Interesting DC charging options per Morningstar + New Meanwells

[BradKW]

I've been toying with the idea of supplying my Morningstar MPPT controller with not only solar DC input, but also plugging into shore power and using a AC-to-DC converter (aka battery charger) and pushing that DC current through the solar charge controller. Reasons:

1) good quality charge controllers are "smarter" than smart chargers and allow user-defined charging profiles.
2) Even the $500++  120v chargers don't really meet the needs of a big L16 battery bank.

It seems like such an elegant solution, I wondered why I couldn't find anything on it. Closest I found, and in keeping with SW's speculation, was that controllers used hard shorts as a method of power management, which would damage a converter. This seemed to only be referenced regarding PWM, not MPPT...so I decided to ask Morningstar tech service. The emails in order:

ME:
 [font=Arial, sans-serif]Hello, I have a Tristar 60 MPPT for my 24v system, and a Trackstar 15 for my 12v system. My question relates more to the Tristar 60, as I continue to have difficulty finding an appropriate mobile converter/charger for when I can plug in.[/font]
[font=Arial, sans-serif]Most of the 120v chargers available for mobile use just aren't designed to meet the needs of my Trojan L16 bank. I would like to know if I can use a 120v charger/converter to provide DC into my Morningstar product, let the TriStar control the output to batteries?[/font]
[font=Arial, sans-serif]It's seems logical, but I can't find any information to support this.[/font]

[font=Arial, sans-serif]Morningstar:[/font]
[font=Arial, sans-serif] [size=small][font=Arial, sans-serif]Hello Brad,[/font]
[/font][/size]


[font=Arial, sans-serif]Can you provide some more information about this alternate charging source? What type of power, voltage, and current is produced by this source? Generally speaking as long as this is a DC source that has a voltage less than the rated max input of the MPPT controller you will have no problem. For example, using a DC power supply(while keeping its voltage lower than the max rating of the controller) is more than fine. The input voltage will still need to be high enough to fully charge the battery bank. For a 24V battery you likely want an input voltage of at least 32V but ideally closer to 35. [/font]



[font=Arial, sans-serif]The only other thing that is recommended for a constant DC output source is to custom program the controller to use a fixed Vmp. The tracking of some alternate sources can get a little messy. When you program the fixed Vmp the controller will lock in and charge once your input voltage reached that voltage or higher. If your input source were to be lower than this fixed Vmp no charging would take place. [/font]



[font=Arial, sans-serif]Regards, [/font]



[font=Arial, sans-serif]Joe Marcellino [/font]

[font=Arial, sans-serif]MS Technical Support [/font]

[font=Arial, sans-serif]Morningstar Corporation [/font]
[font=Arial, sans-serif][size=small][font=Arial, sans-serif]www.morningstarcorp.com[/font][/font][/size]

[font=Arial, sans-serif][size=small]ME: [/font][/size]
[font=Arial, sans-serif]Thanks for your fast response. The only potential negative I've come across is the possibility that charge controllers use hard shorts as part of their power management, which could damage an normal 120v to DC converter. But if that's not the case, I've been looking at some products by Meanwell.[/font]





[font=Arial, sans-serif]They just recently came out with a "battery charger", but it appears to have most of the same characteristics of their standard adjustable AC-DC converters...namely that you need to know far more about electronics than I do to use it properly. [/font]





[font=Arial, sans-serif]http://www.mouser.com/ProductDetail/Mean-Well/RCB-1600-24/?qs=sGAEpiMZZMsYfYypWaYaEXTICtNoOmYg%252bqpGL2C8ejY%3d[/font]





[font=Arial, sans-serif]My thought is to get a 48v / 55amp unit because the 24v one does not supply high enough voltage, and run it through the Tristar 60 and let the Morningstar product control the charging of batteries. [/font]
[font=Arial, sans-serif][size=small][size=small][font=Arial, sans-serif]I'm also open to suggestions [/font][/size][/font][/size]

[font=Arial, sans-serif][size=small][size=small][font=Arial, sans-serif]Morningstar:[/font][/size][/font][/size]
[font=Arial, sans-serif][size=small][size=small][font=Arial, sans-serif] [size=small][font=Arial, sans-serif]I would still recommend using a MPPT controller if you plan on using an alternate charging source. Keep in mind that our controllers are designed to work with solar which is not charging all the time. Moving to a source that may potentially charge your batteries 24 hours/day may shorten the life cycle of the controller. Assuming that your source never exceeds the max input voltage(150V for the TS-MPPT) than there should be little to worry about. I do not know how well or efficient this will work.[/font]
[/font][/size][/size][/font][/size]


[font=Arial, sans-serif]Regards, [/font]



[font=Arial, sans-serif]Joe Marcellino [/font]
[font=Arial, sans-serif][size=small][size=small][font=Arial, sans-serif][size=small][font=Arial, sans-serif]MS Technical Support [/font][/font][/size][/size][/font][/size]

 

[BradKW]

I have more to post on this in general and asking of opinions, but outta time atm... just wanted to add that Meanwell has come out with a new line of actual chargers with built in potentiometers...

 

[AngryVanMan]

That meanwell looks nice! It says in the datasheet it is for building into another finished product, like a UPS system, but it should work fine standalone just like their power supplies do.

Did you rule out a 24V inverter with a battery charger built in? A lot of the bigger/higher end ones come with the charger included.

 

[highdesertranger]

thanks Brad for doing the leg work on that. keep us up to date. highdesertranger

 

[BradKW]

That meanwell looks nice!  It says in the datasheet it is for building into another finished product, like a UPS system, but it should work fine standalone just like their power supplies do.

Did you rule out a 24V inverter with a battery charger built in?  A lot of the bigger/higher end ones come with the charger included.

It would be more fair to say I didn't really understand the game well enough when I purchased my inverter to actually rule them out. Even now, looking at the combo options and digging into their specs, I'm at a loss to explain how sparse the specs are for the charger potion of the devices, often listing only amp output and no voltage range.

But I haven't dug too deeply since I already have an inverter. I paid about $900 for a pure sine 3k, and also didn't forsee the challenges of finding a charger that fits my large L16 bank well. If I were to start over, I would take a much closer look at some of the $2000+ offerings from Magnum that include a charger.

But based on the information in my original post, I may end up better off still, with some new options, new equipment, and maybe new combinations. I suspect I'm heading down the guinea pig path here...remains to be determined with what though  

 

[akrvbob]

I'm very impressed with that tech support!! Obviously, he was intelligent and knowledgeable about his product and solar in general. Even better, he was able to think outside the box to what was probably a whole new idea. I'd consider that exchange a very good reason to move Morningstar to the top of the list for charge controllers I want to buy

 

[frater secessus]

A guy on Youtube did this.  He did 110v --> 24v power supply from a neon sign or something --> Morningstar sunsaver mppt.  He did it because he wanted to control the charging with more granularity. 

Edit:  found it

 

[firebob]

It has been talked about on other forums about using a higher voltage charger with a MPPT controller. It has been a few years, but i'm thinking someone had to use a large set of caps as a buffer to keep the charger and controller working.

With larger batter banks it's better to use a larger inverter with a built in charger that will also bypass when charging. You will need a larger incoming power source; like 30 + amps to make this work.

There have only been 2 companies that came out with inverter/chargers that would "load share" (i think it was called); they were SMA and XW. You were able to use any amperage (had to be the same voltage as the system). You would program the system to only use 40 amps from the genset and the inverters bypass what was needed, charge with the left over amps, or produce more power depending on the current load.

How big is your large is your L16 bank? I did some looking around, but did not see where you talked about it. I do see where you have a 24 and a 12 volt system.


I could ramble for hours, but with out knowing the size of your banks who know if anything i will say will help you.

 

[firebob]

A guy on Youtube did this.  He did 110v --> 24v power supply from a neon sign or something --> Morningstar sunsaver mppt.  He did it because he wanted to control the charging with more granularity. 

Edit:  found it

nice youtube thanks.

 

[blars]

Technomadia has a victron load-sharing inverter/charger, wheeling-it has a different brand. Mentioned on the Nov 2 vlog on youtube. Both are being used with LiFePO4 batteries.

 

[SternWake]

Good to hear progress on this front. Thanks for taking the initiative to correspond with Morningstar about the possibility.


Back before I got my Meanwell rsp-500-15,  I bought a 30 amp 23$ cheapo adjustable voltage power supply, but this cheapo unit had no overcurrent or overvoltage protections.

Meaning I could not set it to 14.8v, hook it to a depleted battery and let it go.  Rated at 30 amps it would feed a depleted battery with nearly 40 amps.  Over 36.2 amps there would be this loud buzzing saying something was not right, So I would have to continuously adjust the output voltage to keep amperage below 36 amps and keep the unit from buzzing, and bump it up slightly every 15 minutes or so, to keep the 30 amp + charge rate going.

At one point, I decided to sacrifice it for science, and I cranked it to 15 volts, hooked it to a depleted battery and let it buzz.  17 minutes later it released the magic blue smoke, and I Ordered the MEanwell rsp-500-15.

Back then, in 2014 sometime I thought why not use a power supply to feed a solar controller whose setpoints are adjustable, and asked on some other forums why this would not work, and got crickets.

Many others obviously thought the same thing and pursued it further in the quest for an affordable automatic charging source that could be programmed.

In my case, I have found that twisting my potentiometer to dial a voltage, while obviously not automatic, is hardly so onerous a duty that it stresses me out.  I basically dial it to 14.7v, and hook up the 45 amp power poles.  Whan amps taper to 0.4 or so, I lower voltage to 13.6.  If I will not be there, or awake, when amps taper to this threshold, I obviously have more time than needed to fully charge as fast as possible, and lower the voltage to 13.6 which is the recommended float voltage of my AGM battery.

However my AGM battery needs the high amp recharge on occassion, and when it is acting up, and not maintianing the expected voltage under loads, the high amp rechargeis the cure, and i want to apply 40+ amps from its most depleted state unitl 14.4 to 14.7v is attained, and then hold it until amps taper to 0.4.  When the battery requires this I do not want 13.6v initiated early even if I have no time limits in which to utilize grid power to charge the battery.

While it would be nice if it would do what I want, automatically, it is not a huge deal to twist a dial once or twice either.

I do not know how the higher rated power supplies themselves would handle the controller inline.  MobileSport got a rsp-750-15 and it apparently needed some more wires hooked up to work properly as a battery charger, like the voltage sense lines, something I did not have to concern myself with on the rsp-500-15.

I'm certainly interested in seeing progress on this powersupply feeding a solar controller front.  it is a shame that the better plug in chargers with adjustable voltage setpoints and amperage thresholds, and temperature compensation are so expensive, and in the case if Xantrex, not reliable.

The end user should not have to cobble together a better solution to an automatic programmable charger, or be a rich Fkucker who can just throw money at the solution, or at new batteries prematurely.

 

[BradKW]

My four (6v) L16's are 420AH each, so if it were a 12v system I'd have an 840 AH bank. Since it's a 24v system, watt-hours are more appropriate, but same difference...I'd certain appreciate suggestions for power supply to the Tristar 60. Just been too busy at work to have any energy to research this week.

Here's another email exchange with Morningstar...like Bob said, this is pretty impressive customer service:

ME:
Thanks again Joe, I feel encouraged enough by the potential for success that I will probably guinea pig myself on this type of setup. If you're interested in the results down the road, let me know and I'll CC you when I post to the forums
Could you point me towards something I can read to help me understand why I would want a fixed Vmp profile for a constant DC input, and weigh how subjective the word "constant" might be in this reasoning?
Much appreciated!


Morningstar:
Hello Brad,
Yes, please let me know how this goes. I am always interested in hearing how our products are being used, especially in a non solar application.

We have no white paper or anything like that as to why you would want to enable the fixed Vmp. From what we have seen it is generally better to use the fixed Vmp when using a power supply, or something with a rather consistent/constant voltage. When you enable the fixed Vmp it will basically stop the sweeping of the charging sources IV curve. Sometimes with a constant DC source the sweeping can get a little messy. This may cause the controller to charge at a non ideal power point, meaning you are not getting all that you may be able to. I am not saying you must enable the fixed Vmp but it is generally recommended.

If you need help with custom programming the fixed Vmp please let me know.

Regards,
Joe Marcellino

 

[firebob]

I thought you had a larger battery bank.
I think i see where your going with this thread now.

I do think there are plenty of solutions out there that will fit you needs besides what you are talking about. I did more searching and there are a good amount of people that had done what your talking about. The down side is very few talk about all the trails and just show off there current setup that working and a lot of time it's very hard to find how well it's working down the road.

 

[BradKW]

If you could link some of your search results, or just the searchstring used, that'd be great...I never have had much luck turning up relevant information.

 

[akrvbob]

Some people ask "Why spend the money on MPPT or one of the premium brands if controllers." and this is one reason why, you can call them up and talk to somebody who knows more than you do about the controllers.

Imagine trying to get this kind of help from any Chinese controller!!

 

[firebob]

I'm sorry i don't save my web page history and not sure what i put in when doing searches. When i was looking i bet i looked for 4 hours and opened 500+ sites.

PM sent...

 

[BradKW]

Looking/Googling what the possibilities might be for a straight AC-to-DC converter to run through my charge controller, and I realized I'm not even sure what the TS-MPPT-60 can handle...or would be best for my needs. 

The Spec Sheet shows a max input voltage of 150v, and also says "up to 3kw". But I find that I've forgotten what the "60" amp rating refers to...max input or output?

Since I'm wanting only 30ish volts to batteries, if I ran say 120v into controller, I assume the extra gets converted to amps...but does the amp output of whatever converter I get basically determine how much goes to battery? Can I overload the MPPT controller by having less than rated voltage input, but too high amps input?

Thanks  

 

[jimindenver]

Never ever exceed the Voltage limits of the controller, it will die. It won't exceed the amp limit, it will clip the excess power instead just as if you had over paneled.

The controller will decide what to do with the power once it comes in with some guidance from you. It will use the voltage you specify and go all out up to its amp limit trying to get the voltage up to that point. After that there is a timed absorption stage that the amps will start dropping as the battery nears full followed by a float to finish it off. Acceptance rate controls the flow at that point, not the controller.

 

[blars]

The 60 is the max output amps. 3kw is only with a 48v battery, half that with 24v or quarter it with 12v.

 

[firebob]

You might need a set of blocking diodes before a set of caps to keep the rest of the ac system happy and to smooth out the ac a little before the CC.