Can battery monitor drain battery?

[B168]

Hi been having problems with car battery dieing so got new battery recently. Seemed to have solved it till a few days ago found car dead again. I left my battery monitor plugged into the cigarette lighter so unsure if this is the cause. I've attached a screenshot of an almost identical monitor specs only difference is mine doesn't charge any usb devices it just monitors battery. It's same brand just that one difference. Could this be the cause if dead battery? Car is 2014 ford fiesta.

 

[Intuit]

From observations with my own 12v adapter, the answer is yes; albeit it, with nothing plugged into it, would take at least a couple of days on a good fully charged battery. Of course, different adapters will have different draw characteristics.

It could be different for modern vehicles but IIRC any parasitic drain beyond 0.06 Amps is considered excessive. I know there's a battery save feature that kicks on delay, dropping parasitic draw to a standard level.

Here's a guide for adding a relay to that front 12v outlet. There's also a switch in the circuit, that can revert it back OEM behavior.. In addition the changes are easily reversible.
Check it out: https://www.fiestastforum.com/threads/guide-amp-remote-turn-on-relay-12v-outlets.29095/

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[B168]

From observations with my own 12v adapter, the answer is yes; albeit it, with nothing plugged into it, would take at least a couple of days on a good fully charged battery. Of course, different adapters will have different draw characteristics.

From observations with my own 12v adapter, the answer is yes; albeit it, with nothing plugged into it, would take at least a couple of days on a good fully charged battery. Of course, different adapters will have different draw characteristics.

It could be different for modern vehicles but IIRC any parasitic drain beyond 0.06 Amps is considered excessive. I know there's a battery save feature that kicks on delay, dropping parasitic draw to a standard level.

Here's a guide for adding a relay to that front 12v outlet. There's also a switch in the circuit, that can revert it back OEM behavior.. In addition the changes are easily reversible.
Check it out: https://www.fiestastforum.com/threads/guide-amp-remote-turn-on-relay-12v-outlets.29095/

.

Thanks


It could be different for modern vehicles but IIRC any parasitic drain beyond 0.06 Amps is considered excessive. I know there's a battery save feature that kicks on delay, dropping parasitic draw to a standard level.

Here's a guide for adding a relay to that front 12v outlet. There's also a switch in the circuit, that can revert it back OEM behavior.. In addition the changes are easily reversible.
Check it out: https://www.fiestastforum.com/threads/guide-amp-remote-turn-on-relay-12v-outlets.29095/

.

 

[jmrtsus]

If it is just a monitor with LCD display it would take almost forever unless it is broken. It is just a cheap Digital Volt Meter and a few milliamps current draw. Our batteries are about 66 Amp Hours divided by .002 amps( 2 milliamps) is 33,000 hours or 3.77 years! Double it and you still have almost 2 years. Even if it had USB jacks with nothing connected current draw would still be very low but not as low as a dedicated LCD monitor. A tiny battery runs an LCD watch for years, I'm also a watch nut and collector and saw some quartz movements rated with a 4 year battery life on a tiny cell. Keep in mind our car is constantly using battery power running the Sync 3 for updates and maintaining the data in the ECM and other systems. So there is no real "OFF" in our cars, just sitting will run the battery down eventually.

 

[SteveS]

Theoretically there should be only trivial power drain from devices like these. But on another forum I participate in for Miatas there have been several members who have experienced battery drain down from the voltage monitors.

 

[Capri to ST]

Keep in mind our car is constantly using battery power running the Sync 3 for updates and maintaining the data in the ECM and other systems. So there is no real "OFF" in our cars, just sitting will run the battery down eventually.

Do you know how long one of our cars would have to sit before the battery loses enough power from the parasitic battery drain that it wouldn't start? Assuming a fairly new healthy battery.

 

[Intuit]

It's not that they will quickly drain the battery low enough that it doesn't crank, it's that they will drop the voltage low enough for them to sulfate more rapidly; significantly reducing their normal usable life span.

 

[jmrtsus]

Do you know how long one of our cars would have to sit before the battery loses enough power from the parasitic battery drain that it wouldn't start? Assuming a fairly new healthy battery.

My wifes Mustang GT went three months.........Got message that battery level was critical and starting disabled. BTW, I did the math for you in post #4.

 

[Capri to ST]

My wifes Mustang GT went three months.........Got message that battery level was critical and starting disabled. BTW, I did the math for you in post #4.

Thanks, that's good to know. I have a battery tender, and if a car's going to sit longer than about 2 weeks I usually put it on there just to be on the safe side.
I saw your calculation in the earlier post, but it appeared to be based on an estimated drain of the device that had been asked about by the OP, a digital voltmeter. My assumption would be that our car has a parasitic drain that is higher than that, and therefore would last considerably less time sitting before it wouldn't start.