July 20, 2004

By: Edgar Wittal
Website: http://www.1st-in-batteries.com

Custom-designed NiMH battery chargers for field use

A three-channel charger for fast charging three 24V NiMH batteries has been custom designed by Lawtronics. The Kent-based charger specialists were asked by Instro Precision to develop a charger unit powered from a motor vehicle that could simultaneously charge three military specification NiMH batteries.

The batteries will be used to power Instro Precision's new range of portable angulation heads, which support electro-optical sensors for use in defence and commercial applications.

There were no off-the-shelf chargers available for the military specification batteries we are using, explained James Winter, senior electronics engineer at Instro Precision, who are world leaders in sensor support systems. We therefore needed a high performance charger designed to our own specifications, and within tight time constraints.

The fan-cooled charger is a modified three-channel version of Lawtronics' ICaMS range. We had to optimise its performance to limit the temperature rise in the batteries, which are housed in an environmentally sealed container, said David Winnett, Lawtronics' technical manager. We designed them to be charged at as fast a rate as possible, without the batteries' own thermistors shutting them down.

The charger unit uses a 32-36V dc supply and incorporates short forming charge, bulk fast charge period, trickle charge and auto reset functions. A soft-start charge routine minimises rejection of sub-standard cells prior to bulk charge. Trickle charging enables continued battery forming for new cells. For more information, see .

About The Author:

Edgar Wittal is a successful author and regular contributor to http://www.1st-in-batteries.com.  A great resource for batteries of all kinds including camcorder, laptop, cell phone and more.