Going on ebay: 28V PSU Power Supply [24V SLA Sealed Battery charger] buy now £27.80

Power General FDA1-150-6

Switch Mode PSU

Output: 28volt 5.36amp Rated: 150watt

PSU features adjustable voltage output and current limitation making it ideal for use as a 24V Battery Charger. Voltage can easily be adjusted to 27.6V for float charging sealed lead acid batteries used in back-up power systems, UPS systems, fire alarm systems etc.

Catalogue of FDA1/2-150 series specifications available as pdf via: [this specific 28V model is, rather irritatingly, not listed. But, essentially, all the specifications, including the unit dimensions, are as stated]

http://www.aultinc.com/products/powergeneral/pspdfs/pspg3637.pdf

Features:

Technical specification
Type SMPSU
Brand Power General
Manufacturer's part number FDA1-150-6
Supply Voltage [ac] 85..250 Vac 47..63 Hz
Output Voltage 28Vdc
Adjustment Range +/- 5%
Output power 150 watt
Max Load 5.36 Amp
Overcurrent protection YES
Soft Start YES
Output power Efficiency 70%

Ripple Noise 2% pk-pk max

Auto-ranging input.
0% minimum load requirements.
Remote load sensing.
Over voltage/Over current/Short Circuit Protection.
Minimum 165,000 hrs mean times between failures.
Soft start feature. Prevents output overshoot.
The unit is self-cooling in normal installation. Moving air is recommended where the unit is installed in a restricted/confined space.

Adjustment Range is specified as +/- 5%. In practice I have found the available open circuit range to exceed 25.2 to 30.4V

PSU is made in the USA to astonishingly high spec. Even the aluminium casing has a brushed anodised finish and is 2.5mm thick. Do not compare this product with the new breed of cheap flimsy far-eastern imports.

Weight : 0.74Kg

Dimensions : length 203mm : width 114mm : height 35mm

Unit is supplied NEW unused but without original packaging.

This PSU is NOT fully encased and must be installed within a suitable enclosure or as a part of another piece of equipment.