question

n0ga86 avatar image

MPPT Solarcharger 250/100 is stuck in absortion

3 days ago it suddenly switched from Bulk to absortion (the orange light slowly blinks) and it wont go back to bulk and wont charge the batteries nor produce what the house consuming in energy.

There's voltage coming from the FV to the charger but 0 A, so it wont produce anything.... the wiring seems fine and everything else looks also fine, I dont know what's wrong and would apreciate any help.


>Spanish inquire<

"Buenas tardes,

hace una hora que mi sistema se quedo pillado en absorción y no carga absolutamente nada desde FV.... adjunto foto y pantallazo.

Revisé todos los cables, tornillos, diferenciales, reinicié el inversor.... no se que mas hacer.

Quisera añadir, que cuando el sol se pone al gestor de carga no lo llega voltaje des de las placas (2-3 voltios solamente) y a la que el sol sale recibe 220-230 voltios 0A y nada de carga, intermitentemente marca como si le llegaran 5watts pero solamente muestra ésa carga de 5 watts durante unos segundos.

Ya contacté con el instalador ayer pero no obtuve respuesta por su parte.... si alguien sabiera a que puede ser debido o que comprobaciones puedo realizar le estaré eternamente agradecido."


fv-no-carga.jpgmppt250-100.jpg

MPPT - Solar Charge Controller
fv-no-carga.jpg (39.5 KiB)
mppt250-100.jpg (32.4 KiB)
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8 Answers
Mark avatar image
Mark answered ·
  1. Are the any errors logged when you check via VictronConnect or the GX device?
  2. Are you sure that the PV voltage hasn't ever exceeded the 250V max PV voltage limit? As that will permanently damage the MPPT, you can check via VictronConnect or the GX device (it is shown in the the 'Overall history' screen).screenshot-20210802-175001-chrome.jpg
  3. The wiring you are using for your battery connection looks like it is only ~4 or 6mm² - this is way too small and unsafe to carry a 100A current. It may have overheated the terminals and internal circuitry. I highly recommend that you rectify this before you start a fire.

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michelg avatar image
michelg answered ·

Hola, que tipo de baterias tienes y a que voltage funciona tu instalacion ? Lo que te sugiero es desconectar todas las fuentes electricas que llegan al MPPT, es decir paneles Y baterias. Te esperas unos 5 minutos, reconectas baterias. y despues reconectas los paneles.

Que tipo de paneles tienes, cuantos, y como van conectados al MPPT ?

Otro problema importante, es el tamagno de tus cables que van a la bateria, son de 6mm2 y insuficientes. Eso puede provocarte un incendio por el calor que van a generar con altos amperios. Buscate cable de 35mm2 (tipicamente cable para soldar) y pon lo para ir a las baterias.

Me paso algo parecido, pero en mi caso fue el corta-circuito de 125A que se estropeo y tuve que cambiar lo.

Ya diras si esto te soluciona el problema. De mi punto de vista, el MPPT se habra sobre calentado, y desconectado en un modo para protegerse.

Michel

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tengo 15 paneles monocrsitalinos eleksun de 370 watts sino me equivoco
JohnC avatar image
JohnC answered ·

Hi @n0ga86

I note too that the mppt is under "External Control". We would need to know what that is?

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n0ga86 avatar image
n0ga86 answered ·

Hello,


and thx for the answers, it under a color control unit.

It didnt report any error as far as I can see, and the batteries we use are 7 pylontech us2000.


About the wiring it was what the installator have chosen to use, we are complet ignorants.... I can say that the unit used to heat up, I dont know if beyond whats normal o not...

How should we proceed? reseting the unit by unplugging everything?


img-20210802-104734-resized-20210802-104834602.jpg

img-20210802-104709-resized-20210802-104835292.jpg

img-20210802-104702-resized-20210802-104835846.jpg


+


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n0ga86 avatar image
n0ga86 answered ·

The overall history


img-20210802-105518-resized-20210802-105537897.jpg


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Hi,

If I understand correct, your PV voltage is way too high and your charge controller wires are undersized. The unit has overheated already. How many panels do you have in serial and how many parallel string do you have ?

Mark avatar image
Mark answered ·

Even though the MPPT does not have an error at the moment, I can see from the error history that BOTH Error #26 - Terminal Overheated and Error #33 - PV over-voltage have occurred. Both these errors are 'self clearing', but depending on the severity of the issue/event that caused them it may still have resulted in permanent damage of the unit. These 2 errors are in line with what I suspected, based on the 2 images you shared in your original question.

I can also see that the max PV voltage recorded in the history is 249.9V; while that is technically 0.1V under the 250V PV voltage limit, it is possible that the PV voltage could have momentarily 'spiked' above this level (due to cloud edge effect) without it being logged. The 250V max PV voltage limit is a 'hard limit' and the PV array must be selected/arranged to leave an appropriate margin to this limit (factoring in increased PV open circuit voltage in extreme cold temperatures). Your current PV array configuration has no margin at all and is not acceptable (particularly if the controller is overheating at the same time from the significantly undersized wiring).

I recommend that you engage a qualified and competent installer to review your system and as a minimum:

  1. Reconfigure your PV array to reduce the open circuit voltage to an acceptable/safe level for this MPPT (that likely means removing a solar panel from each string, and possibly making up a new string from the orphan solar panels)
  2. Review and upgrade wiring as appropriate, the wiring from the MPPT to the battery is well undersized and totally unsafe

In terms of determining if your MPPT is permanently damaged, I would recommend to:

  1. Temporarily disable any 'external control' of the MPPT so that it operates as a 'stand alone' unit, to eliminate that as the source of the issue - the simplest way might be just to temporarily disconnect the VE.Direct cable and connect to the MPPT via the VictronConnect app (to monitor output)
  2. Disconnect all power sources to the MPPT (battery and PV), wait 3 minutes and reconnect

Only perform the above if you are confident that you know what you are doing, if not also refer to a qualified and competent installer for this troubleshooting.

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I'd try a reboot of the CCGX from the screen first. Just in case, you never know..
n0ga86 avatar image
n0ga86 answered ·

img-20210803-084257-resized-20210803-084402344.jpgimg-20210802-174321-resized-20210803-084401200.jpgimg-20210802-174315-resized-20210803-084403424.jpgOk someone came yesterday and did check many stuff.... luckily we didnt set anything one fire, we're fixing it all by tomorrow (fingers crossed).


We're runnin 3 paralel series of 5 PV panels each. (see pic. for details on the PV panels) Should we reconfigure it to 4 parel series 3 of 4 panels and 1 of 3 panels?


Right now the installer that came yesterday will only shiwtch the wirings from the MPPT to the batteries and the inverter for a 16mm2 wires. Should he reconfigure the panels also in order to have more margin in the Voltage aspect on the MPPT?



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I would be questioning the use of 25mm cable between the inverter and batteries, seeing the recommended size would be 70mm?

multi-dc-cable.png


multi-dc-cable.png (95.0 KiB)
from the inverter to the batteries 70mm?? isn't that massive? i have 16,8KWh in storage is that enough to justify that diameter?
There are 2 factors in play.

Voltage drop along the cable length. (Copper cross section)

Insulation heat resistance, (re catching fire when the copper heats up.)

0,5m of wire from the inverter to the batteries, and the insulator can resist up 105ºC, at least that's what the cover of the wire states.

Do the calculations, Voltage drop calculator.

Surely Pylontech has recommendations regarding paralleled batteries?

I'll use the calculator with they guy that's coming to switch the wires to day, which will finally be 25mm2, so I can work cuz atm we've sucking up the batteries since friday and are now at 35% we need to charge them.

After that we'll contact some authorised installator and rethink the whole installation and wiring properly.

It so frustrating.... :(

I am out of advice.

Please contact Pylontech and confirm battery to inverter cable sizing.


It is a false economy to compromise on the wiring/installation - it will only cause issues and cost you more in the long run. The wiring recommendations are carefully calculated and provided for a reason.


There is also no way that the cable length between your MultiPlus and the batteries is only ~0.5m. I can tell just from the photos that you provided that the positive and negative cable lengths are ~1.5m each = ~3.0m total length.


The wiring needs to be sufficient gauge to handle the fuse/circuit breaker current rating. Again I don't know what size (VA) MultiPlus you have, but if it's a 5000VA 48V unit then you should be using a 200A or 250A fuse/circuit breaker to a) not blow/trip under 'peak power' conditions and b) protect the wiring in case of a fault.

It probably is 1,5 meters each wire as you said. The MultiPlus I'm using is the 48V 5000VA 230Vac.

I know that's not the place to ask for all of this, but since my knowlege is 0, and I did pay someone to do all this job because I dont know anything about it and it seems they've done it all worng, I need to know what's wrong and what should be improved, so I can really know that they are not doing some crappy work.

With the ones I've been talking now, when i mentioned to replan the series of PV panels, they told then we would have to switch the wires from the PV panels to the charger because we would vary the A if the configuration is changed, so that gives me a lil more confidence but I wanna be sure they get all right.


And thanks again for all your feedback.

Your system came very close to starting a fire from this photo...

1627977103164.png


This forum is NOT the place for detailed system design, that should be up to your dealer and/or a qualified and competent installer - but I do have significant concerns with all your wiring (and also with the proposal to upgrade the MPPT to battery cabling only to 16mm²).

I don't know what size (VA) your MultiPlus/Quattro is, but even with a smaller size model in a 48V system the current 4AWG cabling (which is ~21mm²) is not sufficient - refer to the recommendations in the MultiPlus/Quattro manual. This can also cause all sorts of other issues like DC ripple and unexpected low voltage shutdown.

The MPPT charge controller has an 100A max output to the battery, but you are only planning to upgrade the wiring to 16mm². I can confirm that 16mm² cabling will become warm even at a constant 50A current and it is normally (depending on type and test spec) only rated to ~90A (before any derating factors are applied). The MPPT terminals accept upto 35mm² cable and that would be my recommendation.

A photo of the MPPT wiring from one of my systems, before the wiring cover went on:

1627978419690.png

Yes, your solar array configuration also needs to be revised, the Voc of those panels is 48.3V, so you are up to ~241.5V before you consider the effect of increased voltage in cool temperatures.

Also you cannot make up a 4th string of only 3 panels if all other strings have 4 panels (the sting voltage must match) - you will need to to either buy an extra identical solar panel or re-wire to have 5 parallel strings of 3 panels in series (or not use the orphan panels).

I also see no DC fusing (at least no fuse between the MPPT and MultiPlus/Quattro), so the list goes on.

Again your installer should already know all of this, if they don't it may be best to look elsewhere.

Have you figured out if the MPPT is permanently damaged yet?

1627977103164.png (1.3 MiB)
1627978419690.png (1.2 MiB)
it's not permanently damaged, i reseted it and works, but I have PV panels shut down since I get the wiring replaced.


I shall speaek with some other installers then... I can't understand how the installer that made me the installation in first place got it all wrong.....

I'm glad to hear that your MPPT survived - I think you got lucky that the outcome was not worse.


Good luck with finding a competent installer to properly correct all the issues and make your system safe and reliable.
Thanks for the help and the support.
n0ga86 avatar image
n0ga86 answered ·

One more doubt, since my inverter is the 48V 5000VA it shouldnt be able to deliver more than 100A when charging the batteries, (which right now could suck up 175A) checked pylntech data.

And the MPPT 250/100 shouldn't be able to deliver more than 100A either, is there anyway that Amperage could rise otw to it's destination? being this the inverter or the batteries? The lenght and diameter of the wire could affect that amperage?

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