12V solar mat regulators

I have the same setup, 2 Ridge Ryder solar blankets, 100w and 150w. I made changes to the set up and they changes have made a great improvement to the battery charging.

1. I didn't use the original PWM charge controllers. I am using a higher capacity MPPT controller. I have tested both types of controllers and found the MPPT provides more power to charge the battery. This makes the most difference when the solar blankets (panels) aren't pointed directly at the sun or in low light. This means if you set up the solar and leave your campsite for the day where you cannot be there to keep pointing the solar at the sun the MPPT controller will recharge your battery in less time. This means you need fewer hours of good sunlight to keep your batteries topped up.

2. I placed the MPPT controller next to the battery, and is permanently connected to the battery. This has two advantages. Firstly by having it at the battery and not at the blanket the controller can monitor the battery with much less voltage drop due to cable length and can more effectively charge the battery.. Also instructions for solar blankets (panels) tell you to connect the controller to the battery before connecting the blanket/panel to the controller. Do this out of order and you will not get a proper charge. By having the charger already connected to the battery you cannot get the order of connection wrong.

Happy to further discuss my set up if interested.

They are great bits of info there Tom, thanks.
All noted for future upgrades.

I am slowly but surely setting the Ranger up further for longer stays . . . primarily now I tour daily, but on an upcoming 6 week trip our little group of 4 vehicles will be camping in at places at least 3 or 4 times for an extra night, to enjoy the surrounds.

At the moment my SOC after an approx 15hr camp / overnight is pretty much 83% every morning, so I feel I should be able to get a day in (even with no driving) and not drop by more than 50% . . . recommended not to go below this SOC often, or by a greater amount.
Although I love the 100w smaller package and much less weight, I am probably taking the 150w panel and this should be ok as the usual backup in standard form, as we will be driving short distances those days to local sights, and the alternator tops off the AGM pretty quick, usually only a coupe of hours.

From what I've read, the PWM controllers are not only cheaper, but known the be more reliable, not 100% sure maybe this is changed in recent years.
I know my brothers off grid home setup has blown a few good quality mppt units over some years, but not sure about vehicle setups reliability and how tracks etc affect the workings.

In the next few years when touring at even more relaxed pace, I will set it up like yours, for ease.
At the moment the PWM controller is fine for me as I usually only take either one or the other panel depending on what I think will be needed.

I take it you connect both your panels up and into the MPPT ?
That would have very good capacity increase and make full use of the MPPT benefits.

I hope this is useful info to Theo (the OP) too.

BTW, the Ridge Ryder panels are now $399 (SCA link 100w) and $499 (SCA link 150w) when I checked last night, their usual retail, but you'd be mad not to wait for the sales . . . just checked, overnight they have dropped the usual 20% sales pricing, just for today !!
$319.20 and $399.20 respectively.

I have had no reliability problems with MPPT, but I did spend a bit on the controller. Yes, I can connect both solar blankets into the one MPPT controller, and have been experimenting with blocking diodes to ensure a shaded blanket does not bring down the output of the non-shaded blanket. I should be finished testing next month.
I am also experimenting with having the 2 solar blankets facing different parts of the sky for when we are long day walks. Being able to recharge camera batteries, having a good cold fridge, and having plenty of light, and still having a battery at 100% SOC at the end of each day is great, and all without running the car or using a generator....
I have spoken to a number of people who believe they don't need much solar as the battery will keep the fridge running for 3-4 days. Unfortunately they are not looking after their battery. As you stated you do not want to use more than 50% of the capacity. If you do, the number of recharges reduces significantly.
We bought our slide on camper second hand and the battery in it was cooked, mainly due to the badly designed 240v battery charger that kept charging the battery without monitoring it. The charger was an Arlec, and I quickly replaced that with a CTek.
Determining an accurate State of Charge is something else I believe requires investing in. Measuring voltage is not accurate. If you want accurate SOC you need a good quality battery monitor, but again they are not cheap. I can justify mine as it means I know I'm looking after the battery, and I can see if there are any issues with the battery or the system as a whole.

Ignoring cable losses from inadequate cabling and wrongly located controllers, changing to series won't make any difference to the panels output. The panels can only ever deliver their rated wattage, whether connected in series or parallel.

However, you are correct in that a seriesed system can be more tolerant of long cable runs or thin wire between the panels and the regulator and therefore may deliver a better result.

But seriesed panels have drawbacks, the major one being that if one panel in a seriesed pair is shade affected, then the output from whole pair, ie including the fully lit one, is hugely reduced. If they were connected in parallel, only the shaded one is affected and the lit one continues to produce.

Totally agree with your MPPT recommendation, but buyers should be aware of cheap Chinese knock-offs that claim to be MPPT but are not. It's very much a case of you get what you pay for, IMO.

I have the cheap one that claims to be MPPT, but isn't.
It does the job and is significantly better than the controller that came on my Aldi panels and would just about boil a battery if you left it alone.

The $30 eBay job is adequate for my needs. I couldn't justify the extra cost of a quality true MPPT controller for a $150 fold out panel that only gets a run a few days a year.

Hi Theo,

The "conditioning" or charging quality that the battery sees is not dependent on whether the solar regulator is PWM or MPPT. It the quality of the charger that's built into the regulator.

Basically a solar controller consists of two parts.

The first part, the front end, converts the output from the solar panels into a format the the second part can use.

The second part is simply a battery charger. That can be a simple one or two stage device that, to the battery, might be the same as a piece of crap 240V charger from a department store or eBay that might overcharge or undercharge or otherwise abuse your battery. Equally it can be a sophisticated multi-stage, programmable device that will massage your battery into 100% state of charge in the ideal manner specified by the battery manufacturer.

The front end can be PWM or MPPT. All either of them do is deliver the output from the solar panels in an acceptable form to the charger component. The battery cannot see beyond the charger component. It cannot see whether there is an MPPT or a PWM between the solar panel and the charger and it doesn't care, all it sees is what it is interested in, that is, what the charger is delivering.

PWM devices are cheaper and often have less sophisticated charger stages in an effort to keep the price down. But not all. A notable exception is the Morningstar series, and there are others. They are comparatively expensive.

More often than not the regulator stuck on the back of a budget solar panel or included with a budget solar blanket will be a PWM type of variable quality.

On the other hand, MPPT devices, the real ones, not the cheap Chinese knock-offs, usually have multi stage charger components of varying sophistication. Generally, you will find those on more expensive solar products.

Thus it's not the PWM or MPPT that determines how well the battery is treated, it's the charger component, and GENERALLY, but not always, an MPPT controller will have a better charger, which may have led to your observation.
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Placing the regulator as close as possible to the battery is a matter of physics, not of opinion or suggestion. Depending on the cable size between the battery and the regulator, the distance can make far more than an "incidental" difference. That is why regulators stuck on the back of solar panels with a 10 metre thin cable to the battery are severely compromised or even useless.
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If you panels' max output is 8.5 amp there is no advantage swapping your 10 amp regulator for a 15 amp one unless it is a better quality regulator, either MPPT to replace PWM, or a higher quality PWM with a better charger component.

A "larger" regulator won't get more amps out of the panels. You could put a 50 amp regulator in there - it will work just the same and will give you no advantage.
What could be an advantage with a larger regulator, though, is if you plan on expanding your system in the future.

Also, longevity. Like all things, a component running close to or at its max it will not last as long as one that is loping along at 50% effort. Whether or not a change from a 10 amp regulator to a 15 amp one is worthwhile for 8.5 amps max panel output is debatable.

Theo, there s much more it that.

A PWM controller will preserve amps and is generally only about 70% efficient. So a 150W solar panel will only give you about 8 -9 amps or about 105W.

A good MPPT controller will preserve power ( watts) is about 95% efficient and will give you about 12 amps and around 140W. It works liek an inverter to give more amps than comes into it from the solar.

A PWM controller wastes the energy as heat.

Thanks Tony. I was about to edit my post to say something similar but you've saved me the trouble.

This article seems to list most of the pros and cons of both PWM and MPPT . . .
Ererdrive PWM vs MPPT

Not sure why they don't list this as a pro of PWM . . .
"More modern charge controllers use Pulse Width Modulation (PWM) to slowly lower the amount of power applied to the batteries as the batteries get closer and closer to fully charged. This type of controller allows the batteries to be more fully charged with less stress on the battery, extending battery life. It can also keep batteries in a fully charged state (called “float”) indefinitely. PWM is more complex, but does not have any mechanical connections to break."

Also this "MPPT controller forces the Solar array to be comprised of like photovoltaic modules".
Yet @Tomdej in his original reply to mine above (reply#1) says he uses a 100w and 150w folding blanket ok.

I guess it's all horses for courses, for small needs you can go PWM or MPPT, and as your needs grow (especially for myself one day eventually entering the lightweight hard floor camper market) you can move to MPPT and multiple panels as needed.

Can you put different solar arrays into an MPPT system using something like a hub, the basic Ctek d250s for example, or others like that ?

[quote]Not sure why they don't list this as a pro of PWM . . .

"More modern charge controllers use Pulse Width Modulation (PWM) to slowly lower the amount of power applied to the batteries as the batteries get closer and closer to fully charged. This type of controller allows the batteries to be more fully charged with less stress on the battery, extending battery life. It can also keep batteries in a fully charged state (called “float”) indefinitely. PWM is more complex, but does not have any mechanical connections to break.[/quote]

Les,

As a generalisation this is simply not true - see my follow-up to Theo above. Both PWM and MPPT do as quoted. It's not the PWM or the MPPT component that controls that, it's the multi-stage charger component that the PWM or MPPT drives. ANY decent solar regulator will "allow the batteries to be more fully charged with less stress on the battery, " It does not depend on PWM or MPPT.

- "MPPT controller forces the Solar array to be comprised of like photovoltaic modules".

To be at its most efficient, MPPT needs panels of similar Vmp. That is the panel voltage at which maximum power occurs, and that is what an MPPT controller is trying to track. If they are the same, easy as. If they are different there will be a compromise and loss of efficiency. Panels don't have to be the same wattage. I have an array of fixed and portable panels of different brands and wattages but similar Vmp they all work perfectly with my MPPT controller.

- "Can you put different solar arrays into an MPPT system using something like a hub, the basic Ctek d250s for example, or others like that ?"

If I understand your question correctly, yes, up to the maximum total solar wattage specified by the controller manufacturer.

Theo,

I think your roof panels will be 24 volt, so they will not suit your setup unless you get a regulator that will accept 24Volt (or higher) panels to charge a 12V system. You also need to consider max amps. There are plenty of suitable regulators around.

First thing is find out exactly what the Voc (open circuit voltage) is of your house panels and go from there.

Cheers

These are the specs of the house panels we've recently replaced.



I'd suggest you'd need a Victron 100/15, or perhaps an Enerdrive unit, with all the bells and whistles, to complement a house panel or two.

Bob

They are nominal 24V panels.

Nominal 12V panels have a Voc of about 21 to 22 volts - they are the ones most of us use in a 12V system.

Nominal 24V panels have a Voc of double that - about 42 to 44 volts.

While the controllers you suggest are great products, Bob, you don't NEED to spend that much if your budget is slimmer. For example, this controller will handle three of your panels.

Cheers

Theo. Look up MPPT vs PWM on you tube. Lots of people do back to back tests.
PWM is old technology there is no need to use it these days. They waste good energy.

Yeah, I’ve got one of those, Frank, and found it okay.

Think you’ll find the Victron I mentioned is quite a bit cheaper than the Jaycar, by around $100 or so.

Bob

Mea culpa, Bob. I didn't research the price of your Victron model. Just assumed bells and whistles on a premium brand would command a premium price.

The Jaycar unit is very good value for money.

Cheers

Hey Tony

Yea done the youtube thing.

Not blowing smoke up anyones bum here but would honestly take peoples ideas and experiences on here x 100 more than anything on youtube.

Its hard to find good info on the net anymore. People say 'just google it'. You can do that, but you've gotta sift through 98% of rubbish to find the tried and tested info you might be lookong for.

Just my take on it.