Battery testing for geeks.

5364 Views 19 Replies 8 Participants Last post by Witek_M, 7 mo ago

Witek_M

Discussion Starter · Jun 30, 2018 (Edited)

For all you geeks out there here is quick look at BM2 battery monitor. Works with Android and iOS. Voltage readout very accurate +/- 0.02V, power consumption 1mA. Stores 30 days of voltage history with sampling rate of two minutes.

Here is main interface. CTEK 0.8A battery charger connected.

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Witek_M

Discussion Starter · #2 · Jun 30, 2018 (Edited)

24 hour battery voltage graph.

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Witek_M

Discussion Starter · #3 · Jun 30, 2018

Cranking test. Shows voltage drop while cranking. With app in foreground it saves last two cranking test automatically.

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Witek_M

Discussion Starter · #4 · Jun 30, 2018

Closeup of voltage during start. Key on, crank, start, air pump comes on causing drop, alternator goes live in 2.5 seconds. One could use scope to get more details but this is good enough. Ripple while cranking shows individual cylinders going through compression stroke.

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Witek_M

Discussion Starter · #5 · Jun 30, 2018

Here is 8 years old Optima battery I have found while cleaning garage in January. Absolutely flat. Charged it with 10 amps charger for 24 hours until charger went into maintenance mode. Disconnected charger, within 5.5 hours voltage dropped to 12V. Reconnected charger, within 30 minutes charger went to maintenance mode. Conclusion, battery has zero reserve capacity. Good for a door stop as it is heavy as hell.:smile

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mattml430

· #6 · Jun 30, 2018

That’s pretty cool. I might get one. Gives some good details about the battery.

Sent from my iPhone using Tapatalk

pte

· #7 · Jul 1, 2018

Thanks I like it & good info. Cheers PTE

khomer2

· #8 · Jul 1, 2018

Nice info post. Cheers.

Reactions: 1

mercbentz

· #9 · Jul 2, 2018 (Edited)

Witek_M said:
For all you geeks out there here is quick look at .... Voltage readout very accurate +/- 0.02V, power consumption 1mA. Stores 30 days of voltage history with sampling rate of two minutes.

Here is main interface. CTEK 0.8A battery charger connected.

Very nice.

Is it showing info as graphs, or you had to do some data post processing?

It's nice to see more and more useful tools....

Take the opportunity to point/show sort of same type of info, collected with the Autel MaxiDiag Elite MD802 MB Scanner live data - "EAM Misc/T15/T15C/T15R/Circ 50" - and uploaded on the Autel MD802 thread.

It is showing Battery Voltage fluctuation during Key going in ascending order from Key OFF, to Key in Position 0 to Position 1, to Position 2 (engine not running) and Position 3 Crank, followed by descending Order: Key in Position 2 (engine running), along with State of Terminal 15C, 15R, 15, and 50, etc....

mercbentz

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Witek_M

Discussion Starter · #10 · Jul 2, 2018

mercbentz said:
Very nice.

Is it showing info as graphs, or you had to do some data post processing?

Those are actual screenshots from the phone. I had to resize them so this forum would not choke on 2880 x 1440 images.

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Kajtek1

· #11 · Jul 6, 2018

New toy I add to my buying list.
Took me over a year watching reviews before I bought Solar tester.
Witek could you measure parasitic draw of the gizmo?
I wonder if you can leave it on car park for a week or 2.

Witek_M

Discussion Starter · #12 · Jul 6, 2018

Kajtek1 said:
New toy I add to my buying list.
Took me over a year watching reviews before I bought Solar tester.
Witek could you measure parasitic draw of the gizmo?
I wonder if you can leave it on car park for a week or 2.

It is 1 miliamp. My 280SEL sits in storage since March with one of those connected. Battery voltage dropped from 12.96 V to 12.69 V.

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Witek_M

Discussion Starter · #13 · Aug 15, 2021 (Edited)

2

Latest software update brought new feature. You can look at voltage history over 1, 7 or 15 days.
Wife drives twice a week. If that much.
Four day inactivity. Voltage starts at 12.73V, drops to 12.56V. Battery is 3.5 years old.

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mattml430

· #14 · Aug 15, 2021

Is this similar to the monitor you have connected to the battery. I want to grab 2 of them for the old cars that sit for weeks at a time.

www.ebay.com.au

12V Car Battery Monitor via Bluetooth 4.0 Voltage Meter Tester LowVolt Alarm | eBay

Find many great new & used options and get the best deals for 12V Car Battery Monitor via Bluetooth 4.0 Voltage Meter Tester LowVolt Alarm at the best online prices at eBay!

www.ebay.com.au

Witek_M

Discussion Starter · #15 · Aug 15, 2021

mattml430 said:
Is this similar to the monitor you have connected to the battery. I want to grab 2 of them for the old cars that sit for weeks at a time.

12V Car Battery Monitor via Bluetooth 4.0 Voltage Meter Tester LowVolt Alarm | eBay

Find many great new & used options and get the best deals for 12V Car Battery Monitor via Bluetooth 4.0 Voltage Meter Tester LowVolt Alarm at the best online prices at eBay!

www.ebay.com.au

Exactly that.

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Witek_M

Discussion Starter · #16 · Nov 21, 2021

2

Quick voltage readout from BM2 compared to $300 DMM.

Battery after overnight rest. Very close.

Product Temperature Measuring instrument Gauge Gas

After around 15 minutes with headlights on. It is so close it is scary.

Electrical wiring Communication Device Gadget Telephony Audio equipment

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khomer2

· #17 · Nov 21, 2021

BM2 works great - installed in all the rides here for quick easy B testing.

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22glc300amg

· #18 · 7 mo ago

Witek_M said:
Quick voltage readout from BM2 compared to $300 DMM.

Battery after overnight rest. Very close. View attachment 2723874

After around 15 minutes with headlights on. It is so close it is scary.
View attachment 2723876

Excellent

Deplore

· #19 · 7 mo ago

Witek, do you have to have the android/iOS device connected the entire duration you want to keep track of the battery info, or does it store it inside its own memory and then you can just interrogate it via android when you connect to it?

Witek_M

Discussion Starter · #20 · 7 mo ago

Deplore said:
Witek, do you have to have the android/iOS device connected the entire duration you want to keep track of the battery info, or does it store it inside its own memory and then you can just interrogate it via android when you connect to it?

No. It stores ~three months worth of data in its own storage. When you connect with new device that data gets retrieved. Takes a few minutes.
Problem is that once someone else connects to it that connection is exclusive. No one else can connect to it. In garage queen facility you need to ask everybody to turn their BT off so you can connect to your own vehicle. Not a big deal but something to keep in mind.

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