Itâs simply there to prevent contact corrosion ⊠theyâre two different contact surfaces ⊠and it doesnât âscratchâ as much when switching.
Whether with or without grease, the disconnect switches must not become so hot under loads well below the rated current.
Thatâs right ⊠and the flat contact surfaces arenât exactly ideal either ⊠but even 60 degrees wouldnât be a death sentence for a technical contact point ⊠I wouldnât trust it to handle 275 A for long ⊠
hello,
this is a rotary switch and it probably needs a bit of lubrication so that it turns smoothly. It is also not designed to switch high currents; it should only be operated when the power is off!
bye
Very interesting â or rather, a little odd. The contacts look as good as new; was the contact pressure correspondingly adequate as well?
The thing with grease is always a bit tricky. It is supposed to protect the contacts against corrosion, but at the same time it can also have an insulating effect. There is always some left between the two metal contacts, as it is never completely squeezed out. Unfortunately, that reduces the cross-sectional area and therefore the current-carrying capacity.
If it were a very high-quality, conductive material, it might even improve the contact, but this âstandardâ grease can only worsen the actual electrical contact.
You can also see that the contact points are still covered in grease, i.e. there is always grease between them.
What do you mean by contact pressure? The pressure of the contacts in the housing? I have no influence over that.
The switches were simply installed as supplied by a major Victron dealer.
If it hadnât been for the post about the melted housings, this would never have been noticed.
Yes, the pressure between the pairs of contacts.
As a user, you have no influence over that, but the designer of the switch does.
I.e. the copper sheet would have to be pressed firmly against the two bolts, for example by means of a spring, to ensure a proper contact.
I gave up on the disconnect switches and installed new Pylontech cables instead. Since I have to travel 300 km to the system every time, itâs certainly the cheaper option. Iâm now monitoring the busbar with the temperature sensor.
Hi everyone,
We have been installing the Victron 275 A battery switches for quite some time and have had very good experiences with them in the past. We practically never encountered comparable problems with the switches we installed previously.
However, since around mid to late 2025 (we cannot say exactly when), the quality and/or behaviour of the switches supplied has clearly changed. Problems have been occurring with switches purchased since the end of 2025, and particularly those purchased in 2026, which we did not experience with the earlier versions.
We are currently observing two types of failure:
With an estimated almost 20% of the new switches, the cable can no longer be secured reliably during initial installation. The screw can be tightened properly and is firmly seated, yet the cable or connection remains able to move inside the switch. With these switches, it is practically impossible to establish a permanently secure clamped connection.
With another proportion of the switches, the connection is initially completely secure and appears normal when installed. However, after a few weeks or months, the cable begins to loosen and move inside the switch.
The crucial point is this: The mounting screw itself is still tight. This is therefore not a case of the screw becoming loose due to vibration or insufficient tightening torque. Apparently, play develops within the terminal or clamping assembly, allowing the cable to move even though the screw remains firmly seated.
We never observed this behaviour in a single instance with the Victron switches we installed previously.
What makes this particularly problematic is that the fault is initially barely noticeable during operation. From the outside, the screw connection still appears to be in proper order, and the screw itself is tight. Unless the cable is specifically checked for movement, it is not apparent that the connection inside the switch has already become loose.
As the contact becomes increasingly poor, we assume that this subsequently results in significant contact resistance. The consequences range from a substantial loss of powerâwith, in some cases, almost no power being transmitted at allâto considerable heating in the connection area.
With several switches, the plastic around the cable connection has ultimately melted, or the switch has suffered substantial thermal damage.
We consider this combination particularly critical: The screw still appears to be properly tightened, while the actual electrical connection inside is no longer sufficiently secure. The problem can therefore remain unnoticed for a considerable time and only become apparent through a loss of power or thermal damage.
For comparison:
In 2024 and 2025, we installed an estimated 20â30 of these switches each year. In 2026, we installed a further approximately 20 units. A significant proportion of the newer switches experienced corresponding problems or failures within just 2â3 months.
Based on our experience with a larger number of these switches, we can therefore conclude that something about the Victron 275 A switches supplied has definitely changed since the end of 2025. The failure pattern occurs with the newer switches at a frequency that is clearly different from that of the switches we used for years previously.
In our view, it should therefore be investigated in particular whether any changes have been made since 2025 to the design of the clamping connection, the materials used, the internal contact components, or the production or assembly process, or whether certain production batches are affected.
In view of the heating described above and the melting damage that has already occurred, we do not regard this as merely a quality issue, but also as a potentially safety-critical problem that should, in our view, be investigated urgently.
