Pv solar install the inverter in loft or garage

zeupater

don0301 wrote: »

I'm not disagreeing with you

the equation you quoted is!

Hi

But you are disagreeing, and once more. it's plain for all to see ....

For information, I haven't quoted an equation at all, just raised 'arrhenius' and it's generalised usage .... I really do suggest that a little more time is expended in researching the subject, perhaps into international standards on reliability testing and prediction and how these standards are utilised by global corporations within product design ...

It could just be possible that the above-reference post would be considered as being inaccurate ....

Note to all considering installations, I believe that the cumulative effect of temperature over time has a bearing on the lifespan of electrical and electronic components and this is totally in-line with both the industry which designs and builds those components and the organisations which are responsible for the relevant standards ...

HTH
Z

don0301

zeupater wrote: »

Hi

But you are disagreeing, and once more. it's plain for all to see ....

For information, I haven't quoted an equation at all, just raised 'arrhenius' and it's generalised usage .... I really do suggest that a little more time is expended in researching the subject, perhaps into international standards on reliability testing and prediction and how these standards are utilised by global corporations within product design ...

It could just be possible that the above-reference post would be considered as being inaccurate ....

Note to all considering installations, I believe that the cumulative effect of temperature over time has a bearing on the lifespan of electrical and electronic components and this is totally in-line with both the industry which designs and builds those components and the organisations which are responsible for the relevant standards ...

HTH
Z

reads like Back tracking to me

I'll just go back to the rofl

don0301

ps. does an uninsulated garage have a higher or lower av. ambient temperature than an insulated loft, that also has solar panels "insulating" it?

or more of your assumptions?

just a thought

zeupater

don0301 wrote: »

are you sure?

how many extra metres?

lets calculate your losses

Hi

Did it at the time, there's plenty of tools available to play with if you want to .... you could start with the SunnyDesign software and model the effect of longer cable runs vs heavier gauge cable on system losses if you would like to expand your knowledge in this area, both AC & DC runs can be modelled ...

HTH
Z

don0301

zeupater wrote: »

Hi

Did it at the time, there's plenty of tools available to play with if you want to .... you could start with the SunnyDesign software and model the effect of longer cable runs vs heavier gauge cable on system losses if you would like to expand your knowledge in this area, both AC & DC runs can be modelled ...

HTH
Z

ac is minimal, your dc losses interest me greatly

yes, I'll be sure to calculate when you submit your measurements

I'm sure for once you might actually be posting something that "helps" people here

zeupater

don0301 wrote: »

ps. does an uninsulated garage have a higher or lower av. ambient temperature than an insulated loft, that also has solar panels "insulating" it?

or more of your assumptions?

just a thought

Hi

As previously posted, I have measured the temperature in our loft, in the house and in the garage .... the house & garage do not go over 40C, however the loft does ....

Regarding backtracking .... it's my turn to :rotfl:... it's plain for all to see. I will once again state that the content, context and intent behind the posts which I am addresssing is totally consistent with what many consider to be serial trolling and as I have described a sound and robust position regarding the title of this thread, I can see no further interest to be served in continuing to operate at such a debased level of discussion ...

All .... consider the position of your inverters carefully and discuss this with your potential installers prior to installation.

HTH
Z

don0301

zeupater wrote: »

Hi

As previously posted, I have measured the temperature in our loft, in the house and in the garage .... the house & garage do not go over 40C, however the loft does ....

Regarding backtracking .... it's my turn to :rotfl:... it's plain for all to see. I will once again state that the content, context and intent behind the posts which I am addresssing is totally consistent with what many consider to be serial trolling and as I have described a sound and robust position regarding the title of this thread, I can see no further interest to be served in continuing to operate at such a debased level of discussion ...

All .... consider the position of your inverters carefully and discuss this with your potential installers prior to installation.

HTH
Z

*pat*

back to rofl

don0301

zeupater wrote: »

Hi

As previously posted, I have measured the temperature in our loft, in the house and in the garage .... the house & garage do not go over 40C, however the loft does ....

Regarding backtracking .... it's my turn to :rotfl:... it's plain for all to see. I will once again state that the content, context and intent behind the posts which I am addresssing is totally consistent with what many consider to be serial trolling and as I have described a sound and robust position regarding the title of this thread, I can see no further interest to be served in continuing to operate at such a debased level of discussion ...

All .... consider the position of your inverters carefully and discuss this with your potential installers prior to installation.

HTH
Z

Does the arrhenius equation just apply at peak summertime in your household?

zeupater wrote: »

Hi

As previously posted, I have measured the temperature in our loft, in the house and in the garage .... the house & garage do not go over 40C, however the loft does ....

Regarding backtracking .... it's my turn to :rotfl:... it's plain for all to see. I will once again state that the content, context and intent behind the posts which I am addresssing is totally consistent with what many consider to be serial trolling and as I have described a sound and robust position regarding the title of this thread, I can see no further interest to be served in continuing to operate at such a debased level of discussion ...

All .... consider the position of your inverters carefully and discuss this with your potential installers prior to installation.

HTH
Z

well said, Sir Humphrey

grahamc2003

Plans are to have a board in the loft to take the inverter plus other bits. Think I'll try to change that and have it above the fuse box in the hall. Not sure what inverter I'm getting, but I think I should really be going for the solaredge system due to the shading I'll get - too late now, but may have it retrofitted with some more panels. Mine must be the cheapest system ever, but had to take what was offered and in their stock, so couldn't have a larger system due to them not having a suitable inverter to take a 1.75kw string and a 1.25kw string (is there a problem with that needing a special inverter?). Scaffolding up - not suitable for painting either the wall or eaves, which I hoped to get done.

Dave_Fowler

The silicon used in the manufacture of semiconductors is relatively stable up to a temperature of 150C. Above that temperature several failure mechanisms occur(mainly due to changes within the semiconductor junction). At temperatures up to 150C, failures due to temperature in semiconductors are mainly due temperature cycling where fractures in bonding wires and substrates can occur. One should note however that the temperature of the silicon in a device under load is not that of the ambient, but is higher depending on the power dissipated. A typical power MOSFET, as used in an inverter, will have a maximum junction temperature of 150C. It may be rated at 250W with a case temperature of 25C, but there is a 0.5C/W temperature gradient between case and junction. So an inverter working in an ambient temperature of 50C with an internal temperture perhaps 20C higher and heatsinks another 25C higher would have the devices running with a case temperature of 95C. This would allow a maximum junction-to-case temperature of 55C. This equates to a maximum power dissipation of 110W.

This reduced power due to higher ambient temperatures is why many inverters have to run at a lower power when they are hot. It is ironic that just when the inverter has a lot of DC power to convert to AC that the ambient is likely to be hot and they are unable to work at full power.

For other components the effects of temperature are different. The most affected components are the capacitors, particularly the electrolytics. Plastic film capacitors suffer from film degradation. A good film capacitor will have a maximum rated temperature of 120C but at this temperature its MTBF will be reduced. Electrolytic capacitors contain a liquid (or gell) electrolyte. Over time, even at relatively low temperatures the electrolyte will degrade. The oxide coating of the plates slowly disolves into the electrolyte and also, because for safety's sake they are usually vented, this degradation increases with temperature.

Resistors are relatively stable up to high temperatures, but their life is again shortened by high temperatures. This is particularly the case with high power wire-wound resistors where the wire deteriorates at a higher rate as they get hotter. Run a house-hold incandescent lamp on 100V and it will last 'forever' but run it hotter at 250V and it will usually fail within 1000 hours.

Whilst it is true that the lower the temperature, the longer the electronics will last, the high temperatures often found in a loft are usually associated with a time when there is maximum power available from the sunlight. This causes the maximum temperature rise within the inverter (usually an increased fan speed helps reduce the internal rise). So if only to allow the inverter to work at full output when the sun is at its strongest then it is surely true that an inverter situated in a lower (and more stable) ambient temperature is best.

Dave F