Author Topic: WARNING - Battery Fuse Holder Contact Melting Issue - WARNING  (Read 188 times)

finalman

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WARNING - Battery Fuse Holder Contact Melting Issue - WARNING
« on: October 10, 2021, 05:33:28 PM »
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 still the fuse link is 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.





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.
« Last Edit: October 15, 2021, 04:24:09 AM by finalman »

Vic

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #1 on: October 10, 2021, 06:22:07 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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

finalman

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #2 on: October 10, 2021, 07:23:40 PM »
30 amp CBi Midnight solar recommended ones.

Fuse was the 40amp Midnite Solar supplied one. The spare I think.

Vic

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #3 on: October 10, 2021, 08:16:16 PM »
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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

finalman

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #4 on: October 11, 2021, 02:47:50 AM »
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
« Last Edit: October 11, 2021, 03:13:38 AM by finalman »

Wizbandit

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #5 on: October 11, 2021, 06:31:55 AM »
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.

finalman

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #6 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.

boB

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #7 on: October 11, 2021, 04:58:48 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

K7IQ  He/She/It

ClassicCrazy

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Re: WARNING - KID COULD HAVE STARTED A FIRE - WARNING
« Reply #8 on: October 13, 2021, 07:21:02 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
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Vic

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Re: WARNING - Batter Fuse Holder Contact Melting Issue - WARNING
« Reply #9 on: October 13, 2021, 08:57:46 PM »
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
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

Steve_S

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Re: WARNING - Batter Fuse Holder Contact Melting Issue - WARNING
« Reply #10 on: October 14, 2021, 03:02:13 PM »
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
Classic-200, Samlex EVO-4024 Inverter/Charger, 1190AH/30kWh of LiFePO4 & 856Ah of Rolls Surette LEAD.