Battery Monitoring -- How I Done It --

[Dellmassive]

heres mine and testing. . . . BM6 Battery Monitor.






scan the QR code for the new APP.



which is called BM6




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it comes with a sticky pad and fork terminals for the battery connection.



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i cut the terminals off and wired into my starter battery fuse box. . .






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in the APP. . .


you get a new choice of battery types including Lithium.




running the APP for a few days we have these plots. . .

the history chart / calender shows options for 1,3,5 days. . .

I've asked support if they can add in 15 and 30 days like the BM2.


this is the battery voltage view for 5days . . .and same as BM2:




then we have the TEMP data . . . Nice =]



then the controversial SOC (state of charge)

this will be an approximation derived from the voltage and some software algorithms . . . . so time will tell how accurate this is.

though you can set a custom profile that can be tweaked to get a better readout for the SOC.




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here is the 1 day plot.

voltage:



one day plot for Temp:



and 1 day plot for SOC:





...

live data will give you this. . .




they have kept the

crank and charge monitors - which i never use and switch off.




they also kept the alarm notifications. . . which again i dont use.





APP version wise we are on: V2.3.0 build 30



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[Dellmassive]

for the few people that say they had a BM2 has fail. . . ( was it @Loz & @mmi )


within the APP under settings -->About --> Feedback


there is a option to contact Leagend customer support.

+++

they are China based so normally reply over night UK time.

they are normally very good at replying.

and in most cases will continue support via email.


........




.........





i have a few ideas for them to improve the APP.

adding 7/17/30 days is a start.




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[Jamie89]

@Dellmassive Thanks for all the content youve put out, its a good read! A few months have passed since you tested the BM6, whats your thoughts on it now? Better than the BM2?

 

[Dellmassive]

@Dellmassive Thanks for all the content youve put out, its a good read! A few months have passed since you tested the BM6, whats your thoughts on it now? Better than the BM2?

well its the same . . . but better, as it now includes the Temp data.

the only gripe i have is the long term history as in 7 days and 15 days is not available. ( hopefully a FW fix?)

it offers 1,3,5 day plots.

but no problems if you allow the unit to sync in the background. - then you will have a full calendar full of data ( you can only view 5 day slices at a time)

but you can export data to excel etc . . . . that's good.



+++

 

[Lukefx]

@Dellmassive is it ok to connect the negative feed for the BM6 directly to the negative terminal? From reading a lot of your posts you say not to connect anything to the negative. Or is that just things that have a load rather than a monitor? Thanks.

 

[Dellmassive]

@Dellmassive is it ok to connect the negative feed for the BM6 directly to the negative terminal? From reading a lot of your posts you say not to connect anything to the negative. Or is that just things that have a load rather than a monitor? Thanks.

Yes the battery monitor is ok direct across the battery as it's a very small power draw compared to the size of the battery. ( Provided the van is a daily driver and not left parked up for months)

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However I have since moved my bm2/bm6 over to my own starter battery fuse box that has its own NEG that I took from the light bracket. (Shown earlier in this thread)



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[Lukefx]

Yes the battery monitor is ok direct across the battery as it's a very small power draw compared to the size of the battery. ( Provided the van is a daily driver and not left parked up for months)

.

However I have since moved my bm2/bm6 over to my own starter battery fuse box that has its own NEG that I took from the light bracket. (Shown earlier in this thread)



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Thanks. I don't have a separate fuse box like yourself and need the monitor as I'm getting some power draw from the starter battery so need to keep an eye on it. I've only got the DC DC charger on the battery so I'm not sure that's enough to drain the battery but I like the idea of having that and the leisure battery on the app.

 

[archersam]

Possibly daft question however would this device let me know if there is drain (either auto or manually by logging in)?

I have a relay for my foglights under the seat (hardwired on a separate swtich). Whilst adding amp etc and then testing I found a new drain. Various items I added I had removed and eventually worked out it was a relay sitting at 0.27 instead of its normal 0.00/0.01

I would rather know about a drain without having to scheule a drain test on the off chance and I know how much you guys rave about this product so thought would ask.

 

[X77GAP]

Great posts as ever @Dellmassive , one stupid question, i have fitted a BM2 last couple of days, should it dor a standard EFB starter battery be set to regular lead acid?

 

[Dellmassive]

Glad you like the threads.

I'd set it to AGM battery.

That's a closer profile for the EFB battery.

 

[X77GAP]

Glad you like the threads.

I'd set it to AGM battery.

That's a closer profile for the EFB battery.

Cheers @Dellmassive

 

[Dellmassive]

some nice xmas break plots added over here:

Battery drain

The draw is low enough it's possible to wire directly, and there is some argument this gives the best chance of an accurate voltage reading. I would however try and add a fuse to the wiring, having seen the inside of a BM2 I'm not really comfortable at the separation as per my post here...

www.t6forum.com

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[Dellmassive]

I finally got my hands on the new Victron IP65 Smart shunt. . . .



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its the new version of the smart shunt, now ip65 rated.

no screen or relay outputs like the BMV712.

but apart from that just as capable.. . .

and im lead to believe has more features over the BT.


ill be fitting a Global 520 unit soon - so keep an eye out for that.


the idea being that the Global 520 and talk over BT with the Smart Shunt, and Smart MPPT and Orion XS dc-dc and REEVO temp sensors . . . meaning that we can now do away with all the VE-direct data cables. - sweet !!

so here is my first look. . .




it has the same M10 terminals




tbc . .

 

[Bigsidavies]

So here’s a crazy one with my Renogy 100ah lithium battery.
After the van hadn’t been used for a few days the lithium battery was dead. Nothing would work on 12v system and the Renogy app couldn’t find the battery.
I knew that a few days earlier the battery had been 92% so I plugged it in to the Victron charger and hey presto it came to life showing 92%. I didn’t pay attention to any other readings.
Fast forward a week and same scenario.
However, this is a screenshot of the Renogy app. Showing 92% charged but only 11.4v and warnings for being under voltage. Bizarre.


What’s the best next step to correct presumably a BMS error?
Should I apply a load (fridge) and let it actually go flat? Or should I put it in charge with the Victron blue smart 12/15?
@Dellmassive any thoughts?

Edit, tried to run fridge and diesel heater and both cut off due to low current. So decide to charge the battery see what happens.
I’ll keep my eye on it. Don’t want it overheating.

 

[Dellmassive]

So here’s a crazy one with my Renogy 100ah lithium battery.
After the van hadn’t been used for a few days the lithium battery was dead. Nothing would work on 12v system and the Renogy app couldn’t find the battery.
I knew that a few days earlier the battery had been 92% so I plugged it in to the Victron charger and hey presto it came to life showing 92%. I didn’t pay attention to any other readings.
Fast forward a week and same scenario.
However, this is a screenshot of the Renogy app. Showing 92% charged but only 11.4v and warnings for being under voltage. Bizarre.
View attachment 226369

What’s the best next step to correct presumably a BMS error?
Should I apply a load (fridge) and let it actually go flat? Or should I put it in charge with the Victron blue smart 12/15?
@Dellmassive any thoughts?

Edit, tried to run fridge and diesel heater and both cut off due to low current. So decide to charge the battery see what happens.
I’ll keep my eye on it. Don’t want it overheating.

yes your BMS is out of calibration . .( it thinks its 90% but really is 10% so flat)

this happens with the BMS self discharge or very small loads that the BMS cant detect. ( the Renogy cant detect loads less than 500mA)

a common symptom with an easy fix - just fully charge the battery.

you need to connect up the charger for a good 24hrs or more to fully charge it.

more info:

Lithium LifePo4 12v Batteries - Time For An Upgrade?

and a B2B charger a solar panel an MPPT some cable some heat shrink bus bars chrimper cable cutter stripper( we'll talk about that one later :rofl: ) mega or midi fuses..........it don't matter which type of van you have a combi a camper what ever.....there always gonna be a whole host of...

www.t6forum.com

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[Bigsidavies]

Cheers Lee @Dellmassive. I was just worried that if the BMS was wrong and the battery IS actually at 92% then it will overcharge and get damaged.
It’s on charge now and taking 15a but only 13v. The Victron is set to Lithium profile.

 

[Dellmassive]

Your fine... The battery won't let you over charge it...

I'd expect your charger to log a good 90ah go into that battery, going by the 11v odd you mentioned.

 

[Bigsidavies]

Your fine... The battery won't let you over charge it...

I'd expect your charger to log a good 90ah go into that battery, going by the 11v odd you mentioned.

Yeah it put 50Ah in yesterday. I’ll put it on again today and see what it pumps in. Cheers.

 

[Dellmassive]

Yeah it put 50Ah in yesterday. I’ll put it on again today and see what it pumps in. Cheers.

just keep going until the charger goes into float mode, - its classed as full when its taking in less than 1A.

i normally restart the charge and make sure it moves to float within a few mins - then you know its charged properly.

the battery BMS will then recalibrate to 100% SoC.

 

[catfood12]

The BM2s are such an amazing piece of kit for the money. I've had them since I first saw the @Dellmassive 'How I Done it' thread.

Regular voltage sampling, a great display and days of data logging. Like a very expensive bit of lab kit!

See my exciting plot below. Purple trace is a lead acid on a Cetek, see the way the conditioning works, with a switch off, then stepped higher voltage charge at 15:00. Blue trace shows an AGM battery and a couple of journeys then a spell on a Cetek, again see the conditioning waveform. Very clever!



I'm using the hacked Multi Battery Monitor V2.0, and whilst it still works, I now get unsupported Android version error messages since the last Android UI6 upgrade.

I'd never seen the BM6 until this thread, so just ordered one from Amazon for testing....