Annual servicing

I had a heat pump installed last year, and today the installer did an annual service. Apart from flushing the fluid to the buffer tank and checking expansion tanks etc, he also checked electrical connections for tightness.
This impressed me and when I mentioned it, he explained that sometimes various high frequency vibrations may be set up which have a tendency to loosen things. They do this check for the first year, at least.
It occurred to me that DC connections for solar and batteries could probably benefit from similar checks, especially in view of some issues reported here. Having said that, my 2021 installation still seems to be ok (fingers crossed, AC3 + 2x8.2kWh). The heat pump is a 9kW Panasonic.

Just to be a pedant 😄 but you are unlikely to get the vibrations with DC (I'm not an electrician BTW) because the current is direct - it doesn;t oscillate whereas AC does and this can cause things to loosen.

I've worked on numerous electric motors including electric vibrators ( screens that separate different sizes of stone etc ). Often the electrical terminations are packed with a plasticine type material which is remarkably efficient at damping vibrations.

wrefordj that’s a great installer to pick up on the vibrations. We’ve found distribution boards arcing away because screw connections have vibrated loose, and we’re a family of electrical engineers so we’re pretty aware of these things.

Modern office buildings tend to use rising busbars with tap off connections at each floor. It is far simpler than big cables to each floor.
https://www.se.com/uk/en/product-range/6760-canalis-ksr/#overview

The busbar typically comes in 2 or 3m lengths and bolted together.

I was involved with fixing the ITN building in Gray's Inn Road in London in the 1980s/90s. Harmonics in the building electrical system was causing some vibrations in the bars. The bolts had loosened leading to poor electrical contact between sections. This lead to increased resistance and heat, which lead to more expansion/contraction/movement, which loosened the bolts more - you can see where this is going. All the busbar had to be replaced.

Busbar joints should be regularly checked with an IR thermometer/gun and torqued up correctly

CW Agreed. Maybe it's the temperature cycling that does the damage?

@SteveCook interesting. I was in the Port Authority offices in Wisbech. They have a vertical helical wind turbine. Resonance? In a moderate wind you don't even need to stir your coffee.

wrefordj i had mine installed by Octopus on 23/11 though it took another month to make it work consistently. Yet to hear from them about Servicing

Roy124 Had my givenergy setup 3 years in January and zero servicing suggested or done. As mentioned earlier the solar panels don’t need anything, as as long as the roof angle is reasonable they will self-clean.

geoffreycoan Wish my pigeons would recognise this and stop testing the theory!!

geoffreycoan I took the 5 year option. Free for year one and basically a maintenance check annually with work as required.

CW we had to pay out for anti bird netting as jackdaws took a liking to the cover but objected to the cables.

We have our panels washed annually by the window cleaners, £2/panel.

No idea what difference it makes but we could see the dust and pollen flowing off.

Roy124 We have our panels washed annually by the window cleaners, £2/panel.

No idea what difference it makes but we could see the dust and pollen flowing off.

i’ve posted it previously, but here’s the annual generation from our 4kW FIT array:

2016 2,904
2017 2,815
2018 3,211
2019 3,029
2020 3,216
2021 2,945
2022 3,152
2023 3,064
2024 2,977

As you can see, goes up and down year to year. No noticeable drop off that I can see over the years either due to panel degradation or dirt. Since fitting in January 2016 (two blokes on ladders, no scaffolding, how times have changed), they were never washed or any maintenance.
When we had the scaffolding up for the GivEnergy panels to be fitted I took the opportunity to jet wash the panels (gentle setting). A bit of lichen in a few spots around the corners of the panels, but nothing significant. The roof tiles were much dirtier and did get a proper clean.

My conclusion that it’s not worth washing the panels. At £2 a panel that would cost me £88!