Battery Monitoring -- How I Done It --

[Higgidav]

I don’t use my van from week to week so I have put a BM2 on both the starter and leisure batteries. I wanted to monitor the leisure battery when camping and starter battery when parked up so I can better judge when I need to take it for a run.

When the van is running, both batteries are charging well and within normal limits. What surprises me is the voltage and % charge readings on the starter battery when the van is parked up for a few days. After a couple of days I get low batt warnings and when cranking I also always get a low cranking warning.

The state of charge readings and inbuilt app warnings don’t seem to correlate to the tables earlier in this thread. Is this because the BM2 algorithms do not take into account the T6 smart alternator setup?

I am coming to the conclusion that I have to largely ignore the % values and associated warnings and that I should focus on the voltage.

So far I have never had an issue starting the van.

After a long run the starter steadily drops from circa 12.5v to 12.3v over a few days. The monitor considers this as Low.

The cranking voltage is always low at 9.32v.

On the starter battery what voltage can I safely let it fall to? I assume anything above 12.1 ish is ok.

What readings do other get for both cranking and after the van has been parked up for a few days?

I have also discovered that you can change the app alarm parameters. What setting have you got?

 

[Dellmassive]

Dont worry about the cranking alarms etc if the BM2 unit.... (just switch them off)

They are more based around non-stop/start motors, ie standard alternator based systems.

Fyi.... as you can see from the 24hr plots our Van's battery will normally drop to 12.1v rest...... which is normal for this van.

This will slowly decrease over 3weeks or so until it will end up a non starter.

The 12.6v in the chart above relates to a bench tested AGM battery after a 100% full charge...

 

[Dellmassive]

Post some of your 24hr readouta for us to see....

Here's a 24hr readout from the starter battery from 6th march.



.

 

[Higgidav]

22 Feb - parked up on campsite
9th Mar - short run after being parked up for a few days.
10th Mar - still parked up.

Voltage looks similar to other posts. I guess this confirms it’s best to largely ignore the % values and warnings.

Still - what is the minimum the battery can safely be allowed to drop to ?

 

[Dellmassive]

"22 Feb - parked up on campsite" - the glitches are most likely when you open the door and the van powers up/lights come on. (12.4v average)

"9th Mar - short run after being parked up for a few days." - (12.4v average)

"10th Mar - still parked up." - (12.4v average)

"Voltage looks similar to other posts. I guess this confirms it’s best to largely ignore the % values and warnings." - yes those readings look normal

Still - what is the minimum the battery can safely be allowed to drop to ? - below 12v at rest could be an issue, I've had 11.6v after an extended parked up session before, the van still started though.

*****

The BM2 SOC % readout is rough guess algorithm based on a SLA battery. The T6 uses an AGM starter battery . . . . which is kept at or around 80% charged by the energy management system.

so in an ideal world the BM2 would report the 80% SOC level for most of the time.

heres my readout from today. . . .it shows 98% SOC and 12.61v. (which is very good for me, normally its around 12.1v)

pic,




this is dude to the fact i have been driving 4-5hrs every day for the last month due to work... so the battery is well charged fully every day.

pic,





.

 

[Higgidav]

Today’s readings

As noted above I am going to ignore the low power status. Shame this is not configurable.

 

[Dellmassive]

Well after a few delivery issues, I finally have it.


** NEW PRODUCT **

Victron does it again . . . . . . https://amzn.to/3azIA5R

This time with the "Smart Shunt" Bluetooth battery monitor . . . . Yes Please . . .

...


Lithium Battery box install to follow shortly.

 

[Ann3x]

@Dellmassive what would you recommend to monitor both the starter and a Lithium leisure battery? Setup as follows:

• Super B Lithium Leisure battery
• Standard AGM starter battery
• Sterling b2b charger
• Hookup mains charger onto leisure battery
• Trickle charge from leisure to starter via the voltronic box

In the future I might add solar.... not bothered by a physical display but remote connectivity is essential for me. It'd be nice to have status for both batteries & solar in the same app - dont mind changing my b2b if this is easier done all-in-one ecosystem.

Can I get away with just a couple of BM2s or does the lithium make this a problem?

 

[mrdanielmh]

Do all the BM2 units come with the v6 firmware to support lithium or did you get yours from somewhere particular?

 

[mmi]

All late arrivals (since early 2019) have been with V6 firmware. The old ones do not seem to upgrade. I'm not sure if there in the sensor is/can be anything specific to lithium - it's just a voltage sensor. I think it's more down to the actual app to take care of alarm thresholds etc.

 

[mrdanielmh]

Ahh nice! Thanks! I've found the bm2 on ebay for about 18 pound, so i was just hoping it would have version 6!

 

[mmi]

Page Not Found - Aliexpress.com

 

[mrdanielmh]

Well bloody hell! Aliexpress it is! Thank you

 

[Dellmassive]

Victron has released a new Software/APP version that has some interesting new additions.

Plus as always it includes all the unit Firmware updates.

Victron Connect V5.20

Victron Energy

Victron Energy - the professional choice for independent electric power

www.victronenergy.com

VictronConnect v5.20 - Connect & Configure Remotely - Victron Energy

Good day, Two posts in one day, that could be a first! With good reason: in addition to the Venus OS v2.53 release there is an updated VictronConnect as well. And not a small change this time as today we’re adding Remote connectivity to VictronConnect. It enables Victron devices – such as Solar...

www.victronenergy.com

.

.



remember you can now connect to your vans Victron GX MPPT solar or BVM monitors remotely . . . .

If you have WIFI in the van you can use a Raspberbi pi runion VenusOS,

or you could use the Victron GSM module,

more info here: Solar Sheds & Other Non-t6 Solar Projects - How We Done It -

.

 

[Dellmassive]

Victron kit remote monitoring.

I've been using the Raspbery Pi for remote monitoring for a while now and love it. . . . .

The regular SMART kit is bluetooth anyway so local monitoring is already included, but if you want to geek out and monitor things from anywhere then look at these . . .

Raspbery pi setup - Solar Sheds & Other Non-t6 Solar Projects - How We Done It -

***

Im using a SIM card based USB 4G Data Dongle to create a local WIFI in the van (for the NAVI & kids & etc etc etc)

im also using LAN for connections on another unit.

***

if you dont have wifi available you can go GSM with a SIM card based unit.

Here is Victrons GX GSM unit - GX GSM - Victron Energy




.

more victron goodies here : Accessories - Victron Energy


.

for BMV712 temp monitoring you need one of these - Temperature sensor for BMV-712 Smart and BMV-702 - Victron Energy



.


for connections to the GX units you will need these - VE.Direct to USB interface - Victron Energy

.


.

to add Bluetooth to a VE unit (that hasnt got it already) - VE.Direct Bluetooth Smart dongle - Victron Energy




.

 

[Dellmassive]

@Dellmassive what would you recommend to monitor both the starter and a Lithium leisure battery? Setup as follows:

• Super B Lithium Leisure battery
• Standard AGM starter battery
• Sterling b2b charger
• Hookup mains charger onto leisure battery
• Trickle charge from leisure to starter via the voltronic box

In the future I might add solar.... not bothered by a physical display but remote connectivity is essential for me. It'd be nice to have status for both batteries & solar in the same app - dont mind changing my b2b if this is easier done all-in-one ecosystem.

Can I get away with just a couple of BM2s or does the lithium make this a problem?

Yes a couple of BM2 units would do the job . . . (for voltage readings)

your Super B Lithium Leisure battery has a monitoring APP already SOH SOC. ( But you could add a Victron BMV712/Battery monitor)

If you swap your kit out to Victron then its one APP for all . . . . . .BUT id still keep the BM2 units as they (same as the CTEK monitors) keep the history log data, which is very nice.

currently only the victron MPPT has history logging AFAIK.

 

[Dellmassive]

All late arrivals (since early 2019) have been with V6 firmware. The old ones do not seem to upgrade. I'm not sure if there in the sensor is/can be anything specific to lithium - it's just a voltage sensor. I think it's more down to the actual app to take care of alarm thresholds etc.
View attachment 66366

very nice @mmi


i went to the Manufacturer in China . . . and asked why my BM2 unit was showing that it was "charging" when it wasn't.

they then said about the Lithium version? . . .

Because the BM2 units fitted to my Lifepo4 Valence batteries where always showing "charging" due to the higher static voltages . . .

so the idea is that the BM2 firmware is tweeked to show the correct thresholds for low/ok/charging etc.


this was the reply:

*****************************************************

Yes, the different between Lithium Battery and Lead-acid Battery is the firmware.
It's the same App.
Best regards

Joan Zhu

M:+86-15179803791 Tel: +86-755-82821859 Skype: 15179803791

Shenzhen Leagend Optoelectronics Co.,Ltd

www.leagend.com




**************************************************


so i imported 2x BM2 unit direct from them as "Lithium versions" - there was no difference in the packaging or units themselves.


these have been fitted and working fine....


so it seams that the Lithium version/APP report the battery volatge/status instaed od "charging" all the time.

so they now show rest voltage as "battery OK" instead of "battery charging"

So there is no real difference . . . . . appart from theabove....


i did as them for the Firmware to do it myself, but they said no. i had to buy a Lithium FW version. ={


**********************************************************************




---

Bluetooth 4.0 Wireless Battery Monitory BM2 - battery tester-Shenzhen Leagend Optoelectronics Co., Ltd

BM2 is a kind of auto battery monitoring for all 12V car batteries, woks via Bluetooth and mobile phone APP, to check the battery status and relative systems in the cars

www.leagend.com

---

 

[mrdanielmh]

Hmmm that's a bit annoying! I've ordered one, so I'll see what mine turns out to be. I couldn't find a 'lithium' version!

 

[cgtmiles]

Hmmm that's a bit annoying! I've ordered one, so I'll see what mine turns out to be. I couldn't find a 'lithium' version!

I might be interested in taking it off your hands if it’s no good for you

 

[Dellmassive]

They are not selling the lithium FW version openly.

It's just the one BM2 everywhere.

Not even sure if the will.

It's the same thing anyway...