Morningstar Tristar 600V vs cheap EG4 500V MPPT Charge Controller are they the same?

I'm looking for a new charge controller that can handle max VOC > 470V. So far I've found these two models, but they have a very different set of prices, so I'm not sure if I'm missing something that the Morningstar has that the EG4 does not.


$989 - 600V - Morningstar Tristar DB TR GFPD

Comes with a GFPD, which oddly in both the Amazon and ebay shop is MORE expensive to get the model without it, possibly because the GFPD version is quite large? Morningstar also comes with disconnect box as well.

My only issue with this is it's physical size (it's 35" tall) and the semi sketchiness of this Amazon/ebay seller instead of a specific site. Looking around on sites it appears to be $300 more there.

A link to amazon:


$399 - 500V - EG4

Why does this say 22A max PV input? Is that really the max I can send? I was hoping to send 250v 40 amps from my PV array, but the 22A seemed low enough I wasn't sure if this is the right MPPT for me.


Any other MPPT recommendations that fit for higher voltage?

Morningstar makes SOLID gear. Several of us can/have shared about thier support after the sale. They didn't even flinch at sending me a new inverter at no charge that was years out of warranty.

22 max input. Give or take that's 2 strings of ~400 watt modules paralleled. That will probably work fine for most folks most of the time and that lines up with other most other CC's I've seen.

I really like my Victron 450/100. 2 x MPPT's @20 AMPS each is really nice. Didn't say it was cheap though but that's probably the one you need. Or two of the EG4's....

OzSolar said:

Morningstar makes SOLID gear. Several of us can/have shared about thier support after the sale. They didn't even flinch at sending me a new inverter at no charge that was years out of warranty.

22 max input. Give or take that's 2 strings of ~400 watt modules paralleled. That will probably work fine for most folks most of the time and that lines up with other most other CC's I've seen.

I really like my Victron 450/100. 2 x MPPT's @20 AMPS each is really nice. Didn't say it was cheap though but that's probably the one you need. Or two of the EG4's....

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Yeah, I like the look of the Victron 450/100 too, also looks like their external measuring ecosystem (like apps, exporting data etc) is good too.

You mentioned that you have 20 AMPS each, but when I was looking at their spec sheet, I thought I should be using the 18 A per tracker based on "Max. PV operational input current". Not trying to call you out, just want to confirm that is the correct number to use when comparing the different MPPTs.

Victron 450/100 Spec sheet:

source: https://signaturesolar.com/product_images/Datasheet-SmartSolar-MPPT-RS-EN.pdf


EG4 500V Spec Sheet

source: https://eg4electronics.com/wp-content/uploads/2024/04/EG4-MPPT-100-48HV-Spec-Sheet.pdf



I only have one line from my panels to MPPT, so can only use 1 tracker. In this case, the two have the same 18A input per tracker right?

Looking at those specs, 18 amp is the maximum it an convert and transfer into the batteries. On a 400 volt array, that is still over 7,000 watts of input power. That is more that it can feed to the batteries, so it will go into power limiting anyways. The 20 or 22 amps spec is the maximum ISC current you should connect. Due to how MPPT tracking works, it is quite possible that the controller will pull higher current spikes while it is hunting for the max power point. If the PV panels can produce too much current, it could damage the input circuit. So it is a good idea to stay below that number.

Out in the real world, it i rare for any PV solar panel to exceed 80% of it's STC rated power and current. But you do need to plan the system so when conditions do produce the maximum power, it won't blow anything up. Having the system go into power limiting/clipping for an hour on a cool sunny day is not a big deal. It happens a few day a year on both my Enphase microinverters and my Victron charge controller. Over paneling by about 15% to 25% is even recommended by many systems. You get the benefit of the greater panel power anytime the production is less than perfect, which is most of the time.

100 amp into a "48 volt" system is about 5,500 watts as the batteries reach full charge. So the 250 volt string would be at 22 amps. That is on the low end of the voltage to make full use of a 500 volt charge controller. Once over 300 volts, the 18 amp input current limit is not going to be the power limiting factor. That works out to 5,400 watts going in.

GXMnow said:

The 20 or 22 amps spec is the maximum ISC current you should connect. Due to how MPPT tracking works, it is quite possible that the controller will pull higher current spikes while it is hunting for the max power point. If the PV panels can produce too much current, it could damage the input circuit. So it is a good idea to stay below that number.

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Thank you, I didn't know to check the ISC is under the 22A max input amps, but I'm confused because I thought I could over panel long as the max Voltage is respected. For example this user from another thread:

The SCC pulls the amps.

Its like my 2W nightlight that pulls (2W / 120V = .0166A). This nightlight is plugged into a 15A receptacle (which is part of a 200A household), which is connected to an "even bigger" grid.

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Given this, how do I calculate the correct max ISC coming from my panels? For example if I have:

12.88 ISC x 8 panels in series x 3 strings, would this be

12.88 * 3 = 38.64A

If so, is the max just 1 string of panels since only 1 * 12.88 would be under the 22A from the SCC?

ddxv said:

Thank you, I didn't know to check the ISC is under the 22A max input amps, but I'm confused because I thought I could over panel long as the max Voltage is respected. For example this user from another thread:

Overpaneling. How much is too much?

I know this has been discussed many times here, and reading into it I think the general conclusion is; Overpanel as much as you want, just don't go above the voltage limits of your charge controller. Is this true? What if I doubled the input but stayed under voltage? I want to know if I can...

diysolarforum.com

Given this, how do I calculate the correct max ISC coming from my panels? For example if I have:

12.88 ISC x 8 panels in series x 3 strings, would this be

12.88 * 3 = 38.64A

If so, is the max just 1 string of panels since only 1 * 12.88 would be under the 22A from the SCC?

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Morningstar makes good equipment, and i'm biased toward made in USA equipment, but you'd be limited in how quickly you can charge your batteries, 60A vs 100A for the EG4. I would choose the EG4 version, I haven't really heard any bad things about this unit.

koppted said:

Morningstar makes good equipment, and i'm biased toward made in USA equipment, but you'd be limited in how quickly you can charge your batteries, 60A vs 100A for the EG4. I would choose the EG4 version, I haven't really heard any bad things about this unit.

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I'm OK with brand, and they seem to have similar specs, but just confused about whether I can safely overpanel over the 22 max short circuit input amps or if that is dangerous. Given that my current panels are 12.88 ISC each, it would seem I could only ever have 1 string as any more would go over the max ISC?

Looking closer at the specs for Victron and EG4 they both mention that the danger is if the polarity is reversed:

"2) A higher short circuit current may damage the controller if PV array is connected in reverse polarity."

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So I guess having a higher PV input Amperage is OK as long as I don't ever mix up the polarity?

If in doubt about the morningstar SCC go to there website and use the string calculator. it iwll tell you how many is good the best way to wire them and even if you overpanel how much is OK.

Daddy Tanuki said:

If in doubt about the morningstar SCC go to there website and use the string calculator. it iwll tell you how many is good the best way to wire them and even if you overpanel how much is OK.

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Thanks, that's a good idea, so I just went ahead and did that. It also does not seem to recommend any over paneling. Basically just a maximum of 1 string. It doesn't even try to estimate for 3 strings.

The dark color for 10 modules + says:

Significant Over-sizing (>30% above Max. Nominal Solar Power) for this configuration.

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its totally dependent upon the panels you are calculating for/using

Many good quality controllers like Victron and Morningstar are able to current limit when over paneled. BUT.....

If you do go above the Max ISC rating, there is a risk. In most conditions, 99.99% of the time, it ill control the current and limit just fine, but it could exceed the safe input current under some conditions. If the current spikes for any reason and it can't correct fat enough, the controller might be damaged and if that happens, they don't have to honor the warranty. Reverse polarity above the ISC limit is certain damage. In the correct polarity, there is a MOSFET or other active switching device that is connecting the input current into an inductor coil. Current in the coil rises quickly, and the switching device ha to shut it off at the correct moment, thousands of times a second. As the power from the array increases, it needs to shorten the on time to limit the current. A slow rise is easy to handle and will work just fine. But a rapid change might not shorten the pulse width fast enough. The current can spike too high and damage components. It is already able to safely handle a fair bit above what it can transfer to the output. Adding more is not going to make any more maximum power.

The listed ISC limit can be handled all the time any time and on't ever harm the controller. It is an added safety to make sure it ill always live in any conditions. Going a little over the ISC limit will likely not be a problem, but if it is, it is on you as you were warned. High voltage FETs or IGBTs get pretty expensive. Want them to take more current, and the cost goes up even more. So then they will rate it for more power and sell it for a higher price. Ho much safety overhead do you want? You could fuse the array input below the ISC limit. But that is still not a sure thing like an array that just can blow up your controller.

Is it worth the risk? Many do it and claim to never have a problem. I'm never the lucky one.

Midnite Hawks Bay 120 would be my choice for a high voltage controller.

seneysolar said:

Midnite Hawks Bay 120 would be my choice for a high voltage controller.

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That does look great, and like my current MidNite Classic 250v MPPT, it doesn't even mention max input amps or watts in their spec sheets, seeming to imply that there is no issue with extreme over paneling?

Is it just that MidNite solar is better designed than Victron/Morningstar? Or maybe they're being more careful. So hard to tell what to do.

Don't know if it was mentioned yet but morning star equipment has no fans, instead large heatsinks. So they are silent. I have the 150/60. It's the only piece of equipment I didn't replace when I rebuilt my system.

seneysolar said:

Midnite Hawks Bay 120 would be my choice for a high voltage controller.

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It's pretty tempting to just choose this one, I don't know why they don't list the max input Amps or Watts but it feels like it's OK versus the other three (EG4/Morningstar/Victron) that make it seem like going +30% is a line that shouldn't be crossed.

ddxv said:

It's pretty tempting to just choose this one, I don't know why they don't list the max input Amps or Watts but it feels like it's OK versus the other three (EG4/Morningstar/Victron) that make it seem like going +30% is a line that shouldn't be crossed.

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I think you are overthinking this input rating. The controller will only pull power from the PV source. The only way it can be over-powered is by voltage. They list a current rating for input so some guy doesn't parallel 16 panels and wonder why he's not getting full output.

Speaking theoretically here (not accounting for losses and efficiency )
120A output at 48v = 5760W
5760W / 470voc = 12A (as in the controller only needs 12A at this high pv voltage to obtain max output)

Now lower the Voc and the current needed goes up. If the controller has a max input of 20A, then 5760W / 20 = 288v So having string voltage under 288v would result in limited output not achieving the 120A rating no matter how many panels are hooked up.

The limiting factor is going to be your single line to the controller and finding a controller that is rated higher than 120A. Your money might be better spent to run another PV line set and split your array into 2 controllers.

But putting all my eggs in one charge controller basket - Midnte Hawks Bay 120 would be my choice. Morningstar is great but you are only getting a 60A controller vs. 120A with Midnite.

While I think morningstar is a great company, i think the programming in the tristar is quite dated. I had a hard time integrating it with our other charge controllers. Also to change any setting requires the unit to be powered down and reset, thus also resetting the absorption counters. They also only would count the absorption, if it remained below 30% pwm. So if you have a load on for an hour which kept the pwm above 30% it wouldn't count... despite the batteries being at the absorption voltage. I believe the tristar is 2000's tech, i am not sure.

Now the genstar is probably a whole new generation of charge controller i believe it came out a few years ago and is more modern. However its only a 200vdc charge controller.

yodamota said:

While I think morningstar is a great company, i think the programming in the tristar is quite dated. I had a hard time integrating it with our other charge controllers. Also to change any setting requires the unit to be powered down and reset, thus also resetting the absorption counters. They also only would count the absorption, if it remained below 30% pwm. So if you have a load on for an hour which kept the pwm above 30% it wouldn't count... despite the batteries being at the absorption voltage. I believe the tristar is 2000's tech, i am not sure.

Now the genstar is probably a whole new generation of charge controller i believe it came out a few years ago and is more modern. However its only a 200vdc charge controller.

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yep I have a grand total of 6 of the morningstar controllers, four, 60 amp units in use, one spare 60 amp unit and a TS 45mppt on my camper. the programming is clunky, but it does work once you figure it out.