Opinions on Renogy 20 Amp MPPT?

[BradKW]

Renogy 20 Amp MPPT

Above link to Amazon, for a low low price of $109 + free shipping. 

The only reason I haven't clicked "buy" yet is I'm having trouble reconciling the low cost when compared to similar sized MPPT's from reputable competitors. About the only MPPTs cheaper are no-names that probably fall under the category of not actually a MPPT.

This will only have two 100W panels attached. But would I be better off with a possibly higher quality PWM for the same price?

 

[BobBski]

I'll be curious about any replies as well because that's what I'm planning on ordering along with 2 of their 100w eclipse panels.

 

[BradKW]

bump

 

[akrvbob]

There is a lot of confusion about MPPT, everyone looks at the very expensive controllers and say that MPPT is extremely expensive, but what they are missing is that you aren't just buying MPPT, you are buying 1) outstanding brand name and reputation of the company 2) American Made 3) usually a longer warranty, and 4) a great number of extra features.

You aren't going to get any of those things, you're just going to get a basic, solid mppt controller. Is that what you want?

Here are three things you will not get and might miss:

1) any kind of LED display
2) ability to set the absorption voltage
3) the ability to set how long it holds absorption voltage.

A Blue Sky 3000i gives you all those things above but cost $300. However, if it doubles or triples the life of your $500 batteries, it might have been money very well spent. Bob

 

[DannyB1954]

This will only have two 100W panels attached. But would I be better off with a possibly higher quality PWM for the same price?

For the additional cost of a MPPT, you could just about add another panel and use a PWM.  300 watts VS 200 = 50% increase. You could upgrade to a MPPT later.
A lot of variables here. If you don't have room or wish to add a portable panel, about all you can do is maximise the output of the 2 panels you have.  I have a inter connect that charges the battery when I drive, so I don't know how that would effect an absorption charge.

 

[29chico]

That MPPT controller has an ambient temp sensor built into it to control the temp compensation feature.  But it does not have a remote temp sensor that can read actual battery voltage.   Since ambient temps will vary much quicker than the actual battery temp, due to the battery's thermal mass, this is a concern if one wants a long and happy life from a lead acid battery.

Yes, I suggest a higher quality MPPT controller that has a real remote temp sensor available for it so the actual battery temp can be used to determine the correct battery charging voltage.

I actually have a new 20a Renogy Tracer controller and the remote meter for it.  It was gifted to me.  Because of the poor temp comp feature I will not sell or give it to someone on this site.  It is going into the to be Craiglisted box.

 

[where ever i may roam]

Being a solar newbe, I purchased that controller as part of a Renogy combo package with (2) 100 watt panels almost 3 years ago. I also purchased an add-on digital display, so that I can see what is going on with my system. I figure that when this controller bites the dust, I will upgrade; for now though, my batteries are usually charged by 9am, my dual AGM battery bank is at 12.8 volts before the sun hits the panels in the morning, so no complaints so far
 
I'm sure there are much better controllers out there, but mine seem to be working out so far, YMMV.

 

[Canine]

Brad,I just saw an identical controller on Amazon for $79.87.Different name but same controller.Good Luck.

 

[SternWake]

 my batteries are usually charged by 9am, my dual AGM battery bank is at 12.8 volts before the sun hits the panels in the morning, so no complaints so far
 
I'm sure there are much better controllers out there, but mine seem to be working out so far, YMMV.

Many people believe that when their solar controller drops to float voltage, that the batteries are fully charged.

This is Incorrect 98% of the time.

With AGM batteries, fully charged can ONLY be absolutely determined when the amps required to maintain absorption voltage drop to a certain level, usually 0.5amps per 100Ah of battery capacity

My low resistance 90Ah Northstar AGM battery, drained to exactly 80% state of charge, takes 3.5 hours before amps taper to 0.40a at 14.46v @77f when instantly brought to absorption voltage on a 40 amp power supply.  It can be recharged safely  to 100% no faster, regardless of the charging source's capability, and is one of the 'faster to fully charged' batteries out there.
It also has a rested fully charged voltage of 13.06v.

My point is do not believe the solar controller, unless you can adjust the time it holds absorption voltage and you can measure the amps the battery is accepting at absorption voltage.

In general once it only requires 0.5 amps to hold an AGM battery at the correct absorption voltage( adjusted for battery temperature), for 100Ah of capacity, then the AGM battery can be considered full

With flooded batteries this 0.5% raises to 2 to 3% of capacity, but one should really confirm with a hydrometer to determine actual full.

There is no magic electricity in any charger or solar controller which goes into a lead acid battery to determine if it is indeed full.  Charging sources follow a procedure, an algorithm.  it follow is regardless of whether it charges the battery fully, or not. It does not and cannot know when a battery is full.  it assumes that it is after following the algorithm, and the human that assumes it is correct....assumes unwisely.

The Appearance of float voltage simply does not mean the batteries are fully charged.  Achieving 100% charged daily or at least regularly achieved will yield a significant improvement in capacity retainment/ battery longevity, compared to the battery which only gets to 97%.

The proper tool for determining full charge, is most certainly NOT the blinking green light indicating a charging source is in float mode.  Certainly not on a deeply cycled battery in regular use, and the deeper the discharge the less chance the preset algorithm comes anywhere close to achieving the ideal end result, which is a 100% charged battery.  97% is NOT good enough, if one wants to get more than half the manufacturer claimed number of expected deep cycles

A solar controller MPPT or PWM whose absorption voltage and duration are programmable, and that are actually programmed by the end user for the batteries and their specific usage( average depth of discharge) will have batteries last significantly longer, basically paying for themselves.

Programming correctly, requires one have an Ammeter and a voltmeter for AGM batteries,  a hydrometer for a Flooded battery.

My K type thermocouple held to my battery casing has revealed much higher than average expected temperatures.  I'd really recommend getting a controller with a battery temperature sensor if one is going to be in super hot or super cold environments.  I am in a mild climate, but my battery temp data had me lowering absorption voltages as my battery has rarely gone below 77F in the last month, and overnight ambient temps have gone into the low 60's.


Of course actually achieving maximum battery longevity might not be worth the extra effort to the end user, and it could be easier to replace batteries sooner, My point is that a blinking green light full charge indicator on any charging source on a regularly deeply cycled battery, is a LIAR, and mocks the human who believes it.  If one does not discharge the batteries much, or at all, on day 2 the green light's pinocchio nose will likely stop growing.

Whether you are offended by this mockery is up to you, but one should at least know if they are being mocked and not make claims of fully charged without actual tools used properly to support this claim.

 

[Canine]

Brad,never mind.It's advertised as a 20 amp controller,but the fine print says it will only handle 130 watts of pv.My apology.

 

[Canine]

Stern,I expect you are right about charge condition.Be that as it may,I'll never come close to achieving full charge on my batteries .As soon as my controllers drop out of bulk charging,my house is drawing more current than the controllers are putting in.So far,I have almost 7 years on my batteries,Although I have been gone about 1/3 of that time.I guess we just have to deal with the situation we have.

 

[DannyB1954]

Perfection is always difficult to achieve, and in most cases good enough is good enough. I don't want to spend an excessive amount of time serving something that is supposed to be serving me.

I relate things to a stereo system. If you are happy to sing along with a $15 radio, life is good. If you want 50% fidelity, it will cost you a hundred. If you want 80% fidelity it will cost you $500, if you want 95% fidelity it will cost you Thousands. There is a point of diminishing returns. If one is running many solar panels and several batteries it becomes more important. The more you have invested the more important it is to care for that system. How much do you need to protect a 200 watt system is up to you. At the moment, I am listening to a $15 radio, and life is good.

 

[BobBski]

Enjoyed your "stereo" analogy DannyB.

 

[SternWake]

A programmable charge controller is hardly a huge expense over the cheapest possible option, but can allow batteries to last 50% longer, if programmed correctly.

Also remember batteries should be measured in total cycles accumulated, not years. 150 deep cycles over 7 years is not an impressive figure although their death is perfectly acceptable by year 7.

500 deep cycles over 2 years is much more impressive.

Actual battery capacity remaining is a total unknown or total guess, unless one can complete an accurate 20 hour capacity test.
When capacity declines to the point it is noticeable to the user, the batteries are already toast, but up until then they were 'just fine'.

Often when battery capacity declines to this stage, the user make a few hail mary attempts to restore lost capacity, usually with no lasting improvement. But the efforts can allow their next set of batteries to perform better for longer, if they apply the knowledge( and equipment needed) gained by those hail mary attempts.
If they had originally recharged to 100%, instead of relying on some flashing green light, the amount of days they could ring the Just fine bell, could be doubled or tripled.

It sucks when on an outing when one day everything is just fine and the next one is trying to source new batteries, or wasting time with a hail mary attempt at dissolving hardened sulfation.

They are just batteries, and only rented, but you can control length of rental contract. Whether efforts to attain a true 100% as often as possible are worth it, is subjective, with no right answer.

But it is inarguable that true 100% recharges significantly increase the total number of cycles and total KWH the Lead acid battery can deliver over the time span in which it is employed.

I 'saved' 35$ back in 2007 by buying the Blue Sky SB2512i instead of the sb2512ix charge controller that allows for a battery temperature sensor.

Worst 35$ i ever saved.

 

[highdesertranger]

comparing a charge controller to a radio is, apples to oranges. a radio is a luxury item a charge controller is a necessity. while I agree totally about the radio. a charge controller is an important piece in the puzzle. best not to scrimp here. I agree everybody doesn't need to run out and buy the most expensive controller out there, but the controller should be capable of doing the most efficient job possible for each individual system. highdesertranger

 

[BradKW]

Any opinions of this combo from Bogart?

https://www.solar-electric.com/bogart-engineering-sc-2030-solar-charge-controller.html

CC + Trimetric monitor + temp sensor = about $300.

Claims to rival MPPT performance when used as a combination, essentially saying the monitor is so good it gives the PWM controller a big advantage.

 

[lisamac]

Perfection is always difficult to achieve, and in most cases good enough is good enough. I don't want to spend an excessive amount of time serving something that is supposed to be serving me.

I relate things to a stereo system. If you are happy to sing along with a $15 radio, life is good. If you want 50% fidelity, it will cost you a hundred. If you want 80% fidelity it will cost you $500, if you want 95% fidelity it will cost you Thousands.  There is a point of diminishing returns. If one is running many solar panels and several batteries it becomes more important. The more you have invested the more important it is to care for that system. How much do you need to protect a 200 watt system is up to you. At the moment, I am listening to a $15 radio, and life is good.

I kinda like my broadcast radio and local TV. It's whether you're the "find what makes you happy" (which is a black hole) or "be happy with what u got".

 

[29chico]

Any opinions of this combo from Bogart?

https://www.solar-electric.com/bogart-engineering-sc-2030-solar-charge-controller.html

CC + Trimetric monitor + temp sensor = about $300.

Claims to rival MPPT performance when used as a combination, essentially saying the monitor is so good it gives the PWM controller a big advantage.

I would guess that the combo in question may or may not out perform a MPPT controller depending on how one used their system.  For example, a solar power user that focuses mostly on using as much of their daily use of energy during the peak sun hours of the day and uses minimal energy overnight may well be better served with a middle of the road MPPT controller.  Another user that was more concerned with having more power available in their battery bank for overnight use could possibly fare better with the Bogart system.

A high end MPPT controller that correctly terminates charge by watching the flow of amps taper into a battery bank would very well best both of the two above discussed controller options.

 

[akrvbob]

I think you may be exaggerating the difficulty of drastically improving the number of deep cycles your batteries give you. Here are the choices I'm offering you:

1) Buy a $100 Renogy MPPT, wire it and forget it. Never think about it again. But, it is NOT going to charge your battery just how it wants/needs to be charged.
2) Buy a $300 Blue Sky 3000i. You wire it exactly the same way but you do one more thing that takes 20 minutes. Not hours, not work every day. No, just 20 minutes out of your whole life. You read the website of your battery manufacturer and find out how YOUR battery needs to be charged. Then you program the Blue Sky that way, then you forget it and never do anything with it again the rest of the batteries life.

Typically the battery might say to charge it at 14.8 for absorption charge and hold it for 2 hours. You set those two parameters right on the face of the Blue Sky and DONE!!!!!! FOREVER!!!!!!! Now, you can do a LOT more to extend their life, but it' not worth it to me and I wont do it. But I can give 20 minutes of my life to get so many extra deep cycles out of my batteries.

You may or may not be able to spend the extra $200, (even though it will more than pay for itself in longer battery life) but I suspect the time isn't really an issue at all.
Bob

 

[jimindenver]

On the 20 amp controller, it is a rebadged Tracer MPPT, the first model they put out a few years back. I've known af a few to use it with the only complaint being the remote display is not accurate. Tracer has newer models that are more advanced. A bit more and you could have a nice PWM controller with all the settings needed. It's only 200 watts, I wouldn't go overboard just to have MPPT on it. Think of the space, money and effort just to avoid a 24 to 12 volt converter.