Why are many kits Series Parallel and not Series?

[kenkoh]

Why does Renogy, Rich Solar and most 800w solar kits configure the panels in series-parallel and not just series using a 40a mppt? This Rich Solar 800w kit uses 4x 200w 24.3v panels which would be more efficient and less wires in a series config would it not? Would it be to lower the amp load?

800 Watt Solar Kit with 40A MPPT Controller

Our most popular kit! For a quieter, more peaceful outdoor experience, replace your generator with our 800 watt solar kit. This kit offers enough power to charge most five or six 12 volt battery banks. Power your RV, boat or trailer with 800 watt kit, it is perfect way to power your off-grid...

richsolar.com

Haven't been here for a while and still a beginner.

 

[rmaddy]

I don't know the specs but it's possible that the combined Voc of the panels in 4S would exceed the charge controller's max PV input voltage. If this is the case then 2S2P avoids that problem.

You also likely get better handling of shade by going with 2S2P over 4S.

Do note that 4S would lower the amps. 2S2P is actually higher amps than 4S.

One issue I see with that kit is that 800W at 12V can be up to 66A of charge current. But the kit only supports 40A. A 40A charge controller can only make use of at most 540W when the battery is at 13.5V. That's a lot of wasted potential.

 

[MisterSandals]

and less wires in a series config would it not? Would it be to lower the amp load

In series, the voltage becomes the combined voltages of all the panels in series and this would likely exceed what the SCC will handle without letting the magic smoke out (bad).
All in parallel, the amperage becomes the combined amperages of all the panels in parallel and this would likely exceed the wiring and connectors supplied. And, the voltage would be the voltage of a single panel and possibly not high enough for the SCC to be able to charge in all lighting conditions (early morning, cloudy, late afternoon). The array voltage needs to be about 5V more than charging voltage to start charging.

So, a combination of series and parallel and series, produces usable voltage and manageable amperage.

 

[kenkoh]

Thank you. The rich 200w panel is 24.3v x4 = 97.2, each panel is 9.8a I think so total for 800w would be 39.2a. So if I want to string in a single series would going with a 50a SCC 150v be the solution?

 

[rmaddy]

The rich 200w panel is 24.3v x4 = 97.2

True for 4S

each panel is 9.8a I think so total for 800w would be 39.2a.

True for 4P, at 4S it would be 9.8A.

So if I want to string in a single series would going with a 50a SCC 150v be the solution?

150V would support those panels in 4S. Though 50A at 13.5V is 675W. If the 800W panels are ever able to produce more than 675W then those extra watts will go to waste.

 

[kenkoh]

I don't know the specs but it's possible that the combined Voc of the panels in 4S would exceed the charge controller's max PV input voltage. If this is the case then 2S2P avoids that problem.

You also likely get better handling of shade by going with 2S2P over 4S.

Do note that 4S would lower the amps. 2S2P is actually higher amps than 4S.

One issue I see with that kit is that 800W at 12V can be up to 66A of charge current. But the kit only supports 40A. A 40A charge controller can only make use of at most 540W when the battery is at 13.5V. That's a lot of wasted potential.

I didn't know that 4s lowers the amps wow. Each 200w panel is 24.3voc so even with 25% headroom it does not exceed the max PV input, and this will be for 24v.

 

[rmaddy]

With things in series you add the voltage and keep the amps the same.

With things in parallel you add the amperage and keep the volts the same.

 

[kenkoh]

True for 4S


True for 4P, at 4S it would be 9.8A.


150V would support those panels in 4S. Though 50A at 13.5V is 675W. If the 800W panels are ever able to produce more than 675W then those extra watts will go to waste.

Thank you. So if I really want to go series 60a SCC works correct? The 800w will be connect to 24v battery setup.

 

[rmaddy]

Thank you. So if I really want to go series 60a SCC works correct?

40A, 50A, and 60A all "work". It's just a matter of how much of the panel wattage you can make use of. 800W of panels may never produce 800W. It depends on how they are mounted, sun angle, clouds, shading, etc. A 60A controller will handle the most. But if your panels can never make more than 675W due to all of the variables, then a 50A controller would be enough.

Edit - I missed the mention of the 24V battery in the previous post. This cuts the needed size of the controller's charge current in half vs that needed on a 12V battery which is what my numbers were based on.

 

[kenkoh]

40A, 50A, and 60A all "work". It's just a matter of how much of the panel wattage you can make use of. 800W of panels may never produce 800W. It depends on how they are mounted, sun angle, clouds, shading, etc. A 60A controller will handle the most. But if your panels can never make more than 675W due to all of the variables, then a 50A controller would be enough.

I'm in the desert best place in the US with 6.5hrs sun daily. No shade. No freezing or snow. Basically I just like series etup and trying to find to best configuration for 800w.

 

[MisterSandals]

The 800w will be connect to 24v battery setup.

800W / 28V (charge voltage) = 28.6A max charging amps from your array (regardless of how configured). You could get by with a 30A charger for a 24V battery.

And 6.5h x 800W = 5200Wh. Enough to charge 203Ah (25.6V) battery in a single day, with no loads.

 

[rmaddy]

You could get by with a 30A charger for a 24V battery.

Oops. I missed the later post that mentioned the 24V battery.

That does reduce the size of the needed charge controller by half vs a 12V battery.

 

[kenkoh]

Thanks guys for your brains much appreciated.

 

[12VoltInstalls]

didn't know that 4s lowers the amps wow

With things in series you add the voltage and keep the amps the same.

With things in parallel you add the amperage and keep the volts the same

^^^ this

if your panels can never make more than 675W due to all of the variables, then a 50A controller would be enough. at 12V as posted later

A case for a 40A or 50A charge controller is if you ever expand you’re already ’there’ to handle more panels.

 

[Minimoose]

Why does Renogy, Rich Solar and most 800w solar kits configure the panels in series-parallel and not just series using a 40a mppt? This Rich Solar 800w kit uses 4x 200w 24.3v panels which would be more efficient and less wires in a series config would it not? Would it be to lower the amp load?

800 Watt Solar Kit with 40A MPPT Controller

Our most popular kit! For a quieter, more peaceful outdoor experience, replace your generator with our 800 watt solar kit. This kit offers enough power to charge most five or six 12 volt battery banks. Power your RV, boat or trailer with 800 watt kit, it is perfect way to power your off-grid...

richsolar.com

Haven't been here for a while and still a beginner.

I have two Rich solar kits. one for each battery bank. The 200 watt OCV is 24.3 for normal temps, but can go up about 4 volts in really cold weather. It's been in the teens here right now and I'm seeing over 25 volts per panel even while hooked up. Rich solar Tech suport told me to add 4 volts in the cold weather. So basically 29x4=116 volts which is over the 100 volt limit of the 40amp controller.

 

[kenkoh]

I have two Rich solar kits. one for each battery bank. The 200 watt OCV is 24.3 for normal temps, but can go up about 4 volts in really cold weather. It's been in the teens here right now and I'm seeing over 25 volts per panel even while hooked up. Rich solar Tech suport told me to add 4 volts in the cold weather. So basically 29x4=116 volts which is over the 100 volt limit of the 40amp controller.

How are you finding the Rich solar kits so far?

 

[Minimoose]

How are you finding the Rich solar kits so far?

I like them so far, but it's winter here and cold so I'm not getting a lot of sun. The 40 amp mppt controllers seem to be doing a good job. I had one controller that was DOA, but they sent me a new one. Every time I have called with questions or a problem I get through pretty quick. Good service for me so far. The panels seem to be well made and voltage is consistent even though I bought the two kits at different times. I hooked up just 400 watts to a battery bank the other day and was pushing 22 amps from the controller to the battery bank. That's pretty good for bright winter sun.

 

[kenkoh]

I like them so far, but it's winter here and cold so I'm not getting a lot of sun. The 40 amp mppt controllers seem to be doing a good job. I had one controller that was DOA, but they sent me a new one. Every time I have called with questions or a problem I get through pretty quick. Good service for me so far. The panels seem to be well made and voltage is consistent even though I bought the two kits at different times. I hooked up just 400 watts to a battery bank the other day and was pushing 22 amps from the controller to the battery bank. That's pretty good for bright winter sun.

How long have you used the kit?

 

[12VoltInstalls]

Rich solar Tech suport told me to add 4 volts in the cold weather. So basically 29x4=116 volts which is over the 100 volt limit of the 40amp controller.

You could go 2S2P and mitigate the max volts issue.

 

[kenkoh]

You could go 2S2P and mitigate the max volts issue.

I'll change controller to 150v, I like 4s better. I didn't know that 40a scc was only 100v my bad.