DIY OG Solar install

[leon.davibe]

Is there not a problem with going too high on the solar panel input?

Yes if you exceed the mppt voltage it pops

Cold weather affects the voltage of panels ie as the panels get colder the voltage increases

And the inverse is also true the hotter they get the lower the voltage gets not earth shattering differences but if you were to close to the top a super cold day can drive it over the limit

The same applies to cloudy days, the shade lets them cool down sun pops out and you get super output with a voltage increase

Different panels types are also affected different

ie the blue panels polycrystaline are worse at this

For a laymen if you go 80% of max voc you should be fine

Or could rip out the specs and find an online calculator to work out the temp adjusted voltages

 

[leon.davibe]

Have to agree with ronswanson

after reading as much as i can when going into solar shops i tried to confirm my understanding of the subject matter by essentially pretend to be "dumb" and ask all the questions to see if what i thought matches what they say

to come to the understanding that many specialists are just people that had spare cash to try a new line of business and actually know very little

now yes you may get guys that actually know what they are doing and are specialists , the problem is you need to discern who gets your money and trust

Imagine walking into a solar shop enquiring about lithium iron phosphate battery to only be told no they don't stock it

Pointed to a pylontech lithium ion battery (which uses lifepo4 )

walk out the door see sign posted on the window lifepo4 which is lithium iron phosphate

face palm

 

[lexity]

Not that I saw. Actually I'm now looking at 2x6 600w panels. A string per mmpt.

So 4x 600w ?

As the the AM5 Vs AM2 thing I read about it, and it didn't seem such a large difference, but I'll read again, probably missed something.

Big difference in price.

Edit: "Plus, a longer cycle life means the LiFePO4 batteries will outlast lithium-ion for up to five times longer." Ok so maybe the AM5 is a better choice!

 

[lexity]

Panel dependant 3panels of 50v that will operate at 40v vmp very close to the 120v mppt startup

If you have any shading and lose section that causes string voltage to drop you end up with almost nothing

If 41v panels even worse then 3 is essentially useless

Imo if budget constraint you can try and get by with 3 x 50v panels if no shading if some shading half cut can save your bacon if at least one half stays intact

If 41v panels you have to have 4 to have the panels work , or pray for snow storms every day

We're looking at 4x 550w (42v):

• 1500VDC Maximum String Voltage (IEC/UL).
• 1100mm solar cable and a pair of MC4 connectors.
• SABS certified.
• 30 Year linear power output guarantee and 12 year structural warranty (read more).
• Super High Efficiency: up to 21.30% module efficiency.
• Typical Output (Watt): 550 + 3%
• Typical Voltage (Vmp): 42.00V
• Typical Amperage (Imp): 13.1A

There is very minor shading. Unless we go from 4 to 5. But can use some IBR space too, for another 2 of these.

Anyone have any feedback from this supplier? (artsolar)

 

[Speedster]

Not that I saw. Actually I'm now looking at 2x6 600w panels. A string per mmpt.

As the the AM5 Vs AM2 thing I read about it, and it didn't seem such a large difference, but I'll read again, probably missed something.

Edit: "Plus, a longer cycle life means the LiFePO4 batteries will outlast lithium-ion for up to five times longer." Ok so maybe the AM5 is a better choice!

Lifepo4 is a lithium ion.

 

[leon.davibe]

Lifepo4 is a lithium ion.

Yes and the colloquial terms
As have been said before all batteries are technically ion

lithium-ion vs lithium ion

The first is the way most refer to nmc type batteries

And technically a lifepo4 is lithium iRon phosphate battery

 

[leon.davibe]

We're looking at 4x 550w (42v):

• 1500VDC Maximum String Voltage (IEC/UL).
• 1100mm solar cable and a pair of MC4 connectors.
• SABS certified.
• 30 Year linear power output guarantee and 12 year structural warranty (read more).
• Super High Efficiency: up to 21.30% module efficiency.
• Typical Output (Watt): 550 + 3%
• Typical Voltage (Vmp): 42.00V
• Typical Amperage (Imp): 13.1A

There is very minor shading. Unless we go from 4 to 5. But can use some IBR space too, for another 2 of these.

Anyone have any feedback from this supplier? (artsolar)

Yes the 4x42v works for a 120v startup in my area with my temps george that lands me at 135v still a bit close to the 120v cut-off mine is half cut

And luckily my shading only covers half the panel other half keeps me in play

While if your shad covers the panel in a way that loses top and bottom one section on the panel lost would mean about 11v lost ie still leaving you in mppt range but only slightly 124v losing 2 would see you get almost nothing

If you are planning on getting more panles later can stick with 42v 60 cell panels

If 4is where you will end i would try and find the same wattage panel in 72/144arangement for 50v voc that way you can lose about a whole panel to shade and still be in play in mppt range

Or the equivalent in sections multiple ie 3 sections on both half cuts

 

[leon.davibe]

How much you get out of panels when dropping out of mppt range ie losing a whole panel to shade left me with 3panels and in cold weather i would fall on the output graph on 1 and in hot weather i would fall on 2

ie i would get production early morning when still cold and 15w mid day due to panels being hotter while with a 50v panel you would not land in the steep section of the graph of a 50v panel with 3 solar panels ie one lost to shade

As the mppt wants to be in the 120v+ region it will drag the panel to max voc where there is very little production on the combo of 42voc panel and the 120v startup voltage

 

[The Darkness]

Yes, I see that.

What happens to the flow of current when it hits the busbar?

Does it split up and go into all the connecting wires/cables?

Based on this comment here, I do not think you should be doing this yourself whatsoever. Get this properly installed and have a COC once completed. Nothing wrong with hunting down the correct equipment and dodging the markups though.

 

[schuits]

So 4x 600w ?


Big difference in price.

No - 12 x 600w. But it's all planning right now. I might not have the funds, so I'll get the solar panel railing installed for future expansion.

Regarding the AM5 apparently the technology in it is better than the AM2, as the leon mentioned
lifepo4 is lithium iRon phosphate battery, which apparently last longer.

 

[Speedster]

No - 12 x 600w. But it's all planning right now. I might not have the funds, so I'll get the solar panel railing installed for future expansion.

Regarding the AM5 apparently the technology in it is better than the AM2, as the leon mentioned
lifepo4 is lithium iRon phosphate battery, which apparently last longer.

Correct. The Am2 is NMC, while the Am5 is LFP. Pretty much all the other brands are LFP too, it's a much better technology for residential storage

 

[RonSwanson]

Based on this comment here, I do not think you should be doing this yourself whatsoever. Get this properly installed and have a COC once completed. Nothing wrong with hunting down the correct equipment and dodging the markups though.

That's what I said right from the start, but here we are.

¯\_(ツ)_/¯​

 

[leon.davibe]

No - 12 x 600w. But it's all planning right now. I might not have the funds, so I'll get the solar panel railing installed for future expansion.

Regarding the AM5 apparently the technology in it is better than the AM2, as the leon mentioned
lifepo4 is lithium iRon phosphate battery, which apparently last longer.

I think what hubble does to stretch the cycles on the am2 is essentially force you into a 20-80 cycle by making the max charge and cut-off voltages to be of such a way that it is technically impossible to fully charge the nmc cells and impossible to discharge to flat and thus promise higher cycles than what is normally associated with nmc



Now i have not read too much on the am2 , it may be that you get the full 5.5kw usable capacity Ie that they use for instance a 140ah cell and sacrifice 20% at each end for cycle stretch and sell it to you as a 100ah battery since that is what you actually get out of it

would love to hear from someone with a am2 that has done the capacity test run to flat ie that you actually get the 5.5kwh useable capacity and not that you pay for what you technically can't use

There is also claims of slightly different chemistries (salt) can't recall where i read that marketing mumbo jumbo

 

[lexity]

Small vs Large panels

I would imagine there'd be some loss due to increased connections and conduit.

But is this really a significant factor?

I haven't so far considered using smaller, more numerous panels to match/replace the 4x 550W large panels, but it would ofc make handling them easier i.e. having smaller panels.

 

[lexity]

Based on this comment here, I do not think you should be doing this yourself whatsoever. Get this properly installed and have a COC once completed. Nothing wrong with hunting down the correct equipment and dodging the markups though.

Thanks for your input.

In your view, does it make sense to have a wire going from positive busbar to negative busbar (with a fusebox in-between)?

 

[lexity]

I think what hubble does to stretch the cycles on the am2 is essentially force you into a 20-80 cycle by making the max charge and cut-off voltages to be of such a way that it is technically impossible to fully charge the nmc cells and impossible to discharge to flat and thus promise higher cycles than what is normally associated with nmc

Now i have not read too much on the am2 , it may be that you get the full 5.5kw usable capacity Ie that they use for instance a 140ah cell and sacrifice 20% at each end for cycle stretch and sell it to you as a 100ah battery since that is what you actually get out of it

Dunno, but it says this on the tech spec:

Cycle Life @ 1C: +/- 6000 cycles @ 50% DOD, Above 3000 cycles @ 100% DOD

would love to hear from someone with a am2 that has done the capacity test run to flat ie that you actually get the 5.5kwh useable capacity and not that you pay for what you technically can't use

There is also claims of slightly different chemistries (salt) can't recall where i read that marketing mumbo jumbo

 

[leon.davibe]

Small vs Large panels

I would imagine there'd be some loss due to increased connections and conduit.

But is this really a significant factor?

I haven't so far considered using smaller, more numerous panels to match/replace the 4x 550W large panels, but it would ofc make handling them easier i.e. having smaller panels.

Per square meter you will land at the same output

If going smaller there are some advantages and disadvantages

More panels means more clamps and connections

But also have less power loss in shading ie if a chimney shadow falls over one 300w panel you lose 300w not 550w

Much easier to handle

I have 455w panels diy and the day i did it i was glad i could not get the 600w panels i initially intended

Also the bonus that it ups your voltage meaning better shade dropping out of mppt range resistance (if the voltage of the string is higher than 4 bigger panels)

 

[leon.davibe]

Thanks for your input.

In your view, does it make sense to have a wire going from positive busbar to negative busbar (with a fusebox in-between)?

Hope you are trolling

The negative and positive busbar never meet only via battery

I would also only go busbar if multiple batteries

So positive busbar and equal lentgh cable to each battery +

Vegetative busbar the same to -

+/- from busbars to inverter

If single battery no busbar just fuse + disconnect inbetween

 

[leon.davibe]

Dunno, but it says this on the tech spec:

Cycle Life @ 1C: +/- 6000 cycles @ 50% DOD, Above 3000 cycles @ 100% DOD

Ok so based on that i deduce that yes you can get the whole 5.5kwh if so desired

Shutdown voltage of the battery ie 44v it is clear that the way the stretch the cycles is by working the nmc light ie normally nmc goes 2.75v to 4.2v ie a 13s battery full range voltage would be flat 35.75v full 54.6v

The am2 voltages is 44/53.6v

Meaning the nmc cells never come close to full or empty

ie the 20-80 notion to extend lifetime

 

[lexity]

Thanks for your input.

In your view, does it make sense to have a wire going from positive busbar to negative busbar (with a fusebox in-between)?

Hope you are trolling

The negative and positive busbar never meet only via battery