Warehouse electrical load: sizing for MHE charging and future racking

Key Takeaways

• Forklift battery chargers range from 3kW to 30kW each depending on battery chemistry, charge speed and truck class, so a fleet of even 10-15 units can represent a substantial, concentrated electrical load.
• Lithium-ion chargers draw materially more power over a shorter window than lead-acid, a lithium pack can reach a full charge in around 2.7 hours, against lead-acid's slower, lower-current overnight charge cycle, so switching chemistries changes the electrical design, not just the battery.
• Material handling equipment (MHE) covers every powered machine used to move, store and retrieve goods in a warehouse, and its charging load should be sized against duty cycle (single-shift, multi-shift or 24/7), not just fleet headcount.
• Sizing the incoming supply for today's fleet only, with no allowance for a future racking expansion or a lithium conversion, is the most common and most expensive mistake in UAE warehouse electrical design, because upgrading a utility connection after the racking is built is far costlier than provisioning spare capacity upfront.

An electrical contractor sizing a UAE warehouse for racking, lighting and office loads alone will consistently undersize the panel, because the largest, least visible load in most modern distribution centres is the battery charging room, not the racking or the lights above it.

What MHE charging actually adds to the load calculation

Material handling equipment (MHE) is every machine and system used to move, store, protect and retrieve goods within a warehouse or distribution centre, forklifts, reach trucks, VNA (very narrow aisle) trucks, and power pallet trucks chief among them. Electric forklifts now handle most indoor lifting in UAE warehouses, valued for having no exhaust, a much lower running cost than diesel or LPG equivalents, and quiet enough operation for food, pharmaceutical and retail sites (Genavco UAE, Warehouse Equipment Guide, retrieved 2026-09-08). Most UAE warehouse fleets run electric forklifts from 1 tonne capacity upward (ARAS FZE, "How to Choose an Electric Forklift in the UAE", retrieved 2026-09-08). Every one of those trucks needs a charger, and the chargers, not the trucks themselves, are what the electrical design has to account for.

Forklift battery chargers are sold in models spanning roughly 3kW to 30kW, with selectable input voltages (208V, 240V, 480V typical) and current draws from 50A to 240A (EVAisun, Battery Charger Buying Guide, retrieved 2026-09-08). A single high-output lithium charger sitting at the top of that range, run continuously across a multi-truck fleet, is a load on the order of a small factory floor's HVAC system, not an incidental office circuit.

Lead-acid vs lithium: two different electrical designs, not two batteries in the same slot

Lead-acid batteries are conventionally charged at around 0.1C, 10% of the battery's amp-hour capacity per hour, which spreads the charge over a long, low-current overnight cycle (EVAisun, as cited above). Lithium-ion packs charge far faster, a full charge achievable in around 2.7 hours on a suitable charger, which supports opportunity charging (topping up during breaks rather than a single overnight cycle) but concentrates a much larger current draw into a shorter window (Topregal, Li-ion Forklift Specifications, retrieved 2026-09-08).

That difference matters for panel sizing specifically because it changes the load profile, not just the total energy consumed. A lead-acid fleet's chargers draw modest current across the whole overnight period; a lithium fleet's chargers draw far more current, but for a shorter window, often overlapping with shift-change peaks if opportunity-charging is scheduled during breaks. A supply sized correctly for a lead-acid fleet's overnight draw can be materially undersized for a lithium fleet's concentrated daytime peak, even at an identical truck count.

Sizing against duty cycle, not headcount alone

Forklift DC chargers should be matched to the warehouse's actual duty cycle, single-shift, multi-shift or 24/7 operation, because that duty cycle determines whether the fleet needs slow overnight charging (single shift, lead-acid tolerant) or fast opportunity charging (multi-shift or 24/7, which pushes toward lithium and a higher concentrated load) (EVAisun, Forklift DC Chargers & Warehouse Duty Cycles, retrieved 2026-09-08). Before selecting chargers, review load weights, pallet dimensions, throughput, aisle widths, rack heights, travel distances and shift patterns together (Mazda Movers, MHE Assessment Guide, retrieved 2026-09-08), since a 24/7 operation with tight aisle turns and high throughput will run its trucks harder and need more frequent, faster charging than a single-shift bulk-storage facility with the same truck count.

A worked example: sizing for today's fleet plus tomorrow's racking

Take a warehouse running 12 electric forklifts on a single shift with lead-acid batteries, each charger drawing a conservative 6kW at overnight charge rate. Simultaneous connected load, if every charger ran at once, is 12 x 6kW = 72kW. In practice, staggered overnight charging rarely hits full simultaneity, so a diversity factor of roughly 0.7-0.8 is a reasonable planning assumption, giving a realistic peak charging load of roughly 50-58kW.

Now plan for the business's own stated growth: a move to a second shift within two years, and a lithium conversion to support it. Doubling truck count to 24 and shifting to lithium chargers at a higher per-unit draw, 10kW average rather than 6kW, raises the theoretical connected load to 24 x 10kW = 240kW, more than three times the current figure. Provisioning the incoming supply and switchgear for only today's 72kW connected load leaves no room for that transition, and retrofitting a utility connection upgrade after racking, conveyor and dock infrastructure are already built is a materially more expensive and disruptive project than sizing the spare capacity into the original design. This kind of forward-provisioning is exactly what a commercial energy optimisation assessment is designed to check, sizing the connection against a stated multi-year growth plan rather than the day-one fleet alone. Run your own fleet numbers and growth plan through the electrical load calculator before finalising a panel and utility connection size.

Frequently asked questions

Does switching to lithium batteries always increase the electrical load?

Not the total energy consumed per truck necessarily, but almost always the peak power draw, because lithium's faster charge cycle concentrates the same or greater energy transfer into a shorter time window. Electrical designs sized around lead-acid's slow overnight draw typically need reinforcement before a lithium conversion.

How much spare capacity should a warehouse provision for future MHE growth?

There is no single verified industry figure for this; it depends on the business's own expansion plans, shift patterns and racking design. The practical approach is to size the panel and utility connection against a stated 2-3 year growth scenario, not just the day-one fleet, since utility connection upgrades are typically the slowest and costliest part of any later expansion.

Do charging rooms need dedicated ventilation as well as electrical capacity?

Yes for lead-acid, which off-gasses hydrogen during charging and requires dedicated ventilation under standard safety codes; lithium-ion charging does not off-gas in normal operation but still requires the electrical design, not just the ventilation design, to be reviewed separately, since the two battery chemistries have materially different power profiles as described above.

The bottom line

The forklift fleet's charging load, not the racking or the lighting, is usually the largest and least forgiving line item in a UAE warehouse electrical design. Size the incoming supply against duty cycle and a stated growth plan, not the day-one truck count, and treat a lithium conversion as an electrical-design decision as much as a battery decision.

Figures verified 8 September 2026 against Genavco UAE, ARAS FZE, EVAisun, Topregal, and Mazda Movers. The worked load example uses illustrative charger ratings within the ranges these sources report; confirm exact charger specifications with your equipment supplier before finalising a panel design.