Cranford Controls

400/BM Series Power Supply Units

Product Overview

These are high efficiency, cost-effective Switch Mode Power Supplies, with Mains and Battery Monitoring and two independent volt free fault outputs, ideal for use in Access Control and general PSU applications. They also feature a regulated 13.8V dc output supplying continuous full rated current to load and a universal mains voltage input.

Standby battery recharging is achieved within 24h for an 18Ah battery. Maximum battery life is assured using deep discharge protection to prevent premature battery failure when operating in standby mode for extended periods. Two sets of volt free contacts are provided to signal (i) loss of mains and (ii) battery and loss of output faults.


  • Full Rated Current to Load + 0.5A battery charging
  • Universal Mains Voltage Input 90V – 264V ac
  • Mains and Battery Monitoring
  • Deep Discharge Protection
  • Electronic Overload Protection
  • Volt Free Fault Output – 1 Mains Fail
  • Volt Free Fault Output – 2 Battery Failure Output / Battery Fuse Failure Output Short Circuit or Low Voltage
  • Mains Status LED Indication Mains Status Output Fuse Fail Output Short Circuit or Low Voltage Battery Low or Missing
  • Mains Transient Protection Front Tamper Protection

This power supply unit meets the essential requirements of the following European Directives Low Voltage 2006/95/EC, EMC 2004/108/EC, WEEE 2002/96/EC, RoHS 2002/95/EC


Part No. 400/4L 400/5L
Input Voltage 90-264Vac
Output Voltage 13.5 – 14.2 Vdc (13.8 Nominal) on Mains Power
Ripple 150mV pk – pk max
Max Load Current 4.0A continuous 5.0A continuous
Load Output Fuse F4A 20mm glass F5A 20mm glass
Battery Capacity 1 x 18Ah Valve Regulated Lead Acid (NP18 size)
Battery Recharge Time To 80% within 24 hours
Deep Discharge Protection Battery disconnected at 10.5V nominal
Battery Fuse Protection F4A 20mm glass F5A 20mm glass
Frequency 50 – 60Hz
Material White powder-coated steel
Temperature Range -10° to +40°C (operating), 75% RH non-condensing -20° to +80°C (storage)
Weight (kg excluding battery) 3.8kg

Note: All model part numbers are suffixed with /12V/BM

Part Numbers

303-036 Switch Mode Power Supply Unit, 12V, 4 Amp – Enclosure will hold up to 1 x 18Ah Batteries
303-037 Switch Mode Power Supply Unit, 12V, 5 Amp – Enclosure will hold up to 1 x 18Ah Batteries