify your fleet? Contact Shaanxi Fenghan Trading — authorized Dongfeng EV truck exporter. WhatsApp: +86 153 1943 1311 | Email: sales@fenghan-trade.com | dongfengevtrucks.com
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