Iam trying to buy solar panel and a stand alone offgrid solar system . I've noticed that some of the panels are 24 /36/48 volts . When you match them up with batteries and inverters does the system have to match the panel voltage ie 48 volt panels with 48 volt inverter .
Does it make a differnce .
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timselectric
If I can do it, you can do it.
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The object is to make your solar array voltage as close to without going over the maximum of your charge controller. Individual panels are wired in series to add the voltage of each panel to the total.
Thanks ✔
Shopping now for system
Don B. Cilly
Energetic energy padawan
No. Just use a decent solar charge controller, it will take care of the volts.
One word of advice though... don't start building a house from the roof down :·)
First, you figure out roughly how much power you're going to need. Then double it. ;·) Then, whoa, that's a lot, maybe I shouldn't use electricity for cooking or heating, figure out how to go without A/C, or a way to do it efficiently... get into off-grid mode. It can be quite rewarding, not just money-wise, soul-wise.
Then, work out how much storage (battery) you would need for that. That's the expensive bit. And what sort of inverter to power your AC loads. Tends to be somewhat expensive too.
After that, you can worry about what panels - and charge controller - you need to keep the batteries reasonably charged.
And consider a decent generator (possibly inverter type) for rainy days and all.
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One word of advice though... don't start building a house from the roof down :·)
First, you figure out roughly how much power you're going to need. Then double it. ;·) Then, whoa, that's a lot, maybe I shouldn't use electricity for cooking or heating, figure out how to go without A/C, or a way to do it efficiently... get into off-grid mode. It can be quite rewarding, not just money-wise, soul-wise.
Then, work out how much storage (battery) you would need for that. That's the expensive bit. And what sort of inverter to power your AC loads. Tends to be somewhat expensive too.
After that, you can worry about what panels - and charge controller - you need to keep the batteries reasonably charged.
And consider a decent generator (possibly inverter type) for rainy days and all.
-
Thanks for the replies . Seems my question is answered.
Thanks for this reply . Explains alot ✔
Rednecktek
Solar Wizard
Those are marketing terms, not real world numbers. What it means is that a "12v Panel" can produce enough voltage to charge a 12v battery, but not enough to do a 24v battery. Likewise a "48v Panel" will produce enough voltage to charge a 48v battery, or a 24v, or a 12v. When you're calculating for your SCC the only time those numbers really come into play is if you're using a cheapie PWM controller. Since the PWM controllers just clip voltage to whatever battery voltage is, going over that is a waste of energy.
For example, if you've got a little 12v panel on a 12v PWM controller and a 12v battery, the panel is probably producing 18-ish volts and the PWM is just clipping that down to the 13.5-ish that your battery uses. Anything between that 13.5 and 18 is just dumped/wasted. If you were to throw a 48v 300w panel on a 12v PWM and battery, that's anything between 13.5 and 60v that's just wasted and only 5 amps going into your battery (and probably fried your little controller in the process anyways!
). That's where the whole 12v/24v/48v panel thing really comes into play and your panel, PWM, and battery all need to be in the same range.Now, let's say that your little PWM just wasn't able to handle those "48v" panels your friend gave you for your birthday and you went and picked yourself up a decent little MPPT controller. Now things start getting good! The MPPT controller is trying to do all its battery math by watts, so your fancy 48v 300w panel is pumping 60v into the controller. The controller knows it's a 12v battery, so it's going to take the extra voltage and convert it to amperage. Now that 5a @ 60v is coming into the MPPT and it's being converted to 25a @ 12v of charging going to the battery. That's a helluva improvement! Since the MPPT can actually USE the excess voltage you gain a LOT more efficiency out of it.
Tl;Dr: PWM Volts In = Volts Out panel amps, MPPT Watts In = Watts Out, total amps.
*Just as a rough reference guide guys, I know it's a bit more technical than that.
littleharbor2
Solar Addict
PWM, Amps in =amps out MPPT, Watts in = watts out.Tl;Dr: PWM Volts In = Volts Out panel amps, MPPT Watts In = Watts Out, total amps.
*Just as a rough reference guide guys, I know it's a bit more technical than that.
12VoltInstalls
life passes by too quickly to not live in freedom
With a mppt SCC the published numbers are not indicative of use. The panel label will have information that is used to calculate parameters. Most “12V” panels these days are not really 12V but rather some open circuit voltage amount higher than charging voltage needs to be for a pwm SCC. Mine are 22V+ for example but people think of them as 12V panels. IIRC like in the 1990s a 12V panel might have been as little as 16-18V open circuit voltage. Even a few years ago “12V” cheapo retail kits that supposedly would keep a utility dump trailer battery charged would only be 13-14V at 1A in full sun on my ideal meter. (people would bring things they bought for installation- everything from winches to horns to solar panels to rescue truck equipment. People are dumb sometimes)
Very very helpfull . Thanks ✔Those are marketing terms, not real world numbers. What it means is that a "12v Panel" can produce enough voltage to charge a 12v battery, but not enough to do a 24v battery. Likewise a "48v Panel" will produce enough voltage to charge a 48v battery, or a 24v, or a 12v. When you're calculating for your SCC the only time those numbers really come into play is if you're using a cheapie PWM controller. Since the PWM controllers just clip voltage to whatever battery voltage is, going over that is a waste of energy.
For example, if you've got a little 12v panel on a 12v PWM controller and a 12v battery, the panel is probably producing 18-ish volts and the PWM is just clipping that down to the 13.5-ish that your battery uses. Anything between that 13.5 and 18 is just dumped/wasted. If you were to throw a 48v 300w panel on a 12v PWM and battery, that's anything between 13.5 and 60v that's just wasted and only 5 amps going into your battery (and probably fried your little controller in the process anyways!
Now, let's say that your little PWM just wasn't able to handle those "48v" panels your friend gave you for your birthday and you went and picked yourself up a decent little MPPT controller. Now things start getting good! The MPPT controller is trying to do all its battery math by watts, so your fancy 48v 300w panel is pumping 60v into the controller. The controller knows it's a 12v battery, so it's going to take the extra voltage and convert it to amperage. Now that 5a @ 60v is coming into the MPPT and it's being converted to 25a @ 12v of charging going to the battery. That's a helluva improvement! Since the MPPT can actually USE the excess voltage you gain a LOT more efficiency out of it.
Tl;Dr: PWM Volts In = Volts Out panel amps, MPPT Watts In = Watts Out, total amps.
*Just as a rough reference guide guys, I know it's a bit more technical than that.
Thanks gor the reply . Have just purchased a 5kw 48volt stand alone system 4x200amp 12 volt lithium batteries . 10 x 550watt panels 48 volt inverter Don't know how long this will take for delivery . Can hardly wait .Those are marketing terms, not real world numbers. What it means is that a "12v Panel" can produce enough voltage to charge a 12v battery, but not enough to do a 24v battery. Likewise a "48v Panel" will produce enough voltage to charge a 48v battery, or a 24v, or a 12v. When you're calculating for your SCC the only time those numbers really come into play is if you're using a cheapie PWM controller. Since the PWM controllers just clip voltage to whatever battery voltage is, going over that is a waste of energy.
For example, if you've got a little 12v panel on a 12v PWM controller and a 12v battery, the panel is probably producing 18-ish volts and the PWM is just clipping that down to the 13.5-ish that your battery uses. Anything between that 13.5 and 18 is just dumped/wasted. If you were to throw a 48v 300w panel on a 12v PWM and battery, that's anything between 13.5 and 60v that's just wasted and only 5 amps going into your battery (and probably fried your little controller in the process anyways!
Now, let's say that your little PWM just wasn't able to handle those "48v" panels your friend gave you for your birthday and you went and picked yourself up a decent little MPPT controller. Now things start getting good! The MPPT controller is trying to do all its battery math by watts, so your fancy 48v 300w panel is pumping 60v into the controller. The controller knows it's a 12v battery, so it's going to take the extra voltage and convert it to amperage. Now that 5a @ 60v is coming into the MPPT and it's being converted to 25a @ 12v of charging going to the battery. That's a helluva improvement! Since the MPPT can actually USE the excess voltage you gain a LOT more efficiency out of it.
Tl;Dr: PWM Volts In = Volts Out panel amps, MPPT Watts In = Watts Out, total amps.
*Just as a rough reference guide guys, I know it's a bit more technical than that.
timselectric
If I can do it, you can do it.
- Joined
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Have fun and be safe.
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