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Geomz avatar image

Why did my MPPT controllers shutoff

Hello,


I have 300AHs of lithium storage, attached to a Quattro 5000/120V/24V, a pair of SmartSolar 100/30 controllers, and monitored by a BMV712, integrated into an ESS system.

Everything was working great until, for some reason yesterday, both mppt controllers suddenly stopped charging the batteries. I only noticed that because that behavior continued into the morning when I noticed there was no solar input even in bright daylight.

No matter what I did, I could not wake the controllers to start charging again. At that time battery SOC was ~40%.

Eventually through some combination of restarting the Quattro, disabling the chargers using VictronConnect, and unplugging the ve.direct cables I was able to get them to cooperate.

When I unplugged the ve.direct cables, they would eventually behave in standalone mode and begin bulking (although even that wasn’t working correctly as they vacillated from absorption to float. The battery voltage was nowhere near the set points for either state.

Plugging the ve.direct cables back in returned the controllers into their errant behavior.

At the time, the absorption light on the controllers was blinking... let’s call it sporadically.

I’d like to understand what happened. From what I can tell, somehow it thought the batteries reached absorption voltage (which they didn’t) the day before. And that errant behavior continued well into the morning when I had to “jiggle the settings”, as it were, to get it working again.

No grid power was involved (no AC in) in this scenario, running purely off batteries and solar.

Can someone explain this behavior to me?

I’ve included some VRM screenshots (from either controller, the same) showing the point it shutdown.

There were no errors reported on the CCGX or on the controllers themselves.


Thanks in advance for any help.



MPPT - Solar Charge ControllerESSLithium Battery
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I don't know, but just observations..

..Your 'Mppt State' is under 'External Control', so it's taking it's orders from elsewhere. Maybe a bms or assistant or suchlike.

..Seems everything is a little 'unstable/undecided'. Might be just your loads prompting that, but you didn't post those.

..In your [288] chart, there's a current dip every 10 min, which is likely just the mppt tracking coinciding with the data sampling (ya get that sometimes). Safely ignored, but it does mean that the mppt is still trying to maximize.

This may not help much, so call it a bump.. good luck tracking it down.

1 Answer
blond2silver avatar image

I would check the following:

If within CCGX - If you are sourcing the overall system configuration on the BMV-700 or 712 battery monitor and temperature is enabled and the DVCC setting for STS is on, I would recommend checking MPPT configuration setting to sure low temperature cuttoff is set to the desired temperature cutoff value.

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