Charger With Low voltage cut out Isolator and transient Suppression Project

Discussion in 'The Projects Forum' started by RodneyB, Apr 15, 2015.

  1. RodneyB

    Thread Starter Well-Known Member

    Apr 28, 2012
    Over a couple of months I have been working on a multitude of projects. When telling a friend of the success he asked me to combine them and make a unit for him that basically combined everything. So to all the kind people who have helped me, "Thank you"

    On my drawing you will see several 0R resistors. These are links so that my PCB can be a single sided board.

    1. the Incoming supply is 28 Volts, it is protected with a 36 Volt MOV and 6 A resettable fuse. U1 provides the 18 Volts recommended for the PB137(U2) to charge the battery.
    2. The Battery and circuit is isolated from the circuit through the contacts of the LZ12 relay. This really is rated at 10 Amps which is an overkill. Also physically a waste of space. I however do not know of either a smaller relay or an alternative way of isolating this.
    . The transient suppression on the output is to protect 35mA from transient spikes. This is used in another circuit is working great. The Under voltage cut out is there to protect the battery this works perfectly Mike M helped be intensively with this for my Inverter system. I was just wondering if there was an Alternative for Q2 which switches less than 1 Amp.

    I have a problem actually setting the under voltage. Is there away that this can be done relatively easily..

    I also am not sure if D2 is required.

    Any advice, corrections or suggested amendments to make it more efficient would be greatly appreciated.