Allpowers foldable solar panel Q

[Scoutn79]

Hey guys.
I am looking for a foldable solar panel for my truck adventures.
I have a 100W rigid panel but it is just a real pain to haul in the truck. Also have a 30W rigid which was the 1st solar panel I bought for this type of use.
Now I am looking to make things easier so I am looking for a 80-100w foldable (like a blanket foldable not suitcase style.)
I have all but set on this Allpowers unit listed on Amazon
https://www.amazon.com/gp/product/B075YRKVMH/ref=ox_sc_act_title_3?smid=A18M12GR6V2Z8F&psc=1

I tried calling the company but the phone number isn't in service so I sent an email.
It says it has a built in charge controller so I asked if it is PWM or MPPT. We'll see what they say.

Does anyone have anything good or bad to say about this company?

I tried looking for other foldable solar panels but it seem they are about 5-8 times the price for the same wattage so that just isn't going to happen.

Darrell

 

[WVI]

That looks pretty interesting.

 

[dwh]

It has a built-in voltage regulator. Possibly two; one that outputs 5v regulated, and one that outputs 18v regulated.

Though that 18v output might not actually be regulated...it might just be a direct output from the solar, which could very well be one setup to have a Vmp in the 18v range.

Whether that output is regulated at 18v or just happens to be a direct output from an 18v solar panel doesn't much matter...either way, hooking that 18v output to a 12v battery could very well overcharge the battery.

So you would still need a proper charge controller between that 18v output and the battery.

If that 18v output runs though a voltage regulator (my guess is it does), then all you need is a PWM charge controller to handle properly charging the battery. You wouldn't need an MPPT charge controller, because the built-in voltage regulator would block the MPPT from being able to adjust the load voltage of the solar.

However, if that 18v output is direct from the solar and doesn't run through some other circuitry, then you could probably use an MPPT controller.

 

[dwh]

I also note that most (if not all) of the Q&A, and at least some of the reviews refer to a "5w" panel, which must be a different unit.

 

[Scoutn79]

It has a built-in voltage regulator. Possibly two; one that outputs 5v regulated, and one that outputs 18v regulated.

Though that 18v output might not actually be regulated...it might just be a direct output from the solar, which could very well be one setup to have a Vmp in the 18v range.

Whether that output is regulated at 18v or just happens to be a direct output from an 18v solar panel doesn't much matter...either way, hooking that 18v output to a 12v battery could very well overcharge the battery.

So you would still need a proper charge controller between that 18v output and the battery.

If that 18v output runs though a voltage regulator (my guess is it does), then all you need is a PWM charge controller to handle properly charging the battery. You wouldn't need an MPPT charge controller, because the built-in voltage regulator would block the MPPT from being able to adjust the load voltage of the solar.

However, if that 18v output is direct from the solar and doesn't run through some other circuitry, then you could probably use an MPPT controller.

If the voltage leavng the panels internal controller is 18 I would never connect that directly to my battery, I wqs hoping to be able to use a MPPT to take advantage of the extra amperes in the morning when the battery is the lowest.

Can you tell me why a MPPT wouldn't work if the 18v leaving the panel is regulated to 18V? What would it matter if the voltage was 18v or 100v? All the controller sees is that the input voltage is above what the battery needs for charging, correct?
Doesn't a MPPT and a PWM controller just monitor battery voltage and adjust output to that and it has no way of knowing what voltage was at the panel before being changed?
Now if the 18 volt is open circuit and regulated (although not stated) down to 12v (14.5ish for charging) then I can see the MPPT not being useful but at that point neither is the PWM.

What about when using a MPPT with an regulated to 18v panel wouldn't it still be able to adjust the amperes inversely?

I saw that on the reviews also. The reviews don't really give any info on that specific product.

Curious

Edit: I noticed in the product pictures it has both battery clips and a lighter plug making me think it isn't 18V output........
Awfully thin wires tho.

Darrell

 

[dwh]

Can you tell me why a MPPT wouldn't work if the 18v leaving the panel is regulated to 18V?

It would work, but it wouldn't be able to adjust the load voltage to get the solar operating at Vmp. Sure the voltage down conversion would still happen, but it's not going to make much difference.

The perceived "amp boost" of MPPT is a bit of a marketing red herring - 100w in is still 100w out no matter what gyrations you apply to the input/output voltage.

The purpose of the MPPT circuit is to adjust the load voltage on the solar side to get the solar running at Vmp to get the max watts that the solar is capable of producing right this minute.

But it can't do that if there is something (voltage regulator) between the solar panel and the MPPT circuit.

AFTER the MPPT does it's magic to figure out the optimum voltage to run the solar at, the output from the MPPT circuit is fed through a voltage converter to drop it to battery voltage.


If the solar is not running at Vmp and your 100w panel is actually only producing 80w, you won't fix that by down-converting to battery voltage. It'll still be 80w in, 80w out.

 

[john61ct]

They are designed for charging screen gadgets, not 12V.

A PWM SC should be fine taking the 18-20V input, just watch you don't go over on the current rating.

MPPT would be a waste of money, unless you bypass their controller, tap into the panel output directly.

 

[Scoutn79]

They are designed for charging screen gadgets, not 12V.

Can you clarify why you say that? The pics show battery clips and a lighter plug plus the add states charging 12v car/boat/RV battery.

I guess I am still a little fuzzy on the MPPT vs PWM issue.
All of the reading and solar company videos I have seen (not JoeBob's video of how he thinks something works) say MPPT has the ability to up the amps as the volts are dropped to keep the same watts going into the battery as are coming into the controller (this is the benefit of the MPPT over the PWN no? Where as a PWN will only drop the volts but maintain the amps is is imputed. This is what can make the MPPT more efficient.
A couple actually show all of the math involved so I am not interpreting what they are saying but understanding the math.
Or am I misunderstanding them.

Darrell

 

[dwh]

PWM is just a switch. A high speed computer controlled chatterswitch.

In bulk stage the switch spends most of its time closed - solar panel directly connected to battery.

Once the bulk stage is complete and the charge controller changes to absorb stage, the switch starts to chatter - quickly opening and closing. It does this to "pulse" the incoming power to hold the battery voltage at a certain point. If the battery voltage starts to rise, it momentarily opens to disconnect the solar. If the battery voltage starts to drop, it momentarily closes to give the battery a pulse of power.

It can vary (modulate) how long (width) each pulse lasts in order to achieve a very precise voltage regulation. PWM - Pulse Width Modulation.


The problem with PWM, is that while the switch is closed, the solar is directly connected to the battery. When the solar is directly connected to the battery, the battery is limiting the voltage of the circuit, so the solar panel ends up operating at battery voltage.

So say you have a solar panel with a Vmp (Voltage of Maximum Power) of say 18v, but the battery is at say 14v. Well, operating the solar at 14v is way outside of the panel's Vmp, so the solar panel is only operating at say 80% efficiency - a 100w panel that is only able to produce 80w max while operating at 14v.


So they came up with a fix for that - separate the solar from the battery so the solar doesn't operate at battery voltage.

Conceptually, an MPPT controller has three sections.

First is the MPPT circuit. What this does is vary the load voltage applied to the solar. It sweeps back and forth to find exactly the right voltage to get the most watts out of the panel. In other words, it finds the panel's Vmp, and lets the panel operate at Vmp. So now that 100w panel in my previous example can produce a full 100w, because it's operating at 18v instead of 14v.

The next section takes the power coming from the panel at 18v, and down converts it to battery voltage so that the 100w coming from the solar gets fed to the battery with minimal loss from inefficiency. 100w in from the solar, 100w out to the battery.*

The third section is a PWM chatterswitch to precisely regulate the battery voltage.


In this situation, someone looks at their meter and sees say 5a from the solar (but that's at 18v) and say 8a out to the battery (but that's at 14v). Woot! An "extra" 3a just magically appeared due to "boost"!

No, it didn't. It's still 100w in, 100w out. An MPPT charge controller doesn't "boost" the power. What it does is reduce the losses due to inefficiency so the whole system can run at 100% instead of running at less than 100%.




*(In reality of course, a few watts are burned powering the charge controller and a few more are lost in the wiring and whatnot. So really it's more like 100w from the solar and maybe 90w or 95w to the battery.)



So let's say you hook this gadget up to a regulated 18v power supply fed by a solar panel. Well first thing is the MPPT section can no longer adjust the panel voltage - so all you can do is hope the panel is operating somewhere around Vmp, because if it isn't...tough luck...the MPPT can't do anything about it.

Sure, you gain a little effiency from the voltage being down-converted to battery voltage but the truth is that's not where MPPT gets its big advantage. The big advantange comes from operating the panel at Vmp so it produces the maximum wattage.

So at that point it's just a question of if it's worth the money to save a few extra watts, or if a cheaper PWM is "good enough".

Actually, the cost/benefit of MPPT vs. PWM generally works out to MPPT not being worth the money for less than 200w of solar. Below 200w, you might as well just use PWM and spend the extra money on beer.

 

[dwh]

Now that folding solar panel has a 5v regulated output for sure. It also has some kind of nebulous "******?" output.

It says 18v output. It also says "laptop/car battery". Well 18v is fine for a laptop, not for a car battery.

But it's got battery clamps and a cig plug. So maybe it's got some kind of charge controller on that 18v output. That's fine for a car battery, but no good for a laptop.

Or maybe they expect you to use your own 12v laptop power adapter.

If that output has a charge controller so it can charge a car battery, then it isn't an 18v output.

******? Dunno.

 

[Scoutn79]

PWM is just a switch. A high speed computer controlled chatterswitch.

In bulk stage the switch spends most of its time closed - solar panel directly connected to battery.

Once the bulk stage is complete and the charge controller changes to absorb stage, the switch starts to chatter - quickly opening and closing. It does this to "pulse" the incoming power to hold the battery voltage at a certain point. If the battery voltage starts to rise, it momentarily opens to disconnect the solar. If the battery voltage starts to drop, it momentarily closes to give the battery a pulse of power.

It can vary (modulate) how long (width) each pulse lasts in order to achieve a very precise voltage regulation. PWM - Pulse Width Modulation.


The problem with PWM, is that while the switch is closed, the solar is directly connected to the battery. When the solar is directly connected to the battery, the battery is limiting the voltage of the circuit, so the solar panel ends up operating at battery voltage.

So say you have a solar panel with a Vmp (Voltage of Maximum Power) of say 18v, but the battery is at say 14v. Well, operating the solar at 14v is way outside of the panel's Vmp, so the solar panel is only operating at say 80% efficiency - a 100w panel that is only able to produce 80w max while operating at 14v.


So they came up with a fix for that - separate the solar from the battery so the solar doesn't operate at battery voltage.

Conceptually, an MPPT controller has three sections.

First is the MPPT circuit. What this does is vary the load voltage applied to the solar. It sweeps back and forth to find exactly the right voltage to get the most watts out of the panel. In other words, it finds the panel's Vmp, and lets the panel operate at Vmp. So now that 100w panel in my previous example can produce a full 100w, because it's operating at 18v instead of 14v.

The next section takes the power coming from the panel at 18v, and down converts it to battery voltage so that the 100w coming from the solar gets fed to the battery with minimal loss from inefficiency. 100w in from the solar, 100w out to the battery.*

The third section is a PWM chatterswitch to precisely regulate the battery voltage.


In this situation, someone looks at their meter and sees say 5a from the solar (but that's at 18v) and say 8a out to the battery (but that's at 14v). Woot! An "extra" 3a just magically appeared due to "boost"!

No, it didn't. It's still 100w in, 100w out. An MPPT charge controller doesn't "boost" the power. What it does is reduce the losses due to inefficiency so the whole system can run at 100% instead of running at less than 100%.




*(In reality of course, a few watts are burned powering the charge controller and a few more are lost in the wiring and whatnot. So really it's more like 100w from the solar and maybe 90w or 95w to the battery.)



So let's say you hook this gadget up to a regulated 18v power supply fed by a solar panel. Well first thing is the MPPT section can no longer adjust the panel voltage - so all you can do is hope the panel is operating somewhere around Vmp, because if it isn't...tough luck...the MPPT can't do anything about it.

Sure, you gain a little effiency from the voltage being down-converted to battery voltage but the truth is that's not where MPPT gets its big advantage. The big advantange comes from operating the panel at Vmp so it produces the maximum wattage.

So at that point it's just a question of if it's worth the money to save a few extra watts, or if a cheaper PWM is "good enough".

Actually, the cost/benefit of MPPT vs. PWM generally works out to MPPT not being worth the money for less than 200w of solar. Below 200w, you might as well just use PWM and spend the extra money on beer.

Thank you. I have a better understanding of the technical part of it now.

So if the panel has a regulated 18V (say a built in PWM or other form of regulator) and then if I were to use a MPPT the PWM wouldn't sense the MPPT wanting more voltage and accommodate it?

I don't see how this will charge a laptop. My last couple Windows based laptops required 19+ volts and I "think" a Apple is 21 or so.

A lot isn't making any sense about this panel. Either a very bad description or they have no idea what is what. The grammer in the Amazon ad isn't very good and that usually turns me away.

But since it is Amazon Prime I can check it out and see and if it is junk just return it.

Darrell

 

[john61ct]

Again it has 2 outputs from their built in controller. USB charger output for charging phones & other screens, 5V.

And 18V nominal (I believe actually between that and 20V, which will charge most laptops.

You could either

A. use the 18V output from their built in controller as input to a PWM controller, or

B. physically bypass their built in controller and put the raw panel output into a good MPPT SC

Both will charge a 12V bank, B much more efficiently but maybe do damage and void the warranty.

Do NOT use the 18V output for any length of time directly onto any battery you care about, unless **you** are the controller, sitting there watching with an ammeter.

A cheap Starter batt, emergency out in the boonies, could be helpful for that, I guess is their point with their marketing.

 

[john61ct]

I don't see how this will charge a laptop. My last couple Windows based laptops required 19+ volts and I "think" a Apple is 21 or so.

That is their intention.

Just like Ryobi and other tool powerpacks, "nominal 18V" means higher. 12V charging voltage is 14V+, etc

And laptops' charging circuitry is tolerant of a wide voltage range.

But personally with expensive gear, I'd check everything first and if I thought it warranted, go through a DCDC converter / stabilizer.

 

[Scoutn79]

Thanks for all the tech explanations dwh and John61ct.
I'm afraid I may be back to the drawing board on this idea. I have a bad feeling, and have asked for clarification, that these panels are not to be rained on....now who thought that was a good idea?

 

[john61ct]

Likely only an issue if you are keeping their built-in SC.

If using your own, that will be mounted at the battery bank, you're not leaving those out in the rain are you?