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Forum Index : Electronics : Testing a home made 60A fuse
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poida Guru  Joined: 02/02/2017 Location: AustraliaPosts: 1418 |
With the building of the mppt controller, I needed an easy to make 60A fuse to be placed on the output or battery connection. The fuse is to protect and isolate things should the mppt MOSFETs used as diodes and/or the MOSFET switches fail and go short circuit. This is what it looks like. I should use some prepackaged solution but I like DIY. I suppose I should be using one of these holders with a 60A version of this fuse I like to use what I have got already at hand if possible.  2 x 30A fuses two of these for $2.20 a pair I tested it, shorted directly via 4.5mm2 cable from my spare battery bank (4 x 12V 200Ah in series, charged to about 56V) link to the video of the test https://youtu.be/1DI3nSb-BqQ It was quite loud when I made contact. It stayed open and did not continue to arc. This is all I want. I do not think I need to protect short circuit on the input. The panels can handle short circuit for long periods and if the battery is hooked up direct to the panels via failed MOSFETs then no problem? The panels I have use diodes that prevent reverse current flow. Overcharged battery is then a problem though. wronger than a phone book full of wrong phone numbers |
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Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1024 |
This is a good way to test thing without wrecking expensive fuses. I have a green 30a fuse on a little air compressor and the bugger keeps burning the green plastic holder and the wire connectors, its ok if its not running too long. Never had this problem with the original fuses or other automotive ones. The one in question is an aluminium fuse, can see the small points at the top of the green plastic. I'm aware of fast blow and slow blow fuses, don't ask an expert at the shop? "oh they all blowup" they say.  I would prefer if these fuse didn't get hot and melt, maybe the others where made of different materials. That went pop rather nicely, Plenty of scorch marks on the table,......just got the video to play. Edited 2020-12-19 21:17 by Revlac Cheers Aaron Off The Grid |
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InPhase Senior Member  Joined: 15/12/2020 Location: United StatesPosts: 178 |
I love it. Could have used female spade terminals to make them swappable. As these are rated at 32 volts, they might fail catastrophically at 48+ V. Maybe use four in a series/parallel setup just in case? |
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renewableMark Guru Joined: 09/12/2017 Location: AustraliaPosts: 1678 |
Rev, lots of the little fuse holders get hot as they don't seem to connect very well with the fuse, sometimes they work ok if you crimp them down so they grab a little harder. In the past I even paired up some small auto ones, but they still melt, fk'n useless. I gave up with the little holders, they always melt. I switched to the maxi type fuse holder, they are about 4 times the size and never get hot and melt plastic all over, also no fire hazard. link That's what I use in the battery box in the ute. On the fixed system at home I use the ANL type, they don't cost much from foo man shoo, they are all made there anyway. link But your one Poida will be just fine with a bit of tape around it.  Edited 2020-12-20 08:17 by renewableMark Cheers Caveman Mark Off grid eastern Melb |
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| noneyabussiness Guru Joined: 31/07/2017 Location: AustraliaPosts: 512 |
Ive used a couple of female crimp terminals to hook blade fuses up all the time, This style, terminals , i find less melting as they are quite open to allow air flow, just zip tie or tape where needed... I think it works !! |
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| johnmc Senior Member Joined: 21/01/2011 Location: AustraliaPosts: 282 |
I also use the ANL type, as described by Mark. The final solution close to the battery ( be aware that the dead short, rating is 4 or more times the stated rating, check the actual ANL ratings). The ANL type fuse, has saved my system when the Inverter failed. Cheers john johnmc |
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| Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1024 |
OK, I will put on some new terminals and give em a crimp, hopefully that will help, or plan B. Another DIY option we might have around, This was an old 100A Bakelite fuse holder, taken apart as it was broken. It had brass contacts that happen to be the correct size to push in descent size fuse, mounted on 20mm perspex.  This is connected to the output of the old 60A MPPT controller 80A fuse, never notices any heat, still not a cheap fuse. Must be many of these and ceramic ones around. Had an electrician tell us all the old ceramic fuse holders should be removed because they could start a fire? All now replaced with plastic breakers in a plastic box......uh. more $$$ I think. Cheers Aaron Off The Grid |
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| BenandAmber Guru Joined: 16/02/2019 Location: United StatesPosts: 961 |
when i solder car type fuses the plastic falls off lol be warned i am good parrot but Dumber than a box of rocks |
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