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pvwkombiwanderer avatar image
pvwkombiwanderer asked

Control maximal Charge Current from SmartSolar MPPT 150/85 with BMV 712

Dear Victron,

I have installed an oversize PV System in relation to the battery in my car (Old VW T2), which I use to demonstrate PV opportunities in Indonesian rural areas. (https://www.instagram.com/pVwKombiWanderer_t2/). All installation is private financed by us and we try to promote renewable energy to rural places in Indonesia without any payback. But step by step the local media ask us for interviews and talks in the television and we start our blog in Indonesian on YouTube :D

1. The Panels can produce 1,16 kWp under STC. Size was chosen based on the maximal allowed space on the roof.

2. SmartSolar MPPT 150/85 charge my battery with an additional SmartBatterySense and BatteryProtect BP-100.

3. Just one Luminious SMF 12V 200h is installed due to weight and lack of space (I know this is not ideal, but it is an old car and 69 kg for each battery is just really heavy)

4. SUOER FPC D1000A Pure Sinus Wave Inverter (1000W continuous power/2000W peak power)

To increase the maximal life-cycle of the battery under tropical high temperature I reduce the maximal charge current to C10, which means 20A. When I demonstrate it to the people I put some big load to my Pure Sinus Wave Inverter. Since my PV System can easily produce more than 80 A on the 12V site at daylight, I need a device which can change the maximal charge current depends from the load.

The BMV 712 can easily read the current and direction of the current which going in and out of the battery and it can be easily connected via Bluetooth to the other devices.

Is there a possibility to drive the MPPT from the SmartSolar MPPT 150/85 with the measured current from BMV 712 so that the net current to the battery is limited to 20 A?


Or is there another device which can do this which is available in Indonesia, because Victron parts I bring directly from Germany? I didn't buy the BMV on those time due to lack of money, but now because of the response and the interest I need a solution.

It is so great to see the people step by step understanding renewable energy and with my background as a physicist i can explain them a lot :D

I am really happy for any advices or helps.

Thank very much.

Best regards,

Pelangi

BMV Battery Monitorsmart solar set-up helpSmart Battery Sensecharge current limitcurrent limit
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6 Answers
wkirby avatar image
wkirby answered ·

You cannot do this directly between BMV and MPPT.

You can do this if you enable DVCC with a Venus device like a CCGX or VenusGX. The good news is that you can also use a cheap Raspberry pi as a Venus device

DVCC is explained in the manual here:

https://www.victronenergy.com/live/ccgx:start

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pvwkombiwanderer answered ·

Thank You WKirby :D

So if I understand what i read about the topic, i need additional a BMV (whatever, cause bluetooth is not supported yet), Raspberry pi with Venus OS and two VE.Direct to USB cable as hardware.

Did i understand it right?

For me it is not clear yet, because this is written in the manual

Color Control GX manual ->

4.4 DVCC features for all systems ->

Limit charge current ->

:

3) DC Loads are not accounted for. Even when a BMV or other battery monitor is installed. For example, with a configured maximum charge current of 50 Amps, and DC Loads drawing 20 Amps, the battery will be charged with 30 Amps. Not with the full allowed 50 Amps

What is than the different to the actual situation, because my DC/AC Inverter have no output information for Venus OS?


Will Bluetooth supported in the future in the Venus OS to avoid the VE.Direct to USB cable, since my batterysense and smartcharger already support bluetooth?

Instead of BMV can I use another shunt?

If what I understand is right, i still need to get BMV and the VE.Direct to USB cable to Indonesia.


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pvwkombiwanderer answered ·

Dear Victor Community,
three months ago I just installed BMV 712 and raspberry pi with Venus OS to my system. All components is connected via VE.Direct to USB. Finally I got those components from Europe.

The Venus OS 2.60 included Node Red. I turn on DVCC with maximal current 20A.
My SmartSolar already have the newest version 1.53 and I see that the SmartSolar see the current from the BMV via VE.smart too.

Will the SmartSolar now produce more than 20 amp if it’s needed for the DC loads but always be aware that the battery just can be loaded with 20 amp?
Did I need additional programming in Node Red?

If yes, can you please give me an example please?

I am looking forward to hear your answer, advices and remarks.

Please stay always healthy.

Best regards,

Pelangi

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pvwkombiwanderer avatar image
pvwkombiwanderer answered ·

Dear Victron team,

At one point my battery have always this behavior.

Did I damage my battery now?

The battery is a one and a half year old 200 Ah Luminous deep cycle battery.

Please give me some of the advices.

Best regards,

Best regards,

Pelang

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2c3497d8-2328-4e33-98c0-cd57462fe359.png (97.0 KiB)
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pvwkombiwanderer avatar image pvwkombiwanderer commented ·

At the deepest dip point The VICTRON battery protector take action And disconnect all loads. After that the voltage is recovered, but if I connect the loads again the battery will make the same dip again and again, till the battery recharge by the sun again.

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pvwkombiwanderer avatar image
pvwkombiwanderer answered ·

Did I write something wrong, so nobody try to answer anything?

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JohnC avatar image
JohnC answered ·

Hi @pvwkombiwanderer

Your battery is probably still ok. Your issue really stems from it not being big enough. That V-sag in your graph is caused by too large a load, by my quick calculations about C5 (or 0.2C, 40A) rate, which also will affect battery longevity. Without a Victron inverter DVCC can't help you with the charging, as everything is read as a dc load.

If you're going to keep doing this, consider opening up your mppt to max and limiting it's (battery) charge by lowering it's Absorb target. Depending on temperature, you may find that limiting to maybe 13.5 - 13.8V is necessary, but I wouldn't be too concerned about seeing up to 40A, as this shouldn't last long with the batts self-limiting.

That way your mppt will wind up as it can under external load, if it has sun. You'll need to experiment of course, but I'm sure you'll find a suitable spot. With your BMV and rPi you at least have good data.

Sorry, I can't help with Node Red.


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Related Resources

Additional resources still need to be added for this topic

Additional resources still need to be added for this topic

Smart Battery Sense Product Page

Smart Battery Sense Manual


Victron BMV battery monitors product page