Inverters - in the loft or elsewhere?????

[polo1]

Hi all,
I'm interested in views/evidence about the options for locating the inverter. I appreciate that the majority appear to located in lofts, but why?

As I understand it, keeping the inverter close to the panels reduces "transmission" losses, but that the higher ambient temps in summer have a detrimental effect on the inverter over time. Is there evidence to support loft location as the (long term financially) better option?

Just a humble spark, who has no plans to start installing, but I am considering getting a system installed in my own home....and I like to understand the pros/cons of different approaches!

Regards.

 

[SolarCity]

If you can, stick it in your garage. If you can't then install it outside. Install it in the loft if you absolutely have to.

 

[Markc]

Inverters in lofts will run and run. The right choice of inverter for a loft is OK in my book but it also depends on access. Like a boiler in a loft access to the appliance has to be considered. Boarding, loft ladder and good lighting. Hand rail around loft hatch in some circumstances also.

Inverters outside on a house wall is last option as far as I'm concerned as it looks nasty and some insurance companies will not pay out if it isn't directly noted that a component of this value is outside. Like a mountain bike in the garden shed for example.

Inside the dwelling garage, utility room etc is option A or B but the down side here is the DC route and the possibility of contact with high DC voltages. Losses on the DC side can be overcome easily so no real concern here but if someone was to cut into a DC cable thinking it to be TV coax then bang. Possibly 600V or more DC.

So the choice is yours. Loft, House or outside.

 

[Worcester]

1) Garage
2) Outside
3) Utility if not too dominant
4) look for somewhere
5) Final case loft

So far, with owners help, I've managed to find a non-loft location 90% of the time.

 

[TonyL]

Depends on the loft temp pre PV by my reckoning

The house faces almost due south with not a shadow in sight on a sunny day. I opted to have the inverter in the garage because of the tremendous summer temperatures in the loft prior to PV. No kit likes heat/cold cycles and the inverter seems to be the high risk item. What I, and no one else, realised was that the shading from the panels has dramatically reduced the temperature resulting from sunshine. So it could have gone in the loft.

The advantage is that you minimise the 12v cable run. O level physics tells you that power loss over 12v is higher than 240v. Evo did some calcs and convinced me it was a marginal thing (3% over 18m). They also used 6mm rather than 4mm for the 12v run.

But since PV is all in the = or - 1% efficiency game, I may well have opted for the roof had I realised this.

Have just clocked up £1,436 in FIT since late March in the Midlands using a 4kw array (Sharp 245 + Sunny 4000TL).

 

[polo1]

Thanks for the feedback guys. It looks like so much of PV - you pays your money......!

The difference between loft and garage is only about 5m, so I think it will be garage for me, with perhaps 6mm cable. There is little risk of accidental damage to the cabling, as it will be contained internaly within a soil stack chase.

Cheers.

 

[Worcester]

@TonyL

Not quite sure where you got your 12Volts from

Strings run nearer 600V than 12 volts, if you've got a string of 12 panels, each output 50V that = 600 Volts

Less of a drop on the DC than the AC! (As O level physics will tell you )

 

[solarsavings]

Perhaps we'll soon see some guidance that says we shouldnt mount inverters in loft spaces because some choose not to. As Markc says if there's good access and lighting what valid reason could there be against fitting an inverter in a loft.

 

[SolarCity]

Perhaps we'll soon see some guidance that says we shouldnt mount inverters in loft spaces because some choose not to. As Markc says if there's good access and lighting what valid reason could there be against fitting an inverter in a loft.

Heat mainly, but dust also.

 

[bommels]

Not only is temp cycling bad, but for example SMA inverters start derating their output power from 45 deg C, which is easily reached in some lofts on those sunny days solar systems like so much....

 

[solarsavings]

Heat mainly, but dust also.

As Tonyl said earlier once the modules have been fitted there's very little heat . Dust on the other hand..................shouldn't be a problem in a felted roof I would have tohught.

 

[edexlab]

We're a non loft company did our first few installs in the loft until we learnt about the possibility of systems derating
but 99% since have been garage /utility /outside ,the odd cellar and even in a couple of ground floor wc's

one landlord we've installed several jobs for had his own 4000tl done by another firm previously, this derates on a regular basis during the summer and also had to replace the varistors after 3 months! whether this was due to heat though I'm not sure.