hello........ and system and component vetting for solar/lithium/all-in-one backup

[ZorbatheGeek]

We have a bit of a small outbreak wrapping up at the moment but it does feel like I’m in an NZ goldfish bowl looking out at a very crazy world.

@ianganderton .......a question about the backup system if I may? Something curious about the solar irradiance for Mombasa (according to this site http://www.solarelectricityhandbook.com/solar-irradiance.html ) - it shows highest annual PV performance if the array is angled for peak winter performance (4 degrees). Diani is 4.27 degrees South. Would that be correct?

 

[ianganderton]

@ianganderton .......a question about the backup system if I may? Something curious about the solar irradiance for Mombasa (according to this site http://www.solarelectricityhandbook.com/solar-irradiance.html ) - it shows highest annual PV performance if the array is angled for peak winter performance (4 degrees). Diani is 4.27 degrees South. Would that be correct?

Are you after maximum PV power generation through a year or maximum performance charging batteries to provide UPS style backup protection?

If you are getting money by selling PV power to the grid then tilting the panels for maximum annual power generation is correct

If it’s backup power only then I reckon it’s best to consider setting the panels for either winter power generation or the time of year you are most likely to get power cuts (if there is one)

Diani is close enough to Mombassa to make very little difference.

 

[ianganderton]

Are you after maximum PV power generation through a year or maximum performance charging batteries to provide UPS style backup protection?

If you are getting money by selling PV power to the grid then tilting the panels for maximum annual power generation is correct

If it’s backup power only then I reckon it’s best to consider setting the panels for either winter power generation or the time of year you are most likely to get power cuts (if there is one)

Diani is close enough to Mombassa to make very little difference.

An alternative look at it is to consider how any tilt will be engineered. Often it is easiest and most cost effective to just mount flat with the roof. Tilt can cause shading and costs that are not worth it. Better to just mount as many panels as possible with some tilt (10% has been recommended) to help rain drain effectively.

 

[ZorbatheGeek]

An alternative look at it is to consider how any tilt will be engineered. Often it is easiest and most cost effective to just mount flat with the roof. Tilt can cause shading and costs that are not worth it. Better to just mount as many panels as possible with some tilt (10% has been recommended) to help rain drain effectively.

Its really to have a backup system to cover for the unpredictability of the grid - but the array will be supplying the bulk of the daytime power requirements as priority. There is a lot of cloud cover during winter (monsoon change) which is reflected in the PV yield figures, but it is also the coolest time of year so less fans and fridge compressor time required?
The site doesn't give figures for peak winter, but recommends an 86 degree tilt, so 10 deg is not going to make the world of difference? Rain capture of approx 20 000l per year is also attractive when doing this.

 

[John Frum]

@smoothJoey you asked how the batteries are aggregated?
My reply:
Not sure what you are asking for?
25mm cable connecting the 2 +ves on batteries together, same for 2 -ves.
One 35mm from common +ve terminal to Midnite and 175A DC breaker (then to +ve inverter) - one 35mm cable from common -ve direct to invererter -ve.

Can you post a picture of the aggregation please.

 

[ZorbatheGeek]

Can you post a picture of the aggregation please.

I only have the pics of the battery terminals that will be used to parallel with 25mm cable

 

[ZorbatheGeek]

Its really to have a backup system to cover for the unpredictability of the grid - but the array will be supplying the bulk of the daytime power requirements as priority. There is a lot of cloud cover during winter (monsoon change) which is reflected in the PV yield figures, but it is also the coolest time of year so less fans and fridge compressor time required?
The site doesn't give figures for peak winter, but recommends an 86 degree tilt, so 10 deg is not going to make the world of difference? Rain capture of approx 20 000l per year is also attractive when doing this.

View attachment 21923

@ianganderton I'm also not clear about the angle of the panels.
Based on the above pic, for year round optimal average output (lhs datasheet) I must angle the panels 86deg - is that tilted north or south?

 

[ianganderton]

@ianganderton I'm also not clear about the angle of the panels.
Based on the above pic, for year round optimal average output (lhs datasheet) I must angle the panels 86deg - is that tilted north or south?

It doesn’t matter too much because you are very close to the equator. For most people they are significantly to one side or the other

I know it sounds obvious but you need to point the panels at the sun. For off grid use I look at it that I need to maximise power production in the worst times of the year. The good times of the year will look after themselves

 

[ZorbatheGeek]

It doesn’t matter too much because you are very close to the equator. For most people they are significantly to one side or the other

I know it sounds obvious but you need to point the panels at the sun. For off grid use I look at it that I need to maximise power production in the worst times of the year. The good times of the year will look after themselves

Ok yes that is what I thought...so if anything tilted 10deg towards north for rain drainage and max PV in "winter" months............the pics were confusing me ?

 

[ianganderton]

Ok yes that is what I thought...so if anything tilted 10deg towards north for rain drainage and max PV in "winter" months............the pics were confusing me ?

Yeah. Rain drainage will help keep panels clean and this will in turn make more of a difference to output than a lot of factors

10% means no shading issues too.

 

[ZorbatheGeek]

@ianganderton ........... it's been alleged by some local Ukunda guys that Lithium doesn't last at the Kenya coast, due to the heat/humidity.
I have yet to hear details of the battery, usage and chemistry - would you know if this is true for LiFeP ?

 

[ianganderton]

Heat is definitely not good for batteries in the long term but plenty of folks on here are in very hot locations (solar forums, who’d have thunk it hey!!) so there is plenty of advice to be had on how to deal with that. If the batteries are at a livable temperature then they are typically good. It’s easy enough to build a well insulated box with some form of temperature adjustment (I.e. a fridge!)

Humidity. The Daini coast is certainly humid and the combination of the sea air trashed electronics when I was there. I remember Sacha’s CDs all fell apart too.

But

Plenty of marine setups on here so this can be dealt with as well.

Use marine grade cables in your wiring and for your charge controllers a brand like Victron which has a background in marine use and that will mitigate most problems.

Just as the questions and you will get good honest answers based on experience.

 

[ZorbatheGeek]

Heat is definitely not good for batteries in the long term but plenty of folks on here are in very hot locations (solar forums, who’d have thunk it hey!!) so there is plenty of advice to be had on how to deal with that. If the batteries are at a livable temperature then they are typically good. It’s easy enough to build a well insulated box with some form of temperature adjustment (I.e. a fridge!)

Humidity. The Daini coast is certainly humid and the combination of the sea air trashed electronics when I was there. I remember Sacha’s CDs all fell apart too.

But

Plenty of marine setups on here so this can be dealt with as well.

Use marine grade cables in your wiring and for your charge controllers a brand like Victron which has a background in marine use and that will mitigate most problems.

Just as the questions and you will get good honest answers based on experience.

Hmm ok that gives me something to go on. My folks are about 10km inland and slightly higher than Diani so the humidity is not as bad.........however it is definitely still tropical.

We have been quoted for a Growatt with built-in MPP ...........Victron goodies would be first prize but will up the cost of the inverter/charge controller section by a factor of 3 or 4 :=(.

I will take your cue and ask more in a dedicated thread.........

 

[ianganderton]

Hmm ok that gives me something to go on. My folks are about 10km inland and slightly higher than Diani so the humidity is not as bad.........however it is definitely still tropical.

We have been quoted for a Growatt with built-in MPP ...........Victron goodies would be first prize but will up the cost of the inverter/charge controller section by a factor of 3 or 4 :=(.

I will take your cue and ask more in a dedicated thread.........

10km inland is a huge difference to the shore line in terms of what it does to electronics etc. much drier. Beach side houses always felt quite damp. Inland no where near as much plus a lot no salt in the air