Easy Solar 48/3000 AC Overload Puzzle

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safiery asked Feb 16, '20

Easy Solar 48/3000 AC Overload Puzzle

Easy Solar 48/3000 has been running perfectly for a year. It is now going into alarm on AC overload. This does not occur immediately but after approx 30 mins. Upon reset, it starts again and repeats this cycle. The load is a swimming pool pump of 1600w. The reset does not co-incide with any pump restart. The pump has been connected with an independent service and operates normally. The physical temperature of the inverter is reasonable and cool enough to hold hand on. Inside the inverter casing has been examined and vacuumed. There is NO AC input. This is stand alone Easy Solar.

Upon reset and restart, the unit starts up with the fam immediately on.

Question is that the overload may be because:

1) a fault of the inverter power electronics that cant maintain this 60% power level

2) a fault of the thermistor that provides the internal temperature which may set a derated limit

Thoughts please....

MultiPlus Quattro Inverter Charger

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Answer 1 · 2020-02-17T05:34:42Z

JohnC answered · Feb 17, 2020 at 05:34 AM

Hi @safiery

I'd look first to your pump. It may have some issue like a faulty capacitor, which mightn't trip a 16A? breaker, but the inverter will know.

This isn't uncommon, and I've suffered it myself. And I've seen pumps totally replaced for the sake of a new capacitor. (I remove them for free, ha. Add a $50 cap and have a good pump).

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Answer 2 · 2020-02-17T08:50:15Z

petajoule answered · Feb 17, 2020 at 08:50 AM

Some remarks:

a) You mean the pump has 1600W, not 1600kw. The latter would need a little bit more juice. ;-)

b) The physical temperature of the inverter is reasonable and cool enough to hold hand on.

This proves exactly nothing, as b.1) When you can't hold your hand on it it's way too late already, b.2) The temperature within the inverter is of interest, not the surface.

Is the fan on before the reset? (I did get that it is after)

What is the ambient temperature?

There is an interesting Video with Johannes about overload conditions: https://www.youtube.com/watch?v=4SXtGIx0x5w

There you can also hear, that the rating of your "3000VA Inverter" is "for 30 minutes at ambient temperature ~ 20°C" Plusminus.

If the fan is not on before the reset and the ambient temperature is low, then it more looks like a fault within the pump (some overheating problem, coils with spurious shorts, problem with the cap as JohnC mentioned etc.).

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Answer 3 · 2020-02-17T09:53:46Z

safiery answered · Feb 17, 2020 at 09:53 AM

Thank you @PetaJoule and @JohnC

error:

and the typo is well spotted. We had the cover off the unit to evaluate what might be happening. The fan came on 15mins before the overload condition. After reset it came on immediately. The ambient was around 30 deg C where it is located. Johannes Video has been previously studied. Appreciate your thoughts...

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klim8skeptic ♦ commented · Feb 17, 2020 at 09:57 AM

Disconnect your pump, and substitute a similar sized load. Ideally resistive like a heater.

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petajoule commented · Feb 17, 2020 at 10:51 AM

The fan came on 15mins before the overload condition.

and

The ambient was around 30 deg C where it is located.

are pretty indicative. You can try the "similar load" advice of @klim8skeptic, but if that's not available, you might want to try to observe operation at night time or with a significantly lower ambient temp. If the system holds (longer) then...

Possible solutions:

* lower ambient temp - better venting

* drive pump not constantly, but try intermittent operation. (turn pump off 5 minutes after fans go on, allow the FETs to cool down)

All this is under the assumption that the pump is ok. If it isn't, these suggestions might cure your problems now, but it's actually just addressing the symptoms.

Out of the box question:

How big is the pool? Because the pump should be able to sip the pool water once in 5 hours. 1.500 W can sip roughly 33m³ an hour, so pool size 165m³, subtract some losses for filters etc. 150m³ - is the pool that big?

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safiery petajoule commented · Feb 17, 2020 at 08:21 PM

@PetaJoule the pool is that big. As a diagnostic, we will run the tennis court lights (1kw ) plus another smaller load to make up (0,5kw) for several hours and observe.

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JohnC ♦ commented · Feb 17, 2020 at 12:03 PM

I expect you'll find that ambient temps don't have much say normally. Mine occasionally sees 46C, and the fans only seem to run when I put a load on.

Internally it's likely only the mosfets attached to the large heatsink that are an issue, and I've always suspected (I don't know) that the fans coming on are triggered by the load, not as a response to actual overheating.

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petajoule JohnC ♦ commented · Feb 17, 2020 at 12:17 PM

Yes, there's this question:

https://community.victronenergy.com/questions/15536/fan-control-quattro-10k-and-15k.html

unfortunately unanswered (and probably only Victron staff could). I am very intersted in an answer to

Anybody know the exact criteria for fan starting on Quattro?

myself, because so far its only hypotheses. If the fans would be triggered just by some load (x time), that would seem like a pretty blind flight to me.

There's also https://community.victronenergy.com/questions/1464/quattro-48500070-100100-vs-quattro-48500070-100100.html

with its

Fans are mounted on the top of the cabinet for a lower air speed. This improves cooling and there is less wear on the components. It also has a smarter fan control that, where possible reduces the fan rpm.

---

We do have a recent 3p installation with 3 x 48/5k/100-S Quattros, but honestly so far I haven't observed any difference in behavior or loudness to regular 48/5k/100 Quattros.

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safiery JohnC ♦ commented · Feb 17, 2020 at 08:32 PM

@JohnC @PetaJoule and @klim8skeptic based on this thread of suggestions, our assessment is:

1) the fan came on immediately after a "rested reset" suggests that it is triggered by the load which is too high.

2) it is mid-summer and hot/humid at 30-35 (though the inverter charger is in a well ventilated position with no sunlight loads )

3) We did test with electric toaster that went to 1700W which ran perfectly. But it had a timer and we only ran for 10mins.

4) The wiring to the pump may be dropping voltage too much. It is a 20m run at 2.5mm2.

5) The load has automatically reset a few times and come back on again. This suggests the functionality is as specified.

Our action will be to replace the pump, noting the capacitor inspection. And re-test.

Thank you for the insights.

Bruce

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