I'm talking about the BCD600 or any other power supply left connected to the 24 volt supply.
I'm not sure what bit you are missing, if at all, so I'll post a bit more, we are possibly on the same channel......not sure.
With the BCD600, (or any other 24 to 12 volt power supply or battery charger), they are designed to output a set voltage and/or current, and may have 1,2 or 3 stages which vary the voltage and/or current.
Forgetting the stages, (the stages are basically constant current until a set voltage is reached, then constant voltage with variable current depending on load) the main thing they do is output a voltage which is high enough to charge a battery or maintain a certain voltage. Lets say that voltage is 13.8 volts.
This is enough to constantly float charge a battery, therefore " AT ALL TIMES" the charger is connected to the 12 volt battery it will be charging (24/7), UNLESS it has reduced the 24 volt supply batteries down to 19 volts (BCD600), which in anyone's terms is FLAT.
It will also be supplying any load connected to the 12 volt battery at all times that it is connected. On top of this it also has a 10% inefficiency , so what ever current that is required to float charge the battery (constant voltage applied) an additional 10% is used. However, the efficiency of these and other units are not linear to output, at lower outputs the efficiency usually falls away quickly. (If you need a 300 watt inverter, don't buy a 600 watt one and run it at half load as you will waste energy due to the lower efficiency at reduced rated output)
The BCD600 will eventually TOTALLY DISCHARGE your 24 volt batteries if it is not disconnected, the rate of discharge is determined by the load which consists of devices hooked up to the battery plus the constant float charge going into the 12 volt battery. (This could be 0.5 amps 24/7. This ids determined by the electrical/chemical characteristics of the particular battery) This will happen unless the 24v batteries are being topped up by the alternator.
To stop this happening a VSR of some sort (or other method) is required to disconnect the BD600 from the 24 volt supply.
TLC Norway wants to use a VSR instead of an IGN keyed relay or a manual switch, because he may forget to flick the manual switch, and he doesn't want it connected and charging when the IGN is on and the engine is not running. If he was happy with a IGN keyed relay than that would effectively isolate the power supply when the IGN was not ON, and it wouldn't drain the batteries. (Unless IGN was left on)
There is nothing wrong with a BCD600 or his power supply, they both work in a similar fashion and will both discharge the 24 volt battery system to dead flat unless he implements a system to disconnect them from the 24 volt supply.
Please be clear, the BCD600 does not have anything in built to stop it totally discharging a set of 24 volt batteries UNLESS it is effectively disconnected from the 24 volt supply.
