Series or parallel?

[MassEffect]

Is it more effiect for charging to run one verses the other or simply a matter of keeping volt's and amp's within the limit's of wire's and the charge controller?

 

[svetz]

Slowest rate of charging is probably the most efficient, less turned into heat. Of course, if you're waiting for your EV to charge to go the next 250 miles you probably want it complete by the time you finish your bio/coffee break.

 

[MassEffect]

Fair enough...Thanks for your response!

 

[time2roll]

Unless high voltage is a concern I am generally inclined to go series.

 

[MassEffect]

It's only a 400 watt system. I go parallel for the amperage because amperage is current and the higher the current the faster and more complete the charge that occurs. Since I have a small 12 volt system the 18.5 volt's are plenty to charge the batteries so Current seems the better choice for me and to tell the honest truth is has worked flawlessly so far! Is there a benefit to series other than keeping volt's and amperage within the limits of the wire and charge controller so more panel's can be in an array? I can't find any myself. Now when and if I can add more panel's I will add a second charge controller and run an array to each one that way I can set up an array for the early part of the day and one for late pate of the day so I can maximize what my solar panel's can offer!

 

[snoobler]

It's only a 400 watt system. I go parallel for the amperage because amperage is current and the higher the current the faster and more complete the charge that occurs.

That is generally NOT the case. Higher current charging can also be less efficient, and battery chemistry matters. If ANY kind of lead acid, you're approach is a great way to shorten the lives of batteries.

Since I have a small 12 volt system

All the more reason to keep current to suitable levels.

the 18.5 volt's are plenty to charge the batteries so Current seems the better choice for me and to tell the honest truth is has worked flawlessly so far! Is there a benefit to series other than keeping volt's and amperage within the limits of the wire and charge controller so more panel's can be in an array?

Depends. We haven't established whether you're using PWM or MPPT controller. If you're PWM, you MUST put them in parallel. If MPPT, it's not going to make a lot of difference except in very low light conditions. A 2S2P should perform a bit better in lower light conditions. If you're on PWM, you're never going to see more than 80% of rated power. MPPT has the potential to allow 100% of rated power.

Parallel panels have an advantage when it comes to shading. Panels in series are affected by shading more than panels in parallel.

I can't find any myself.

Have you compared on vs. the other, or are your conclusions research-based?

Now when and if I can add more panel's I will add a second charge controller and run an array to each one that way I can set up an array for the early part of the day and one for late pate of the day so I can maximize what my solar panel's can offer!

You can do this on the same controller provided your parallel strings are the same voltage.

 

[MassEffect]

I use a 60 amp MPPT charge cotroller. Yes I research before I do anything. Sometimes I get it right and sometimes I get saved. I look at, and like the analogy of electricity can be compared to a river. Like I said I have not been able to find one thing that suggest's that panel's in series offer's any benefit over parallel for charging in small system's now it's possible it does but for the life of me i can't find the information. How much it help's or don't...I went through an apprenticeship to become a stationary engineer. And I have to believe the physic's of electricity are still the same today that they were when I learned about it. Sir if you have some literature that shows me higher volt's and lower amp's are better than higher amp's ad lower voltage is better for charging the batteries, as long as the boundaries of the system are kept intact...I would love to have that knowledge! Thanks!

 

[MassEffect]

To be fair...it is a simple emergency back up system and the 4 panel's can only produce 21.64 amp's mazimum under Ideal and perfect condition's...if I had or was running a lager complicate system I would probably use both method's for a litany of reason's.

 

[time2roll]

I like the simplicity of series solar panels. Plug and play with MC4. No combiner box or fuses to develop connection issues. Since you already have MPPT this is a slam dunk. Just don't go over the Vmax controller rating.

At this level the issue of efficiency and shading etc is about equal either way.

 

[snoobler]

I use a 60 amp MPPT charge cotroller. Yes I research before I do anything. Sometimes I get it right and sometimes I get saved. I look at, and like the analogy of electricity can be compared to a river. Like I said I have not been able to find one thing that suggest's that panel's in series offer's any benefit over parallel for charging in small system's now it's possible it does but for the life of me i can't find the information. How much it help's or don't...I went through an apprenticeship to become a stationary engineer. And I have to believe the physic's of electricity are still the same today that they were when I learned about it. Sir if you have some literature that shows me higher volt's and lower amp's are better than higher amp's ad lower voltage is better for charging the batteries, as long as the boundaries of the system are kept intact...I would love to have that knowledge! Thanks!

You indicated simply:

It's only a 400 watt system. I go parallel for the amperage because amperage is current and the higher the current the faster and more complete the charge that occurs.

Note that neither you nor I referred to voltage in that context.

Bottom line is that your battery has a charge rating. Exceeding it is detrimental to its life with no "more complete charge" benefit.

The very concept of "absorption" charge, which occurs at a constant voltage, is direct evidence of the inaccuracy of your statement. You can't get ANY battery fully charged at ONLY high current. Charging must include a constant voltage/decreasing current absorption phase to fully charge.

 

[wholybee]

Are we discussing panels or batteries? It isn't really clear, and it makes a difference discussing parallel/series.

 

[Rednecktek]

If he's got a MPPT on there, does it really matter? The charge controller will adjust the current and voltage into the batteries based on the programming of the controller and the draw of the batteries.

Or am I missing something?

IMO, just from the playing around that I'm doing to feed the 12v bus of my camp, paralleling would be better for when the shade hits the panels as only the amperage from the shaded panel will take a hit rather than the entire bundle. If you had 4 panels you could even arrange them to take advantage of different sun angles through the day (my place has hills and trees, so about 2 hours of direct sun at best) by having some that face better up to noon and some that face better after noon rather than having all of them getting good charge from 11:30-1:30.

Or so are my thoughts about small systems like ours.

Please correct me if I'm missing something important.

 

[wholybee]

If he's got a MPPT on there, does it really matter? The charge controller will adjust the current and voltage into the batteries based on the programming of the controller and the draw of the batteries.

Or am I missing something?

IMO, just from the playing around that I'm doing to feed the 12v bus of my camp, paralleling would be better for when the shade hits the panels as only the amperage from the shaded panel will take a hit rather than the entire bundle. If you had 4 panels you could even arrange them to take advantage of different sun angles through the day (my place has hills and trees, so about 2 hours of direct sun at best) by having some that face better up to noon and some that face better after noon rather than having all of them getting good charge from 11:30-1:30.

Or so are my thoughts about small systems like ours.

Please correct me if I'm missing something important.

In the morning and evening before and after good sun, a panel will not make enough voltage to charge a battery. A 100W panel might only make 10V, which will not charge a 12V battery. But, put 2 of them in series, and you extend your charging day and get more total power from the day. Also, higher voltages with less current means less power lost due to long wire runs, and allows smaller wire to be used. If you parallel panels then you increase current, lose power to heat(wires get warm), and need to size up the wires. If shade is an issue, the best solution is to use separate controllers, although paralleling panels mitigates the issue somewhat.

Being able to series panels for higher voltage is probably the best reason to switch from a PWM to MPPT controller.

 

[Hravn]

If he's got a MPPT on there, does it really matter? The charge controller will adjust the current and voltage into the batteries based on the programming of the controller and the draw of the batteries.

Or am I missing something?

IMO, just from the playing around that I'm doing to feed the 12v bus of my camp, paralleling would be better for when the shade hits the panels as only the amperage from the shaded panel will take a hit rather than the entire bundle. If you had 4 panels you could even arrange them to take advantage of different sun angles through the day (my place has hills and trees, so about 2 hours of direct sun at best) by having some that face better up to noon and some that face better after noon rather than having all of them getting good charge from 11:30-1:30.

Or so are my thoughts about small systems like ours.

Please correct me if I'm missing something important.

I have exactly this situation, bad roof angles, with shade, but decent exposure in the am and then again in the pm most of the year. So I'm contemplating 4 360 watt panels, with voc or 37.6 in two in series strings, brought in parallel into a epever 50 amp 24 v charge controller (150 v max so the two strings) feeding an ep4 24 volt 200 ah battery (assuming I can get one), otherwise 4 100ah lifepos combined for 24 volts, and a 3000 watt inverter. This gets me going for now and maintains flexibility and components for a larger rack system set up ultimately farther from the cabin with much better all day exposure.

its for 3-4 days at time use, running lights, small fridge, computers and tv for a few hours a day etc. ultimately a well pump too.

 

[12VoltInstalls]

What did you - OP m- wind up doing?

go parallel for the amperage because amperage is current and the higher the current the faster and more complete the charge that occurs. Since I have a small 12 volt system the 18.5 volt's are plenty to charge the batteries so Current seems the better choice for me

That’s not exactly correct- amps are proportional to volts and watts. You’ll likely get more amps per day with at least 2 in series:

100W panel might only make 10V, which will not charge a 12V battery. But, put 2 of them in series, and you extend your charging day and get more total power from the day.

Did I miss whether you (OP) tried series 2S2P? That will get you the more amps you desire.