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Using a 12V battery tester to monitor 12V battery?

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Couldn't you wire in a volt meter
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I don’t think a monitor would actually help. All you would see is a battery draining then getting charged later. The car needs software with proper algorithms to monitor a trend and give out a more ample warning. That could only come from Tesla at this point.
 
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I don’t think a monitor would actually help. All you would see is a battery draining then getting charged later. The car needs software with proper algorithms to monitor a trend and give out a more ample warning. That could only come from Tesla at this point.
Seeing battery draining and voltage dropping are good enough for me. It tells me I need a new battery. The last thing I need are "algorithms"; I prefer to keep it simple!
 
I use this $29 one from Amazon. https://www.amazon.com/gp/product/B01MT4583U/ref=ppx_yo_dt_b_asin_title_o02_s01?ie=UTF8&psc=1

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Works good and automatically synchs (via bluetooth) with the app when I approach the car. Handy to see how many times the car wakes up from a deep sleep. If the battery is charging, the car is awake.

Here is a screen shot of the graph. It shows battery level for the whole 24 hours. The car was awake and charging 3 times that day. The car was not driven that day. The vertical line with "12.68v" is a point on graph I had touched to show the value at that time (20:03 hrs). Just slide your finger along graph to see level for any point in time.

The device holds 30 days of data, so as long as you synch with it at least every 30 days you will have months worth of data.

Note: my battery is original and 2 years old. Still seems to hold a good charge.

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I use this $29 one from Amazon. Works good and automatically synchs (via bluetooth) with the app when I approach the car. Handy to see how many times the car wakes up from a deep sleep. If the battery is charging, the car is awake.

Here is a screen shot of the graph. It shows battery level for the whole 24 hours. The car was awake and charging 3 times that day. The car was not driven that day. The vertical line with "12.68v" is a point on graph I had touched to show the value at that time (20:03 hrs). Just slide your finger along graph to see level for any point in time.

The device holds 30 days of data, so as long as you synch with it at least every 30 days you will have months worth of data.
Nice; I even like this one better than what I have (CTEK). It does more and is cheaper.
 
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lots of discussion on this mate.

to answer your question - YES its worth it to get one of these gadgets.

Low cost way to monitor your 12V Battery

others above here also have posted similar products.

im running a ohmmu battery with a conventional 12v monitor and it does the job you are asking.

if you are worried about your battery failing, may be time to get an ohmmu.. ;)
Yeah I saw that thread - was specifically curious about the types I'd posted since I can periodically check other ICE cars as well. Plus I thought a proper test involved having the car off for at least an hour? Not quite possible w/ the Tesla. Appreciate the input from everyone.
 
if you are worried about your battery failing, may be time to get an ohmmu.
I'm not convinced. I want to buy a 12v that has more capacity than my OEM, 2.5 year old 12v between 13.1 and 12.6 volts. I chatted with Ohhmu at length and will mention two things here (I'll add the entire chat in the Ohmmu thread later):

  1. Ohhmu reduced the size of the battery ~ 1/3 to circumvent the Tesla error issue. They say that the error occurred because the battery Ahr passed was out of spec. Does the 12v circuit even have an Amp counter ?
  2. Ohhmu promised me a discharge test so that I could evaluate their battery but they did not follow through.
 
You've been here since Dec 2018, so you should be able to find the answer to this reoccuring question (replied to on/off here many times since at least Q2/3 2018).

Irrespective of brand, there are inherent differences (mostly pros given the application) between a standard Lead-Acid/Gel/AGM and a LiFePo4 chemistry based cell... especially ones equipped with a BMS, like Ohmmu's v1 and v2 offering.