question

maxtosea avatar image
maxtosea asked

Why PV only produces during high loads?

I have a 2600w solar array all on separate 100/50 MPPT's. On average it's producing around 800w even if my batteries are from 60-90%. But if i turn on a high load it jumps to 1500w. My question is why doesn't it charge at 1500w even when my battery are at 60%?

MPPT ControllersSolar Panel
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Matthias Lange - DE avatar image Matthias Lange - DE ♦ commented ·
More informations about your system are needed.

What components do you have? Settings? Some screenshots?

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maxtosea avatar image maxtosea Matthias Lange - DE ♦ commented ·

I have 4 330ah life-po4 ,smart shunt ,two 12/2000 Multi in parallel, 2 battery Protect 2 Orion 12/30 DC DC charges for alternators, four 545w panels each on own 100/50 mppt, two 160w panels in series on own 100/30 mppt. All my settings are set to life-po4. My mppt setting are 10-14v

But for some reason my PV watts doesn't exceed 8pp-1000 unless I'm using a large load even if the batteries aren't at 100%

Cerbo GX

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maxtosea avatar image maxtosea Matthias Lange - DE ♦ commented ·

screenshot-20230417-041710.png

Here's some

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5 Answers
snoobler avatar image
snoobler answered ·

Always worth triple checking connections.

Is Cerbo DVCC enabled?

If so, do you have a charge current limit set? If so, that's a charge limit, and the GX will not permit charging to exceed that TOTAL value from all connected sources, i.e., if set to 50A, it will prevent all the MPPT and the MP charging from AC-in from sending more than 50A to the battery. Period.

That value does not affect loads. If loads pull battery voltage down, the Cerbo will only restrict charging. The chargers can supply as much as they're able to power the loads.

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maxtosea avatar image maxtosea commented ·

Thank you i did have it set to 50 . What would you recommend the setting be at?

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snoobler avatar image snoobler maxtosea commented ·
There you go. That's why it wouldn't pull more for charging.


50A means 50A * 14.5V = 725W into the batteries. Only loads can force more PV power.


If you do not need to restrict charge current, and with 1470Ah of LFP battery capacity, I would say you don't - you're good to 500A+, turn that feature off unless you want to restrict charging.


The most common reason for this is batteries that can't safely accept the full output of all attached chargers. Lead-acid batteries typically can only take 0.1-0.2C where LFP can typically take 0.5C+, so it's common to use this feature to ensure the lead-acid batteries do not receive excessive charge current. With LFP, this is more often a concern due to a BMS limitation.


If your full PV output + your two MP at full charger output would exceed your battery charge rating, I would limit it to that value.

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maxtosea avatar image maxtosea snoobler commented ·
What about shore power DC chargers and I also have a 5k generator

The Max charge rating for victron 330ah are 400amps. Should I keep it at 300 just to be safe?

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snoobler avatar image snoobler maxtosea commented ·

Isn't each MP only capable of 80A charging for 160A total?

60A on the Orions

2136W in solar for 167A@12.8V

So assuming all chargers are operating at max possible output (They NEVER will)...

387A

1681711498408.png

With 4 in parallel, theoretically you could go to 1600A (minus a little for uneven current sharing).

Even with the recommended charge current of < 150A, 4 of them puts you at 600A.

You are certainly free to limit it however you like, but your equipment can't even deliver the maximum charge current for a single battery, let alone 4 in parallel.


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1681711498408.png (38.9 KiB)
maxtosea avatar image maxtosea snoobler commented ·
Thank you so much. I was going crazy trying to figure this out. We're charging around 1800w now about 90-105 amps
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snoobler avatar image snoobler maxtosea commented ·
You're welcome. I had to use it for the stated purpose - lead acid batteries. My batteries could only handle about 30A input while my array could provide up to 50A.
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maxtosea avatar image maxtosea snoobler commented ·
I have 1 more question. Life-po4 is supposed to go down to 10v correct. I have mine set for 10.5 but whenever it reaches around 11.7 the inverter shuts down saying low battery alarm. I've checked all my settings and even the configuration in the inverters and they all say 10.5.
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kevgermany avatar image
kevgermany answered ·

We need to know your MPPT settings, batteries, how you get the state of charge and any other devices in the system.

First guess is MPPT settings.

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maxtosea avatar image maxtosea commented ·
Moth setting is algorithm 1 10-14

Using the smart shunt for SOC please see comment below. I posted all my devices

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maxtosea avatar image
maxtosea answered ·

I have 4 330ah life-po4 ,smart shunt ,two 12/2000 Multi in parallel, 2 battery Protect 2 Orion 12/30 DC DC charges for alternators, four 545w panels each on own 100/50 mppt, two 160w panels in series on own 100/30 mppt. All my settings are set to life-po4. My mppt setting are 10-14v

But for some reason my PV watts doesn't exceed 8pp-1000 unless I'm using a large load even if the batteries aren't at 100%

Cerbo GX



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maxtosea avatar image
maxtosea answered ·

screenshot-20230417-041728.pngImage Caption


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maxtosea avatar image
maxtosea answered ·

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