Dash Warning Light for DC to DC Charger

Garry
You could use a redarc voltage sensing relay P/N VS12 and wire it to an alarm as in their diagram.
You would wire it to the 12 volt side of the DC DC charger so that if the charger fails it would trigger the relay and alarm. You could also wire in a relay controlled by the ignition switch in the supply circiut so that it only works when the ignition is turned on. Check it out on the redarc site as it should suit to do what you want.

Murray

Hi Garry,

Arranging for a pair of 'reverse' repeater LED's on the dash is not difficult if you know your way around electronics but complex to provide detailed instruction for the inexpert.

An easier, and more effective arrangement, may be achieved by simply installing a digital voltmeter on the dash connected to the 12v auxiliary battery. This will not only provide indication of charging activity but also will supervise the battery's SOC when not on charge.

Yes it would but if you set the set voltage say .3 .4 volts lower than the float voltage of the charger that should let you know that it has failed. If the charger fails the 12 volt battery voltage will decrease hence triggering the relay letting you know that the charger has failled.

Murray

Quote "and I could extend these to display on the dash. However lights coming on (like a normal ignition light) rather than going out if there is a charging issue"

Easy to do. One relay per circuit will do the trick if the outputs for these lights will drive a small relay. Wire your conversion circuitry to the ignition circuitry. Wire the indicator light extensions to its relay. Wire your dash indicator to the NO side of a change over relay contact. When the chargers indicator light fails the relay will release and the NO contact will light up your warning light. (If you are keen enough you could also wire a pizo buzzer in parallel with that light.)

Thanks to everyone for your ideas - they have focussed my thoughts.

What I am going to try is to run a micro relay (the type that is off when has power applied) from the wiring that works the inbuilt output led on the charger. Switched power for the dash light will go through the relay so that when the charger is making power the relay will cut power to the dash light with the ignition on. If there is an issue the relay will open allowing switched power to the indicator light - when the ignition is off the dc charger is off and there is no power available to the dash light.

However the on fault is that that if the system is working the the dash light will never light up so I will not know if the globe/led has blown. I will use a time delay relay to actually switch on the DC charger when the ignition is switched on so the dash light will illuminate until the charger is switched on by the time delay relay.

I appreciate the advice provided - it has been very helpful.

Garry

Just for interest, my isuzu nps 300 had 5 x redarc bc to bc 24volt to 24v charges they just kept failing the 6th one was built for my truck & now seams to be working fine the std bc bc charger that can run 24v to charge 12v has not mist a beat.