need help sourcing correct components

[NochiLife]

Aha, yes, Joe Marcellino, who I have contacted in the past (actually regarding the warranty on my unit). Yes, I was referring to the "disconnect" coil command.

[littleharbor]

Got a follow up reply from Morningstar tech yesterday. It seems there was originally a recommendation to use tandem breakers in the TS-MPPT instructions which they had realized was potentially dangerous. Removed from further manuals.


Yes I did have a chance to read through most of that forum post. The excerpt in the manual he is referring to was from the original operation manual(from about 10 years ago) for the TS-MPPT. This excerpt has since been removed from the manual and it is recommended to have separate disconnects, one for PV and one for the battery. To be transparent we have seen failures in the past due to improper shut down/startup(battery removal with solar connected and/or reconnecting the battery with solar still connected) with the TS-MPPT. Typically we did not see these failures with double pole breakers but we still thought it would be beneficial to change the manual and be on the safe side. It also makes system troubleshooting significantly easier when each(PV and battery) has their own breaker/disconnect.





Another comment in response to his/other posts. When he states disconnect mode I assume he is referring to a coil command where you can 'disconnect' solar. This is a charging disconnect coil command which will stop charging but it obviously cannot physically disconnect solar from the controller, it will just leave solar in an open state(should measure Voc on solar panels). Disconnecting the battery with input power still applied (while the controller is still charging) can damage the battery circuit of the controller because the remaining power in its inductors and capacitors can no longer be dissipated in the output to the battery. This will result in a sudden high voltage transient back feeding through the battery circuit as they discharge ultimately damaging the controller.





Regards,





Joe Marcellino


MS Technical Support


Morningstar Corporation

https://www.morningstarcorp.com

[NochiLife]

Well, it turns out my Morningstar Tristar manual was dated 2010...and the new one is dated 2018. First of all, my old download says that it has to have a "minimum battery fuse/circuit breaker rating" of 75A. The new manual says that "...These protection devices are external to the TriStar MPPT 150V controller, and must be a maximum of. ..90 amps for the TS-MPPT-60/M." And in the new manual, I can't find any reference to tandem breakers.

(I did notice that the new manual does specify, "Damage to the controller may result if the battery is removed while the TriStar MPPT 150V is charging." Putting it in disconnect mode technically stops it from charging. But that's only possible with a MODBUS/RS-232 connection.)

Guess now I need to find some different breakers...

It wouldn't make any difference if a tandem breaker had dual amp ratings--you couldn't trip a properly rated breaker with solar if you tried, as the maximum power current is generally very close to the short-circuit amps. The breaker there simply provides a disconnect--well, and maybe protect the solar panels if the MPPT goes berzek. The thing I like about tandem breakers is that if the battery breaker trips, it will also cut the solar. But evidently that method isn't kosher anymore.

[littleharbor]

Inquired with Morningstar regarding this and this was their response;

For Morningstar charge controllers you will want to have separate circuit breakers (Single Pole Breaker), 1 each for the solar input and battery input. This gives you the ability to Disconnect the Solar while leaving the battery connected. Disconnecting the battery prior to disconnecting solar, or disconnecting both battery and solar simultaneously can damage the charge controller.

Hope this provides clarity.

Regards,

MS Tech Support

[littleharbor]

Interesting though. This may be from an older manual I got online but it is pretty clear about Keeping the battery connected till solar has been removed.

To Power-down WARNING: Risk of Damage ONLY disconnect the battery from the TriStar MPPT 150V AFTER the solar input has been disconnected. Damage to the controller may result if the battery is removed while the TriStar MPPT 150V is charging.

Also typically you would have a higher amp breaker on the output of the MPPT controllers in relation to the higher voltage/lower current input. Do they make tandem DC rated breakers in dual amp ratings?

[NochiLife]

Sorry I missed your question...however, it's worth noting that if the documentation would recommend a tandem breaker, the only option is a simultaneous "on" upon power-up. At least on the Tristar, it goes through approximately a 3-second boot-up procedure before turning the MPPT on. Tech support didn't frown on it when I talked with them, and it didn't void the warranty--after all, it's suggested in the manual.

[littleharbor]

So, all good when disconnecting the Tristar. What about CONNECTING? Is the internal circuitry such that you can simultaneously flip the battery and PV? That is what I was referring to.

[NochiLife]

"Disconnect" mode (at least in the case of the Tristar MPPT) is where the MPPT internally shuts down, and is not using the solar at all. At least according to their tech support, the basic reason for "batteries first, then solar" (or simultaneous) is because their switching regulator cannot regulate down far enough with no battery load, to avoid overvoltage of the output circuitry. Thus, if its powered on solar, but no batteries, the output voltage will rise beyond the maximum rating, damaging the unit. But if it's in internal "disconnect" mode, the MPPT is shut off anyway. It's like a "power switch" controlled via MODBUS.

EDIT: when the one Tristar MPPT blew out, it tripped the (then) 70A breaker I had on the batteries. Breakers are literally lifesavers!

[Mike90250]

Actually, the Tristar spec would really like the controller to be put in "disconnect" mode before turning off the battery breaker. I concluded that there was no way a solar breaker would ever trip (because a solar panel's "maximum power point amps" is from a breaker's point of view the same as "short circuit amps"), and using a tandem breaker would make it shut the solar off IF the MPPT breaker tripped for whatever reason. (And yes, if you read the manual, you'll notice that my 63A breaker is less than the recommended 75A breaker...but as it has a 60A output current limit, I don't see why that breaker should trip [it hasn't.] Also, 63A was the biggest size I could buy...)

The breakers for charge controllers are to protect the wire, in case the controller shorts out. Use wire large enough to handle your projected amps, and protect the wire with a breaker.

What is the "disconnect mode" ? Is that a term for removing the solar power before shutting off the controller ? Simultaneous breaker action is odd, generally all MPPT controllers want solar to never be applied unless battery is connected.

[NochiLife]

MPPT controllers really need to be connected to the battery bank FIRST so that they can boot up before PV input is added. This tandem breaker should have the individual sides separated so that upon energizing the controller the PV isn't simultaneously energized.

Technically, you are completely correct. However, in the Morningstar Tristar TS-MPPT manual, it states the following on page 27:

A disconnect is required for the battery and solar circuits to provide a means for removing power
from the TriStar MPPT 150V. Double pole switches or breakers are convenient for disconnecting
both solar and battery conductors simultaneously.

MOD NOTE - The above double pole suggestion was from an OLD manual and has been removed from current manuals. It is not recomneded to use dual breakers for the CC in and out.

It does go on to talk about "turning the battery disconnect on first, then the solar", but that's assuming that they are separate.

Actually, the Tristar spec would really like the controller to be put in "disconnect" mode before turning off the battery breaker. I concluded that there was no way a solar breaker would ever trip (because a solar panel's "maximum power point amps" is from a breaker's point of view the same as "short circuit amps"), and using a tandem breaker would make it shut the solar off IF the MPPT breaker tripped for whatever reason. (And yes, if you read the manual, you'll notice that my 63A breaker is less than the recommended 75A breaker...but as it has a 60A output current limit, I don't see why that breaker should trip [it hasn't.] Also, 63A was the biggest size I could buy...)
Now, that being said, I did have a Tristar explode on me (trying to change the configuration settings, and yes, in disconnect mode each time I cycled power--just one time there was a orange flash and a "pop" three seconds after I turned it on [after completing it's power-up cycle]); fortunately Morningstar was gracious and replaced it VERY quickly under warranty.

[littleharbor]

[QUOTE=. I used a 400vDC-rated tandem 63A breaker to simultaneously disconnect both solar and battery lines from the MPPT (so if the MPPT tripped the battery breaker, solar would also be disconnected).
.[/QUOTE]

MPPT controllers really need to be connected to the battery bank FIRST so that they can boot up before PV input is added. This tandem breaker should have the individual sides separated so that upon energizing the controller the PV isn't simultaneously energized.

[NochiLife]

Maybe a little misunderstanding...I'm not sure what "big headache" I saved you from. Pretty much all MPPT units (that I'm aware of) top out at 150v, so my statement was intended more as "just so you're aware when wiring the system up", and not "there's a problem here." Technically, Morningstar Corporation does make a 600v MPPT, but I don't think it's worth the extra cost...especially not in a smaller system. My Morningstar TS-MPPT-60 has a maximum of 150v; I'm running a 3x4 configuration (dozen panels, but they're a much lower voltage), with a 120voc rating. Works fine.

I really don't understand the reason for the "maximum series fuse" rating, though I'm sure it's there for a reason. You will obviously need a DC-rated breaker to disconnect the solar panels (NOT to be confused with an AC-rated breaker--it is considerably harder to "break" a DC arc, and the breaker has to be designed to handle a high DC voltage), but if you ran two separate lines from the three panels, you'd probably be fine. (Gurus who understand how this works are more than welcome to correct me here ). I used a 400vDC-rated tandem 63A breaker to simultaneously disconnect both solar and battery lines from the MPPT (so if the MPPT tripped the battery breaker, solar would also be disconnected).

I briefly glanced over the Internet, and really couldn't find too much about the all-in-1 units: people either like them or they dislike them. As I mentioned, I personally have no experience with them--but with the little loads you're planning on running, you should be just fine. Those units can also be paralleled for expansion in the future. Definitely cost effective if they work...and definitely a waste of money if they don't .

[Mcmullen7242]

Under 50c/watt--you're doing really good . Congrats.
ONE NOTE: These panels have a relatively high voltage, which can cause a slight problem with the typical 150v MAXIMUM limit on most MPPTs (the all-in-1 system maxes out at 145v). Typically, the higher the voltage running into the MPPT, the better, as less power will get lost in the wiring. THE PROBLEM: with the panels' Voc (open circuit voltage) at 64.2v, you can only run TWO panels in series (= 128.2 Voc). Your options are to go with an even number of panels (2,4,6, etc.), or put all three in parallel (which...um...will go beyond the "maximum series fuse" rating of 15A).


Kudos on your energy conservation; it's the things that can't be turned off (like a 'fridge) that can cause energy headaches on an off-grid system. Basically, if you end up being low on power, turn something off. Or just go to bed

I might put a personal "plug" in for a deal on eBay for truly unlimited data through a "back door" AT&T hotspot plan (for use with an external hotspot, not a phone). I wasn't sure if it was just a gimmick or not, but for $4, the seller sent me the instructions...and it works. I have to admit that I went through about 35GB the first month...no "slowdown" or anything else like that. The recurring monthly bill (from AT&T) is $35.08. You will need an AT&T compatible hotspot (I like the AirCard 770s...it supports all the bands), and make sure you have AT&T coverage in the area. https://www.ebay.com/itm/AT-T-Unlimi...t/292830364708

That's funny you brought that up about the hotspot on AT&T, I actually just started doing that a few months ago and I've been going through 100-200gb a month with my brother and it's been great. Thanks for looking out though man. The propane appliances definitely cost me a lot up front but I didn't want to deal with that on solar and always having to be worried about the lights going out. I mainly will just be using the solar for entertainment and non necessities. Thanks for the info on the panels, saved me a big headache. I'll look into some charge controller and that can handle it and then go for a separate charger and inverter system. I want to be able to upgrade as time goes on so willing to spend money on the right inverter up front.

[NochiLife]

The panels will be just under 50 cents a watt. They are model spr 305 wht u. I want to upload a pic of the specs but won't let me so here they are:
peak power 305 watts
voltage 54.7
current 5.58
open circuit voltage 64.2
short circuit current 5.96
maximum series fuse 15

Under 50c/watt--you're doing really good . Congrats.
ONE NOTE: These panels have a relatively high voltage, which can cause a slight problem with the typical 150v MAXIMUM limit on most MPPTs (the all-in-1 system maxes out at 145v). Typically, the higher the voltage running into the MPPT, the better, as less power will get lost in the wiring. THE PROBLEM: with the panels' Voc (open circuit voltage) at 64.2v, you can only run TWO panels in series (= 128.2 Voc). Your options are to go with an even number of panels (2,4,6, etc.), or put all three in parallel (which...um...will go beyond the "maximum series fuse" rating of 15A).

Thank you guys for the info. I am in rainbow, ca on a south facing flat. The average peak sun here for solar is 5.5 hours year round. Also all my appliances are propane (fridge, stove, water heater). The only things being used on the solar would be my internet router (about 5-10 watts, two TVs (80 watt and 100 watt), two Xbox ones (230 watts max), 2 phone chargers (10 watts), 2 MacBook chargers (170 watts) and 4 fans 65 watt fans (only 2 running regularly). I am sorry for the long reply as I am living without power and my data ran out the other day so had no internet.

Kudos on your energy conservation; it's the things that can't be turned off (like a 'fridge) that can cause energy headaches on an off-grid system. Basically, if you end up being low on power, turn something off. Or just go to bed

I might put a personal "plug" in for a deal on eBay for truly unlimited data through a "back door" AT&T hotspot plan (for use with an external hotspot, not a phone). I wasn't sure if it was just a gimmick or not, but for $4, the seller sent me the instructions...and it works. I have to admit that I went through about 35GB the first month...no "slowdown" or anything else like that. The recurring monthly bill (from AT&T) is $35.08. You will need an AT&T compatible hotspot (I like the AirCard 770s...it supports all the bands), and make sure you have AT&T coverage in the area. https://www.ebay.com/itm/AT-T-Unlimi...t/292830364708

[Mcmullen7242]

I really like that all in one system, I'm going to look more into that. Thanks nochi.
Sdold I was thinking of getting batteries similar to this but different voltage:

https://www.amazon.com/gp/aw/d/B01KN...1WR?th=1&psc=1