which mppt controller

[socaldmax]

Originally Posted by hellosailor

Socald-
"The controllers may end absorption charging at slightly different times, but this will typically be of little or no consequence to the health of the batteries."
Okay, you've just quoted Morningstar as saying "one ring to rule them all" will typically not be necessary. In simple English "typically" means sometimes, it won't work as well as a single unified control, either.
Apparently some other manufacturers think having one unified control beats having two controllers with specific wiring, temperature compensation, and "always" instead of "typically".
It sounded like the OP wanted to ensure he would not having dueling controllers. Not typically, but all the time.
Then too, there is something to be said about installing and using just one controller--and having a second one sitting in a box as a spare, instead of box of them being vulnerable to lightning strikes, etc. if two are in use all the time.

Their use of the word "typically" was just the avoidance of using the word "always" which is an absolute that everyone should strive to stay away from.

Morningstar sells a networking system so that their controllers can be used in massively parallel systems as well as in pairs. They chose to point out that you don't need to buy their hub for their controllers to work in unison.

That was just one example of quite a few that all said the same thing: if the 2 controllers are set to the same voltages, they will work just fine together. One article even told the user that 2 different models of controllers would work fine, as long as they were set to the same voltages.

There is no such thing as "duelling controllers." They both add current to the battery bank until they reach their setpoint, then shut off.

Please, show me an expert source of solar info that claims it happens.


Yes, having a spare controller in a box might be a good thing, but if it was a lightning strike that caused the first one to fail, chances are the solar panels are fried as well, since they were all tied together feeding that one controller.

Brand new solar controller + dead panels = expensive paperweight.

[jbinbi]

OK, as the OP, wanted to get this back on topic a bit.

Appreciate comments, but as I stated
1. want high reliability, which is why I stated the brand names I have heard of; blue sky, mangnum, victron, morningstar. Wanted real world input if anyone had it on these, or maybe other 'standard' brands. Didn't want the thread to devolve into buying from amazon, and btw, i do know electronics, I say have an 800 number meaning it is not fly by night operation. when something breaks, and I bought it from some place in China, and I am in the US, it does me no good if I can't reach that company, they possibly don't exist anymore, etc. If it is a US company that OEMs a china product, I am fine with that, I can actually reach them and get my issue resolved.
2. I only wanted 2 controllers with Blue sky. They are 30A each, and they are actually made to run together. They have wiring from 1 to the other.
3. The rest of them have enough A to have a single controller.
4. Leads me to another question. Assuming I have 2 panels in parallel, and do put it into a single controller, do you actually put both wires from each panel onto the solar input terminal on the controller, or should i use a dc bus to combine the 2 panel's wires and take a single wire over to the controller?

[hellosailor]

Whether you run all four wires to the MPPT input, or combine them and run one pair of heavier cables to the MPPT input, won't really matter as long as the voltage drop is the same either way. Which will depend on your wire selection.
Running one main run is certainly neater, but running two separate runs would give you the option of "just" disconnecting one if it failed, and having the other one still in place. Again, where it is convenient to mount a watertight junction box would matter more than which way you did it.

[socaldmax]

Originally Posted by jbinbi

Assuming I have 2 panels in parallel, and do put it into a single controller, do you actually put both wires from each panel onto the solar input terminal on the controller, or should i use a dc bus to combine the 2 panel's wires and take a single wire over to the controller?

You use a pair of combiners.

[jbinbi]

Originally Posted by socaldmax

You use a pair of combiners.

Socal, thanks again for all your help on my questions! Do you have a link/manufacturer, where to get them etc.

[socaldmax]

They sell them all over Ebay. You can also buy the bare MC4 connectors to make up your own cables from the combiner to the solar controller. They can be bought for as little as $1/pair, the combiners are available for $5-6/pair.

[Livia]

Longevity: We are six years into our BlueSky MPPT and no problems. We have a Magnum inverter-charger (not MPPT) and also no problems. Had to use Magnums support during install, excellent. Never needed the BlueSky support which also a compliment!

[Barra]

Originally Posted by socaldmax

Their use of the word "typically" was just the avoidance of using the word "always" which is an absolute that everyone should strive to stay away from.

Morningstar sells a networking system so that their controllers can be used in massively parallel systems as well as in pairs. They chose to point out that you don't need to buy their hub for their controllers to work in unison.

That was just one example of quite a few that all said the same thing: if the 2 controllers are set to the same voltages, they will work just fine together. One article even told the user that 2 different models of controllers would work fine, as long as they were set to the same voltages.

There is no such thing as "duelling controllers." They both add current to the battery bank until they reach their setpoint, then shut off.

Please, show me an expert source of solar info that claims it happens.


Yes, having a spare controller in a box might be a good thing, but if it was a lightning strike that caused the first one to fail, chances are the solar panels are fried as well, since they were all tied together feeding that one controller.

Brand new solar controller + dead panels = expensive paperweight.

Well im no expert so you can ignore me if you want but having added a second mppt controller to an existing one after adding more panels I can say that one can sense the volts of the other and prematurely go to float. Quite annoying.

Simplest solution was to wire all panels to one controller rather than muck around trying to get 2 to work together. I would recommend the KISS approach of a single controller as theres no real benefit just potential problems.

[socaldmax]

Originally Posted by Barra

Well im no expert so you can ignore me if you want but having added a second mppt controller to an existing one after adding more panels I can say that one can sense the volts of the other and prematurely go to float. Quite annoying.

Simplest solution was to wire all panels to one controller rather than muck around trying to get 2 to work together. I would recommend the KISS approach of a single controller as theres no real benefit just potential problems.

There are plenty of benefits, but both of them need to be set to the same absorption voltage. If one goes to float a few minutes before the other, then chances are you were at the very tail end of topping off your batteries anyways, so one controller running a few minutes longer than the other is no big deal.

For some people who have a lot more panels, they have no other choice but to run 2 controllers, they simply put out too much current for one 60 amp controller.

[Barra]

Originally Posted by socaldmax

There are plenty of benefits, but both of them need to be set to the same absorption voltage. If one goes to float a few minutes before the other, then chances are you were at the very tail end of topping off your batteries anyways, so one controller running a few minutes longer than the other is no big deal.

For some people who have a lot more panels, they have no other choice but to run 2 controllers, they simply put out too much current for one 60 amp controller.

No that wasnt what was happening. the second controller was switching off with batt volts 12.8 at times so way before it should have. ie it was sensing the charging volts of the other charging source. Can happen with alternators too but thats another story.

Not sure what the plenty of benefits are except as you say large installations - then your forced to do it but god knows why you would choose to do it.

[socaldmax]

Originally Posted by Barra

No that wasnt what was happening. the second controller was switching off with batt volts 12.8 at times so way before it should have. ie it was sensing the charging volts of the other charging source. Can happen with alternators too but thats another story.

Not sure what the plenty of benefits are except as you say large installations - then your forced to do it but god knows why you would choose to do it.

How many solar systems do you own? How many have you installed?

I own 2 of them, and I've installed 15 or 16. Out of those systems, 3 of them have used parallel solar controllers (2 Eco-Worthy and 1 Morningstar MPPT 60s), and all have worked as described - charged to the set voltage and shutoff within a minute or two of each other.

I take it you didn't read the quote above from Morningstar stating that they will work in parallel without a network controlling them. AFAIK, all of the mfrs make the same claim. However, if you can find a solar controller mfr. that disagrees, I won't argue that point, merely point out that they're probably outnumbered by the other mfrs 10:1.

I've never seen a solar controller shut off when an alternator or generator was charging unless the other charging source was set higher than the solar controller. On both of my systems, the solar controller is set to 14.8v, the battery chargers are set to 14.4v. If I do fire up the genny during the day, I'll see system voltage climb much faster to 14.4v, then slow back down as it continues to 14.8v as the solar controller continues to pump out power.

Solar controllers and battery chargers have no means of detecting alternate sources of power - all they do is monitor voltage and shut off when they reach the setpoint.

If they behave in any other way, my strong suspicion is they are defective and should be repaired. If my system had behaved that way, I would have contacted the mfr, talked to them and requested an RMA. What brand was this? They're not all the same, there are 3 or 4 brands I'd stay away from based on what I've seen over the years.

As for parallel benefits, I thought they were obvious, but we can run through them.

1. Cheaper. You can buy a good quality 20A controller with excellent menu and display for $100. The 60A Morningstar will cost you close to $650 with a display, so 3 of the 20A units are 1/2 the price.

2. Redundancy. If one goes down, you still have the others making power while you make repairs.

3. Ease of troubleshooting. Simply swap units and see where the problem is, if your voltage readings didn't already convince you.

4. Efficiency. A lot of large scale rooftop systems use microinverters to convert to 220v AC on the roof, then run that down to the breaker panel. In a sailboat environment, there is the potential for lots of shading, so each panel gets it's own controller and is always at it's MPP. If 2 or more panels share a controller and there is no shading, the controller can easily determine MPP since it's the same for all of them. But if one or more is shaded then the MPP is different for each of them. As most people are aware, you cannot have different DC voltage levels on the same wires, they end up averaging out, which now results in none of the panels being at MPP. Some are too high on their curve, some are too low. They're still putting out some power, but a lot less than normal. With separate controllers, each panel is always at it's MPP adjusted by it's own controller getting maximum solar harvest under those conditions, even if it's partially shaded, it doesn't affect any other panel. This is probably the most common reason for multiple controllers.

5. Flexibility. Depending on the boat, it might be easier to run multiple sets of smaller cables down multiple stanchions rather than a large set down one stanchion, or mount one controller on the port side and the other on the stbd side, every installation is different.

[Emerald Sea]

Surprised you didn't list the Outback MPPT chargers. USA made. We have the FM80 charger connected to series wired 990w solar pumping into our lithiums. Its been an absolute champ!

[Captain Bill]

Originally Posted by jbinbi

OK, as the OP, wanted to get this back on topic a bit.

Appreciate comments, but as I stated
1. want high reliability, which is why I stated the brand names I have heard of; blue sky, mangnum, victron, morningstar. Wanted real world input if anyone had it on these, or maybe other 'standard' brands. Didn't want the thread to devolve into buying from amazon, and btw, i do know electronics, I say have an 800 number meaning it is not fly by night operation. when something breaks, and I bought it from some place in China, and I am in the US, it does me no good if I can't reach that company, they possibly don't exist anymore, etc. If it is a US company that OEMs a china product, I am fine with that, I can actually reach them and get my issue resolved.
2. I only wanted 2 controllers with Blue sky. They are 30A each, and they are actually made to run together. They have wiring from 1 to the other.
3. The rest of them have enough A to have a single controller.
4. Leads me to another question. Assuming I have 2 panels in parallel, and do put it into a single controller, do you actually put both wires from each panel onto the solar input terminal on the controller, or should i use a dc bus to combine the 2 panel's wires and take a single wire over to the controller?

I own a bluesky 2512i with a remote panel. I cannot recommend this controller. It has undersized connectors. The literature recommends 8awg wire for 300w and the distance to the panels. Unfortunately the unit only has 14awg connectors. My old pwm controller I replaced (it had failed after 10 years and a lightning strike) put out much more power. I used to see in thechigh teens quite regularly with it, but have never seen more than 14a with the blue sky ( maybe because I had to use small pigtails to connect it to my 8 awg wire). It also will not go into equalize mode. Also their battery monitoring function sucks. It cannot keep track of amp hrs in versus out for more than a day. Judging by charging voltage the batteries are near full yet the monitor reports thm as only 80% after a few days of not getting to 100%, even though the charging voltage is at 14.5 and the amps are down to 3 the monitor reports 83%. It suddenly jumps to 100% when the target 2.4 amps is reached. The next day 14.5v and 3a reports 99% charge.

[hellosailor]

Bill-
Had you asked Bluesky about those, ah, quirks in their controller?

[Captain Bill]

Originally Posted by hellosailor

Bill-
Had you asked Bluesky about those, ah, quirks in their controller?

Yes, but my options were send it back to them 3-4 weeks turn around time or live with it. As a fulltime cruiser i could not affordvto be down that long. By the time I went to the boat yard for a month it was out of warranty. Even if I had sent it to them they weren't going to put begger connectors in the box. I proposed that I send them the unit I had and that they send me a loaner in the meantime, but they wouldn't do it.

They told me that my old controller was inacccurate and that their voltage/amperage reports were much better. I could often get my batteries to go into float on a sunny summer day justvwith solar. I have never had that happen with the bluesky. I always have to precharge with the genset or engines to get to 100% with the bluesky. I will never buy another one of their products.