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diy solar

Help with connecting the system

J

Jancho

New Member
Joined
Feb 21, 2022
Messages
9
Hello everyone!
How would you connect the following (click name for the item specification):

1) Panels x4
2) Inverter/Charger (1) or let me know if this weaker one would do as well: Inverter/Charger (2)
3) Battery x4 (1) or let me know if better: Battery x4 (2) or even Battery x4 (3)
4) Generator - somethign around this lines

Let me know which items would you prefer (regarding inverter/charger and battery options) and how would you make a schem of the connections. Do I need saparate charge controler when I want to have generator connected or I can simply connect it to the inverter/charger as the solar array. If I do need, which charge controler would you suggest? If I will connect everythign myself, which part would you warn me about? Where should I add (and what type) of circle breakers? And last, how would you connect (series/paralel) the array/batteries and how thick wire do you suggest to use?

Thank you in advance!
 
Code: 
legend {
    {} { functional block }
    nn|UUU| { un-fused busbar position where nn is wire guage in mm2 }
    nn|NNN| { fused busbar position where nn is wire guage in mm2 and NNN is fuse ampacity in amps }
    <-> { bi-directional current flow }
    -> { uni-directional current flow }
    <- { uni-directional current flow }
    dpst { double pole single throw breaker }
    mrbf { marine rated battery fuse }
}
dc_domain { * lynx_power_in
    lynx_power_in {
        backplane {
            left {}
            right {}
        }
        branches.positive {
            50|UUU|<->250A_mrbf_fuse<->battery.1.positive
            50|UUU|<->250A_mrbf_fuse<->battery.2.positive
            50|UUU|<->250A_mrbf_fuse<->battery.3.positive
            50|250|<->all_in_one<-dpst_breaker<-panels_in_series.positive
        }
        branches.negative {
            50|UUU|<->battery.1.negative
            50|UUU|<->battery.2.negative
            50|UUU|<->battery.3.negative
            50|UUU|<->shunt<->all_in_one->dpst_breaker->panels_in_series.negative
            50|UUU|<->premises_bond
        }
    }
}
ac_domain {
    |<-master_breaker<-all_in_one<-generator
    |->branch_breaker->branch_circuits
    |->...
}
I would modify a lynx power in using this guide
to have 1 fused position and then I would make the diagram above
 
Last edited:
Jancho said:
I believe I posted a link for exact panel type:
AS-6M30-HC 320W~340W MONOCRYSTALLINE MODULE
Click to expand...
I believe that is a range of panels not a specific panel.
We need to know the VOC and VIMP of the panel in order to know how to configure them and which all_in_one to choose.
Ideally we want 4 in series as that should give the highest performance as long as you don't have shading issues.
 
The All-In-One (AIO) inverter/charger/controller: The cheaper one will do... depending for what, obviously.
Except, it has a maximum solar input voltage (open circuit) of 100V. The better one takes 500. If you want to wire your panels in series, 100 won't do. But you could do parallel, or series/parallel.

The batteries. Those AIOs are 24V. So you would need two 12V batteries in series, and then paralleled to the other 2 in series.
The only suitable ones are the AGMs (1). If you could afford better ones like LiFePO4, you could be happy and not worry about them much. If you can't, use the AGMs and worry about them. ;·)

The generator. Those AIOs will very likely have a problem with a non-inverter-type one. They usually can't synchronise the phases.
Get an inverter-type one if you can.

The panels look just fine.
-
 
smoothJoey said:
I believe that is a range of panels not a specific panel.
We need to know the VOC and VIMP of the panel in order to know how to configure them and which all_in_one to choose.
Ideally we want 4 in series as that should give the highest performance as long as you don't have shading issues.
Click to expand...
Im sorry, I didnt notice. It's the 335w one. at STC its: Voc = 41V, Isc = 10,24A, Vmp = 34,4V, Imp= 9,74A, Maximum System Voltage= 1000V DC / 1500V DC, Maximum series Rating = 20A
 
Jancho said:
Im sorry, I didnt notice. It's the 335w one. at STC its: Voc = 41V, Isc = 10,24A, Vmp = 34,4V, Imp= 9,74A, Maximum System Voltage= 1000V DC / 1500V DC, Maximum series Rating = 20A
Click to expand...
The lower capacity all_in_one can't accept 4 of those in series.
I guess you will want to go with the higher capacity unit or you could do 2s2p.
2s2p means 2 in series to make strings and 2 strings in parallel.
 
Don B. Cilly said:
The All-In-One (AIO) inverter/charger/controller: The cheaper one will do... depending for what, obviously.
Except, it has a maximum solar input voltage (open circuit) of 100V. The better one takes 500. If you want to wire your panels in series, 100 won't do. But you could do parallel, or series/parallel.

The batteries. Those AIOs are 24V. So you would need two 12V batteries in series, and then paralleled to the other 2 in series.
The only suitable ones are the AGMs (1). If you could afford better ones like LiFePO4, you could be happy and not worry about them much. If you can't, use the AGMs and worry about them. ;·)

The generator. Those AIOs will very likely have a problem with a non-inverter-type one. They usually can't synchronise the phases.
Get an inverter-type one if you can.

The panels look just fine.
-
Click to expand...
Thanks for the insights. The battery number 1 is however C100 type, isnt like C20 ones more suitable for solar systems? :unsure:
 
Since those are agm batteries I believe the low voltage disconnect should be 12.6 volts.
I'm sure one of the members who knows lead acid can confirm or deny.
 
I only know about three words of Croatian, but those (other) batteries look like car starter ones - nowhere near deep cycle.
Consider the fact that with LFP (LiFePO4) you can use 90% of the capacity, with lead-acid, half of that.
-
 
Honestly, I tried to find LiFePo4 ones, but guess what, I couldnt find any. Either they are too much for my budget or they seems like they ship from china (I get nervous getting expencive batteries from China). Do you have any leads where I can find them at good price? I guess 5 kw lithium ones are better then 11kw AGMs, right?
 
If you want 4 batteries you can do this setup
Code: 
legend {
    {} { functional block }
    nn|UUU| { un-fused busbar position where nn is wire guage in mm2 }
    nn|NNN| { fused busbar position where nn is wire guage in mm2 and NNN is fuse ampacity in amps }
    <-> { bi-directional current flow }
    -> { uni-directional current flow }
    <- { uni-directional current flow }
    dpst { double pole single throw breaker }
    mrbf { marine rated battery fuse }
}
dc_domain { * lynx_power_in
    lynx_power_in {
        backplane {
            left {
                positive<->250A_anl_fuse<->all_in_one<-dpst_breaker<-panels_in_series.positive
                negative<->shunt<->all_in_one->dpst_breaker->panels_in_series.negative
            }
            right {}
        }
        branches.positive {
            50|UUU|<->250A_mrbf_fuse<->battery.1.positive
            50|UUU|<->250A_mrbf_fuse<->battery.2.positive
            50|UUU|<->250A_mrbf_fuse<->battery.3.positive
            50|UUU|<->250A_mrbf_fuse<->battery.4.positive
        }
        branches.negative {
            50|UUU|<->battery.1.negative
            50|UUU|<->battery.2.negative
            50|UUU|<->battery.3.negative
            50|UUU|<->battery.4.negative
            50|UUU|<->premisis_bond
        }
    }
}
ac_domain {
    |<-master_breaker<-all_in_one<-generator
    |->branch_breaker->branch_circuits
    |->...
}
 
Last edited:
There are some Chinese vendors who have gained quite a reputation here, but they seem to sell only individual cells, with which you have to build a battery yourself. Not really a task for beginners.
I got my LFP batteries (Pylontech 24V) at a store, not far away. Put them in the boot of the car. Expensive? Yes. Worth it? Yes.

They're probably easy enough to find in northern Italy, around Venice... or maybe contact Shenzen Luyuan, they can probably send you a pre-built one (just guessing). They have a good reputation. They're still expensive, but if you can afford to think "in the long run" and account for a "no worries" factor...
-
 
smoothJoey said:
Since those are agm batteries I believe the low voltage disconnect should be 12.6 volts.
I'm sure one of the members who knows lead acid can confirm or deny.
Click to expand...
That is way too high. In practice, I lean toward starting charging under 12.4 hot and 12.2 cold.

Did you know that the cranking Amps rating involves determining how many Amps can be drawn for 15 seconds that drops the Voltage to 9.6V? CCA is rated at 32F.

I have an inverter that will run my AGM down to 10V for one minute. It shuts itself off before the AGM is done! Usually it is the device that cannot handle the current.
 
gelmjw said:
cranking Amps rating involves determining how many Amps can be drawn for 15 seconds that drops the Voltage to 9.6V?
Click to expand...
This is irrelevant to batteries suitable for solar; the plates even in suitable cheap marine batteries have far less surface area and the battery is designed for moderate discharge over long periods and frequent discharge/charged cycling.
CCA is a rating for starting batteries with thin plates and large surface area designed to deliver 400- or even 600A for a short period. Cycling them kills them in a much shorter time.
gelmjw said:
have an inverter that will run my AGM down to 10V for one minute. It shuts itself off before the AGM is done! Usually it is the device that cannot handle the current.
Click to expand...
That’s not loving your battery much
 
12VoltInstalls said:
This is irrelevant to batteries suitable for solar; the plates even in suitable cheap marine batteries have far less surface area and the battery is designed for moderate discharge over long periods and frequent discharge/charged cycling.
CCA is a rating for starting batteries with thin plates and large surface area designed to deliver 400- or even 600A for a short period. Cycling them kills them in a much shorter time.

That’s not loving your battery much
Click to expand...
Batteries don't have feelings!
 
Jancho said:
Honestly, I tried to find LiFePo4 ones, but guess what, I couldnt find any. Either they are too much for my budget or they seems like they ship from china (I get nervous getting expencive batteries from China). Do you have any leads where I can find them at good price? I guess 5 kw lithium ones are better then 11kw AGMs, right?
Click to expand...

5kWh lithium (at 80% to 90% DoD) would have somewhat lower usable capacity than 11 kWh AGM (at 50% to 80% DoD).
Some people say 50% max DoD for lead-acid. My system is configured for 70% DoD disconnect loads (but keep AC coupled PV going), 80% DoD shut down.

Lithium will typically cost several times as much and is expected to last 5x to 10x as many cycles (both chemistries come in a range of prices and quality or at least trustworthiness.) It can recharge faster, 0.5C vs. 0.12C or 0.2C

For me, AGM because it is grid-backup, only expect to cycle a couple hundred times in a decade.
For nightly deep cycling, lithium might last a decade (or longer).
FLA is more maintenance, but if shallow-cycled most of the time (because sized for 3 days without sun), premium quality ones are reported to last 15 to 20 years.

Some sources of lithium batteries/cells are same or lower up-front cost than AGM, so more of a no-brainer (if temperature can be kept in the range they like for charging.)

So your selection should depend on usage, money, environment, tolerance for maintenance.

12VoltInstalls said:
Maybe not but if you love your batteries they last longer and put out more
Click to expand...

Peukert and all, low voltage under heavy load probably isn't so bad, if it represents voltage drop and not low SoC.
Only some systems use estimate of SoC in addition to voltage. And of course you want to ride through momentary voltage dip for surge loads.
 
Hedges said:
Peukert and all, low voltage under heavy load probably isn't so bad, if it represents voltage drop and not low SoC.
Only some systems use estimate of SoC in addition to voltage. And of course you want to ride through momentary voltage dip for surge loads.
Click to expand...
The proposed all in one options don't seem very sophisticated and the user seems pretty new to this.
 
12VoltInstalls said:
Maybe not but if you love your batteries they last longer and put out more
Click to expand...
We agree that batteries don't have feelings.

At another end of the spectrum of goals for the battery is "I want power when I need it.".

Beauty is in the eye of the beholder.
 
Hedges said:
low voltage under heavy load probably isn't so bad, if it represents voltage drop and not low SoC.
Only some systems use estimate of SoC in addition to voltage. And of course you want to ride through momentary voltage dip for surge loads.
Click to expand...
Exactly.
gelmjw said:
"I want power when I need it."
Click to expand...
I’m getting that fine with flooded batteries

The question of up front cost was raised; I was agreeing with lead batteries as an option. I added beyond a year or maybe two with my observations of others - and a lot of boats and campers- people are replacing those quite often. Even with solar.
Whereas I get years out of fla batteries.

Beauty may be in the eye of the beholder. At the same time the bank account balance is in the eye of those that can add and subtract. I started solar with fla knowing my cash AND that I might have to replace in a few years. But not expecting to.
Today they are still going strong.
 
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