Basically one of the PCB fuse holders melted the solder surrounding it and it sagged and touched the other one. It got so hot the leg on the fuse actually distorted in shape and the fuse link was still intact. The 30A CDi branded breakers did not trip either. The fuse being used was a 40A either the original or spare included ones. I was lucky in the fact that I happen to be checking on the system when it was failing and noticed the screen flickering thankfully before the fuse's plastic caught fire and burnt the house down.
(https://i.imgur.com/UqqQgzY.jpg)
(https://i.imgur.com/96exkyb.jpg)
EDIT: Another thread with the PCB damage fuse issue. I too noticed the last few days the master kid (this one) was entering float to early and only providing afew watts solar input. The morning of the fault my inverter was giving an low battery warning which I though was strange as the previous days were sunny. Afew hours later I saw the Kid LCD screen flickering and shut it off immediately.
http://midniteftp.com/forum/index.php?topic=3813.0
UPDATE: Thankyou to the support staff at Midnite who have shipped a replacement Kid. I do hope they change the design of the Kid in the future and remove the internal fuses.
They also asked if I was removing the battery fuse to turn off the Kid as they mention others were doing but I was not.
Quote from: finalman on October 10, 2021, 05:33:28 PM
... The 30A midnite solar breakers did not trip either. The fuse being used was a 40A. I was lucky in the fact that I happen to be checking on the system when it was failing and noticed the screen flickering thankfully before the fuse's plastic caught fire and burnt the house down ...
So, what is the type and current rating of the breaker between the battery and the KID? The quote, above seems a bit ambiguous.
Personally, would not use a 40 A Fuse in those fuse holders.
'Tis good that you were around. FWIW, Vic
30 amp CBi Midnight solar recommended ones.
Fuse was the 40amp Midnite Solar supplied one. The spare I think.
Hi finalman,
Thanks for the reply.
OK, so there IS a CBI MNEPV (DIN-rail breaker) between the battery and the KID's battery terminal (?).
I had thought that the absolute maximum current rating for the ATC size fuses, was 30 Amps.
MN DC breakers are rated for continuous current, at the handle rating, without tripping.
It appears that one fuse blade was not making good contact with its KID fuse terminal on the PCB. If there was a connection between the two fuse terminals on the PCB (a short twix the two terminals), that should not be the end of the world. This could cause less current to flow through the fuse, but, who knows? The MNEPV breaker would still protect the battery cable to the KID, if the cable was sized for 30 Amps, or more. The Al enclosure would probably contain warm/hot parts. The plastic fuse cover is probably a fire-retardant type plastic ... guessing.
Predicting what might, or might not happen is a difficult thing to do. And am making too many guesses/assumptions.
Am not trying to make-light of your situation, later. Vic
Yeah my brother is an auto electrician and also said poor contact would have caused the melting issue but the fuse itself from memory was replaced with an inbox spare one at least 6 months or more ago and hadn't had an issue since then so it wasn't touched.
I'm now put off by buying CCs with fuses on the PCB and I will not risk using the kids again after having this happen. Also checking the old blown Kid fuses one of those shows signs of the plastic melting but blew before the Kid PCB solder melted. Hopefully I'll get this one serviced but after that they'll both be being sold.
I also have two 150V classics that I haven't had any problems with apart from the annoyance of changing failing fans. Those I'll keep until they eventually fail.
EDIT: Another thread with the fuse issue:
http://midniteftp.com/forum/index.php?topic=3813.0
This is a known issue with early serial number KID's. We discovered tolerance differences in the thickness of the fuse blade and coupled with fuse holder terminals having tolerance differences it resulted in loose connections. We now check the fuse holder at assembly to insure they are tight. The reason for the 40A ATC fuse is with the price of PV modules so cheap people were running the KID at 100% output or a full 30 Amps. Again, tolerances in the 30A ATC fuses made "Overseas" (We don't manufacture ATC fuses in the USA that I know of, no profit?) would blow at a full 30 amps or less. And because of the way the KID regulates the output current it could tap 35 amps briefly (The KID is capable of 50 amps!!, but the present terminal would not carry it nor will the heatsink) so that is why the 40A ATC fuse.
Melted KID fuse holders are one of the things that carry Lifetime Warranty repair at no cost. That is the best we can do for something that happens out of our control.
But you blow afew fuses and have to replace them each time the fuse will be less tight and the problem might reoccur.
Why even have the fuses inside of the kid? especially if the poor connection causing heating issue is known and might reoccur.
Quote from: finalman on October 11, 2021, 04:38:18 PM
But you blow afew fuses and have to replace them each time the fuse will be less tight and the problem might reoccur.
Why even have the fuses inside of the kid? especially if the poor connection causing heating issue is known and might reoccur.
The original reason to add a fuse, as I remember, is that a lot of people do not add a breaker which is really required for NEC and is common sense. I don't think we anticipated the problem that you experienced.
This is one good reason our controllers are UL or ETL or TUV listed. Unfortunately nothing is 100%
I also remember that we had another blade fuse that was not a listed part and we used a better part. But if the connection is not tight, then it is a production issue that we normally try to find before what happened to your Kid happens to anybody. This is also a reason why all of our controllers are inspected running power using a FLIR infrared imager to try and catch bad connections. Now we have many other inspections that happen in production. For instance, AOI or Automatic Optical Inspection of every circuit board soldered SMT components before they go to the next step and then to their preliminary test and programming.
We will help as best as we can with this, if you would like.
Thank you for this post though ! We need to know both the bad and the good.
boB
Quote from: Vic on October 10, 2021, 06:22:07 PM
Quote from: finalman on October 10, 2021, 05:33:28 PM
... The 30A midnite solar breakers did not trip either. The fuse being used was a 40A. I was lucky in the fact that I happen to be checking on the system when it was failing and noticed the screen flickering thankfully before the fuse's plastic caught fire and burnt the house down ...
So, what is the type and current rating of the breaker between the battery and the KID? The quote, above seems a bit ambiguous.
Personally, would not use a 40 A Fuse in those fuse holders.
'Tis good that you were around. FWIW, Vic
Vic - now we have the answer to our discussion on the other forum post - this from Wizbandit why some Kids ( like mine ) had 40 amp fuses in them.
Larry
Larry said, " Vic - now we have the answer to our discussion on the other forum post - this from Wizbandit why some Kids ( like mine ) had 40 amp fuses in them".
Hi Larry, YES, indeed, it is nice to have THE answer from MN.
73 Take care, Vic
Little late on this... I have a KID as well so had to look.
I'm a "Recovered" hot rodder & show car builder, a lesson learned quite a while back is that not all fuses are the same regardless of appearance. I saw 10A fuses take 25A to blow and 10A fuses not make it past 5A, these were offshore "noname" brand. I thought WTF is up with that and low & behold several videos on YT and other tech info available (commercial comparisons) and sure enough, there is some serious crap out there.
To that end, I've always suggested & recommended Quality Name Brands whenever possible for all safety equipment like fuses, DC Switches and more. There have also been major changes within that sector - corporate merger's & buyouts which doesn't help a Lot... Cooper, Bussman, Eaton is all one company now.
The PICO Catalogue (UAP/NAPA & Others) carry quality components "still" as far as I know.
In case anyone is unfamiliar, there are Circuit Breakers in ATC/ATO Format which can be used as well.
DigiKey, Mouser carry them and I believe LittleFuse is still making them too. (now also owned by Eaton).
Hope that helps, Goo Luck
Midnitesolar sent me a replacement KID without wanting this one back due to postage costs with me being in Australia. Now I have begun replacing the fuse holders by direct soldering a single thick copper wire strands.
I have a question to do with the load/clipper contacts. Now my KID is the regular model MNKID-B that came with the fuse contacts only for load and not the clipper. Is their any reason why the standard MNKID-B model would not work with the clipper if I was to use a bridge wire aswell on the clipper contacts?
(https://i.imgur.com/0NaJnJX.jpg)
Quote from: finalman on November 20, 2021, 07:44:17 PM
Midnitesolar sent me a replacement KID without wanting this one back due to postage costs with me being in Australia. Now I have begun replacing the fuse holders by direct soldering a single thick copper wire strands.
Why not solder in a proper fuse holder, like a Maxi Fuse, rated for higher current? Or making a fuseable link ? Or maybe you have external breakers installed ???
Quote from: mike90045 on November 21, 2021, 01:14:13 AM
Quote from: finalman on November 20, 2021, 07:44:17 PM
Midnitesolar sent me a replacement KID without wanting this one back due to postage costs with me being in Australia. Now I have begun replacing the fuse holders by direct soldering a single thick copper wire strands.
Why not solder in a proper fuse holder, like a Maxi Fuse, rated for higher current? Or making a fuseable link ? Or maybe you have external breakers installed ???
He shouldn't need a fuse at all as long as he uses a proper circuit breaker. People not using breakers was the reason for that 40A.
I'm not sure about the clipper question. Will try to find out.
boB
The kid does not have the rest of the drive circuitry for a clipper, it would take a special wind kid to drive the kid clipper but due to design issues on the clipper it was never really released so long answer is no, You can not solder a wire on the clipper side and do anything useful with it unfortunately
Official reply from MidNite Solar support:
"We made a Wind KID model with a wind curve tracking program, but the KID could not handle the in-rush of current. A regular KID does not have the wind curve program, but it would behave the same in terms of being damaged by the current. The only charge controller we offer to work with wind is the Classic line."
So I guess I'll direct solder the Load contacts only.
So been a while since I replaced all of the fuse links with thick wire. Now thinking about reassembly and I contacted midnite solar about getting a replacement thermal pad but they mistakenly sent me a keypad instead. All for no cost to me but it costed them $72USD postage.
I'm not going to ask them to resend as it would just be a waste of money on their part. When I could probably get one for cheaper. I still have the old one so I'll be able to cut the replacement to the same shape.
Can someone please let me know the thickness and mw/k rated thermal pad I should purchase.
Also anyone know the N.m torque setting for the 3 mosfet clamp screws?
I now only just noticed two things on this faulty KID before I try to put it back together.
1. The 63v 1800uF capacitor positive lead\leg was split in two. Would the molten solder on the fuse terminals have caused this?
2. The two large CD29H 160v 1000uF capacitors look bulged on the top. Is this normal?
Capacitor leads are usually solid copper wire, and i don't see how it could split in two. Or do you mean it broke in the middle/end somewhere ?
Capacitors usually have a couple of score marks on the end, so they split slowly when failing. ( instead of like a firecracker ) When they start to bulge, I call that a signal for end of life. I'd replace them with like kind, or are you still under warranty ?
Quote from: mike90045 on April 10, 2022, 07:22:41 PM
Capacitor leads are usually solid copper wire, and i don't see how it could split in two. Or do you mean it broke in the middle/end somewhere ?
It was split about half way down the length of the lead\leg. I didn't cut it so I don't know why it was like that.
With all of the things I've noticed after the original fuse issue I'll probably bin this KID for safety reasons.
Capacitors are sometimes the first to go in MPPT charge controllers over time.
I wouldn't throw it away just yet. Maybe we can send you some capacitors or if it is under warranty, MidNite should certainly be able to replace those capacitors with new ones.
How long has this Kid been running ? Years ? Months ? Weeks ?
The caps could not wear out very quickly but over years of use, especially in hot environments and near full current charging, those things can make them wear out sooner rather than later.
boB
So I just decided to use this KID as a portable battery charger so I finished the repair on this KID by extending the remaining capacitor lead on the one with the split leg using copper wire.
As for the two two large CD29H 160v 1000uF capacitors that I said were possible bulging at the top, if I push on the top of them it feels like they are under pressure inside and they spring back. Is this normal or should It not feel like there is an air pressure buildup?
Quote from: mike90045 on April 10, 2022, 07:22:41 PM
Capacitor leads are usually solid copper wire, and i don't see how it could split in two. Or do you mean it broke in the middle/end somewhere ?
I actually think the lead/leg popped like a fuse from memory. The break was just as the the lead/leg went from horizontal to vertical. Say about 4mm coming from the cap was still there.
Quote from: boB on April 10, 2022, 10:11:33 PM
How long has this Kid been running ? Years ? Months ? Weeks ?
Would have been 3-4 years but I'd be pretty sure the loose and then melted fuse connection caused my capacitor issues.