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Murphy's friend Guru Joined: 04/10/2019 Location: AustraliaPosts: 651
Posted: 07:28am 15 May 2024
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Both items arrived today but there were no instructions how to program that A30 relay included. Surfing through different sellers of this item on Ali found one that had the info I was looking for. So I did a screenshot and attach it here for those who might find it useful:
The programming is sequential, stepping through each digit & function with the 'SET' button. Changing the digits at each function with the 'ENTER' button.
dLO means LED display on time in minutes, set to 00 and it's on all the time. If its set to time out then it will only come on again after the power+ is disconnected briefly.
I set mine so the relay comes on at the upper limit, as this only happens in a fault condition to disconnect the MPPT (via Kilovolt Rly.) one can save about 1 W of standby power. The relay contact is SPST so the Kilovac can be connected to be on or off when the A 30 Rly is ON.
I have a question about the Kilovac: the power terminals are labelled: +A1 & -A2 I plan to wire the MPPT + output to +A1 and the battery + terminal to -A2.
Is this correct?
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1685
Posted: 07:37am 15 May 2024
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Hi Klaus, I have the same A30 - thank for saving me time.
Yes +A1 is normally input, however I had one running for a long time under brutal conditions the other way around. I think it may matter under very high voltages, possibly ARC suppression magnets or such. . Edited 2024-05-15 18:23 by KeepISIt's all too hard. Mike.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 853
Posted: 09:59am 15 May 2024
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I had the same question when I installed mine and came to the same conclusion ... but now that they are in ... I realise they often have reverse current flowing through them.
The one for the Warpverter I installed with the battery supply to the A+ ... but of course when it's backfeeding, there's lots of amps going the other way.
And same for the battery disconnect one ... a lot of the time current is flowing out of the battery to the inverter ... but there's massive current flowing the other way when there's lots of sun and the inverter is not using a lot ... potentially over 200 amps.
The battery lead was getting quite hot when I fitted the battery disconnect one and I had to have a couple goes at getting it all tight enough. The stud base is not a very large diameter compared to the lug ... so I fitted a larger stainless washer between them. Had to remove it to stop the voltage drop and hence the heat. All seems good now, though I will check it regularly to make sure it behaves.
Cheers, Roger
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1685
Posted: 11:22am 15 May 2024
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Hi Rodger, I have operated the Kilovac many times at 600A DC input at 50vdc with the connections reversed, so it appears not to faze them, like I said, it may be different at +300vdc though.
Looks neat, I find the terminal area is fine if the cable connectors are correctly sized, but it also depends on the quality of the connector, I have almost zero voltage drop across the terminals at a constant 200A with quality cable connectors, some are crap.
I know you are aware of all of the above, and especially washer quality and the flatness of both the connector and washer. I've been caught out on both of those before, it's amazing how the slight imperfections really show up in heat and voltage drop when trying to draw 500A through the system, sure highlights any weakness when starting high surge startup loads. .It's all too hard. Mike.
rogerdw Guru Joined: 22/10/2019 Location: AustraliaPosts: 853
Posted: 02:33pm 15 May 2024
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So 600A x 50V = 30,000W ... how long was it supplying 30kW?
I was trying out my big ducted aircon and the Warpverter + house was drawing 10,500Watts.
That's only 210A and that seemed extreme ... though that was for 5 minutes at a time.
When I fitted the first Kilovac inside the Warpverter, all the connections were with thick solid copper bar ... so I haven't had any heating issues there. The battery one though, I was afraid the lug was softer and the small diameter stud base would compress into the lug and become loose. I think it's going to be okay but I will keep an eye on it.
Initially I got quite a fright when I felt the fuse and it was hotter than I could hold ... and thought it was the fuse dropping the voltage and causing the heating ... but it was the battery lead connection on the contactor that had a voltage drop.
That heat transferred through the contactor and into the fuse ... and being in the enclosed box, got very hot. Lucky I spotted it quickly ... plus the box is made of fusebox backing material ... so is pretty robust. It does run cool now though, thankfully.
All a learning process. Cheers, Roger
KeepIS Guru Joined: 13/10/2014 Location: AustraliaPosts: 1685
Posted: 11:12pm 15 May 2024
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It's a 590A Peak DC positive going 100Hz inverter waveform current, you can see that on the current testing waveforms that I posted in the old thread. The peak is normally between 570A and 600A, it's a short duration startup of a huge 30 year old double head Air compressor.
Normally it would not start, or slow start, when used with any extension lead on a work site, it burnt out the motor in short order. The owner had an extra heavy duty motor fitted and then gave up.
I was offered the compressor for next to nothing. Our 3m high 3HP Dust extractor draws 520A to 540A for around 3 seconds, the inverter starts both as if they were on Mains AC.
When you measured the ducted aircon, did you use a peak holding DC clamp meter? if not, it won't be correct and will read low, and even those can have trouble with transients.
I use a DSO and a big hall effect current Sensor, accurate to 500A and rated to be only slightly out at 750A. Response time @50A/μS, 10%-90% ≤7 us.
I have measured 1000A on that when compared against a big resistive current shunt, it was slightly slower in response compared to the R-Shunt once past 500A on the way to 1000A.
Using that device and my DSO, I designed the Peak reading Analogue Meter for the Inverter, I know what loads cause a problem and the startup current of everything.
Some will say, it's only a short transient, but guess what components STILL have to handle that current, regardless of the duration..
I understand you dismay at the heat, I had exactly the same experience, I ended up replacing 3 big 0G crimp connectors on the DC leads, that solved the heat issue in those and I had a very Big fuse block terminal header, and nothing I did would stop it from getting red hot, I replaced it with another identical Block and it has been perfect ever since ?????
Like you, I routinely check the tightness of everything for a month or two after initial installation, then every 6 months after that. I include the LiFEPO4 Battery Cell link bars in that. It's all too hard. Mike.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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