Asking for help modifying existing solar array for better performance

[noelex 77]

Originally Posted by autumnbreeze27

If you look at the panels from high up on the stern, I numbered them
1-2-3-4 (dodger/lensun)
5-6-7-8 (bimini/renogy)

Power readings when covered:
1=143W 2=143W 3=134W 4=141W
5=260W 6=275W 7=272W 8=270W

Unless the amount of sunlight falling on the dodger and bimini was very different, your test indicates there is a problem with the wiring (probably a bad connection) of the panels on the bimini.

This would fit in with the low overall output you are recording from your system.

[barnakiel]

Originally Posted by tinkrman69

lithium or lead acid you shouldn't rate your storage to 50% usage. you may be able to keep a high voltage at a lower charge, with lithium,but it doesn't mean it won't take the time out of its over all life.

Tinker,

Can you PLS expand on why we should not rate the lithium ones to 50%.

I ask as I imagined 90% (meaning 90% empty)and beyond was OK. I judged from how e.g. the laptop, smartphone or tablet battery is getting used.

Is life the only consideration? And if so, how does 50% vs 95% life expectancy compare with lithium?

Thanks,
b.

[autumnbreeze27]

Please help me keep the thread on track. I don't have a storage issue, don't need to discuss that.

I'd like to discuss this more, so you think I have a problem on the bimini because the voltage doesn't drop when I shade a single panel? Does that mean the bimini isn't providing any juice at all? That would be an interesting discovery.

Power readings when covered:
1=143W 2=143W 3=134W 4=141W
5=260W 6=275W 7=272W 8=270W

[newhaul]

Breeze with the numbers you posted I would have to say that there is a wiring issue between the Bimini array and the controller.

[noelex 77]

Originally Posted by autumnbreeze27

Please help me keep the thread on track. I don't have a storage issue, don't need to discuss that.

I'd like to discuss this more, so you think I have a problem on the bimini because the voltage doesn't drop when I shade a single panel? Does that mean the bimini isn't providing any juice at all? That would be an interesting discovery.

Power readings when covered:
1=143W 2=143W 3=134W 4=141W
5=260W 6=275W 7=272W 8=270W

If the panels are experiencing the same conditions then covering each panel should have the same effect. There is obviously a large disparity in your case between covering the Bimini panels verses covering the dodger panels.

This indicates a significant problem, which is also evident from the low total output you have indicated in your first post.

Installing two or more solar controllers will only produce a slight improvement. It is much more important to trace the the cause of this fundamental problem.

The bimini panels are producing much less than they should be. The output of the bimini panels could be zero or just lower than it should be (once again assuming the sun on the bimini and dodger was similar when you did the test).

You need to find the cause.

[pbmaise]

It sounds like you live aboard. Dump the solar controllers and switch to individual pairs of wires to each panel with a circuit breaker for each panel. This would eliminate loss caused by controllers and eliminate wire connection points. Panels are small enough you are not looking at very large wire or circuit size.

Just be sure to turn off some panels if leaving boat extended period to manually avoid cooking batteries.

I automatically have loads turn on if batteries reach a high voltage to help prevent cooking.

[noelex 77]

Originally Posted by pbmaise

It sounds like you live aboard. Dump the solar controllers and switch to individual pairs of wires to each panel with a circuit breaker for each panel. This would eliminate loss caused by controllers and eliminate wire connection points. Panels are small enough you are not looking at very large wire or circuit size.

Just be sure to turn off some panels if leaving boat extended period to manually avoid cooking batteries.

I automatically have loads turn on if batteries reach a high voltage to help prevent cooking.

I don't think that is a great idea as a perminant solution especially with lithium batteries. However, it could be used as a short term test to try and isolate the problem.

MPPT controllers don't usually have a loss. They often have a slight gain compared to direct connection and that is assuming the best case for direct connection ie the panels are 36 cell models.

[autumnbreeze27]

Ok, made some progress.

Each pair of panels is wired in series with 12 awg that runs to the controller. So I have the ability to go 4 controllers without any extra wire runs.

I tested the bimini panels today. Using the towel trick I only got a power drop when covering panels 3 & 4, so the problem was panels 1 & 2

So I disconnected panels 1 & 2 from being in a series and tested each panel individually, and found one panel that is dead. Is there any way to troubleshoot a panel that's not working? I've removed the plastic cover on the wiring and tested continuity between the plug and the post inside, and it's good, so the problem is somewhere deeper.

I'm debating if I just run the dodger panels on one controller and the bimini on another, or if I run them port and starboard as I originally intended. (Port would only have 1 pair in series).

The other option is to run the 3 panels on the bimini in parallel to the new controller, but would my 12 awg wiring be a problem then? Distance is about 10'

[newhaul]

Originally Posted by autumnbreeze27

Ok, made some progress.

Each pair of panels is wired in series with 12 awg that runs to the controller. So I have the ability to go 4 controllers without any extra wire runs.

I tested the bimini panels today. Using the towel trick I only got a power drop when covering panels 3 & 4, so the problem was panels 1 & 2

So I disconnected panels 1 & 2 from being in a series and tested each panel individually, and found one panel that is dead. Is there any way to troubleshoot a panel that's not working? I've removed the plastic cover on the wiring and tested continuity between the plug and the post inside, and it's good, so the problem is somewhere deeper.

I'm debating if I just run the dodger panels on one controller and the bimini on another, or if I run them port and starboard as I originally intended. (Port would only have 1 pair in series).

The other option is to run the 3 panels on the bimini in parallel to the new controller, but would my 12 awg wiring be a problem then? Distance is about 10'

Breeze run the three panel set to the new controller in series the minimum wire for your 20 feet of run ( remember to measure both ways) would be 16awg. So your 12 agw is fine until you can sort out what the problem is ( or renogy gets a new panel to you ) .

[barnakiel]

"Cheap flexible"? Not AURINCO by an chance?

Just asking. Webb had like 4 out of 6 fail or something like this. See his blog.

You DID make my head turn in circles and so I will toss in my bed now. I do like the challenge, and I do like that you do not let go.

I wish you best luck trying the possible mods and I stay tuned to hear what the final set up is.

Thank you for your resilience. This is very seamanlike.

b.

[autumnbreeze27]

The panel that died is renogy 100w flexible replaced late sept last year due to fire hazard.


Sent from somewhere in the Pacific

[barnakiel]

Interestingly, having had a good long look at your proposal, I found I would be tempted to wire it all 'quite contrary'. That is, I would wire the panels:

- all of the dodger set - as one - in series,
- all of the bimini ones - as one - in series,

Then the two series I would parallel and feed this (at "" 48V) into an (single) MPPT of adequate A capacity (I think a 25A or 30A unit).

I believe this might give better harvest when the boom is amidships and shades both the port and stbd center ones.

???

b.

[autumnbreeze27]

I like the way you think, I'm going to run the aft 3 in series tomorrow and see what the results look like.

[autumnbreeze27]

I've been sick, I had to dive into the water to save something the admiral dropped... and I'm pretty sure I got sick from that exposure. Marina San Carlos does not have a pump out, so you can guess where most of people's waste goes.

It sucks.

Anyhow, back to my solar dilemma. I tested the bad panel yesterday and it was working, so this morning since I didn't feel half as bad as I have been, I went out and re-wired the bimini panels to be in series.

It's probably not a good time to test, because it's sprinkling and very cloudy, but here's what I'm getting out of the panels:

Dodger Array 33.5V 0.7A Charging at 1.8A
Bimini Array 14.2V 0.4A Charging at 0.5A

I would expect the voltage to be higher on the series, so I'm guessing there is still something wrong. Will try the towel shade thing a little later when there is more sun.

[barnakiel]

I think there are no by pass diodes. As you noticed the voltage is way to low.

We have rigid panels nominal 12V that easily deliver 17+ Volt on the up side.

I think with flexible panels that have sealed connection boxes fitting a diode may be difficult. You may get locked into using them in parallel unless a by pass diode is in each each sealed connection box.

But with voltage this low, I think there are no diodes in their boxes. (?)

Too bad with the water and your stomach. I get this sometimes just because of the effort after cleaning the hull. take care & get well!

b.