Hey guys!

A while ago I installed some silar panels - 2x 160W Cinco panels. Now the angle of theae panels are close to horizontal as I'm not about to shell out thousands of rands to kit out my crazy landladys garage roof as it was the only place facing north and isn't covered by a tree...

They seem to be working just fine. But I can't help feeling I'm missing out on over 40% of my power output.

 

I'm getting at peak just under 180W output from the pair. (around 14A)

I'm not sure which of the parameter on the datasheet to look at.

The PTC are 160W.

The current is around 9A(8.7something)

The peak voltage is 18, though my MPPT controller keeps it at around 13.4, not sure if that may be it. (It's the one built into my axpert)

I'm a complete novice when it comes to solar.

Am I right to think something is wrong?

 

Yes you are right. As seasons change, the sun gets higher or lower in the sky. Thus there is no one optimal angle for panels (anywhere on earth, though the problem may become an academic one at locations close to the equator). On the Highveld, horizontal is pretty good in mid-summer, but will perform poorly in mid-winter.

Okay, but almost 50%?

Something I forgot to mention was my cables are also pretty long. Though still. I'd be wery worried if my cabels were dissipating 150W...

 

59 minutes ago, Bobster. said:

Yes you are right. As seasons change, the sun gets higher or lower in the sky. Thus there is no one optimal angle for panels (anywhere on earth, though the problem may become an academic one at locations close to the equator). On the Highveld, horizontal is pretty good in mid-summer, but will perform poorly in mid-winter.

 

You can use this link to easily check the best panel angle for your location and time of year: https://footprinthero.com/solar-panel-tilt-angle-calculator

I would suggest testing this by propping the panels up on a windless day and see what difference it makes. Not all day, just at midday, prop them up, check the change on the inverter and then put them back down. That will at least show you what could be possible with an angle change.

Edit: also make sure you put enough load on as the panels will only produce what you need and if the battery is full that won't be much.

Edited September 17, 20223 yr by jumper

On 2022/09/17 at 11:59 AM, jumper said:

 

Edit: also make sure you put enough load on as the panels will only produce what you need and if the battery is full that won't be much.

We can add if your inverter is set to charge a certain maximum like 20/30/40A from PV even if they are flat it will reduce the PV used. My 2.4kW clone only charged some 50% SOC lithiums at 21A (540W) and from the grid even if set to 30A only does 17A. When I started the heat pump it got 1250W from PV and still charged the battery at about 3A in full sun. This weekend was the 1st time after I modified my 6S1P string from the grid tied to 3S2P to connect from PV to my Axpert during LS. Very happy to see my plan worked spot on.

@Adagio

Your panels could produce about 220W in full sun if you change the angle to about 28 degrees. Thus they are doing OK for panels that are flat on a roof. Another panel is perhaps cheaper than a structure to change the angle. Output is a bit lower now than on the colder days of August.

On 2022/09/17 at 11:59 AM, jumper said:

You can use this link to easily check the best panel angle for your location and time of year: https://footprinthero.com/solar-panel-tilt-angle-calculator

I would suggest testing this by propping the panels up on a windless day and see what difference it makes. Not all day, just at midday, prop them up, check the change on the inverter and then put them back down. That will at least show you what could be possible with an angle change.

Edit: also make sure you put enough load on as the panels will only produce what you need and if the battery is full that won't be much.

Yeah the optimal angle should be around 34is but I'm not spending a hunk of cash on a house im not intending to stay in for more than a few more months.

17 hours ago, Scorp007 said:

We can add if your inverter is set to charge a certain maximum like 20/30/40A from PV even if they are flat it will reduce the PV used. My 2.4kW clone only charged some 50% SOC lithiums at 21A (540W) and from the grid even if set to 30A only does 17A. When I started the heat pump it got 1250W from PV and still charged the battery at about 3A in full sun. This weekend was the 1st time after I modified my 6S1P string from the grid tied to 3S2P to connect from PV to my Axpert during LS. Very happy to see my plan worked spot on.

@Adagio

Your panels could produce about 220W in full sun if you change the angle to about 28 degrees. Thus they are doing OK for panels that are flat on a roof. Another panel is perhaps cheaper than a structure to change the angle. Output is a bit lower now than on the colder days of August.

Yeah I thought so. I just wanted to be sure. My long cable runs were my primary problem. I overestimated them because I don't plan on staying here for long but they were also dropping like 50W.

I have a third panel. I just don't have the cash for the brackets and stuff right now.

2 hours ago, Adagio said:

Yeah the optimal angle should be around 34is but I'm not spending a hunk of cash on a house im not intending to stay in for more than a few more months.

Yeah I thought so. I just wanted to be sure. My long cable runs were my primary problem. I overestimated them because I don't plan on staying here for long but they were also dropping like 50W.

I have a third panel. I just don't have the cash for the brackets and stuff right now.

So with knowing you loose 50W due to the long runs your panels are doing very well. Without it getting 230W from 320W PV is very good. Those MPPTs in the Axpert do really work very well.

3 hours ago, Adagio said:

Yeah the optimal angle should be around 34is but I'm not spending a hunk of cash on a house im not intending to stay in for more than a few more months.

I totally understand, I was just suggesting that so you could test their output at the best angle to see whether the problem might lay elsewhere and possibly ascertain exactly how much you are losing in the cables.

1 hour ago, jumper said:

I totally understand, I was just suggesting that so you could test their output at the best angle to see whether the problem might lay elsewhere and possibly ascertain exactly how much you are losing in the cables.

I'll give it a go if I got some free time!

Sanity check: Is this definitely the Axpert model with MPPT, or with PWM charge controller?

For the next few months heading into summer, just leave it be. Anything you spend on 2 panels will be a waste, the money will not be made back except if you prop it up with a couple of bricks (don't do that). Most you could improve is around 10-15%, say a quarter of a unit of power per day. High level thumbsuck.

9 minutes ago, GreenFields said:

Sanity check: Is this definitely the Axpert model with MPPT, or with PWM charge controller?

For the next few months heading into summer, just leave it be. Anything you spend on 2 panels will be a waste, the money will not be made back except if you prop it up with a couple of bricks (don't do that). Most you could improve is around 10-15%, say a quarter of a unit of power per day. High level thumbsuck.

Is there a way I can tell the difference? The sticker on the side says MPPT though it has no branding and I got it broken and fixed it.

It's not MPPT.

It doesn't say MPPT on the side. And from what I know about MPPT this is a PWM.

3 hours ago, Adagio said:

It doesn't say MPPT on the side. And from what I know about MPPT this is a PWM.

 I just figured that a PWM charge controller could be another possible reason why you may be seeing reduced power relative to a model with MPPT charge controller. Was just speculating, but if you've confirmed the model is a PWM version, that could be a plausible explanation to consider.

Yeah. I feel a lot better about my 200W output now.

Thanks guys!