Installing an inexpensive 12V battery monitor

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electriceddy said:
12.6 V is a good floating voltage, battery appears to be good SOH
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Thanks for that confirmation. I was a little worried about the big dip down to 12.15V after shutting the car off. But I guess some systems were drawing from the 12V battery for a bit before shutting down? At least now I can keep an eye on it. :)
 
Toolworker said:
Has anyone been able to prevent the BM2 app from running in the background on Android? I only want it to run when I start it myself.

It is on the Settings list of Always Sleeping Apps, but keeps running anyway and keeps a notification showing, including on the lock screen. If I kill it, after a while it pops up again.

Is there any reason not to turn off notifications? Are any of the alarms useful? The Power Alarm might be if it can measure SOC, but it probably triggers on voltage.
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I am getting concerned about the Android app. I was suspicious because it defeats the prohibition on running in background, so I rummaged around.

One of the reviews on Amazon says "It requires all kinds of permissions from the phone and downloads all kinds of Chinese tracking software just to run a bluetooth app." Does anyone know how to judge the credibility of that?

I can say that it has used over a megabyte of data bandwidth since I installed it, and I see no need for that. It asks for storage access permission and doesn't seem to need it; I disabled the permission and my data is still there.
 
Robbert said:
... I turned the car on for a little while, and the voltage shot up to 14.3V (charging). After turning the car off, the battery dropped to 12.15V, and has slowly crept back up to the 12.57V over the last hour.
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The voltage tends to be somewhat elastic after either charge or discharge but 12.15 is a bit low. You can see here where I entered run mode for 30 sec to change the charge limit setting. The draw on shutdown does take a bit off the top and you can see how long it took to recover in the next event when an overridden-timer traction battery charge started. The glitch at 1800 is when I opened the rear hatch cover.

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Toolworker said:
I am getting concerned about the Android app. I was suspicious because it defeats the prohibition on running in background, so I rummaged around.
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I use both types of phone for this and the Android used about 850 KB data but I did have location enabled, now disabled. I did find this comment from the developer in the app reviews:
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KiwiME said:
I use both types of phone for this and the Android used about 850 KB data but I did have location enabled, now disabled.
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Yes, I now understand that location can use internet.

I wasn't able to connect to Bluetooth with location disabled; were you? Both the app and Android say it's required to access Bluetooth starting with Android 6.0.
I did find this comment from the developer in the app reviews: ...
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Yes, the developer replied over and over that we can put BM2 on the list in Settings - Battery that prohibits it from running in background. But that's a bunch of BM. I did that, but I back out of the app using back-arrow and the notification remains that it's still running in background, even on the lock screen.

When I force the app to stop, that finally kills it. But a few hours later it is back running again.
 
The app did not restart by itself, or at least I couldn't find it in Settings, Device car, Memory after sitting overnight.
 
KiwiME said:
The app did not restart by itself, or at least I couldn't find it in Settings, Device car, Memory after sitting overnight.
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I hadn't seen it restart for several days. Then I went to the garage this morning and was fiddling with the charge cord, plugging and unplugging it. I walked outside the garage, looked at my phone, and there on the lock screen ...

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Perhaps it wakes up every so often, looks to see if it's near the car, and decides that it wants to run whether I want it to or not. And once started it has to be killed manually.

I can't ever see it in Settings, Device, Memory even after taking it off the Always sleeping apps list. But the KillApps app does show it running, until I kill it. And it persists in the notifications (Clear doesn't remove it) and on the lock screen.
 
This monitor stinks. My 12v battery died again. I thought, at least I will be able to see exactly what happened and when. Well, no such luck. When the 12v supply went away, it lost its stored data. Not a particularly clever design for a piece of test equipment.
 
KiwiME said:
Well, why not, nothing else to do ... 1.8 mA with no connection or 2.5 when monitoring with the app. When initially connecting it goes up to 3.5 for a few seconds.
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Thanks, @KiwiME. So power consumption a bit more than 1 Ah / month, which is down in the noise with everything else the car does.

Toolworker said:
This monitor stinks. My 12v battery died again. I thought, at least I will be able to see exactly what happened and when. Well, no such luck. When the 12v supply went away, it lost its stored data. Not a particularly clever design for a piece of test equipment.
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I tried an app that keeps the screen on, but it's no use. Leaving the BM2 app running with the graph screen up, it still won't read data - only when going from the home screen to the graph screen. If you want data, you've got to go get it yourself.
 
I love the damn thing but I haven't had any battery failures either. Note also that there there are many posts on this so any question you might have has likely already been answered.
 
KiwiME said:
I love the damn thing but I haven't had any battery failures either. Note also that there there are many posts on this so any question you might have has likely already been answered.
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I'll order one tomorrow, spent enough money today :-p
 
Just got my BM2 from AliExpress and ready to hook it up and give it a try. But just read through this thread and concerned about running in my phone background (Android). I have enough apps already draining it (have to charge almost every day), and don't want to add to that problem.

How is it working now for you guys? Is it a heavy drain on your phone? And does the disable work, or does it keep coming back on?
 
Why would you need to run an app in the background if you're not polling the monitor all
the time? Maybe I'm missing something, but you can always go into settings -> apps and
force-stop the thing.

I charge my Android phone *maybe* once every week and a half or longer. It runs almost
nothing while it's just being a phone.

_H*
 
hobbit said:
Why would you need to run an app in the background if you're not polling the monitor all
the time? Maybe I'm missing something, but you can always go into settings -> apps and
force-stop the thing.

I charge my Android phone *maybe* once every week and a half or longer. It runs almost
nothing while it's just being a phone.

_H*
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I was under the impression with past posts on this thread that it would keep starting up to run in the background even after force stopping it. But from what you say, doesn't take much anyway, so not to worry about it. Thank you for your response.

I am going to hook it up for a while to my Kona EV to see how it charges the 12V. I have never had a problem (like some others on this forum), but just curious to see what mine looks like. The BMS update was done earlier this spring. However, I have another ICE car that is driven much less frequently, so more concerned about that battery. It might be an interesting comparison, too.
 
R P said:
I was under the impression with past posts on this thread that it would keep starting up to run in the background even after force stopping it. But from what you say, doesn't take much anyway, so not to worry about it. Thank you for your response.
Click to expand...
I haven't looked into it for a while, so my memory is foggy. But I seem to recollect that it turns on location services (maybe needed for Bluetooth), places a permanent notification on the screen, and there are some mutters in the app reviews about sending location data back to China.

Please don't take these as assertions, just vague recollections, and someone correct me if they're wrong. But at one point I did have a reason for uninstalling the app from my phone and putting it on an old spare smartphone that I leave on a charger in the garage, just to monitor the battery.
 
I accidentally stumbled on this little gem, a Hyundai-branded bluetooth battery monitor! Perhaps they've finally realised there's a market for this sort of thing. And it's visibly fused, always a good thing to avoid annoying questions. This will look way more legit in my car when the tech spys it.
It seems to draw more current but can work down to 4V so that's an improvement.
I downloaded the app (iOS) and it doesn't find the BM2 but otherwise the menus look identical enough that it's clearly from the same manufacturer. The specs are not clear about the logging period or memory duration (BM2 is 2 min and 1 month, resp).

Amazingly I can order it locally. It's $79 so I think I will get one to check it out.

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