J. Boonzaaijer

Mobile power source for construction professionals

Boonzaaijer Header

The driving workshops of the experts at J. Boonzaaijer contracting company are equipped by WhisperPower with electricity systems providing 230 volt sockets. The craftsmen can now work independently at locations they need to perform their jobs.

“My batteries are always fully charged,” is the practical answer of Dirk Bolt to the question how he achieves the electricty network aboard his working van. 27 year old Dirk is chief operator at construction company J. Boonzaaijer from Loosdrecht in the centre of the Netherlands. A lot of the tools he works with, are battery-powered. A series of batteries for various tools is permanently connected to a charging bank inside his impressive van. Even with the engine stopped and the van’s alternator not providing any charging current, enough electric power is available to charged these batteries.

A water cooker and a coffee maker are also connected to 230 volt power supply to provide for a warm drink or soup at working locations. Even heavier tools that do not have a battery, will run from the van’s electric power supply. A circular saw, an angle grinder or compressor are also part of Dirk’s tool collection. Using an extension cable, he can use these at job locations. “Only when I need to use these tools for longer periods, I need to start the van engine to prevent the battery of the van electric system to be discharged too much,” Dirk comments. His employer Maarten Boonzaaijer adds: “The good thing with this system is security. When a tool demands too much current from the battery, it will shut down. This prevents damage to our equipment and in the same time prevents draining the battery.”

Boonzaaijer Whisperpower


WhisperPower installed 230 volt networks with 50 Hertz alternating current in three mobile workshop vans of the familly business J. Boonzaaijer: one Ford Transit and two Mercedes Sprinters. The standard alternator in the vans will charge the starting battery first. This is charged swiftly, often within minutes after starting the van engine. The alternator will keep turning as long as the engine is running, and the current created is now used to charge the larger 200 Ah battery that feeds the 230 volt electric system. The WP Suntrack Duo ensures a stable charging current. Solar panels on the roof may be connected to the same charging regulator.

When the battery of this system has provided strong currents for a longer period, it may be recharged using a wall socket of the land based electricity grid. For this purpose, the WP Supreme battery charger is on board together with the WP/AC Basic charger kit, with cable, 230 volt sockets with a LED indicator and current breaker. From the display of the WBM battery monitor, the craftsmen in their vans can review remaining charging level of the battery. The WP Sine Converter 12V 2000W – 230v 50 Hz provides electric power identical to the power supply from wall sockets in European countries. Standard battery chargers as supplied with the battery-electric tools of the construction specialists are connected to it. A number of sockets in the vans enable the use of electric powertools that do not have a battery but take power from a socket.

Boonzaaijer Single Line+diagram Page 0001
System drawing

Family company

Dirk takes his van to jobs at bridges and locks in waterways, where he performs repairs to damaged infrastructure. The contracting company specialises in installation, maintenance and repairs to the wooden trim along such structures. Six brothers run the company together, which their father started some sixty years ago. They come from a big family with nine brothers and three sisters. The second generation sees the majority of the brothers active in the company. “My brothers and I all take on projects for which we are responsible from the beginning to the end,” Maarten explains the unique company structure. “This way, we have no dispute about leadership. The downside is that we rarely get to work together.”


Employee Dirk Bolk welcomes the 230 volt network in his van as an improvement of the job. “Thanks to the sockets, I do not need to carry generators around,” he explains. “My next job is to repair a lock door that was hit by an inland cargo ship. To repair this door, I need to cut a part of the steel structure out of it and then replace this with the wood lining attached. With my workshop van, I can go to such jobs independently and I even have coffee and soup at hand. The system works fine. Only some five times every year, I charge the battery from a wall socket, just to be sure to lengthen its life span. Normally, the battery is charged sufficiently just by driving home from a job.”

J. Boonzaaijer website