Problem With Renogy MPPT 60A

[RVAngelus]

Ohms law:

V = I * R

Voltage = Current * Resistance.

Since Current, I = 0A, there should be no change in voltage between the two points. Period.

What can I do?

 

[sunshine_eggo]

What can I do?

Find the problem. Something is wrong between the battery and the MPPT.

At night with NO sun at all on the solar panels:

MPPT reported voltage:
Meter on MPPT battery terminals:
Meter on Battery terminals:

 

[RVAngelus]

Find the problem. Something is wrong between the battery and the MPPT.

At night with NO sun at all on the solar panels:

MPPT reported voltage:
Meter on MPPT battery terminals:
Meter on Battery terminals:

Tomorrow I will disconnect the panels and post the results.

 

[RVAngelus]

Find the problem. Something is wrong between the battery and the MPPT.

At night with NO sun at all on the solar panels:

MPPT reported voltage:
Meter on MPPT battery terminals:
Meter on Battery terminals:

Here are all the tests carried out:
MPPT test connected directly to the batteries without a fuse
Battery 1 (13.25)
Battery 2 (13.25)
Busbar (13.25)
MPPT terminals (13.25)
Voltage indicated on MPPT (13.25)

With solar panels connected and battery directly connected to the MPPT without a fuse
MPPT terminals (13.37)
Voltage indicated on MPPT (13.3)
Battery 1 (13.29)
Battery 2 (13.29)
Busbar (13.30)

 

[sunshine_eggo]

With panels connected, was any current flowing?

Are you using solid wire or coarse strand wire? You should only use fine strand wire with these:

 

[RVAngelus]

With panels connected, was any current flowing?

Are you using solid wire or coarse strand wire? You should only use fine strand wire with these:

View attachment 219221

Yes, the panels were charging the batteries. Honestly, I have no idea about the wire... I should check... These are the ones if it helps (https://www.ebay.it/itm/26641410879...lp:3650466&itmmeta=01HZCWD5CA8GT0N459XVXNJQTG). They are the 10 mm² ones.

 

[sunshine_eggo]

Yes, the panels were charging the batteries. Honestly, I have no idea about the wire... I should check... These are the ones if it helps (https://www.ebay.it/itm/266414108796?itmprp=cksum:26641410879686019fdba0ea4cc08274d017f998b11f|enc:AQAJAAABUPuhkRI%2B91UKQWudeuFB0sxSbl8Kf7q2qAJkBq6SyaHCakjtWkOM6RXwX38EBShHsGnXFLZW44lqs7elgBvFWTvUzfAG7on%2B4P2hmnCEzJt%2Bv5efZJuLU3QdWwNtsCw6mC8k6bFHyjwpTwVNSOHKTlAd9dlL1z5aTGGnd0DqPaG63x5kYQCsUb2N2s%2BVdJImOGYQXWCK5M9lv41Bi2lCxFsDqx6K1LiicIs5%2FZ4hfVkPeHHx5OTF9R2iVXDpjg79IxcI4axWjbnQZAGKFA0VRf1dfXDmxKWbxfRLca6dabYu0Km8itMLFjbfrQVHF6rt1QH0dFtJ2YxaqX8pVcuIdVXy9oWxrhnN1q7ehi2jnoS0DGbJHzOFErroecqygR6s9J9IknsghXYgY8FKo7NAghiirNW4Ej9DCPrO%2F7r9UxHukCNd64cqEQDqmbvvPB2WeQ%3D%3D|ampidL_CLK|clp:3650466&itmmeta=01HZCWD5CA8GT0N459XVXNJQTG). They are the 10 mm² ones.

I suspect you can compare your wire to those pictures easier than I can read Italian.

 

[RVAngelus]

I suspect you can compare your wire to those pictures easier than I can read Italian.

Hahaha, okay, I’ll do it tomorrow! But what’s wrong now? Isn’t it normal for the voltage to increase if the batteries are charging?

 

[sunshine_eggo]

Hahaha, okay, I’ll do it tomorrow! But what’s wrong now? Isn’t it normal for the voltage to increase if the batteries are charging?

Yes, but how much it increases is important.

I was doing an experiment earlier. MPPT reported/terminals measured 14.2V. Battery terminals measured 13.85V. About 20A was flowing.

This 0.35V difference made the connections so hot, I couldn't touch them. I altered the connection and cut the drop to about 0.2V, and the temperature dropped notably.

 

[RVAngelus]

Yes, but how much it increases is important.

I was doing an experiment earlier. MPPT reported/terminals measured 14.2V. Battery terminals measured 13.85V. About 20A was flowing.

This 0.35V difference made the connections so hot, I couldn't touch them. I altered the connection and cut the drop to about 0.2V, and the temperature dropped notably.

Here I am, I imagine it's the fourth type.

 

[sunshine_eggo]

Definitely not fine strand, but not terrible.

What I expect to see when I look at stripped wire is a bright copper color. What I'm seeing with your wire is discoloration. This is typical of corrosion and heat. If I had to make a guess, I would say that wire is burned, corroded or has some undesirable coating on the strands.

If burned or corroded, it could be a bad connection (poor contact or simply loose) in the MPPT terminal.

Can you cut that portion off and strip fresh wire to see what it looks like?

 

[RVAngelus]

Sicuramente non fine filo, ma non terribile.

Quello che mi aspetto di vedere quando guardo il filo spellato è un colore rame brillante. Quello che sto vedendo con il tuo filo è uno scolorimento. Questo è tipico della corrosione e del calore. Se dovessi fare un'ipotesi, direi che il filo è bruciato, corroso o ha un rivestimento indesiderato sui trefoli.

Se bruciato o corroso, potrebbe trattarsi di una cattiva connessione (scarso contatto o semplicemente allentato) nel terminale MPPT.

Puoi tagliare quella parte e spellare il filo fresco per vedere che aspetto ha?

No, questo è un cavo identico a quello che ho installato, e ho scattato una foto solo a scopo dimostrativo. Scusate se non l'ho specificato prima. Il filo installato è in rame pulito; questa, invece, l'ho usata per avviare il furgone visto che era di scorta ed è diventato incandescente.

 

[sunshine_eggo]

No, this is an identical cable to the one I installed, and I took a photo for demonstration purposes only. Sorry if I didn't specify it earlier. The installed wire is clean copper; However, I used this one to start the van since it was a spare and became hot.

understood

 

[RVAngelus]

understood

So what do you think? Is the system okay as it is, or do you think any modifications are needed?


4o

 

[sunshine_eggo]

So what do you think? Is the system okay as it is, or do you think any modifications are needed?

tighten those terminals down hard. If you get the charge voltage and current you expect, and there is no heat being generated anywhere between the battery terminals and the MPPT battery terminals, you should be good.

 

[RVAngelus]

tighten those terminals down hard. If you get the charge voltage and current you expect, and there is no heat being generated anywhere between the battery terminals and the MPPT battery terminals, you should be good.

Ok, thanks for your help