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Solar question, existing setup...


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Flexible panels installed 2014 or 2015, 4 X 100w.

Marked on the terminal box DLC, and under that, PV-DLC605. Through an mppt controller.

 

one has died and I want to replace it , but I'm told the maximum output voltage of a new panel must be the same as existing.

What is the voltage for the above? It's not marked anywhere.

Is that requirement correct?

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Can’t tell model or make from that. PV-DLC605 Is the diode box only, not the panel. Ideally the max voltage should be the same to get the best output from the array, but it’s not actually essential. Are the panels wired in series or parallel? Check the open circuit voltage of a good panel when it’s sunny, and match or get close to that for the new one.

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What are these solar panels you talk of.

Just install 2 alternators as another thread covers and be done with this Green tree hugging anti global warming witchery.

Nothing like the constant lullaby drone of a Bay full of vessels generating power for their devices.

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Can’t tell model or make from that. PV-DLC605 Is the diode box only, not the panel. Ideally the max voltage should be the same to get the best output from the array, but it’s not actually essential. Are the panels wired in series or parallel? Check the open circuit voltage of a good panel when it’s sunny, and match or get close to that for the new one.

Thanks Matt. I think I've seen 18 or 19v in the past but will check it. Burnsco have something similar in physical size buts it's 17v.

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What are these solar panels you talk of.

Just install 2 alternators as another thread covers and be done with this Green tree hugging anti global warming witchery.

Nothing like the constant lullaby drone of a Bay full of vessels generating power for their devices.

Damn right about the generators.

Those panels ran a freezer all day every day from 2015 to 18, winter and summer. Doing it again now after a few months off.

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I'm adding a maintenance panel and when discussing that with system guru there was no mention of voltage matching and I was told 'just grab a good panel that will fit'.

 

But that maybe related to size, the maintenance panel only needs to give me 4-5amps per 24hrs, so it'll only be 10-12W. Guru is fine with that one being connected 24/7 into the same grid that the 100W/s will be hooking into when required.

 

I do have some flash control gear, no idea if that has any input into it.

The maintenance panel isn't for your lithium is it? :wtf:

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KM, lets get it right!

 

AMPs are current flow. Amp Hours are capacity. There is a huge difference in a panel that can give 4-5 amps, and one that can give 4-5 amp hours per 24 hours.....

 

And, your 0.2a draw as above is 4.8 amp hours per day actual draw. There are losses and inefficiencies in charging, you'd really want 5.5-6 amp hours per day out of the panel to keep up with this.  Allowing for crap weather, but still getting this charge, I'd use a panel of around 30w to be certain. That's 30w/13.6v = 2.2 amps x 3 hours useful charge in winter = 6.6 Ah. Thats guessing available sunlight, and using 13.6v as the float voltage for the batts...

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KM, lets get it right!

 

AMPs are current flow. Amp Hours are capacity. There is a huge difference in a panel that can give 4-5 amps, and one that can give 4-5 amp hours per 24 hours.....

 

And, your 0.2a draw as above is 4.8 amp hours per day actual draw. There are losses and inefficiencies in charging, you'd really want 5.5-6 amp hours per day out of the panel to keep up with this.  Allowing for crap weather, but still getting this charge, I'd use a panel of around 30w to be certain. That's 30w/13.6v = 2.2 amps x 3 hours useful charge in winter = 6.6 Ah. Thats guessing available sunlight, and using 13.6v as the float voltage for the batts...

and if its for a lithium battery, floating isn't needed, Charge to full and stop.  Cycle the bank down to 80% DOD and recharge only when you have an opportunity or need. If your system is set up well, repeat 2000 +/- times….

But I fear were getting off topic... :roll:

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It's important to have similar panel voltages. Like 12V to 12V and 24V to 24V. But the differences in Voltage to age of panel is not important. Current output of the panel does not matter. You can have a 10W panel and 200W panel connected together if you wanted. Just as long are both have the same Voltage rating.

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It's important to have similar panel voltages. Like 12V to 12V and 24V to 24V. But the differences in Voltage to age of panel is not important. Current output of the panel does not matter. You can have a 10W panel and 200W panel connected together if you wanted. Just as long are both have the same Voltage rating.

Why? The SP regulator simply takes the parallel voltages and combines them? So you are saying if one panel is shaded producing 14v and one is in the sun outputting 21v this is going to cause...what?

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Why? The SP regulator simply takes the parallel voltages and combines them? So you are saying if one panel is shaded producing 14v and one is in the sun outputting 21v this is going to cause...what?

Depends on how they are connected, ie Series or parallel.

In series, the voltage is going to drop to that of the lowest panel. Series is great on a House where there is clear unobstructed view of the Sun and all panels are getting the same light and producing the same output. The Voltage is high and thus a longer length of wire and/or smaller diameter can be used with less loss.

On a boat, because a shadow can fall across a panel, Series is not always the best method. In series, the voltage will drop to that of the lowest outputting panel only when it is shaded. If you have a 24V panel and a 12V panel in series, you will get 36V output

I parallel connection, it does not matter what happens to one or more panels as far as shadows are concerned.The Voltage will also be that of the highest outputting panel. However, if you have a 24V and a 12V panel connected in parallel, the 12V panel will be adding nothing to the batteries. Simply because the 24V panel will be doing all the work.

 

It is not the reg that combines the panels by the way. The combining is the actual way you connect them. Series is basically daisy chaining. You increase Voltage, but current always stays the same. Parallel always keeps the Voltage the same, but increases the Current. The Power of the panels is the Sum of the Voltage and Current.

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