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 . .
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.
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 !!
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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)
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
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.
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!!
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)
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.
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.
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same cycle the following day . . .
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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 . .
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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:
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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>
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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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