Gabriël Posted February 22, 2019 Share Posted February 22, 2019 the fuse between my pvs and the inverter has gone again. i have gone through two 25amp fuses and this last one was a 30amp fuse. the last one lasted about two months. the specs of my system are below, any ideas? i do not think this is a healthy situation. Quote Link to comment Share on other sites More sharing options...
Jaco De Jongh Posted February 22, 2019 Share Posted February 22, 2019 photo voltaic panels : 8x305w renesola 72 cell panels in 4 strings [17.46amp isc] - Hi Gabriel The amps stated doesn't look right. If you max out the capacity the fuse should blow. Imp is 8.44Amps x 4 Strings = 33.76 Amps. On a good cool day with cloud edge effect and the correct load you will pop a 30amp fuse easily. My opinion, your fuse is rated to low. Gabriël 1 Quote Link to comment Share on other sites More sharing options...
Coulomb Posted February 22, 2019 Share Posted February 22, 2019 1 hour ago, gabriel said: the fuse between my pvs and the inverter has gone again. I think it's dying of loneliness Perhaps a fuse per string would be in order. Gabriël and Gabriel_2018 2 Quote Link to comment Share on other sites More sharing options...
Gabriel_2018 Posted February 22, 2019 Share Posted February 22, 2019 What kind of fuse is it? Sometimes cylindrical fuses damages are caused by temperature at nominal, or lower, current. You could use a NH fuse if it happens again. Quote Link to comment Share on other sites More sharing options...
Gabriël Posted February 22, 2019 Author Share Posted February 22, 2019 38 minutes ago, Javi Martínez said: What kind of fuse is it? i'll remove it later and post a pic, its made in mexico Quote Link to comment Share on other sites More sharing options...
Gabriel_2018 Posted February 22, 2019 Share Posted February 22, 2019 1 minute ago, gabriel said: i'll remove it later and post a pic, its made in mexico A spicy fuse then... Quote Link to comment Share on other sites More sharing options...
Gabriël Posted February 22, 2019 Author Share Posted February 22, 2019 48 minutes ago, Javi Martínez said: A spicy fuse then... hot, very hot, a chilate de pollo special - it burned right through... Gabriel_2018 1 Quote Link to comment Share on other sites More sharing options...
Gabriël Posted February 22, 2019 Author Share Posted February 22, 2019 hi @Javi Martínez, here is the fuse which blew, in fact it is the new one, the paper on the blown one turned a yellow/brown color.... trump would say this fuse is over the wall Quote Link to comment Share on other sites More sharing options...
flamegrilled Posted February 22, 2019 Share Posted February 22, 2019 Something to consider and check ? https://www.youtube.com/watch?v=SNXqozR_kAk&t=182s Quote Link to comment Share on other sites More sharing options...
Gabriel_2018 Posted February 22, 2019 Share Posted February 22, 2019 Ya, another brick in the wall... It is a cylindrical fuse. You can try a NH Fuse. Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted February 25, 2019 Share Posted February 25, 2019 Mersen fuses are good fuses, nothing wrong with that. @gabrielLooking at your signature, Quote photo voltaic panels : 8x305w renesola 72 cell panels in 4 strings [17.46amp isc] - 2440watt total although cloud-edge effect can push production for short periods to 2.9kw I take it you have 2 panels per string, for the 4 strings. Do you have one single fuse for everything, or one per string? IF you run 2x 305W panels per string, a 20A fuse on each string will be sufficient. Quote Link to comment Share on other sites More sharing options...
Gabriël Posted February 25, 2019 Author Share Posted February 25, 2019 1 minute ago, SilverNodashi said: Do you have one single fuse for everything yes Quote Link to comment Share on other sites More sharing options...
___ Posted February 25, 2019 Share Posted February 25, 2019 1 hour ago, gabriel said: yes So a 305W panel makes what... around 36V at peak power, that's about 8.5A Isc right? Times 4 strings... I mean, we've been through this before, how on earth did we not see that fuse is about half of what it should be? Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted February 25, 2019 Share Posted February 25, 2019 1 hour ago, gabriel said: yes You need to put a fuse on each string, before they are combined into a single string for the inverter. I don't know how your wiring looks like, but this is normally done before the bus bar (if you use it). So, I would use 4x 10x38 fuse holders, one on each string. Then, put a Class1 or 2 (depending on your area) PV surge arrestor, and then combine the 4 strings into one for the inverter. You could also add a 600V or 1000V DC isolator between the surge arrestor and inverter. But since you're not supposed to unplug the solar panels with a load on (The MC4 want you about this ), I normally switch off the inverter before I pull the fuses out, for maintenance purposes. Gabriël and Riaanh 1 1 Quote Link to comment Share on other sites More sharing options...
___ Posted February 25, 2019 Share Posted February 25, 2019 4 hours ago, SilverNodashi said: You need to put a fuse on each string, before they are combined into a single string Yeah we've been hashing that one out forever too. More than two strings... you must have individual string fuses. As I recall though, your installer paralleled it up on the roof... so what we're really saying is perhaps it is time to get it all fixed up. One fuse for them all means very little. Well, presumably it might blow if you get struck by lightning, but in normal operation, the fuse will always be sized around 25% larger than the max current that will ever flow there, and since the max current will always be the max current cause that's what the panels can do (unless struck by lightning), the fuse will essentially never blow and is now useless. Gabriël 1 Quote Link to comment Share on other sites More sharing options...
Gabriël Posted February 25, 2019 Author Share Posted February 25, 2019 11 minutes ago, plonkster said: what we're really saying is perhaps it is time to get it all fixed up. yeah, i recon so too. i'll get a team up there to tidy up and fix the wiring and bring the four strings separately from the roof into the garage [read inverter room - sounds impressive :-)] then i will implement : 4 hours ago, SilverNodashi said: So, I would use 4x 10x38 fuse holders, one on each string. Then, put a Class1 or 2 (depending on your area) PV surge arrestor, and then combine the 4 strings into one for the inverter. You could also add a 600V or 1000V DC isolator between the surge arrestor and inverter. and rest more assured Quote Link to comment Share on other sites More sharing options...
Coulomb Posted February 25, 2019 Share Posted February 25, 2019 And then the fuse won't be lonely any more. Sorry if I was a bit too subtle with my wisecrack. Gabriël, bluwater and ___ 1 2 Quote Link to comment Share on other sites More sharing options...
Gabriël Posted February 25, 2019 Author Share Posted February 25, 2019 Just now, Coulomb said: Sorry if I was a bit too subtle with my wisecrack. not at all! Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted February 25, 2019 Share Posted February 25, 2019 4 hours ago, gabriel said: yeah, i recon so too. i'll get a team up there to tidy up and fix the wiring and bring the four strings separately from the roof into the garage [read inverter room - sounds impressive :-)] If your roof has easy access, or at least, the combiner box has easy access, you could leave it up on the roof as well. Quite frankly, it's safer to cut the energy flow as close to the source as possibly. I haven't had to change my own fuses in a couple 'o years. Gabriël 1 Quote Link to comment Share on other sites More sharing options...
Guest Posted February 26, 2019 Share Posted February 26, 2019 14 hours ago, SilverNodashi said: Quite frankly, it's safer to cut the energy flow as close to the source as possibly. As true as this is, in some cases it will take too long to get to the box, get ladder, climb up ... in those is it not better to have it easier accessible? Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted February 26, 2019 Share Posted February 26, 2019 3 minutes ago, The Terrible Triplett said: As true as this is, in some cases it will take too long to get to the box, get ladder, climb up ... in those is it not better to have it easier accessible? As a I said, if he has easy access to the roof. Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted February 26, 2019 Share Posted February 26, 2019 I'm trying to figure out if my fuses are correct now? I have strings of 3x300W panels, with a 15A fuse on the positive and negative before the string are combined. Does that make sense? The panel output is 8.5A, should I have 10A fuses rather? Quote Link to comment Share on other sites More sharing options...
Guest Posted February 26, 2019 Share Posted February 26, 2019 18 minutes ago, SilverNodashi said: As a I said, if he has easy access to the roof. You did indeed. I'm still quezy with the word "roof" and "combiner box" in the same sentence. That's just me. Quote Link to comment Share on other sites More sharing options...
DeepBass9 Posted February 26, 2019 Share Posted February 26, 2019 18 hours ago, plonkster said: One fuse for them all means very little. Well, presumably it might blow if you get struck by lightning, but in normal operation, the fuse will always be sized around 25% larger than the max current that will ever flow there, and since the max current will always be the max current cause that's what the panels can do (unless struck by lightning), the fuse will essentially never blow and is now useless. You should have a lightning arrestor as well so send any lighning induced spikes to earth. ___ 1 Quote Link to comment Share on other sites More sharing options...
SilverNodashi Posted February 26, 2019 Share Posted February 26, 2019 9 minutes ago, DeepBass9 said: I'm trying to figure out if my fuses are correct now? I have strings of 3x300W panels, with a 15A fuse on the positive and negative before the string are combined. Does that make sense? The panel output is 8.5A, should I have 10A fuses rather? 10A might still blow, occasionally so use a 12A rather. Or get some 12A spares and use the 10A till it blows ___ 1 Quote Link to comment Share on other sites More sharing options...
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