Which panels and charge controller?

[AlreadyGone]

Doing an Astro, so my roof space is limited (~56" x 84"). So far, I seem to be able to do a Fantastic-fan and either 330w or 300w of solar. What I'm looking at is this:

A) 2x 165w "Everbright Solar" panels run length front to back - 

Dimensions: 59 x 26 1/2 x 1 3/8 In.
Electrical Characteristics:
Peak Power (Pmax): 165 W +- 3%
Voltage at Peak Power (Vmp): 18.10 V
Current at Peak Powre (Imp): 9.12 A
Short Circuit Current (Isc): 9.58 A
Open Circuit Voltage (Voc): 22.81 V
Maximum System Voltage (UL): 600V DC
Maximum System Voltage (IEC): 1000V DC
Series Fuse Rating: 15 A

165 Watt Solar Panel

or

B) 3x 100w Renogy panels run length side-to-side-

Maximum Power: 100W
Maximum System Voltage: 600V DC (UL)
Optimum Operating Voltage (Vmp): 18.9V
Open-Circuit Voltage (Voc): 22.5V
Optimum Operating Current (Imp): 5.29A
Short-Circuit Current (Isc): 5.75A
Weight: 16.5lbs
Dimensions: 47 X 21.3 X 1.4 In

Renogy 100 Watt 12 Volt Monocrystalline Solar Panel-See Specifications

The larger wattage panels either will not fit with a Fantastic-fan install or they will use up less space...and offer less wattage. So, right now, regardless of $/watt, where they are purchased or a number of other variables...

1) Renogy has an acceptable name/reputation in the van dwelling community....is anyone familiar with "Everbright Solar"? $340 shipped for 330w vs. Renogy's $415 shipped for 300w. Panels only on both.

2) It seems to me that the Renogys x3 will push about 15.87 amps, and the Everbrights x2 will push 18.24 amps. Would a 20amp MPPT charge controller be sufficient, or would I need to step up to, say, a 30A controller?

 

[MrNoodly]

Standard first question: What are you planning on powering? Because you might not need 300+W of solar. If you do need that much, there are single panels with dimensions that might fit better, as well as simplifying your mounting and cabling.

Standard second question: How much battery are you planning on charging with your panels? Because there are suggested panel/battery ratios.

 

[AlreadyGone]

Standard first question: What are you planning on powering? Because you might not need 300+W of solar. If you do need that much, there are single panels with dimensions that might fit better, as well as simplifying your mounting and cabling.

Standard second question: How much battery are you planning on charging with your panels? Because there are suggested panel/battery ratios.

Personally, I don't see the point on being limited with electricity. If I could fit 1,000w up there...I probably would.

"The larger wattage panels either will not fit with a Fantastic-fan install or they will use up less space...and offer less wattage."

I'm looking at 200ah or more. Not sure at this point if I want to shell out for Lifeline, or go with Trojans...or even the Duracell. Not sure about 12v or 2x 6v. Those are all things that I still need to try to sort out.

 

[jonsun]

Solar Blvd 140w 17v for $105

Morningstar TS-45

The big thing is to get a real charge controller that has dip switches for voltage output. No need for the MPPT stuff with 17v panels and 14.8v charge voltages....And if you're way over building the system.

 

[John61CT]

Yes, never mind a little extra cost, maximize watts output.

I'd even consider getting creative about fan(s) placement to get even more.

The panels will NEVER output the max-rated Amps, and a good controller will be conservative, so 10% margin should be fine.

Note with MPPT like Victron you can actually stack higher voltages (not amps) for greater efficiency in conversion and reduce volts dropped.

But in series you will lose even more from any (ANY) partial shading, even a bit of bird poop can drop most output.

To optimize for shading, more/smaller panels in parallel are better, or even each their own cheap controller.

 

[AlreadyGone]

Solar Blvd 140w 17v for $105

Morningstar TS-45

The big thing is to get a real charge controller that has dip switches for voltage output. No need for the MPPT stuff with 17v panels and 14.8v charge voltages....And if you're way over building the system.

I definitely don't understand about the "No need for the MPPT stuff". What I understand so far is that if the budget allows...go with MPPT. If not, then PWM will do. Also, how can I tell if a controller has "dip switches"?

Ok, the PDF for the Morningstar TS-45 states:

"Fully Adjustable – DIP switch provides user with a choice of 7 different digital presets and custom settings via RS-232."

Otherwise, how would I know? Doesn't seem to be a lot of info given out, generally.

Yes, never mind a little extra cost, maximize watts output.

I'd even consider getting creative about fan(s) placement to get even more.

The panels will NEVER output the max-rated Amps, and a good controller will be conservative, so 10% margin should be fine.

Note with MPPT like Victron you can actually stack higher voltages (not amps) for greater efficiency in conversion and reduce volts dropped.

But in series you will lose even more from any (ANY) partial shading, even a bit of bird poop can drop most output.

To optimize for shading, more/smaller panels in parallel are better, or even each their own cheap controller.

The fan is going rear center. There is even a flat area like it was made for it. LOL

So, 20 amp should be ok with either set of panels?


So, the 2x 165w panels and this controller would work well, right? In parallel or series...

Dealing with the 3x 100w Renogy, I would have either 3x 12v sources/panels, or need to jump to 36v for series...meaning that the 3x just complicates the situation....for me anyway.

 

[highdesertranger]

that flat area on the roof IS THERE for a vent. highdesertranger

 

[Spaceman Spiff]

Doing an Astro, so my roof space is limited (~56" x 84"). So far, I seem to be able to do a Fantastic-fan and either 330w or 300w of solar. 
. . .
1) Renogy has an acceptable name/reputation in the van dwelling community....is anyone familiar with "Everbright Solar"? $340 shipped for 330w vs. Renogy's $415 shipped for 300w. Panels only on both.

2) It seems to me that the Renogys x3 will push about 15.87 amps, and the Everbrights x2 will push 18.24 amps. Would a 20amp MPPT charge controller be sufficient, or would I need to step up to, say, a 30A controller?

One can never have too much solar.

A couple of considerations: 

• Larger panels are cheaper per watt, are more awkward to install, more susceptible to partial shade.
• Smaller panels are easier to work with when installing and when wired in parallel are less susceptible to partial shade.

I have 2 Renogy 100W panels and they work fine for me, never heard of Everbrights; although solar panels seem to be a commodity item now.  I would recommend going with a 30 amp controller as there is a rare occurrence called 'cloud edge effect' where for a few minutes your panels could output above rating; I like to have lots of margin.

I definitely don't understand about the "No need for the MPPT stuff". What I understand so far is that if the budget allows...go with MPPT. If not, then PWM will do. Also, how can I tell if a controller has "dip switches"?
. . .

So, 20 amp should be ok with either set of panels?


So, the 2x 165w panels and this controller would work well, right? In parallel or series...

Dealing with the 3x 100w Renogy, I would have either 3x 12v sources/panels, or need to jump to 36v for series...meaning that the 3x just complicates the situation....for me anyway.

Not needing MPPT depends on a number of factors, the major one is budget.  I went with a good PWM controller as the tradeoff for me was another panel.  I couldn't afford both: second 100W panel = ~5.9 more amps, MPPT = ~2.5 additional amps (in bulk mode, once you get to absorption they work the same).

 IMO you are better off with a quality PWM controller than a cheap MPPT controller.  Again, I would recommend a 30 amp controller as it has more headroom: its not working so close to max, it is made to dissipate heat better, smaller controllers are generally at the bottom end of a manufacturers offerings (could mean more cost cutting).

The Vicron MPPT controller looks like a good unit.

 -- Spiff

 

[jonsun]

I definitely don't understand about the "No need for the MPPT stuff". What I understand so far is that if the budget allows...go with MPPT. If not, then PWM will do. Also, how can I tell if a controller has "dip switches"?

Ok, the PDF for the Morningstar TS-45 states:

"Fully Adjustable – DIP switch provides user with a choice of 7 different digital presets and custom settings via RS-232."

Otherwise, how would I know? Doesn't seem to be a lot of info given out, generally.

They only do that boost thing in bulk or when you're on load output. 17v system is so small over voltage after cable run it's just ridiculously unnecessary. And since you're over building you won't get into bulk anyway making it even more useless.

Also If you get a cheap mppt you will lose a ton because the charge voltages are preset way too low. A hundred dollar mppt is just a total waste of money. You have to get a good controller no matter what.

You know by first looking up battery specs for absorption voltage. Then you reference the controller manual to set the dip switches to where you need....This is WAY more important than mppt.

For batteries just go with Trojans 6v. They give you the specs and all. They're​ proven and quality.

 

[akrvbob]

Not needing MPPT depends on a number of factors, the major one is budget.  I went with a good PWM controller as the tradeoff for me was another panel.  I couldn't afford both: second 100W panel = ~5.9 more amps, MPPT = ~2.5 additional amps (in bulk mode, once you get to absorption they work the same).

He doesn't have enough room on the roof, he can't add any more panels so MPPT will get him the maximum out of what he can fit.

 

[akrvbob]

There is a great deal of misunderstanding about MPPT out there, so disregard most of what you hear about it. Buy a quality MPPT controller and you'll maximize the power going into your batteries and get the longest possible life out of them.

I'd strongly recommend the Blue Sky 3000i. You can set the absorption voltage up to 15 volts and then set how long it holds it there. That one thing is the very most important thing you can do to get the longest life out of your batteries. More importantly, you can set it right on the controller, nothing else to buy to do it.

Money spent on panels and controllers is never spent again (unless you buy Chinese junk, then you buy it over and over again)  but buy a crap controller and your batteries will need replacing every few years.

Over the lifetime of your system, batteries will be the single largest cost!! A quality controller will pay for itself many times over in extended battery life. Spend the money and buy a quality MPPT controller which gives you maximum power out of your panels and into your batteries. But much more important, it will give you maximum control over the charging of your batteries.

 

[jimindenver]

They only do that boost thing in bulk or when you're on load output.

This is incorrect. The buck converter is active in all modes converting excess voltage to extra amps. It is the MPPT program that is only active in the bulk mode.

 

[AlreadyGone]

There is a great deal of misunderstanding about MPPT out there, so disregard most of what you hear about it. Buy a quality MPPT controller and you'll maximize the power going into your batteries and get the longest possible life out of them.

I'd strongly recommend the Blue Sky 3000i. You can set the absorption voltage up to 15 volts and then set how long it holds it there. That one thing is the very most important thing you can do to get the longest life out of your batteries. More importantly, you can set it right on the controller, nothing else to buy to do it.

Money spent on panels and controllers is never spent again (unless you buy Chinese junk, then you buy it over and over again)  but buy a crap controller and your batteries will need replacing every few years.

Over the lifetime of your system, batteries will be the single largest cost!! A quality controller will pay for itself many times over in extended battery life. Spend the money and buy a quality MPPT controller which gives you maximum power out of your panels and into your batteries. But much more important, it will give you maximum control over the charging of your batteries.

"I'd strongly recommend the Blue Sky 3000i. You can set the absorption voltage up to 15 volts and then set how long it holds it there. "

Ok, after reading Sternwake's info-sharing in the thread here: EU2000i to charge batteries? I'm beginning to understand what you are getting at.

Is the ability to "set the absorption voltage up to 15 volts and then set how long it holds it there" the same as the "DIP switches" mentioned above?

This is also why I'm undecided about batteries. I thought it was relatively simple and straightforward, but apparently it's not...and I'm beginning to understand the recommendation of starting with a "beginners-set" of batteries. I've learned through hobbies and in life, generally,..."Buy right, Buy once". So, I was considering shelling out for good quality batteries, like Lifeline. Now I'm thinking maybe I should just get a couple of Duracell GC2s...Inexpensive ($85), can pick them up locally (Sam's club)...and do the hands-on learning with them.

He doesn't have enough room on the roof, he can't add any more panels so MPPT will get him the maximum out of what he can fit.

That was kind of my take on it: Better charging control and greater charging efficiency.

 

[jonsun]

^ Nope. They're just PWM chargers that do a tiny boost with excess voltage.. if you have it and if the batteries are low enough to accept it. if you're worried about an extra few amps you maybe might see a few times a year hook your alternator up or get a little genset with the hundreds you save.

for a while there it was more economical to buy 24v+ panels and they had their place with those but that's outdated now.



it is a humorous study in the human psychology though. you have to ask yourself do I actually understand what I'm buying or just figuring "I cant afford not to have this"

 

[jonsun]

under the best conditions for them, which means running batteries way down daily (which costs you $$ in the long run), it will get you in one week what your alternator/generator can do in 1 hour.

if you're running your batteries that low you're way better off spending the $200 on a bigger bank which of course further renders MPPT totally useless (as it will never see the boost mode)

in solar where you over-build the system to make up for weather inconsistencies, marginal charging gains that cost 50-100% of what the entire system does are pretty silly.

so from a financial efficiency perspective they just don't make sense. I don't know about you but Im not a millionaire and am always looking for ways to save money.

 

[AlreadyGone]

that flat area on the roof IS THERE for a vent.  highdesertranger

And that is where a 14 x 14" hole will be cut.

One can never have too much solar.

A couple of considerations: 

• Larger panels are cheaper per watt, are more awkward to install, more susceptible to partial shade.
• Smaller panels are easier to work with when installing and when wired in parallel are less susceptible to partial shade.

I have 2 Renogy 100W panels and they work fine for me, never heard of Everbrights; although solar panels seem to be a commodity item now.  I would recommend going with a 30 amp controller as there is a rare occurrence called 'cloud edge effect' where for a few minutes your panels could output above rating; I like to have lots of margin.



Not needing MPPT depends on a number of factors, the major one is budget.  I went with a good PWM controller as the tradeoff for me was another panel.  I couldn't afford both: second 100W panel = ~5.9 more amps, MPPT = ~2.5 additional amps (in bulk mode, once you get to absorption they work the same).

 IMO you are better off with a quality PWM controller than a cheap MPPT controller.  Again, I would recommend a 30 amp controller as it has more headroom: its not working so close to max, it is made to dissipate heat better, smaller controllers are generally at the bottom end of a manufacturers offerings (could mean more cost cutting).

The Vicron MPPT controller looks like a good unit.

 -- Spiff

The more I'm finding about Everbright panels and company...the more comfortable I am getting with them. They apparently have Made in the USA panels:

These panels are made from solar cells made in Oregon, and the solar panel assembly was done in the Silicon Valley, California!

Good customer service. I'm not really finding anything negative about their products or company.

Yes, install is part of it...I will be working alone. But more importantly to me, is maximizing the amount of wattage for the space, building a quality system overall that I don't need to worry about, and "buying Right and Buying Once". The batteries are apparently going to be an exception to that last part, but it is what it is.

They only do that boost thing in bulk or when you're on load output. 17v system is so small over voltage after cable run it's just ridiculously unnecessary. And since you're over building you won't get into bulk anyway making it even more useless.

Also If you get a cheap mppt you will lose a ton because the charge voltages are preset way too low. A hundred dollar mppt is just a total waste of money. You have to get a good controller no matter what.

You know by first looking up battery specs for absorption voltage. Then you reference the controller manual to set the dip switches to where you need....This is WAY more important than mppt.

For batteries just go with Trojans 6v. They give you the specs and all. They're proven and quality.

Right. I'm not looking to spend $400-500 or more on a charger...unless is was absolutely necessary for some reason(s). I don't think that it is.

So, if I'm understanding this right, at least generally, the DIP switches on the Morningstar PS-45 (after setting them) will do the same thing as the 7 point adjustment of the Blue Sky Energy SB3000i that Bob recommends, right? "To provide optimal charge control for various battery types all digital setpoints for charge control and load control are user adjustable."

Blue Sky Energy SB3000i - PDF

IF I'm understanding this correctly: Bulk charge starts at under 70% or 80%, so at that point MPPT is of benefit. But after the 70% or 80% is reached...then things function as a PWM? Quality being equal.

Nope. they're just PWM chargers that do a tiny boost with excess voltage.. if you have it and if the batteries are low enough to accept it. if you're worried about an extra few amps you maybe might see a few times a year hook your alternator up or get a little genset with the hundreds you save.

for a while there it was more economical to buy 24v+ panels and they had their place with those but that's outdated now.



it is a humorous study in the human psychology though. you have to ask yourself do I actually understand what I'm buying or just figuring "I cant afford not to have this"

It's neither actually. I don't claim or pretend to genuinely understand what I'm looking at, nor do I gotta have this that or the other. I've been in non-buying mode for 1 yr now. I don't need it...I don't buy it. However, I still try to make reasonably intelligent, bang-for-buck type decisions. Hence, my initiation and participation here. My intention is to get what I need in Quality for the long-haul....but I still seek bang-for-buck. That's why your input here is valuable to me: You are going against the grain, against the blind herd mentality and saying things that may very well be knowledge-based, yet ruffle a few feathers in the process...we are similar in that.


So, if you or someone else, would care to break down in, at least somewhat, layman's term what, when, how the claimed benefits of MPPT are not really accurate...or point to a link...I'm definitely all ears!

 

[AlreadyGone]

under the best conditions for them, which means running batteries way down daily (which costs you $$ in the long run), it will get you in one week what your alternator/generator can do in 1 hour.

if you're running your batteries that low you're way better off spending the $200 on a bigger bank which of course further renders MPPT totally useless (as it will never see the boost mode)

in solar where you over-build the system to make up for weather inconsistencies, marginal charging gains that cost 50-100% of what the entire system does are pretty silly.

so from a financial efficiency perspective they just don't make sense. I don't know about you but Im not a millionaire and am always looking for ways to save money.

Right now, I am planning on a battery isolater and a generator (gotta vitamix I use). So, IF I undertand correctly: If I never go below 80%...then MPPT is meaningless? If I do go below 80%on the battery bank...then I can boost to the 80% with the solar and alternator and/or generator, right? Above 80%...it's all the same with a small efficiency increase of the MPPT....? That about right?

 

[John61CT]

I don't have an axe to grind either way between mppt and pwm, still very much learning myself, but here is a little bit that might help clarify the reasoning.

Having a proper custom set voltage is important, not only to go high in order to maximize amps put into the battery, that only applies when your battery Bank specifies a charging voltage higher than what a fixed controller puts out. Lots of battery chemistry actually require a very specific voltage that should be matched by the controller, and in my opinion you don't want to have to replace your controller just because you change what type of batteries you start to use.

Lifeline AGM can ask for 15V+, others no higher than 14.7, LiFePO4 wants around 13.8 for longevity.

Now if you don't want to spend the extra money that an adjustable setpoint will cost you , just make sure your batteries match your controller or vice versa. And in my opinion, make sure that controller is cheap enough that if you do decide to change to a chemistry that requires a different voltage, it's not going to be too painful for you to replace the controller.

 

[John61CT]

The issue about how to depleted your batteries are, is that they require much higher output below the constant voltage absorption stage. As they get closer to 100% then the current required is a very tiny fraction of what they needed between 50% and 80%.
Now aside from voltage, the ability to set the time that the batteries are held in absorption at that higher voltage is critical. Too many controllers, in fact mainstream charge sources in general, drop down to the float level voltage much too early. So you definitely want to look for that ability as well as setting the voltage to a custom set point.

The idea is that the controller only goes to float when current has dropped to a certain level that you can adjust. Next best is in absorption time that you can set in minutes or hours. If it is not adjustable, then look for a unit that calculates the absorption time based on a formula that looks at how depleted they were, usually how long they were in bulk constant current stage.

 

[John61CT]

You also want to be able to adjust the float voltage.

Some batteries don't want to be put on float at all, but I haven't come across a controller that just stops.

Of course sunset usually does come , but that only helps when the batteries are being pulled down every day.


So, these adjustability features are only found in more expensive controllers, and have nothing to do with mppt compared to pwm.

Also, nothing specific to solar, applies just as much to alternators, generators and shore power charges, all of which are made much more expensive when you require such adjustability.

So one strategy is simply to stick to choosing charge sources with a certain charging profile, and only buy batteries that fit within those specs.

Another way to go that gives you more flexibility, is to buy a powerful high-end dc-to-dc "battery to battery" charger that has all the adjustability features.

Put a very low end starter type battery on your charge source as a filter, and then use the DC to DC charger to give a nice customized charge profile to your expensive bank.

This allows you to take a just ability out of the requirements for all of your different charge sources, and makes your electric system portable from one vehicle to another, without having to refit the alternator.