(2) 12V Solar Panels....Series or Parallel?

[Rbertalotto]

I have (2) 140w 12V panels. The Bogart Engineering solar controller can operate on 12V or 24V input. Is there any advantage or disadvantage to wiring the panels in series for 24V rather than parallel for 12V?

[NinerBikes]

OP is only now thinking about gauge of wire to run his 2 panels in parallel. In a new thread. Been on RVnet 10 years and hopes to pay it forward... :W

Really?

[Almot]

grizzzman wrote:

Ding Ding Ding!!!!!!!! Refreshing to say the least:B

Flush!!!
There are people who live off solar and people who experiment ;)...

[grizzzman]

red31 wrote:

Almot wrote:

red31 wrote:
That's the benefit of PWM, no transformer to waist energy on small systems.

Has been debated many times, and the consensus seems to be that main benefit of PWM for small (but still multipanel) systems is the cost.

Only if you ignore the heating issue with MPPT. Our good experimenter BFL has shown this as well as those poorly disappointed with their MPPT performance in real life compared to expectations. Let's remember BFL has the back of his open to what ever breeze there is, roof mounted would be even hotter, NOTC comes to mind and the coefficient of lost peak power with cell temperature.

Ignore bucking losses if you like.

Ding Ding Ding!!!!!!!! Refreshing to say the least:B

[full_mosey]

MEXICOWANDERER wrote:
I am going to "Do" the toad before I depart to the south. Now that I have found "Locomotive Grade" cable the battery is going to be relocated to the trunk and it looks like a Sam's Club AGM might be in the offing. A hundred forty dollar 68 amp hour group 34 flooded or a 179 dollar group 31 AGM? Duh!

Out West, Sams Club has the $199 Johnson Controls 31C 100AH AGM(Energizer). That is what I use.

In the East is where you find the $179 Deka(Duracel). I wish I had this one.

HTH;
John

[red31]

Almot wrote:

red31 wrote:
That's the benefit of PWM, no transformer to waist energy on small systems.

Has been debated many times, and the consensus seems to be that main benefit of PWM for small (but still multipanel) systems is the cost.

Only if you ignore the heating issue with MPPT. Our good experimenter BFL has shown this as well as those poorly disappointed with their MPPT performance in real life compared to expectations. Let's remember BFL has the back of his open to what ever breeze there is, roof mounted would be even hotter, NOTC comes to mind and the coefficient of lost peak power with cell temperature.

Ignore bucking losses if you like.

[Almot]

BFL13 wrote:
So do I, but a quick wire swap makes it 24v 🙂 Then you need to find some 12v as stated earlier.

Yes. There are (relatively) inexpensive DC-DC converters to run 12V loads off 24V bank. But this complicates things, more parts to fail. And you are right that non-solar charging and inverters also need to be 24V-compatible.

What SMK said - if they go to 500W, then they could consider 24V. Makes sense lowering the amps then. As it is now, with their current setup - this is just a geeky stuff, toying around.

[BFL13]

Almot wrote:

BFL13 wrote:
I posted my good results with 24v panel and 24v batts using both MPPT and PWM.

He's got 12V bank.

So do I, but a quick wire swap makes it 24v 🙂 Then you need to find some 12v as stated earlier.

You can even "tap" one of the two 12v batts in series to get 12v, but PT goes bananas when I say that, so I won't.

[Almot]

red31 wrote:
That's the benefit of PWM, no transformer to waist energy on small systems.

Has been debated many times, and the consensus seems to be that main benefit of PWM for small (but still multipanel) systems is the cost.

[Almot]

NinerBikes wrote:
Most people either do a search here, or do their research/homework first, before they buy their charge controllers,and solar panels.

Amen to that 🙂

[Almot]

BFL13 wrote:
I posted my good results with 24v panel and 24v batts using both MPPT and PWM.

He's got 12V bank.

[Slownsy]

The bogart controller is good for op to 36A and will then taper of. I have 4/150V panels= 600V feeding 2 260A flooded batteries with temp sensor and no issues haven't had to ad water in 4 months.
Frank

[NinerBikes]

Most people either do a search here, or do their research/homework first, before they buy their charge controllers,and solar panels.

[MEXICOWANDERER]

I am going to "Do" the toad before I depart to the south. Now that I have found "Locomotive Grade" cable the battery is going to be relocated to the trunk and it looks like a Sam's Club AGM might be in the offing. A hundred forty dollar 68 amp hour group 34 flooded or a 179 dollar group 31 AGM? Duh!

[red31]

http://www.dekabatteries.com/assets/base/0139.pdf

find the agm charge & float at various temps, bottom page 11

If ya buy into IUI use concord AGM otherwise use generic AGM no finish!

specs

http://www.eastpennmanufacturing.com/wp-content/uploads/Intimidator-Marine-Flyer-1741.pdf