Asking for help modifying existing solar array for better performance

[autumnbreeze27]

I removed the bimini solar panels this morning (because you don't work on the boat outside once the sun gets very high, it's hot as hell down here)

I just tested them, noon local time, so the sun is pretty much straight up.

Unfortunately I did not label them before I took them off, so I have no idea which panel is which compared to previous tests, but here's the results:

2 Panels put out 5.4A, one puts out 4.3A, and one puts out nothing at all.

[barnakiel]

Originally Posted by autumnbreeze27

I removed the bimini solar panels this morning (because you don't work on the boat outside once the sun gets very high, it's hot as hell down here)

I just tested them, noon local time, so the sun is pretty much straight up.

Unfortunately I did not label them before I took them off, so I have no idea which panel is which compared to previous tests, but here's the results:

2 Panels put out 5.4A, one puts out 4.3A, and one puts out nothing at all.

Bingo.

You may try to pry open the faulty one's box. Smell the internals and look for any broken connections on the face side of the panel too. Who knows, maybe it is still fix ' able.

Otherwise shopping time or else go as is. I think you are keeping the 4.3A one.

Let us know what you found in the box.

Cheers,
b.

[autumnbreeze27]

When I contacted Renogy they offered to replace the panels with the regular glass panels (bigger/heavier), so I went with that option.

I'm going to wire them up parallel. I'm going to rewire the dodger while I'm waiting so it is parallel as well.

[socaldmax]

When you mount the new panels, make sure you have at least 1" gap for some air to cool the panels. The temp. coefficient should be on the panel label or the spec sheet.

[newhaul]

Originally Posted by autumnbreeze27

When I contacted Renogy they offered to replace the panels with the regular glass panels (bigger/heavier), so I went with that option.

I'm going to wire them up parallel. I'm going to rewire the dodger while I'm waiting so it is parallel as well.

That's great news keep us posted on the install and the numbers.
Pm if you need help

[motion30]

[ QU OTE=Moontide;2153061]I have 3X240 panels and regularly see 60 AH output (maybe 2 out of 5 days depending on how much we have taken out the day/night before). Have a Morningstar MPPT 60A controller. One nice thing about Morningstars is that they log daily data internally and they have an ethernet connection. I can go back and check a dozen parameters by day since the install.

The comment about battery moniters only showing the net is spot on.

Regarding wiring, I wired my panels in parallel to avoid shade on one panel taking down the array. They are 35 volt (nominal) voltage and I used #4 wire from the panels to the controller.

Funny how you forget how much juice you use sometime but my panels have put out 240,000 AH in 4-1/2 years, and still going strong. Certainly cost beneficial vs. running a generator.[/QUOTE]

that certainly is excellent performance. I have 3 275 watt panels. and an outBack controller. I rarely see 50 amps, average is usually in the forties. it seems I am making an average of 280 ah a day the best day so far has been 330 amp hours

[autumnbreeze27]

Today's the big day... solar panels are due to arrive any time now! [Edit] Guy came by and said manana, TIM (This Is Mexico!)

Yesterday was my first day with parallel wired panels on the dodger, unfortunately it was overcast for a lot of the day so I never got full sun, so I didn't do any towel testing.
Max power out: 304W (of 400W)
119Ah / 1590Wh

Old array, highest voltage was 481W (of 800W)
199Ah / 2960Wh

Old array, highest power out 405W (of 800W)
256Ah / 3480Wh

Unfortunately I couldn't afford another Morningstar MPPT-60, and the secondary controller EPEVER 30A MPPT Tracer A Series 3210A + MT-50 Display doesn't log daily output, so I won't have a definitive way of measuring the difference, just seat of the pants watching the victron battery monitor.

Comparing yesterdays output to the previous 3 days of running serial/parallel the difference was 33% more power on 2 of the 3 days, and the one 50% more power day. Too many variables (clouds, shading from working on the boat, etc) to have a definitive answer, but it is clearly significant improvement.

[autumnbreeze27]

The solar panels were finally delivered. We got them installed last night.

I had the battery charger running last night, so this morning at dawn I had about 93% on the battery before I shut it off.

The solar was running pretty good this morning, both arrays putting out around 6-7A each, the new ones were producing about 1A more it seemed, I didn't document it since there was heavy shading and low sun angle.

Now we are in full sun, almost straight overhead:
I'm getting 19.8A off the new array, and 0.2A off the old array. Batteries are getting close to full, so you think the one controller has shut down the old panels?

I'm going to leave the battery charger (shore) off all night tonight to see how they work tomorrow with a lower starting point, we usually start the day around 70%

[autumnbreeze27]

Went to check my full sun reading today, and observed only 0.2A coming off the dodger panels (tracer 30a controller)

So I went out and inspected the panels, no shading, so I thought temp might be a problem. Measured 127F on the dodger panels (no air gap) and 107F on the bimini (new panels with lots of air gap)

Went back down and looked and it was reading 17A?? Going to have to keep an eye on it. Not sure if I'm running in to issues because I have 2 controllers going? The morningstar has a battery sensor wire, the tracer does not.

Tracer 30A Controller
4 X 100W Lensun panels wired in parallel on dodger
Array 15.2V @ 15.7A, To battery 14.V @ 17A

Morningstar MPPT-60 Controller
4 X 100W Renogy (new) wired in parallel on bimini
Array 14.4V @ 19.3A, to battery 13.66V @ 19.4A

[socaldmax]

Originally Posted by autumnbreeze27

Went to check my full sun reading today, and observed only 0.2A coming off the dodger panels (tracer 30a controller)

So I went out and inspected the panels, no shading, so I thought temp might be a problem. Measured 127F on the dodger panels (no air gap) and 107F on the bimini (new panels with lots of air gap)

Went back down and looked and it was reading 17A?? Going to have to keep an eye on it. Not sure if I'm running in to issues because I have 2 controllers going? The morningstar has a battery sensor wire, the tracer does not.

Tracer 30A Controller
4 X 100W Lensun panels wired in parallel on dodger
Array 15.2V @ 15.7A, To battery 14.V @ 17A

Morningstar MPPT-60 Controller
4 X 100W Renogy (new) wired in parallel on bimini
Array 14.4V @ 19.3A, to battery 13.66V @ 19.4A

As long as the batteries are in bulk or absorption charge mode, multiple chargers will not conflict with each other, the batteries will just soak up all of the current from all of the chargers. If the chargers have slightly different charge profiles and let's say one is set to 14.2v and the other is set to 14.5v, as soon as the batteries hit 14.2 that charger will go into float mode, the other charger will continue to charge until it hits 14.5.

What is interesting is the indicated voltage difference between the 2 chargers. Not too sure if that's an issue with thin wire, or uncalibrated measuring circuits. That's why I prefer thicker wire, less voltage drop to the batteries, so 14.6v at the solar controller doesn't end up being 14.0v at the batteries, which is nowhere near fully charged.

The other issue you may be experiencing is a well known problem with Tracer solar controllers. While other (better) controllers, like all of them, use algorithms that lock onto the correct MPPT voltage very quickly and track them in real time, the Tracer algorithm is well known to wander all over hell and back. MPPT for a specific panel might be 37v, but the Tracer controller will wander on down to 24v, then meander on up to 42v, and so forth. It spends an appreciable amount of it's time NOT on the correct voltage, thus harvesting less than pretty much any other brand of MPPT controller out there, including $100 ones.

There's a good chance you could connect the panels directly to the batteries and harvest more power, if you didn't have to worry about occasionally overcharging.

[socaldmax]

Personally, if that was my solar setup, I'd run the panels in series pairs, to get higher voltages like about 29 to 31v, then parallel the pairs. Since whatever shade you get is usually linear, you can determine which pair of panels will get shaded simultaneously and hook those up in series.

This way you'll get less power losses through the cables, the voltage to the input of the chargers will be higher than charging voltage earlier in the morning and later at night and the MPPT controllers will have a higher voltage margin to charge with.

I've seen panels get partially shaded by the sun, their voltage drops down to less than 14 volts and you get virtually nothing out of the controller. If they'd been hooked in series, then the controller would still be seeing 28v and doubling the current from the panels.

As you pointed out, you don't get much shade from the boom, etc, so doing them in series/parallel will help a little.

[autumnbreeze27]

I only saw good reviews on amazon, and didnt run in to any major problem threads anywhere, but I guess I didn't look hard enough.

So you think I should put everything back the way it was, eh?! Maybe I should hook both arrays back to the morningstar?

Using the numbers from yesterday in full sun:
Dodger Array 15.2V @ 15.7A, 0.37V drop estimate true array 15.57V
Bimini Array 14.4V @ 19.3A, 0.77V drop estimate true array 15.17V

Right now the bimini comes down on one pair of 10awg. I still have 12awg run in there, I could split the bimini and take one half of the panels down the 10awg pair and take the other half down on the 12awg pair, that would lower my voltage drop to around 0.3V

Here's the settings for my tracer:
Over 14.5
Charge Limit 14
Over Volt Rec 13.2
Equal 14
Boost 14
Float 13.8
Boost Rec 13.2
Low Volt Rec 12.6
Under Volt Rect 12.2
Under Volt Warn 12
Low Volt Disc 11.1
Discharge Limit 10.6
Equalize time 0
Boost time 10

My morningstar is set to 14V, no float.

Attached is a diagram and a pic of the tracer

[socaldmax]

That Tracer looks exactly like the one I have, except mine is a 40A version. All you have to do is watch the Tracer Vmp run up and down over a period of 15 min or so, then watch the Morningstar sit pretty much at Vmp with very little variation, much more stable output.

Yes, I prefer either 24v panels that put out roughly 28v at Vmp, or 12v pairs in series for the same output V for the reasons stated above. If I'm installing an odd number of panels (3), I've also just connected them all in series to get around 85v, but that was on a platform with no shading.

I would also recommend increasing your charge V to whatever the mfr recommends, like 14.8 or whatever; 14.0 looks a little low and is not fully charging your batteries. If you're only charging your batteries to 80 or 85% and discharging them to 50% then recharging, you're only really getting 30 or 35% of the total cap.

Looking at it another way, getting that last 15 or 20% of total capacity is netting you an extra 30 to 40% of usable capacity.

[autumnbreeze27]

Battery is LifePO4.

I'm going to leave them parallel for the next leg of our adventure, to see in the real world what the difference is. We're in this slip: the boat doesn't rock, it doesn't change orientation to the sun with the wind.

Right now I'm debating if rewiring the bimini panels yet again is worth a 0.37V gain

Only a few days left until we cast off.

[socaldmax]

Originally Posted by autumnbreeze27

Battery is LifePO4.

I'm going to leave them parallel for the next leg of our adventure, to see in the real world what the difference is. We're in this slip: the boat doesn't rock, it doesn't change orientation to the sun with the wind.

Right now I'm debating if rewiring the bimini panels yet again is worth a 0.37V gain

Only a few days left until we cast off.

Ooops, forgot about LiPo, disregard the voltage thing.

Rewiring is obviously a personal choice. I would, but that's just me.