Confusing myself here, I have 4-250w, 24v panels. 2 Strings in series, giving me 500w each string at 48v. Then both strings in parallel, giving me 1000w (1KW) at 48v. Do the amps increase or stay at 20amps per string, (20 amps total for both strings) or do the amps increase to 40 amps going into parallel.
Dirk
Solar Calc.
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graynomad
Re: Solar Calc.
A 250w panel gives about 10A, you have 2 in series so you only get 10A from a string because series increases voltage but not current.
Then you have two strings in parallel, parallel increases current not voltage, so you have 2x 10A or 20A total.
Put another way 1000 watts divided by 48 volts = 20.8 amps.
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Rob
Then you have two strings in parallel, parallel increases current not voltage, so you have 2x 10A or 20A total.
Put another way 1000 watts divided by 48 volts = 20.8 amps.
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Rob
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Kelvin12
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BruceS
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Re: Solar Calc.
Dirk is this on your bus/motorhome?
48V so I assume you have a MPPT regulator?
Are your house batteries 12V or 24V?
48V so I assume you have a MPPT regulator?
Are your house batteries 12V or 24V?
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BruceS
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BruceS
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Kelvin12
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Re: Solar Calc.
G'Day Bruce,
House batteries are 24v with an MPPT controller (Terry 1 favorite controller)....
Dirk
House batteries are 24v with an MPPT controller (Terry 1 favorite controller)....
Dirk
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T1 Terry
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Re: Solar Calc.
What brand Dirk? You will have more hassles than herding cats if you try and combine a low priced MPPT controller and lithium batteries 
T1 Terry
T1 Terry
A person may fail many times, they only become a failure when they blame someone else John Burrows
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Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
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dapope
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Re: Solar Calc.
Would it not be better to have all panels in parallel to reduce the shading effects?
Wobblybox on wheels
Pace Arrow. La de da, property in two continents..
Pace Arrow. La de da, property in two continents..
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Kelvin12
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Re: Solar Calc.
Terry,
Morning Star 60amp. I am going with AGM's can't get my head around the lithiums. Maybe later. I have 2 - 260 A/H's ready to go. I am not all that concerned about the weight and reckon these are the best option for me.
Dadope,
2 strings in series and then into parallel was a suggestion by another member. The panels are on either side front and rear of the bus.
Dirk
Morning Star 60amp. I am going with AGM's can't get my head around the lithiums. Maybe later. I have 2 - 260 A/H's ready to go. I am not all that concerned about the weight and reckon these are the best option for me.
Dadope,
2 strings in series and then into parallel was a suggestion by another member. The panels are on either side front and rear of the bus.
Dirk
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Kelvin12
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Re: Solar Calc.
Thank you all for the replies. Another problem, with the panel wiring I have 3m of cable (4 lengths @ 3m) from the 2 strings of panels to the circuit breaker/isolator switch. Then another 9m from the switch to the regulator and onto the batteries, (2 lengths @ 9m). Will 6mm square cable do the job.
Dirk
Dirk
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BruceS
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Re: Solar Calc.
Is it correct that it'll be 48V all the way to the regulator & then a short run to the batteries?
My first impression is that you might need heavier wire for the 24V section.
Some sparky will no doubt confirm or suggest something.
My first impression is that you might need heavier wire for the 24V section.
Some sparky will no doubt confirm or suggest something.
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BruceS
Mannum, SA
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BruceS
Mannum, SA
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