A flat battery on a single vehicle is an inconvenience. Across a fleet it is a recurring cost: recovery call-outs, missed jobs, premature battery replacement and vehicles off the road. Most of it is preventable, and the fix is well understood. It just has to be designed in rather than hoped for.
Why fleet vehicles go flat
Batteries on working vehicles fail to start for a small number of recurring reasons:
- Auxiliary loads with the engine off. Warning beacons, work lights, tail lifts, refrigeration, inverters and payload equipment all draw from the battery whenever the engine is not running. On a vehicle that spends its shift stationary with equipment live, this is the biggest single cause.
- Parasitic drain when parked. Telematics units, trackers, alarms, cameras and standby electronics draw small currents continuously. Over a weekend or a period off the road, that steady drain alone can flatten a battery.
- Short-trip duty cycles. Delivery and service vehicles that make many short journeys never fully recharge, so the battery drifts down over days.
- Ageing and cold. Battery capacity falls with age and with temperature, so a battery that coped last year may not cope this winter.
The common thread is discharge below the point where the battery can crank the engine. Stop that, and the vehicle always starts.
What battery protection does
A battery protection device sits between the battery and the non-essential loads. It continuously monitors the battery voltage while the engine and charging system are off, and disconnects the non-essential loads before the battery is pulled down to the point where it can no longer start the vehicle. When the engine restarts and charging resumes, it reconnects.
Crucially, a good device does this drawing almost nothing itself (very low quiescent current), so it does not become part of the problem it is there to solve.
The Battery Guard range
Intellitec’s Battery Guard is the original product of this type. It protects against over-voltage, under-voltage and exhaustive discharge, and the range spans the load profiles a mixed fleet throws at it:
- Compact units: Battery Guard 10A and 18A for lighter auxiliary loads, both 12/24V.
- Battery Guard 2000: 100A and 200A models, 12V and 24V, for heavier loads.
- Battery Guard 3000: a fully programmable power management version, 100A and 200A, that continuously monitors available battery voltage and lets you set disconnect and reconnect thresholds to suit the vehicle.
- High-current BGB250: 250A protection with the lowest possible quiescent current.
Application-specific variants matter for a mixed fleet: the PSV models suit buses and coaches, and the CD Tail Lift models are designed specifically to protect engine-start batteries from tail-lift loads, one of the most common flat-battery causes on delivery and distribution vehicles.
Building it into a fleet
Battery protection is most effective as a standard fit, not a reactive one:
- Match the rating to the load. Choose the Battery Guard current rating for the vehicle’s auxiliary loads, not a generic figure.
- Set thresholds by role. On programmable units, set the disconnect point to protect starting while giving the crew reasonable runtime for their equipment.
- Cover the parked case too. Isolating standby loads, or protecting against slow parasitic drain, matters as much as protecting against on-shift auxiliary use.
- Layer with load management. On complex vehicles, combine battery protection with prioritised load-shedding so lower-priority loads drop before anything critical.
The payback
Fitting battery protection as standard turns “will it start?” from a daily gamble into a non-issue. It cuts recovery call-outs, extends battery life by keeping cells out of deep discharge, and keeps vehicles available. For a fleet operator, the cost of a Battery Guard is small against the cost of one stranded vehicle and a replaced battery. All Battery Guards are UK manufactured.