Vistron Mppt error 26

[fermat]

HI, new here. I need some advice. I have installed on my sailboat a solar array to tend my house batteries.
I have: 3 LG 330w(pmax) mono solar panels. I have seen them generate up to 1006w out in the Fl keys.
I have 3ea LiFePO batteries(275ah ea). The panels are tied(in parallel) to the MPPT (victron 150/70).
The panels are wired to the MPPT and the MPPT to the Battery bank.
Recently I had, over 11 days, 3 errors on different days. Two were consecutive days and the third was 11 days later. Each time the charge cycle never completed. Twice the MPPT remained in Bulk phase and the first time it went into absorption but never Float.
Each time the error presented it showed as Err 26 (Charger Terminal Overheat). {VICTRON: Power terminals overheated, check wiring, including the wiring type and type of strands, and/or fasten bolts if possible.}
I do not have a battery charger in the system. I thought the MPPT handled that part.
Anyway, I was hoping for some feedback. TY

 

[rmaddy]

What size wire do you have from the SCC to the batteries? For a constant 70A load you should be using at least 4AWG marine grade high quality pure copper stranded wire rated for 105ºC.

Also make sure your SCC is mounted correctly with proper spacing around it for ventilation.

 

[chrisski]

I got this from the manual about needing to use finely stranded wire so it can crush flat for a good contact area:

https://www.victronenergy.com/upload/documents/Manual_SmartSolar_MPPT_150-70_up_to_250-100_VE.Can/MPPT_solar_charger_manual-en.pdf

 

[rhino]

You should check exactly what the error says to check. Also, if you think the cables are being stressed at all from movement you can get a wire box for the Victron solar controllers. The wire box doesn't just protect the terminals from being touched but also adds cable clamps that press against the insulation of the cables to add extra level of protection against the cables being pulled out.

 

[HRTKD]

A loose connection could be the cause. Remove the cables from the terminals and check for scorching on the cables and insulation.

Depending on the voltage of the battery when you being charging, you may be hitting the output amp limit of the MPPT.

Can you post a picture how the solar charge controller install?