Battery Monitoring -- How I Done It --

maybe get some battery terminal covers for the battery,

and cover the metal hold down bar with cloth Tesa tape?

To reduce the risk of any short circuits if the bar rattled loose?

maybe also swap for Nylock nuts to stop them coming loose?
 
@JasonW

what are those white cables on the NEG battery post for?

The BM2 NEG is fine . . . . . but the whites? . . . . shouldn't they be on a chassis ground.?

what are they feeding/connected too?

1609843508864.png
 
Thanks all and @Pete C for spotting this.

My memory is clearly short as I had put some contingency in place but I've also added to this.

See below for pics;

The bar is embedded at each end on the wood, which I can't push it out so I'm confident it will hold it.

The lid also secure the vertical bolts from sliding.

I've also just wrapped the bar in duct tape for good measure!

IMG_20210105_115538.jpg

IMG_20210105_115534.jpgIMG_20210105_115016.jpg

IMG_20210105_115003.jpg

IMG_20210105_115000.jpg

Unfortunately I can't secure the bar on the side as it pulls the battery out of position.

@Dellmassive I did consider that option but it wouldn't fit!

Thanks again all.
 
This is a really helpful thread. I've currently got a Leisure battery with a CTEK D250SA and monitoring both the Leisure battery and the Starter battery with 2 x CTEK Battery Sense. This has worked fine for me (although the CTEK Battery Sense App is really buggy, and often crashes... as well as the scales on the Y axis of the graphs being really stupid and not possible to change).

I'm about to add a solar panel to charge my Leisure battery, and after much thought (and discussion with various very helpful people on here!) I plan to wire that to my D250SA, so that it will also charge my Starter Battery when the Leisure Battery is full.

My question is around monitoring... Do I replace the CTEK Battery Sense with 2 x BM2's? Alternatively, I'd ideally be able to log data from the panel in terms of how much power I'm getting from this... Obviously if I was using a Victron MPPT instead of the D250SA, then I'd be able to do all this directly via Bluetooth, but ideally want to be able to use the start battery charging function on the D250SA... I don't suppose the BM2 gives helpful charging stats (similar to what I'd get from the Victron?). Or do I need to plump for a Victron Battery Shunt? Or is there another monitor that would give me what I'm looking for?

Thanks all!
 
Hi all,
I recently purchased a Ctek battery sense for my leisure battery and found it quite useful info.
So I purchased a second sense for my starter battery. only problem is, after a week, my starter battery was at 80%,
now sits at 28%!! Surely, this little bluetooth unit cant drain that much? Can it?

Originally connected across the battery, then put the neg down to chassis, didn't really make any difference.

Any suggestions??
 
for those with a Victron bmv712.. OR A Victron SmartShunt battery monitor.

there is a new FW v4.05 released.

1612731962144.png

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make sue the app on the phone is updated then connect to the bmv712/smartshunt like normal.

1612731989054.png1612732006586.png




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***


looks like there is a new FW for the Smart Battery Protect as well:

new FW v2.05

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the 65A version

1612732463843.png

1612732479921.png


and 100A version

1612732493926.png1612732502841.png1612732512248.png1612732520929.png

....





...
 
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I love battery monitoring . . . and love it even more when it explains whats going on with your 12v system problem . . . .

well this is one of those occasions. (winter 2020/21)

The 12v system on the solar shed failed, fell over & went offline =[

solar shed project here > https://www.t6forum.com/threads/solar-sheds-other-non-t6-solar-projects-how-we-done-it.16457/


Lets see what happened . .

This is the battery Bank, 2x 100ah SLA Leisure batterys . .


1613126144404.png

they are charged via Solar on the roof and a victron mppt controller (currently a 100/20),

due to the poor winter weather we are having . . . the solar yield is VERY LOW with next to no Watts being produced,

the solar panels are covered in snow, which dropped the MPPT output to 0W.


1613126327131.png

we have LEDs light around the shed and garden that run from the above 12v system,

They are are also controlled via 12v WIFI timer switches, when the lights are running they draw around 2A.

This dayly draw cycle is fine when there is enough solar to recharge the batterys during the day . . . . . but not this day !!

...


We have a BM2 monitor on the battery bank (obviously) that we can read the voltage . . .

this is a Normal day, the battery bank starts at about 12.6v.

Then starts to get some solar charge from 9am to 4pm... (the LED lights run from around 4pm to midnight atm)

1613126643817.png

but look what happens the following day . . .

The battery voltage had dropped to 11.5v . . . . the solar kicked in but just didnt have enough power to recharge the battery bank . . . so by 8pm we was down to 10.5v

1613126748325.png

the same occurs the following day . . .

you can see the WIFI timer shuts off the LEDS lighting around midnight which causes the battery voltage to jump up a bit . .

then the solar kicks in 8am - 4pm

then the LEDS drop the power down again, by midnight we are down to 10v again.


1613126912889.png

the following day its game over . . .

there was snow on the panels that totaly cut any power. . . . so the battery bank stayed at around 10.5v . . .

that was untill about 6pm when the wifi timer kicked in an turned on the LED lights . . . .

within 3hours it had dropped the battery bank voltage to down below the min 9v the BM2 can read . . .

now strangely enough it was at this point that i noticed something was odd? . . . the Garden LEDS were on . . . . but very DIM?

it was about 2330hrs when i went out to see what was going on, sure enough the voltmeter in the shed was reading 8v !!! still enough to run the LEDs!!

1613127166815.png

at this point i had to get the batterys charged again before they were damaged permanently . . . i had the CTEK MSX5 in the shed and clipped it on.

you can see the imitate response, the battery voltage rises to 13v . . . (just before midnight)


1613127294413.png


you can see the chargers effect on the BM2 the following day . . the charger takes the battery up to around 14v in bulk stage,

them moves to absorb stage at around 1430hrs,

you can see the effects of the lights switching back on again at 1800hrs.


1613127330782.png


the following day we are back to normal . . .

the EHU charger is still connected and keeping the batterys maintained at around 13.6v

you can see the LEDs switching on around 1800hrs and off around 0030hrs.

1613127548805.png

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same cycle the following day . . .

1613127573312.png


..



ill leave the EHU Charger connected till the sun come back, hopefully around march 2021.


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heres some more of the monitors running in the shed . . . the BMV712 shows the battery back now at 100%, the orange mark at the top relates to a FW update due . .



1613127693672.png1613127711697.png

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we have a local VE Network running in the shed, The BMV712 is sharing data with the MPPT and SmartBatterySence.

that can be seen here:

1613127758780.png


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smart battery sense monitor look like this:

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and the Victron local BT devices seen from the APP>

1613127894490.png


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So why show you this . . . . . ?

well this is exactly the same as what's happening in your Van with its 12v system.

whether its the starter battery or leisure battery, you can see that running 12v loads causes the battery to drain down.

you can see that the battery need charging, either by alternator, EHU or solar etc.

you can see the effects of running loads on the battery's voltage,

and what happens you connect your charger.



have a look at these bits that i used in the shed :

Bm2 : Quicklynks Battery Monitor BM2 Bluetooth 4.0 Device Car 12V Battery Tester: Amazon.co.uk: Car & Motorbike
CTEK MXS 5 : https://amzn.to/2Z9ZQv1
Victron mppt : Amazon.co.uk : Victron mppt
Victron bmv712 : Amazon.co.uk : Victron bmv712

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if your wondering what the Raspberry Pi is for . . . . well it connects the Victron kit to the cloud, so you can have remote access and data logging like this . . you can see how to do that over on the solar shed thread.

Victron kit is awesome =]



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@Dellmassive Do you know what caused the fairly rapid drop in battery voltage here (from your post above), between 2am and 8.30am? My Leisure battery in the van has started doing the same thing occasionally.


"The battery voltage had dropped to 11.5v . . . . the solar kicked in but just didnt have enough power to recharge the battery bank . . . so by 8pm we was down to 10.5v

1613126748325.png
 
Also, the green % charged/full figure on the BM2 - it goes up, as the voltage figure goes down. i.e. still having issues with my portable solar through the CTEK. The supplied PWM took the battery from 11.8, to 14v (according to the BM2) and it showed 89% full. I switched the panel to run through the CTEK = no orange charging light, green flashing power saving light, voltage on the BM2 dropping to 12.4v, but the green % figure on the BM2 app screen rises to 99%.
Confused.
 
@boxelder

These reading are relevent to the state of charge of the battery...

Ie if the battery was very low and you put 2hrs of solar in... its still a very low battery..... so even with a minimal power draw the voltage will plumet.

What I would do here is connect the battery up to a decent smart charger for 24hrs.... so you know the battery is 100% charged.


Then over the next 24hrs and 48hrs monitor the drop in voltages.

Have a you got a decent charger?.....

70ah battery AGM may take 10 hours on a 7A smart charger.
 
Have a you got a decent charger?.....
No, but figure I'll need one if we can't get out more soon. So the rapid drop on your monitor trace is just when it reaches a critical low voltage and drains ever more quickly?
After a few hours of solar, it's reading 12.9V and 100%. Presume that % just relates to voltage level.
 
@boxelder

if you are referring to this pic . . . (from to solar shed above)

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then yes the rapid drop is due to the battery being very low . . . there was nothing left in the battery.

the % SOC on the BM2 is more a guide line for older style SLA wet flooded batteries . .

AGM & EFB+ batteries hold a much higher voltage so can make that reading look a bit off . . .

what's more important is the time vs voltage chart (like above) . . . that will show what happening.

+++

remember a charged AGM can show 12.8v or more. . . even when its very low on capacity.

i tend to think of batterers as buckets of water . . with a pipe or tap at the bottom.

1616862130272.png


when you charge them to 100% its a bucket full of water . .

The water pressure at the bottom tap is the voltage.

the amount of water flowing through the tap is the current.

as the bucket drains out the water there is a slight reduction is the water pressure (as there is less weight of water pushing down) - same is true in a battery and voltage (the voltage will drop slightly as the battery drains),

now imagine the bucket is almost empty . . . the pressure will be less as less water pushing down (same for the battery. its almost empty but there is still some pressure or voltage reading)

also imagine your solar power putting a few pints of water back into the bucket . . . . it will up the pressure slightly - but its not filling the bucket up to 100% . . . its still mostly empty. (this will show as a slight rise in voltage . . . but the bucket is still mostly empty)

at this point its time to leave the solar connected for a few days - to keep adding pints back into the backet . . .

or

Connect up a smart charger to the battery for 12-24hrs - which is the equivalent of taking the bucket to a tap and filling it up to 100% full.

...


im my graph above the garden LEDs had over a number of days, drained out more power than the solar could put back in per day . . (due to winter)

the net effect was that the battery just run flatter and flatter every day . . . until the point where it was flat and the voltage fell off the cliff.

...

1616862210503.png
 
@boxelder

have a quick look at the charger thread . . .





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