Is this an appropriate device to monitor 12V on a model 3?

[Dolemite]

I recently purchased one of these:

https://www.amazon.com/gp/product/B...&pf_rd_p=5ae2c7f8-e0c6-4f35-9071-dc3240e894a8

Today I pulled my 12V battery, let it rest for an hour, and tested. I set the tester to 650 CCA, which is what our OEM batteries are (https://cdn.hankook-atlasbx.com/PRD...-a26f-5af2aeaef0ba/ATLASBX카다로그_최종(책자)-압축됨.pdf).

Car is 7/2019 build, battery 6/2019. <11K miles on the car. Results:

Is this a valid test for the TM3's "use case?" We're not cranking up a massive engine, but I imagine if it's good on that front, it should be alright?

FWIW I do not want to get one of those devices that you affix to the battery & monitor via an app/bluetooth.

 

[jjrandorin]

(moderator note: bumping this back up after moving it out of 12v thread. Re considered and this is a separate issue so moved it back to regular section and out of master thread)

 

[lUtriaNt]

its a regular battery so yes id trust the product you bought. if you are unsure go to a local parts store and have them test it also.

i use the 12v monitor that you dont want to use on the ohmmu battery and it is accurate.

 

[Dolemite]

its a regular battery so yes id trust the product you bought. if you are unsure go to a local parts store and have them test it also.

i use the 12v monitor that you dont want to use on the ohmmu battery and it is accurate.

sankou. Just trying to keep things simple. Do you guys know whether it’s recommended to let a 12V battery “rest” unhooked from anything for a certain number of hours before testing? To get a more accurate read on its condition?

 

[Chisale]

How quick does it display the results? Is it running a series of voltage draw down tests or is it just measuring the voltage at that moment. It shows the guy on the Amazon page just affixing it to his battery while on the car. But then again, the battery isn't doing anything when the car is off in an ICE car is it?

 

[Dolemite]

How quick does it display the results? Is it running a series of voltage draw down tests or is it just measuring the voltage at that moment. It shows the guy on the Amazon page just affixing it to his battery while on the car. But then again, the battery isn't doing anything when the car is off in an ICE car is it?

It depends on the car, I guess - my BMW only went to “sleep” after 16 mins of being parked. God knows wtf the Tesla does.

I think it displays the results in something like 5 - 7 seconds.

 

[Chisale]

It depends on the car, I guess - my BMW only went to “sleep” after 16 mins of being parked. God knows wtf the Tesla does.

I think it displays the results in something like 5 - 7 seconds.

So if it's that quick then I'm guessing that all it's doing is measuring the nominal DC voltage and internal resistance. So, yes, to get the best measure of your battery with only that you would want to remove it from the car and let it sit for a while. It's not a great test but better than nothing and would surely show if it is on its last legs or not. The issue with leaving it on the car and testing it there is that the EV is constantly going to be using (and recharging) the battery for its various idle uses. That's my amateur battery opinion. Would love to hear somebody weigh in who knows more.