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Wick

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  1. OK, I'm reading up and trying to understand this. A 250VDC fuse rating means that we can suppress arcing up to and include 250VDC - but not beyond? Is that correct? But if over that figure, we're in trouble? So we then want the highest fuse voltage rating that we could get, so as to suppress arcing up to 400, 600VDC and so on, if we could get that at the same cost as 250VDC ?
  2. I'm confused too, because I don't get why one would use a 250VDC fuse on connection to a 66VDC (max, 58VDC nominal) input on the inverter. It seems to defeat over-voltage protection... unless there is something I'm not grokking here? I'm trying to protect the EasySolar's input port. Certainly if it were 100-120V (2x) protection even, I could swing that. But 250VDC is 4x higher than the rated voltage on that wire. About the disconnect - which I presume you mean by physically decoupling the fuse from its holder, or swinging out the holder if it is the hinged sort - noted.
  3. OK, sure, clarified. So here's my quibble with that. Those are all rated 400VAC / 250VDC and upward. Don't get me wrong - I'd love to - as they're available for collection here in P.E. with holders (58mm) and I could go buy them tomorrow and get started - but they're not at anywhere near a 60-100V rating. My EasySolar's rated inverter input is max 66VDC. I would rather fuse accordingly?
  4. Yes, referring to the internal fuse in the Victron EasySolar-II unit, should that blow. Mine is 3kva so may need external fusing too. Hmm, I've been assuming I should use a 100-125A 58V fuse on battery positive. But if that's already what's inside the EasySolar...? I think you previously recommended 500V ceramic fuses? Do you still stand by this or should I get a voltage rating closer to the max current passing through (5500W peak @ 50+V = 100-110A)? Still seeking 58V fuses at reasonable cost... Victron MIDIs were not available locally...
  5. What is the difference between those fuses, and fuses on the greater circuit? They must be very fast blow, no? I notice Victron does not sell replacements - they have to service the device to replace these. Why can a fast blow fuse on the circuit, not serve the same purpose?
  6. Addition for other folks who might browse this thread... Use "high rupture current" (HRC) DC fuses between battery bank and inverter / charger / other devices, especially for high discharge rate / low internal resistance battery like LiFePO4. Why? When a DC fuse breaks, there can still be an electrical arc powerful enough to "jump the gap" - which means your fuse has failed in its task and your goodies on the other end, like your inverter charger, will likely be fried. HRC prevents this. 3A fuse can have a rupture current of as high as 40 000A! Obviously special case, but illustrates the point. This relates to @plonkster's mention of ceramic fuses - the highest rupture current fuses are nearly always ceramic. Locally, these include Bussman tubular and box fuses, and Littelfuse (also Pudenz) bolt/box fuses. So far, we have been talking about DC fuses sensitive only to current. ... Now, as a specific category of HRC, there are semiconductor DC fuses. MIDI and MEGA fuses should generally support high rupture current - but it's on you to check, based on your setup. Semiconductor fuses are made of semiconductor materials that are sensitive to both current AND voltage. For example, you will see voltage ratings on Victron DC fuses but not on all Bussmann DC fuses - that is the difference in construction talking. Semiconductor DC fuses and ceramic fuses are typically different in construction, rupture time and current rating . If you're not sure - look on the fuse to see if a voltage rating is displayed. If not, best be careful and get something that is specifically voltage-rated to your application. If you're not too worried, an AC circuit breaker generally does the same job - current AND voltage based trip - although depending on conditions, it may take longer to trip (higher current) or shorter (higher voltage) as compared with a simple fuse. This delay can mean the difference between your equipment being good or scrap.
  7. Grandmaster @plonkster , what sayest thou of ANT + Victron connection via RS485? Hast thou arcane knowledge hereof?
  8. Correct but only 19 units available. So do you know if they can talk to Victron?
  9. One belated question for you @Gerlach, have you ever connected Smart ANT BMS to Victron MultiPlus / MultiGrid / EasySolar? I'm wondering if they can chat.
  10. Thanks. The above makes sense; learnt something new today.
  11. Nice one @Tariq - yes well worth it given the relative ease of installation. In the end I have gone with 100A Victron midi fuses for 58V - R200 per fuse and R150 for the holder, through Livestainable. I still feel a fuse is better than a CB between inverter / charger & LiFePO4 where energy density is high and the last thing you want is a battery to discharge too quickly. As for fuses between cells / batteries... not sold on this aspect if they are all new, balanced cells as mine are. @plonkster have you ever done this?
  12. Just to confirm re RCD / RCBO... So 30mA is the rating to stop fibrillation in the body if something does happen. The secondary rating in 2-digit Amperes - is this just the same as any other CB? Just acts as a CB at that level of current? Any benefit for me, in this small mobile setup, to using RCBO?
  13. Re 500V - noted. Victron mega fuses are indeed that expensive - do a search and you'll see everyone trying to coin $30+ off you for these. Ridiculous. However I'm guessing regular brand mega fuses should be roughly as good...? Those can be gotten a lot cheaper as you say. Nice to know about the bussman ceramic cylinder fuses - they have some nice closeable holders + the 80-100A fuses at AC-DC in town. One less thing to ship.
  14. Good to get some ICTRON & general fusing advice from those in the know, first thing in the morning. Thank you both. Useful to know one can get away with 25mm sq. I went with 35mm sq. on EasySolar manual's recommendation... can't hurt if I ever want to run a higher load. 80A + and -, got it @Jaco de Jongh. Wasn't sure if there was a benefit to fusing both ends. @plonkster's comment seems to confirm. I should get away with 250VDC if available, SmartSolar only rated up to that anyway? I shall keep several! (provided they don't cost R500 each like mega-fuses ) Appreciated. I get this feeling from the many sources I've looked at, Victron and otherwise. Going to rather play safe than sorry, no offense @Jaco. A little extra resistance is not going to kill me, but fusing may save me. From what I've seen (e.g. this), breakers should work OK here? Would you opt for fuse or breaker, @plonkster? 12A PV string fuses - OK - "in" = on the input side? Which is that? Doh. From what I read, amperage fluctuation from MPPT can be high... maybe not 5A though? Isc on panels is 10.16A so I agree 12A should be enough in general... the panel-attached cables are MC4 rated 15A, 4mm sq. core. Overall cable losses should be low - 10-12m total for 3-4 series panels (including their own attachments).
  15. Hello all, wondering if you can advise on my selections. System specs in my signature. One thing I'm wondering about is where to use CBs vs actual fuses - I am fairly sure fuse is needed on battery, but is it needed on PV as well? Or will CBs do for PV? Battery-positive to EasySolar-II 100-125A DC Midi fuse for battery (Victron Wiring Unlimited claims slow blow for DC...?) + fuse holder - should be fast blow? (F or preferably FF) Am using 35mm / AWG 2 with a rating of 105-120A (48V 240Ah battery). So an 80-100A fuse should work for battery @ ~80% of cable ampacity rating. Better to go 100A as it is a very short cable (2m each for positive and negative)? - and actually EasySolar-II manual recommends 125A. However I doubt I will be drawing anything near as high (48V @ 100A = near 5kva, much higher than the inverter's 3kVA recommended for regular use). PV to SmartSolar 250/70 15A DC blade fuse for each of 1-2 series of PV in parallel OR 15A DC circuit breakers to save replacing fuses? or is a fast blow fuse safer? 30-80A 160-250VDC master fuse / CB between PV array's individual fuses and battery - ceramic 55mm Bussmann? AC Distribution box 32A total (matches 48/3000/35-32 rating 16A heater, stove, water heating, aircon 10A computer & digital equipment (should be 16A? swap?) 2A lights 30mA "high sensitivity" RCD / RCBO (63A standard? or 32A?) Thanks for any advice you can offer. Let me know if any clarifications are needed.
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