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woodysranch asked

MPPT 75/25 to Power Station

I have a portable 200 Watt Mono PERC panel with these specs
Voltage … Open 26.72V, Working 21.5V;
Current … Open Max 9.35A, Short 9.79A

I have a standalone Power Station by BougeRV model Fort1000 1120Wh. The power station has a PV input with specs max input 8 Amps, 12 to 30 Volts. I would like to connect the panel direct to the PV input on the power station, but I am worried that it could exceed the max input current of 8 amps.

The customer service folks at BougeRV tell me the power station has a built in MPPT, but are advising me that I must not connect a panel that would exceed the input limits of the power station. I bought a Victron 75/15 and limited the amps to 8, connected this to the power station, but was told this might fault the power station.

Here is what they said to me – which makes no sense at all.

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The power station itself has a built-in MPPT. If controllers that already have MPPT are connected together, mutual exclusion will occur in the power station as the final end of the solar input, causing the power station to trigger the protection function and stop working, causing unnecessary damage.

Your MPPT can change the current control within 8A, and the voltage will drop accordingly, but the final key is the problem of the two MPPTs.

With the Victron connected, it will be limited to 8A, but it does not ensure that a solar panel above this current will cause irreversible damage to the power station when connected.

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Can anyone tell me what BougeRV is talking about with this Mutual exclusion thing.

Can anyone explain what could possibly be wrong with using the Victron 75/15 to provide a controlled input to the power station of 8 amps

MPPT Controllers
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klim8skeptic answered ·

@WoodysRanch Can anyone tell me what BougeRV is talking about with this Mutual exclusion thing.

You can not connect the output from 1 mppt to the input of a 2nd mppt.

Hook the battery output of the victron mppt directly to the battery (with a fuse close to the batt).

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woodysranch answered ·

Since the Power station is completely enclosed, you cannot access the battery terminals directly. You must connect the Panels to the PV input.


It would make sense that the built in MPPT would limit input amperage to the max it can handle, but the company is not disclosing that it will do this.

What is the risk of connecting one MPPT to another?

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klim8skeptic avatar image klim8skeptic ♦ commented ·

@WoodysRanch What is the risk of connecting one MPPT to another?

In order of severity,

It wont work very well

It wont work at all

It may damage one, or both mppt's.

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woodysranch avatar image woodysranch klim8skeptic ♦ commented ·

Unfortunately a few months ago when there was sun, no snow and when I was not smart enough to think there could be a problem I connected to the Victron 75/15, updated firmware, set max amps to 8, connected it to my Power Station, put the panels in the sun and observed that the current was constrained to 8 Amps. I only did this once, and apparently got away with it because everything is still working and the power station was recharged, then went to float mode.


So now that I cannot /should not use the 75/15 in this configuration, should I expect the built in Power Station MPPT will limit the current to 8 amps, or do I need to fuse the connection? If I fuse it, what value?

I expect since the max current solar panel output is just under 10, it would need to be almost ideal sun conditions to generate max solar power output, so most of the time there wouldn't be a problem..

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