ClintonDBN Posted September 17 Share Posted September 17 As per the title, what am I overlooking here? I have three series strings of panels each connected to their own Victron MPPT. I need to connect these to my 48v battery bank, so my thinking was a busbar/fuse holder/lynx. Considering price, and my system not being massive, I was leaning towards a fuse holder on the +ve and a busbar on the -ve. This is where I got confused! The Victron Busbar 250A 6P goes for around R900 while the Victron Fuse holder 6-way for Mega-fuse 250A goes for around R500. Why? I'd expect the fuse holder to be more expensive. What am I overlooking? Yes, an alternative is the lynx distributor or lynx power in (tweaked with fuses) but I'd be in for more money for no more than looking prettier (from what I can tell, but maybe I'm missing something here too). Quote Link to comment Share on other sites More sharing options...
GerhardK83 Posted September 18 Share Posted September 18 The main difference between a busbar and a fuse holder is that the busbar does not offer any protection, it is merely a conductor to conduct current. As per the photo of the Victron fuse-box above there is a busbar included so that it is not necessary to purchase a Lynx where one is not needed and I see that there is also a cover for the fuse-box included. I see that there are a couple of different busbars available from Victron with and without covers and different amperage ratings as well. Calculate the maximum current which will flow between the output of the MPPT's and the battery and then decide on a suitable busbar to be used on the one side, also ask yourself if you want to upgrade at a later stage and take that into consideration. Have a look at these videos Quote Link to comment Share on other sites More sharing options...
ClintonDBN Posted September 18 Author Share Posted September 18 Thanks for the response. You've reinforced why I'm confused by the pricing, and it's not just one source, they all show that discrepancy in price. If the fuse holder offers more, then why so much cheaper. Essentially the busbar is just one component in the fuse holder, yet it costs more. That's what I'm not getting. Yeah, l enjoy Explorists videos. Quote Link to comment Share on other sites More sharing options...
Chunks Posted September 18 Share Posted September 18 I think they discounted the fuse holder because the fuses are so expensive. Quote Link to comment Share on other sites More sharing options...
ClintonDBN Posted September 19 Author Share Posted September 19 My thinking is to buy the fuse holder to use as a busbar, instead of buying the busbar. I was just checking there wasn't something I was overlooking. Quote Link to comment Share on other sites More sharing options...
TaliaB Posted September 19 Share Posted September 19 If you are going to use just the busbar are you not fitting fuses to the busbar on the positive output side of the mppt? The fuse holder uses mega fuses they are around R50/fuse depending on rating. Quote Link to comment Share on other sites More sharing options...
ClintonDBN Posted September 19 Author Share Posted September 19 6 minutes ago, TaliaB said: If you are going to use just the busbar are you not fitting fuses to the busbar on the positive output side of the mppt? The fuse holder uses mega fuses they are around R50/fuse depending on rating. Where are you finding mega fuses rated for 48v systems at R50 each? The issue I'm finding is they don't have sizes small enough (I have three panel strings with a charge controller each needing 50a, 80a and 100a fuses) and they're definitely more than R50 each. The price I could settle on but not much point in getting fuses that are too big. I was going to inline fuse each mppt using midi fuse holders (they offer the fuse sizes l need). This diagram is still a work in progress but item to critique and suggestions. The busbar/fuseholder/lynx in is all about getting three MPPT cables onto one battery connection. Quote Link to comment Share on other sites More sharing options...
ClintonDBN Posted September 19 Author Share Posted September 19 I have found mouser and digikey that offer smaller littelfuse mega fuses but cost is high after delivery - R1316 for three fuses! Quote Link to comment Share on other sites More sharing options...
TaliaB Posted September 19 Share Posted September 19 59 minutes ago, ClintonDBN said: I have found mouser and digikey that offer smaller littelfuse mega fuses but cost is high after delivery - R1316 for three fuses! Yes i see the 48v rated Mega fuses is 4 x the price of the 32v version. Your drawing seems ok only for the string on the 250w panels(4S) 150/85 mppt the Voc is high i would do 2S2P on that array. Quote Link to comment Share on other sites More sharing options...
ClintonDBN Posted September 19 Author Share Posted September 19 (edited) 1 hour ago, TaliaB said: Thanks for spotting the solarworld string issue. I had picked that up, which is why I highlighted it. I asked this question on a thread specific to my entire set up. Your opinion? Edited September 19 by ClintonDBN Quote Link to comment Share on other sites More sharing options...
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