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humax avatar image
humax asked

MPPT 75/15 does not charge properly until kick stated

Hi,

I have a strange problem I hope someone can throw a light on...... The Victron MPPT 75/15 is running with a 160W solar panel on a campervan. The battery is a LifePo4 and the correct profile and settings are configured. I have a BMV712 and Smart battery protect 12/65, Blue Smart IP22 12/15 mains charger and Battery to Battery charger for when on the move. The BMV and MPPT share battery and voltage using VE.Smart. The voltages and currents quoted below are from a slightly overcast day and the battery 90% full.

The MPPT enters bulk mode OK but just sits there providing from 0 to 0.5A charging current with sun on the panel. The panel is at 20V to 22V.

screenshot-20210525-114538-medium.png

If I disconnect the solar panel and reconnect, the MPPT sits as it should be in the off position with over 25V as it is off load at this stage. The MPPT then wakes up into bulk mode, the panel voltage falls to 20V to 22V and the zero or low current resumes.

If I disconnect the solar panel and inject a 25V power supply into the MPPT it comes alive into bulk mode after a few seconds as it should and starts charging at 3 to 4 amps depending on the battery condition, etc. Once I have the MPPT kicked into life, I can disconnect the power supply, reconnect the solar panel, wait a few seconds for bulk mode and the MPPT is now putting in 4 to 5 amps.

screenshot-20210525-115504-medium.png

Same wiring, same settings, same solar panel, similar skies. If I disconnect the solar panel and reconnect after waiting a few seconds, the MPPT pauses as it should but will start up again and works fine.

It will stay in this working mode happy charging away all day until light obviously goes. The next morning it will sometimes charge properly but most often the same kick start process has to be used to bring it back to life.

I have tried factory resets, latest MPPT firmware and even the current v5.42beta2 in cast that fixed anything. The solar panel is providing enough voltage (>5V) above battery and the panel will deliver the current once the MPPT is kick started.

I am confused. Is the MPPT faulty? Is there anything else I can try? Thanks.

MPPT SmartSolar
screenshot-20210525-114538-medium.png (95.1 KiB)
screenshot-20210525-115504-medium.png (98.5 KiB)
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4 Answers
humax avatar image
humax answered ·

Any ideas?

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justin-b avatar image
justin-b answered ·

I have a very similar problem. I don't have to inject any voltage. I just have to disconnect all loads, then it will start charging and providing power when the loads are re-connected. The next day it'll go dormant until I do the disconnect/reconnect thing again! Have not figured it out!

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sek avatar image sek commented ·

Same problem for me, not charging if the load is connected and drawing power.

start charging whenever the load is disconnected...

very annoying...

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klim8skeptic avatar image klim8skeptic ♦ sek commented ·
@Sek Open up a new question and supply the details about your system.


Battery voltages, PV voltages and current. Details of PV panels.

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sek avatar image sek klim8skeptic ♦ commented ·

Hi @klim8skeptic I did open up a question a few days ago but no reply to it...


I have to add all the details you mentioned still.


https://community.victronenergy.com/questions/235842/mppt-7510-not-charging-battery-while-load-is-conne.html


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johanndo avatar image
johanndo answered ·

Do you use any signals from your BMS to control the charge (DVCC and such?)

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kevgermany avatar image
kevgermany answered ·

It would be good to know the battery specifications/type and the battery settings in the MPPT as screen shot from the cog icon.

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