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samin8r avatar image

MPPT 150/70 Once battery full wont all come back on line to charge?

Hi Guys

I've been having dramas in regard to 5x MPPT's charging in the morning fine but once battery is full (BYD Lithium's) they wont come back and charge when battery percentage drops and load increases? Usually one out of 5X will charge but the rest sit at small Wattages (5w 8w etc.?)

These are coupled to a CCGX and utilise a USB hub.(Industrial)

Any help would be appreciated as I have tried all sorts of fix's?


Regards Tim

MPPT - Solar Charge ControllerBYD
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@samin8r, Just to clarify the situation as I am also interested in the answer to your question.

Are you saying?

When the load increases it is being supplied jointly by the battery and a single MPPT and not by the available PV power through other available MPPTs when this happens?


Yes that's basically it. It seem when we turn on the air conditioner which is a fair load 5kw+ 1X MPPT will work and the others seem to drop off and it will start drawing of the battery?

samin8r avatar image samin8r Guy Stewart (Victron Community Manager) ♦♦ ·

G'day Guy

How have you been? That would be great if you wouldn't mind?

Did you still have my details?

I noticed when my wife turned off the ac this afternoon and restarted some time after 4x out of 5X came back on line?

Regards Tim

5 Answers
JohnC avatar image
JohnC answered ·

Ok, leaving aside the hub issue. Given your mppt's aren't synchronised, they'll produce to a V target independently. Call it 'manufacturing tolerance', but in practice some will reach it and wind back earlier than others.

Your screenshots are actually quite useful, and 'ccgx2' shows 2x 'wound back' at an up-there 55.82V. I'd actually expect that to happen. And it won't hurt anything, if that's what you want for your batts.

If they didn't wind back up when the V dropped, then you would have a problem. The mppts will only see V, not SOC or anything else.

Note I'm assuming a simple system, and if you're using firmware addons, then say so and the experts can wade in.

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John

By simple system this is a DC coupled off grid system. Not using Firmware addon's (assistants) .

I have tried to keep it simple in that respect.

samin8r avatar image
samin8r answered ·

The most I could fit directly is 2X USB's and possible one VE Direct to the CCGX.

The issue is all the MPPT's will work when charging the battery but once the battery is full it then drops two to three MPPT's off no matter what the AC load is?


ccgx1.jpg (180.6 KiB)
ccgx2.jpg (376.6 KiB)
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That picture shows a full battery that is not discharging. So there is nowhere for the additional MPPT solar to go?

The other MPPT’s likely won’t pick up again until the battery voltage drops.

samin8r avatar image samin8r Guy Stewart (Victron Community Manager) ♦♦ ·

Guy

Do you think that the Voltage setting is set too high in the parameters?

Should this be adjusted lower?

This was from memory at another setting but Victron sent out an update with the BYD batteries stating it was to be changed some time last year?

JohnC avatar image
JohnC answered ·

The usb hub is worth a harder look at if you haven't already. It should be externally powered, is it getting power, etc.

'Weakness' here could explain your symptoms. Have you another you could try?

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yes I have swapped different brands used cheaper ones had the same issue.

The one Im using is more reliable than the others and it is powered 12-48vdc in.

Have some serious ventilation on all components as it has been quite hot here (46C) max mostly early to low to mid 40s.

I do plan to put a RC A/C to cool and regulate all components. in future.

Could this be it really?

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samin8r avatar image
samin8r answered ·

Yes all MPPT's are set to the same numerical setting for the battery type.

The model of the Regulator is the 150/70.

All units have been updated to the latest firmware.

Running a CCGX and VRM. Open circuit voltage is 110vdc

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Paul B avatar image
Paul B answered ·

Tim are all the MPPT units set to lithium battery type,

whats the open circuit PV voltage and

what is the model of the Solar regulator

are they all on the same version of firmware (maybe check each one using a victron bluetooth dongle and the victron connect app, when the mobile phone is connected to the internet)

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