Solar Enough ?

[thinwater]

Any expereince with Sun Electronics?
SUN Solar Panel 85 Watts 18.30 Vmp [SUN-ES-85W-18.3V] - $157.25 : Solar Panels, Inverters and PV Systems | Worlds Lowest Price, Powered by Nature!

I have limited space--I can fit 2 of these.

[noelex 77]

Originally Posted by Feral Cement

There is only one location where this slipper can tolerate 200W of solar on a 27' boat - davits off the stern (which seems to be a good location, in general).

Is there something wrong with the panels I was proposing?

Suntech Solar Panel 200 Watts 26.20 Vmp [STP200-18/UB-1 A-1] - $368.00 : Solar Panels, Inverters and PV Systems | Worlds Lowest Price, Powered by Nature!

One of the reasons I chose them is that they are only 58.4" long (most are 61 - 63") and since my transom is only about 50 inches wide, that dimension is important. At $1.84 per watt, they were not the cheapest in the store, either.

The solar panel you listed looks good, at least on paper, and its important the dimensions are suitable, which they obviously are.
The only problem is that the voltage is forcing you to use a MPPT controller because its not a 12v panel. As per my previous post recomending a suitable inexpensive MPPT regulator is difficult.
If you cannot find a suitable 12v (or 2 panels ) that will fit well at a reasonable price then this panel may be the best alternative, but I think its worth exploring the cost and suitability of panels that would not require an expensive or poor performing regulator.

[jaredko]

I agree with noelex, your plan looks good, just need to find the right controller. I'd suggest you take funjohnson up on his offer for his bluesky, it's a quality unit and his price is fair.

[Heart of Gold]

Originally Posted by noelex 77

The solar panel you listed looks good, at least on paper, and its important the dimensions are suitable, which they obviously are.
The only problem is that the voltage is forcing you to use a MPPT controller because its not a 12v panel. As per my previous post recomending a suitable inexpensive MPPT regulator is difficult.
If you cannot find a suitable 12v (or 2 panels ) that will fit well at a reasonable price then this panel may be the best alternative, but I think its worth exploring the cost and suitability of panels that would not require an expensive or poor performing regulator.

I'm adding panels and found this recommendedMPPT controller at not a bad price:
Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

[Feral Cement]

Originally Posted by noelex 77

The solar panel you listed looks good, at least on paper.
The only problem is that the voltage is forcing you to use a MPPT controller because its not a 12v panel.

Oy vay.....

I thought ALL panels put out more than the "target" voltage and ALL charge controllers adjusted that voltage to properly charge the batteries without ruining them. What spec am I interested in - VMP? Open Voltage? - and what value am I looking for?

To further add to my confusion is this page that says that PWM and MPPT charge controllers have different goals, and that the PWM will do more to prolong battery life:

MPPT vs PWM charge controllers by Blue Sky, Morningstar, OutBack and Xantrex

According to that, PWM extends battery life and MPPT gets the most from the panel to the battery, but you can't have both. So I find a panel that fits my boat, but puts out too much voltage to use a cheap, battery preserving CC - again, ya can't have both.

Be nice - I'm just another PC (Poor Cruiser) riding FRP on the ICW in the USA. YMMV

John

[Heart of Gold]

Originally Posted by Feral Cement

Oy vay.....

I thought ALL panels put out more than the "target" voltage and ALL charge controllers adjusted that voltage to properly charge the batteries without ruining them. What spec am I interested in - VMP? Open Voltage? - and what value am I looking for?

To further add to my confusion is this page that says that PWM and MPPT charge controllers have different goals, and that the PWM will do more to prolong battery life:

MPPT vs PWM charge controllers by Blue Sky, Morningstar, OutBack and Xantrex

According to that, PWM extends battery life and MPPT gets the most from the panel to the battery, but you can't have both. So I find a panel that fits my boat, but puts out too much voltage to use a cheap, battery preserving CC - again, ya can't have both.

Be nice - I'm just another PC (Poor Cruiser) riding FRP on the ICW in the USA. YMMV

John

Here is a spec sheet of the controller I chose and it kinda splains about its qualities. And its made on this continent or assembled at least. If you charge a battery at its recommended voltage and keep it full it will last longer. This is why I chose an MPPT as it will get all of the amps out of the panel it can.Cheers

http://partsonsale.com/MPPT250.pdf

[Feral Cement]

Originally Posted by Heart of Gold

Here is a spec sheet of the controller I chose and it kinda splains about its qualities.
http://partsonsale.com/MPPT250.pdf

Back at post #80 in this thread, the BZ 250 was not highly recommended. I did find the Bluesky 2512ix for $190 w/free shipping, but that comparison page

MPPT vs PWM charge controllers by Blue Sky, Morningstar, OutBack and Xantrex

suggests that PWM does more for battery life than MPPT.

See, I AM paying attention!

John

[jaredko]

John, that article is not well written. Quality controllers, both PWM and MPPT will be fully optimized to maintain the batteries. The added benefit of the MPPT is that it can convert more of the panel's output to usable amps.

A PWM controller discards some energy to lower the panel's voltage to the correct level for battery charging, an MPPT controller efficiently converts it.

Panels are referred to by their nominal voltage that aligns with the batteries they are meant to charge. The actually operate at a higher voltage for a number of reasons. You want to look at the Maxiumum Power Voltage Vmp, which will be about 18v for a 12v nominal panel, 36v for a 24v panel, etc.

To use a higher voltage panel with a 12v battery, you need to use MPPT because it will efficiently lower the voltage to the correct level for your battery. A PWM controller does not have this ability and needs a 12v nominal panel.

Your options as I see them:
- PWM controller with a different, 12v panel. Cheapest option, but you are getting less power from the panel. $90 for a Xantrex C35. There isn't a panel on sunelec that meets your criteria by itself, your only way with that vendor would be 2 Yingli 85w panels (no idea about their quality) wired in parallel for 170w with a total area of 56"x40" ($233 ea). Total cost ~$556

-Funjohnson's Bluesky at 175$ plus your suntech 200w panel for 368, $543.

- New bluesky for $250 plus the suntech, 618.

So unless you can find a 200w 12v panel from another vendor that is the size you are looking for, or can find a way to fit a 65" panel, looks like the bluesky controller is the way to go.

[Feral Cement]

Originally Posted by jaredko

John, that article is not well written. Quality controllers, both PWM and MPPT will be fully optimized to maintain the batteries. The added benefit of the MPPT is that it can convert more of the panel's output to usable amps.


Your options as I see them:
- PWM controller with a different, 12v panel. Cheapest option, but you are getting less power from the panel. $90 for a Xantrex C35. There isn't a panel on sunelec that meets your criteria by itself, your only way with that vendor would be 2 Yingli 85w panels (no idea about their quality) wired in parallel for 170w with a total area of 56"x40" ($233 ea). Total cost ~$556

-Funjohnson's Bluesky at 175$ plus your suntech 200w panel for 368, $543.

- New bluesky for $250 plus the suntech, 618.

looks like the bluesky controller is the way to go.

One last question (I hope): Would there be any significant long-term difference in battery life between:

a "12V" panel with a PWM controller and

the panels I listed with the Bluesky CC?

Thanks - that last post really brought things into focus, I think.

John

[noelex 77]

Originally Posted by Feral Cement

Oy vay.....

I thought ALL panels put out more than the "target" voltage and ALL charge controllers adjusted that voltage to properly charge the batteries without ruining them. What spec am I interested in - VMP? Open Voltage? - and what value am I looking for?

A “12v “panel will have these sort of specs for voltage
Voltage under load about 18v
Open circuit voltage about 23v

The panel you listed has considerably higher voltages than this and is not suitable for a 12v battery with a non MPPT regulator.

Originally Posted by Feral Cement

Oy vay.....

To further add to my confusion is this page that says that PWM and MPPT charge controllers have different goals, and that the PWM will do more to prolong battery life:

MPPT vs PWM charge controllers by Blue Sky, Morningstar, OutBack and Xantrex

Yes it does seem to say that, but its wrong. As far as the battery is concerned MPPT regulators and simpler PWM regulators ( actually both types of regulators are PWM ) are the same. Both use the adjustable equalize, boost, absorption and float voltages. The only exception is some cheap regulators, particularly MPPT regulators, which only use a single, or 2 step, charge level. These regulators should be avoided. They will damage the battery or reduce the output from the solar panel.
Unfortunately consumers want MPPT regulators at a cheap price so manufacturers are producing some regulators that don’t have adjustable 3 or 4 stage charging, but if you get a quality MPPT regulator it will incorporate the correct charging profile.

[jaredko]

All other things being equal, the MPPT controller will give you better battery life, because the extra amps it delivers to the batteries will allow it to reach a full charge more often.

[noelex 77]

Originally Posted by Feral Cement

One last question (I hope): Would there be any significant long-term difference in battery life between:

a "12V" panel with a PWM controller and

the panels I listed with the Bluesky CC?

Thanks - that last post really brought things into focus, I think.

John

Bluesky make reasonable quality products. My only concern with the 2512ix is how to adjust the voltage thresholds for different battery chemistries. This seems to require an optional part, but this is not clear.
The charge voltage thresholds should be adjustable. If they are not matched correctly battery life will be shorter
If they are adjustable (or if you are very lucky and the default settings are correct for your batteries) the battery life will be as good as is possible.

[noelex 77]

A caveat on the 2512ix and you proposed panel is that the recommended maximum Voc is 28v for the 2512ix . The proposed panel exceeds this with a Voc of 33.4v. Unfortunately this makes the Bluesky controller unsuitable.

[Feral Cement]

Originally Posted by noelex 77

A caveat on the 2512ix and you proposed panel is that the recommended maximum Voc is 28v for the 2512ix . The proposed panel exceeds this with a Voc of 33.4v. Unfortunately this makes the Bluesky controller unsuitable.

Well, of course - if they were well-matched, I'd have a "solution", and we know how awkward THAT can be.

Sheesh.... Plan C?

John

[jaredko]

Wow, good catch Noelex, that is a picky unit! Might have to revise my thoughts on bluesky. Perhaps we can go back to looking at the morningstar 15a controller? I think the conditions where John could actually get more than 15a into the batteries would be pretty rare. It may cost him 2-3 ah each day if he is in ideal conditions, but if the alternative is going down to a 170w array to fit the space, he will still be ahead.