question

scys avatar image
scys asked

150/70 MPPT Fails to Charge

I have recently installed a SmartSolar 150/70 that is managing two 450 watt Renogy panels that are connected in series. The output of the 150/70 is connected to the battery bus. The 150/70 is charging two 300-amphour LiFePo4 batteries wired in parallel. Also charging the batteries is a Victron 3000/120 2x120 inverter/charger. The system is monitored by a Cerbo GX.

Immediately after installation, the solar charging system worked well. My client cycled the batteries to about 50% and the solar charging system was producing between 4 and 5 kWh. Then it stopped, staying stuck in float mode and only sporadically charging.

I have set the solar controller to 14.0 absorb, 13.4 float and 0.1 re-bulk. When operating on batteries with the inverter drawing about 50 amps the battery voltage stays at around 13.1 volts and the 150/70 stays in float mode and produces no power despite 70 volts being available on the pv side. Obviously, it should be in bulk mode and providing as many amps as possible.

I have reset the 150/70 by disconnecting power on both sides of the unit. When I do so, the controller operates correctly for a cycle or two and then reverts to its previous bad behavior.

Given that the re-bulk value is set to 0.1, which should cause the 150/70 to go into bulk mode at 13.3 volts, this feels like a firmware problem, but perhaps I’m missing some other parameter in the system that is overriding that re-bulk parameter.

Any suggestions?

MPPT Controllers
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3 Answers
kevgermany avatar image
kevgermany answered ·

Try a software upgrade if you haven't done it already.

But if that doesn't work, sounds like the controller is faulty.

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scys avatar image scys commented ·
Mmmm. Firmware is up to date.
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klim8skeptic avatar image klim8skeptic ♦ scys commented ·
Post a screenshot of the mppt's settings.

And a screenshot of the mppt's "detailed" history.


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JohnC avatar image
JohnC answered ·

Hi @SCYS

You make mention of an 'Also charger'. If this is on while the mppts are charging then it will interfere with them. This sort of thing can be managed, but requires a little careful attention to set up properly. Please advise if you need help with this..

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scys avatar image scys commented ·
John, testing was done with the inverter/charger in invert mode. There was no charge source other than the 150/70.
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3dclassen avatar image
3dclassen answered ·

I do have a similar behavior on my MPPT 100/50. It´s all working well, but after a while it stops charging. I figured out, that this phenomenon happens, when the battery drops below a specific SOC, I think it´s below 85%, but this is not verified. If the battery is at around 95-100%, all works fine.
On the screenshot you see, that it stopped charging for more than a week

1692600123778.png

I than switched all fuses off, leaving the MPPT without power for about a week, switched all on again and it started charging.


The MPPT has the latest Firmware, all is connected correctly.

Dows anyone have a clue, what could be the problem?
Kind regards,
Daniel


1692600123778.png (36.4 KiB)
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Alexandra avatar image Alexandra ♦ commented ·
@3dclassen

Hi Daniel,

It will be the rebulk offset that triggers the next bulk cycle. So check that

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3dclassen avatar image 3dclassen Alexandra ♦ commented ·
Hi Alex,

thanks for the reply.

I will take a look at it, next time I have access to the bluetooth interface.

Are there any recommended settings for my problem, regarding the rebuld offset?

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3dclassen avatar image 3dclassen 3dclassen commented ·

I do have the exact same problem again, sun is shining and the MPPT 100/50 is not charging.

@Alexandra : Can you explain what the rebulk offest is and how I can retrigger it to charge?


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Alexandra avatar image Alexandra ♦ 3dclassen commented ·

@3dclassen

See re bulk offset explained here in expert/advanced settings. (B ii.)

For lifepo4 I usually set it to 0.1v.

Are you using ESS?

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