diy solar

diy solar

few questions about solar power....

quick question , hypothetically of course.. lets say i get a better mppt.. and 2 massive panels that say it can provide 320 watts each.. if i stick both panels into said "better" mppt.. will only get 320 watts or a combination of both.. so 320watts X 2 ?
 
corporal_Canada said:
quick question , hypothetically of course.. lets say i get a better mppt.. and 2 massive panels that say it can provide 320 watts each.. if i stick both panels into said "better" mppt.. will only get 320 watts or a combination of both.. so 320watts X 2 ?
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You will get 640 watts but the mppt has to support the 640watt and the two panels vmp added together (series) has to be higher than the mppt's minimum working voltage.
 
ThaiTaffy said:
You will get 640 watts but the mppt has to support the 640watt and the two panels vmp added together (series) has to be higher than the mppt's minimum working voltage.
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thank you... but i will either pick an mppt that has a maximum of 80 or 100amps or ask some of you to pick one out for me...
as for voltage.. each solar panel might lose a few volts, i tend to add an extention to the wires coming out of the solar pnels to reach my window...
and this time i will go to the nearby store and TEST each panel before giving them a single penny... im ASSUMING each panel will have an output of 18-20volts.. so it needs to have 17 amps ???how can i test that if my multimeter can only handle a maximum current of 10 amps ??? or am i wrong again ??? (it happens)
 
corporal_Canada said:
thank you... but i will either pick an mppt that has a maximum of 80 or 100amps or ask some of you to pick one out for me...
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No idea but post anything you find and I'm sure others can give you some suggestions
corporal_Canada said:
as for voltage.. each solar panel might lose a few volts, i tend to add an extention to the wires coming out of the solar pnels to reach my window...
Click to expand...
It's not a couple of volts your talking less than 30ft with the correct cable your talking fractions of a volt
corporal_Canada said:
and this time i will go to the nearby store and TEST each panel before giving them a single penny... im ASSUMING each panel will have an output of 18-20volts..
Click to expand...
Most larger modern day panels range from 30-50 voc. The little 18v 30w panels I have for irrigation systems are 21v voc.
corporal_Canada said:
so it needs to have 17 amps ???how can i test that if my multimeter can only handle a maximum current of 10 amps ??? or am i wrong again ??? (it happens)
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You have no way of testing a panel in a store for current safely unless you hook up a load or run a dead short both of which I doubt they would allow unless they're clueless.
 
ThaiTaffy said:
No idea but post anything you find and I'm sure others can give you some suggestions

It's not a couple of volts your talking less than 30ft with the correct cable your talking fractions of a volt

Most larger modern day panels range from 30-50 voc. The little 18v 30w panels I have for irrigation systems are 21v voc.

You have no way of testing a panel in a store for current safely unless you hook up a load or run a dead short both of which I doubt they would allow unless they're clueless.
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i will demand that they place both panels on the ground in the parking lot... if they want any hope of making a sale... Quebecers were making similiar demands in target stores all across my home province before target ran back home and shut down.. but assuming it is 30 volts... that will still exceed the 10 amps any cheap multimeter can handle...
 
Remember - you are dealing with 12v50ah AGM batteries - 2 in parallel. Max chrge current of each is 11.2 amps, but that would probably heat them up good.

12.8v * 22.4a= 286.72w

That is the maximum wattage you can use unless you replace your AGM batteries with LFP batteries, any more than that and your AGM batteries will boil dry and be kaput.
 
robbob2112 said:
Remember - you are dealing with 12v50ah AGM batteries - 2 in parallel. Max chrge current of each is 11.2 amps, but that would probably heat them up good.

12.8v * 22.4a= 286.72w

That is the maximum wattage you can use unless you replace your AGM batteries with LFP batteries, any more than that and your AGM batteries will boil dry and be kaput.
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i am aware, however im using a "hypothetical" scenario.. and in said scenario i am seeing 4-5 x 12v lifepo batteries linked in parallel giving me 1000 ah total i believe..
 
robbob2112 said:
Remember - you are dealing with 12v50ah AGM batteries - 2 in parallel. Max chrge current of each is 11.2 amps, but that would probably heat them up good.

12.8v * 22.4a= 286.72w

That is the maximum wattage you can use unless you replace your AGM batteries with LFP batteries, any more than that and your AGM batteries will boil dry and be kaput.
Click to expand...
btw, just wanted to point out.. that i find it adorable how you repeatedly use that expression Kaput... which comes from the German term Kaputt.. meaning.. destroyed or bricked...
you can ALSO say.. the AGM batteries will boil away all the battery solution... and the cathode and anode will become calcified... i admit i do dumb things at times.. but with a impressive 178 iq, i promise you.. im eating up all the information that you.. and all of you are throwing at me.. and it is being stored in my 2.5 million gigabyte brain, although i have this weird gift where i remember key details and they7 stick with me.. like the "dont put batteries on a concrete floor" thing.. wives tale or not.. it did resonate with me since 2006 until today... ..

but shouldnt the mppt (or SCC) stop charging or reduce charging the power bank and prevent killing the bank ??? regardless of the solar panel input ???

however... Kaputt :)
thank you as always...
 
Large PV array and large SCC will cook the battery with over-current.

SCC will regulate max voltage to avoid charging battery to over-voltage.
But it will deliver all available current, which could far exceed what battery can handle, resulting in battery over-temperature and boiling off electrolyte.

SCC should have a temperature sensor, adjusts charge voltage based on battery temperature and shuts down for over-temperature. But that alone isn't sufficient to protect against over-current damage.

PWM SCC will deliver PV panel current to battery until max voltage reached.

MPPT SCC will convert peak available watts into W / Vbat = I current, possibly a multiple of PV panel current.

Some MPPT SCC, hybrid, or AIO can be programmed for a maximum current output. That lets you over-panel but not exceed a target charge current.

Typically if this is a stand-alone SCC, it will deliver up to a fixed current (e.g. 30A) but doesn't know if that is going into battery or powering loads through the inverter. So if inverter is drawing current, battery gets less. That can be OK with lithium which is fine with any lower charge current, but FLA would like a minimum current to stir the electrolyte. AGM may also prefer higher current.

Hybrid or AIO can be set for a battery charge current, which it will hit if sufficient PV while also supplying loads.

Some fancy MPPT SCC use a battery shunt to know how much current actually goes to battery, will deliver more current if loads are using it while regulating what goes through shunt.
 
corporal_Canada said:
btw, just wanted to point out.. that i find it adorable how you repeatedly use that expression Kaput... which comes from the German term Kaputt.. meaning.. destroyed or bricked...
you can ALSO say.. the AGM batteries will boil away all the battery solution... and the cathode and anode will become calcified... i admit i do dumb things at times.. but with a impressive 178 iq, i promise you.. im eating up all the information that you.. and all of you are throwing at me.. and it is being stored in my 2.5 million gigabyte brain, although i have this weird gift where i remember key details and they7 stick with me.. like the "dont put batteries on a concrete floor" thing.. wives tale or not.. it did resonate with me since 2006 until today... ..

but shouldnt the mppt (or SCC) stop charging or reduce charging the power bank and prevent killing the bank ??? regardless of the solar panel input ???

however... Kaputt :)
thank you as always...
Click to expand...


You used it and I wanted to make certain you understand me when I give you a warning ....
 
corporal_Canada said:
thank you.. but i do feel somewhat belittled each time you repeat that word as if you are addressing someone from a 3rd world... kinda unfair bud..
Click to expand...
you did kind of skip over my question btw :)

but shouldnt the mppt (or SCC) stop charging or reduce charging the power bank and prevent killing the bank ??? regardless of the solar panel input ???
 
wandered back into the store that sells those huge solar panels.. they are about the length of a chevy cavalier... and they have mc4 connectors.. so im thinking that i will need an mppt that uses mc4 input ??.. will that mppt need 4x mc4 input or will i link the 4 solar panels into 1 cable coming into my home ?
YES this is hypothetical but i am taking steps to make this happen including having my own car soon.....
 
corporal_Canada said:
wandered back into the store that sells those huge solar panels.. they are about the length of a chevy cavalier... and they have mc4 connectors.. so im thinking that i will need an mppt that uses mc4 input ??.. will that mppt need 4x mc4 input or will i link the 4 solar panels into 1 cable coming into my home ?
YES this is hypothetical but i am taking steps to make this happen including having my own car soon.....
Click to expand...
It depends on the MPPT specs.
You could wire them in series or parallel or a combination of both.
Normally you would crimp a ferrule on the end that is going into the MPPT.

To give better advice we'd need the specs on the panels you are considering and the MPPT.
 
Sorry no intentions of being mean or anything but I'm curious you can't fit a ground rod but your landlord/lady is going to let you put multiple 20-30kg PV panels on the heavily damaged roof? Have you considered the logistics of even how your going to attempt to get them in place? Surely shopping around and getting smaller wattage more compact panels might be a better idea to stay under the radar.
 
ThaiTaffy said:
Sorry no intentions of being mean or anything but I'm curious you can't fit a ground rod but your landlord/lady is going to let you put multiple 20-30kg PV panels on the heavily damaged roof? Have you considered the logistics of even how your going to attempt to get them in place? Surely shopping around and getting smaller wattage more compact panels might be a better idea to stay under the radar.
Click to expand...
if you have seen the past photos of the roof i have access to, you will see that my landlord does not care about what she does not see...
 
42OhmsPA said:
It depends on the MPPT specs.
You could wire them in series or parallel or a combination of both.
Normally you would crimp a ferrule on the end that is going into the MPPT.

To give better advice we'd need the specs on the panels you are considering and the MPPT.
Click to expand...
the MPPT will only be ordered when i have 4-5 lifepo batteries duct taped together and i will ask all of you for the best mppt to order for my setup...
 
corporal_Canada said:
the MPPT will only be ordered when i have 4-5 lifepo batteries duct taped together and i will ask all of you for the best mppt to order for my setup...
Click to expand...
I would use kapton tape to hold individual cells together to build a battery. I would stick with sets of 4. 4 for 12V, 8 for 24V, 16 for 48V.
corporal_Canada said:
View attachment 224426

those are the panels, claim to be 320 watts each.. they sell for 90-100$ each, i dont know anymore, the north american market is a punchline at this point....
Click to expand...
Without detailed specs on the panels it's tough to give good advice. I'd guess they are around 40VOC.

How do you plan to mount them to your roof?
 
42OhmsPA said:
I would use kapton tape to hold individual cells together to build a battery. I would stick with sets of 4. 4 for 12V, 8 for 24V, 16 for 48V.

Without detailed specs on the panels it's tough to give good advice. I'd guess they are around 40VOC.

How do you plan to mount them to your roof?
Click to expand...
yank em up the stairs and ask the concierge to place them on the roof i imagine...... i have no problem returning to the store and takinga photo of the back.....
 
corporal_Canada said:
at this point and time i trust NOTHING from lazada, but if you can help me save money... please share the link....
Click to expand...
Sorry I stand corrected lazada.ph is a minefield of junk best I could see was 560w jinko panels but a single is near $150, not posting a link as I don't know how to break it up from being affiliated therefore against rules.
 
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