Voltage question not specific to tech

[hunterdan]

I'm working on a marketable product. I'm trying to figure out.....Can my car battery deal with a Constant 6v parasitic drain? This thing I'm working on needs a constant 6v when car is off.
None when car is running. I have found a 12v to 6v reducer that would pwr the item from the car battery I just don't know about the constant 6v drain overnight?
If that's too much drain then I'm guessing a separate 6v battery maybe in engine compartment or trunk being charged via the alternator with maybe a voltage reducer in the charging wires?
Thanks

 

[RatLabGuy]

Voltage isn't what drains the battery, its current (amperage).
You need to know how many amps your device draws.
If it is mA, you're fine.

If you don't have a proper ammeter, most multimeters have a current setting, place it inline between your device and the battery positive terminal.

 

[Hokie_YJ]

Voltage isn't what drains the battery, its current (amperage).
You need to know how many amps your device draws.
If it is mA, you're fine.

If you don't have a proper ammeter, most multimeters have a current setting, place it inline between your device and the battery positive terminal.

What he said. Most vehicles have some parasitic draw especially newer stuff. Anywhere from 50mA to 85mA or so is pretty normal. Once you get to 100mA it’s getting a little too high. My tractor currently has a 166mA draw that I haven’t been able to find yet and I had to put a disconnect on the battery terminal for now to keep it from running it down.

 

[braxton357]

The dc stepdown "buck" converter will be drawing decent current even when your 6v whatever isn't on, after anywhere from 2-5 days yeah your battery would probably need a jump. Plenty of other things in vehicles are drawing milliamps for volatile memory, leds, and other cancer causing things.

 

[LT1JEEP]

What he said. Most vehicles have some parasitic draw especially newer stuff. Anywhere from 50mA to 85mA or so is pretty normal. Once you get to 100mA it’s getting a little too high. My tractor currently has a 166mA draw that I haven’t been able to find yet and I had to put a disconnect on the battery terminal for now to keep it from running it down.

Is the starter or alternator or wiring oil soaked? I have found that oil will cause a power draw on electrical parts.

 

[Hokie_YJ]

Is the starter or alternator or wiring oil soaked? I have found that oil will cause a power draw on electrical parts.

I don’t believe so. But I honestly just haven’t had time to dig in to it much at all. I just went and bought a new battery and the disconnect. It’s relatively new Kioti (2016) and I haven’t noticed any leaks yet.

 

[Jeff B]

figure your amp draw and put a solar charger on a couple of 6 volt rechargeable batteries,

 

[Ron]

The dc stepdown "buck" converter will be drawing decent current even when your 6v whatever isn't on, after anywhere from 2-5 days yeah your battery would probably need a jump. Plenty of other things in vehicles are drawing milliamps for volatile memory, leds, and other cancer causing things.

This.
If you are developing a product a pcb with a wider voltage operating range would be cheaper than any converter, resistor based or otherwise.

 

[RatLabGuy]

The dc stepdown "buck" converter will be drawing decent current even when your 6v whatever isn't on, after anywhere from 2-5 days yeah your battery would probably need a jump. Plenty of other things in vehicles are drawing milliamps for volatile memory, leds, and other cancer causing things.

This. Any DC conversion = energy loss. I don't know what you're scheming but if you're designing a product, you'll need a switch that if in front of the buck converter. IOW plan to make that converter part of the device, not a separate thing.
As @Ron mentioned ideally the whole thing would be 12v. But the truth is very few electronics actually run on 12v, they pretty much always have a built in converter, its just not connected when the thing isn't "on"