Wick

Thanks. The above makes sense; learnt something new today.

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?

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?

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.

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).

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.

For all my fellow Victron fans out there:

@Gerlach Sounds great. I'm a simulations / graphcis programmer so might write some code at some point for monitoring - Pi sounds good, Arduino better, they say, for low-level signal monitoring... bit of C code for low power consumption. Frankly though, I'd rather someone else did the work. @Louisvdw Yes that's where I got the Daly I don't really want. Should just have bought cells from Bain. Thanks for the Smart ANT link! I am very keen to get 2x Smart ANT or Smart 123 BMS. If you know of ANY local sources with stock, please shout! I don't want to wait months for arrival! I do not agree with using 1x BMS and paralleling cells beneath this. Suppose even cells top-balanced and in parallel can still go out of balance over time - and the BMS will be none the wiser. Better to do 2x BMS and have that redundancy of 2 batteries / packs; if you need to take one down for maintenance, you can still rely on the other.

Thanks folks. I'd be interested in any locally supplied lithium cell monitoring system, but to my knowledge there is currently nothing (affordable) - stock is all overseas. What irks me the most is the lack of visible cell monitoring. This has to be easy to put on a cheap display from even a passive BMS, since it is monitoring cell values anyway, but they just don't provide a few pins to output the data for monitoring. Let's hope the cheap ones like Daly will improve in the coming months. You can go with the little LCD cell balancers, but that is a separate device supporting only 8 cells / channels - I have 32 that I need to see together, on a PC or 'Droid screen, all at once. What is the cost of the AntBMS, as a matter of interest? The cheapest REC apparently comes in at $400 (reputedly, though some say there are additional overheads), and the Smart123 Gen3 @ $400. Of course these exclude shipping etc. to S.A. @Gerlach, appreciate your remarks on getting Daly to work with a Victron setup - this gives me confidence to order the Victron stuff. I'm not really comfortable being in a smallish space with an Axpert / RCT / Mecer that might crash and burn due to poorly spec'ed components.

Have a cheap passive Daly 2p16s 48V BMS. EasySolar + BMV on the way. Not comfortable with that BMS, at all. Active management seems much saner given LiFePO4 bank cost. Voltage and current are main concerns in the southern hemisphere. Could a BMV-712 Smart talk to an EasySolar-II to tell it when to shut off charge?