I have a store front with a marketing light array that I am using that needs 12V power. I am running it from a battery. I was hoping a could mount a light behind the counter that would indicate the battery is low, then I would connect the charger. When the charger is connected my door alarm would be off. Now, I see that I can latch gound to it and run it in low power mode. I just tried it, and I can tell from behind the counted when it is dim. Which would tell me to disconnect door alarm and charge battery for the light array. I hope this makes sense.