I wish to connect 7 X TSM-545W-TS4 solar panels to my 5kW Deye inverter on PV1 MPPT input but my electrician says that the current rating of the solar panels is too high for the inverter MPPT input. I do not agree and need some advice.

The inverter has 2 X MPPT inputs rated at 13A input current each (17A Isc)

The TSM-545W-TS4 solar panels can deliver a higher current than the rating of the MPPT input. Common logic would say that this should not be an issue as the MPPT will only use the current it requires.

Is it correct to say that one should only be concerned with the string voltage to ensure that does the latter not exceed the rating of the MPPT input?

I have attached the Deye inverter nameplate and the solar panel datasheets.

This inverter manual also only makes reference to the Voltage when selecting the solar panels.

Any advice would greatly appreciated.

TRINA SOLAR SPEC SHEET.pdf

Deye is known to throw "Fxx overcurrent" error once the PV current goes above MPPT max limit. Way before you hit max Isc limit. Then it restars and after a couple of minutes you will see that same error again.
If you will use inverter just for charging the batteries and powering loads, you can avoid most of the errors via limiting max charging current.
If you will use inverter for exporting energy back to the grid, you will face these troubles a lot.

While it will not blow up, it's not a good idea to run a device outside manufacturer-specified boundaries. Therefore, I would go for a model with a stronger MPPT or use panels with a lower Imp & Isc.

I know of a Sunsynk that ran for a couple of months on the PV current limit. The installer was supposed to pull in two channels but paralleled the strings. The inverter is still running.

I agree with @Youda the Trina TSM-545W-TS4 panel has a short-circuit current (Isc) of over 18A, while the JA Solar 545W panel typically has an Isc around 13.94A.

This large difference comes down to several key design factors: 1.TSM-545W-TS4 panels use 210mm cells (also called “large-format” or “ultra-high current”)while JA 545W panels often use 182mm cells, which produce lower current but higher voltage per string.

2. TSM-545W-TS4 has more strings in parallel increasing current. JA panels tend to have a more balanced series-parallel layout optimized for lower current.

Trina’s design focuses on high current to match low-voltage, high-current MPPT inputs — especially for inverters designed to extract max power in hot or shaded conditions. Do not exceed the Mppt ISC current input specified by the OEM as it will void your warranty.

13 hours ago, TaliaB said:

Do not exceed the Mppt ISC current input specified by the OEM

I haven't looked at the spec sheet for the Deye, will do so in a minute and if they specify Isc for panels then I must say I have learned something new, but the way I see it is:

The inverter/MPPT input can do nothing about the Voltage presented, but can certainly limit the current allowed to flow and thus a 17A Isc panel on a 13A Max current allowed to flow MPPT input should be perfectly fine, you will not see the rated power from your panel(s) since the current is now limited to less than Imp, presumably, but it should work fine and not cause any damage.

---

Well, blow me over with a 5V fan, the picture of the Deye actually does say Isc 17Ad.c + 17Ad.c , now this is probably Chinglish. after all, WTF is Ad.c ? But now the question comes in, they do not specify NOCT or STC and heck at STC the panels of 18 and a bit A is fairly close to the 17A that Deye specify, I'd say it should still be ok, but maybe @Vaughn Kretzmann should get the input of the inverter supplier, current is something the inverter can limit, I still believe that the panels should be fine for that inverter, but getting confirmation from the supplier, maybe even in writing, is probably the safest route to go.

Edited July 7, 2025Jul 7 by Kalahari Meerkat
well, blow me over with a 5V fan...

FYI, this is what Deye inverter does if the panels are able to supply higher current than Deye's MPPT Imp-max.

When the AC load is minimal and the battery is full, then there is no problem.

But once you switch-on a higher load, it causes PV current spike and Deye throws this error (instead of trying to limit the current).

=> not a good idea to connect PV modules that can go over Deye's Imp-max.

9 hours ago, Kalahari Meerkat said:

WTF is Ad.c

Ampere, direct current...

11 hours ago, Kalahari Meerkat said:

Well, blow me over with a 5V fan, the picture of the Deye actually does say Isc 17Ad.c + 17Ad.c , now this is probably Chinglish. after all, WTF is Ad.c ? But now the question comes in, they do not specify NOCT or STC and heck at STC the panels of 18 and a bit A is fairly close to the 17A that Deye specify, I'd say it should still be ok, but maybe @Vaughn Kretzmann should get the input of the inverter supplier, current is something the inverter can limit, I still believe that the panels should be fine for that inverter, but getting confirmation from the supplier, maybe even in writing, is probably the safest route to go.

Always speaking under correction, but I'm not comfortable with the idea to use these panels. Under normal operating conditions, okay, the inverter can limit the current it draws. The question is, what would cause the inverter to draw Isc? Simply, a short-circuit. Quick google search suggests it might be due to a blown fuse, faulty isolator or contactor, or an internal rectifier fault, faulty panel, earth faults, electrical surges, etc.

The Isc rating of the inverter is never specified at either STC or NOCT, basically the inverter doesn't see the solar radiation or ambient temperature directly, it just sees current on the inputs. Isc-Current at STC and NOCT is a specification inherent to the solar panel, the current you'd expect when short-circuiting the +ve and -ve cables of the panel. If the panel can provide up to 18A Isc at STC in the event of an inverter internal short-circuit, then that will be above the current that the inverter is rated and expected to survive under those conditions. Maybe it's only just above, but it still is above.

Basically, my fear is just that a repairable fault may become irreparable. And the question I'd always ask along with that is, WHY? WHY would one want to use panels in a setup that will forever limit the power you can get from the panel to max 75% of rated capacity?

Edited July 9, 2025Jul 9 by GreenFields

23 minutes ago, GreenFields said:

The Isc rating of the inverter is never specified at either STC or NOCT

Has anyone blown up an inverter because the panels could exceed Isc?

14 hours ago, frivan said:

Ampere, direct current...

yes, well I get so cheesed off at KwH and other things like Ad.c, sorry, in both cases fail, try again. Ampere are only A and d.c is not correct for DC aka Direct Current. As for KwH Kelvin what Hectares? kWh would be ok and correct instead, that a Outer Mongolian company uses Ad.c instead of A DC should be rejected and not accepted, maybe someone from Deye will wake up and fix these kind of screwups...

Back to Ad.c, I was going to suggest Anno Domini

12 hours ago, GreenFields said:

The question is, what would cause the inverter to draw Isc?

The only two reasons I can imagine is the inverter design, actually its MPPT input, has flaws or it is faulty...

21 hours ago, Youda said:

=> not a good idea to connect PV modules that can go over Deye's Imp-max.

well, in this case it seems to be a problem, but since the Inverter is really incapable of controlling the current allowed to flow, I'd say its a bug in this inverter rather than the norm...

12 hours ago, GreenFields said:

The Isc rating of the inverter is never specified at either STC or NOCT, basically the inverter doesn't see the solar radiation or ambient temperature directly

True, that comment on my end was just for the heck of it, however it is not entirely irrelevant, if the conditions where the panels are to be installed are close to the NOCT conditions then the Isc is less than 15A which is within specs, if the conditions are more like the ISC conditions (1kW/m^2 vs 800W/m^2 solar irradiance), then of course the 18-odd A Isc is beyond limits.

8 hours ago, Kalahari Meerkat said:

d.c is not correct for DC aka Direct Current

I have seen d.c. being used for direct current... I think in IEC standards.

The bigger issue may be that people want to use subscript and don't have the facility in specific text editors.

My old SunSynk 8.8kW machine just clips the current without any issues or error messages. Notice the date, and all is still fine.

I have now connected 13.1 kWp in the last month or so, and am looking forward to getting through rain and cloudy days this summer.

15 hours ago, frivan said:

for

16 hours ago, frivan said:

I have seen d.c. being used for direct current... I think in IEC standards.

maybe, I can't say, the convention when I was growing up, seemed to the AC and DC, nowadays, I do see Vac and Vdc, used, but never with full stops and certainly not as d.c as Deye seem to want to use it, I guess if they wrote ADC then someone could come along and ask what Analog to Digital Converter are they referring to...

As it is, referring to @TimCam's post, his inverter is limiting the current, there's no such thing as clipping, unless you refer to the output of an amplifier, which will clip, when the power that is being asked to be produced is exceeding its limits, usually a Voltage thing, more than a current thing, in that scenario.

Either way, since the SunSynk 8k8W is the same hardware, I am led to believe than the Deye 8k8W inverter, the Deye should also handle the current correctly, but it seem, assuming the hardware is the same, that the software on the Deye is full of roaches and other bugs, if it actually does what @Youda's post above showed.

11 minutes ago, Kalahari Meerkat said:

As it is, referring to @TimCam's post, his inverter is limiting the current, there's no such thing as clipping, unless you refer to the output of an amplifier, which will clip, when the power that is being asked to be produced is exceeding its limits, usually a Voltage thing, more than a current thing, in that scenario.

• Actually, an inverter can rely on the speed of the CPU to limit the PV current on the fly only if there's enough margin between "power capping" level and actual limits of the inductors and silicon used in the MPPT. For example, many Victron's MPPT chargers are designed for 70A of PV current, while their "power capping" happens way before that limit. Therefore, it's safe to put many more panels on them.

• SolarEdge (ongrid inverters) have a similar feature - their MPPTs are designed to safely cap 30% of power (and current) that is above rated power of the inverter.

• Old standalone MPPTs that were designed for charging lead-acid batteries were able to avoid overcurrent issues too, because lead-acid batteries don't like to accept charge when the SOC is high (contrary to lithium which sucks any amount of current supplied, although being at 99% SOC). And when there's nobody to suck the excessive current from the battery-side of the MPPT, then there's no way for current to appear on the PV-side of the MPPT. (I saw guys having like 12kW of PV modules on a 4kW MPPT, just to survive EU winter)

28 minutes ago, Kalahari Meerkat said:

Either way, since the SunSynk 8k8W is the same hardware, I am led to believe than the Deye 8k8W inverter, the Deye should also handle the current correctly, but it seem, assuming the hardware is the same, that the software on the Deye is full of roaches and other bugs, if it actually does what @Youda's post above showed.

Speaking of Deye, SunSunk, JASolar and other rebrands - base of the firmware is identical, casing and topology too. But each large-scale OEM customer of Deye can alter some of the parameter based on the target market. Including logo, quality of selected components and FW limits. For example, there are Deye models with MPPT designed for 2x 26A and others designed for 2x 50A, while the rated AC output is the same.

Long-story-short, as a technician I always try to follow the manufacturer's spec sheets when designing a system.

Some Solis models would switch off immediately if 20A from panels is used as input when it has a 13A max input rating. They also cap the current if it reaches the 13A but will remain at its design output.

6 hours ago, Youda said:

Long-story-short, as a technician I always try to follow the manufacturer's spec sheets when designing a system.

Yip, and as an installer who has to maintain legal requirement and warranties, it's best to follow the manufacturer's spec sheets.

But for the private households who are willing to push the envelope a bit.... 🤔