diy solar

diy solar

Yet Another Noob Diagram! (But pretty'ish)

Oh haha, yes I haven't even put together yet, that's not how I'm mounting! Was just showing where the mount would sit.

I bought this off local reputable oz ebay seller - the mount was cheaper w' fuse, than cheapest mrbf bluesea mount w' no fuse locally. If ebay fuse proves dodgy I'll buy readily available blue sea fuses.

The fuse body is ceramic yet the fuse itself looks weird? It does fit the mount pole and fitted nylon(?) nut (steel inside nut), mount seems quality. Pics:
That fuse looks like a knock-off.
Please show the side with writing on it.
A bluesea marine rated battery fuse looks like this.
 
That fuse looks like a knock-off.
Please show the side with writing on it.
A bluesea marine rated battery fuse looks like this.
I'm familiar with the bluesea as detailed, the only writing on my fuse is clearly visible in attached pics.

you can tell it's not the same as bluesea (cover only over fuse, not whole ceramic body) - but functionally it seems the same? (I was confusing lower amperage MRBF fuses with the type of fuse on the higher amp BlueSea MRBF fuses - the fuse itself on mine now actually looks the same to me ?‍♂️)
 
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I'm thinking the rare power hungry stuff I might run would be fine on 3kwM (power tools mainly, tool/phone chargers)

Tool/phone chargers are not power-hungry. They'll run fine on the small inverter.
Any actual non-battery-powered tool you'd like/need to run?
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I'm familiar with the bluesea as detailed, the only writing on my fuse is clearly visible in attached pics.

you can tell it's not the same as bluesea (cover only over fuse, not whole ceramic body) - but functionally it seems the same? (I was confusing lower amperage MRBF fuses with the type of fuse on the higher amp BlueSea MRBF fuses - the fuse itself on mine now actually looks the same to me ?‍♂️)
We don't know the breaking capacity of the mystery fuse.
Just because it has a similar form factor to the MRBF fuse doesn't mean its breaking capacity is comparable.

This fuse for example is very similar to an MRBF but only has a breaking capacity of 2000 amp at 32 volts.
 
Tool/phone chargers are not power-hungry. They'll run fine on the small inverter.
Any actual non-battery-powered tool you'd like/need to run?
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I realise that, that was re power tools, drill, circular saw, jigsaw, other things I might get my hands on.
 
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The drill... depending how big it is, if not used for long periods and not strained too much, should work on the 1K. So should the jigsaw.
Circular saw... get a generator :·) It's a good thing to have to charge on rainy days, and run things like... circular saws ;·)

The panels... 24V means they have a Voc of some 40V, right? In series, some 80V. Your MPPT should take those easily, but check the specs.
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The drill... depending how big it is, if not used for long periods and not strained too much, should work on the 1K. So should the jigsaw.
Circular saw... get a generator :·) It's a good thing to have to charge on rainy days, and run things like... circular saws ;·)

Very good and obvious points, and I do have a generator and now feel a bit daft.

The panels... 24V means they have a Voc of some 40V, right? In series, some 80V. Your MPPT should take those easily, but check the specs.
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MPPT: Max solar input: 100V(25℃) 90V(-25℃) (Winter has suddenly hit so consistently <25c now)

PV : Voc of each panel: 40.9

I must have had wrong info in my noggin, so PV in series is adding that Voc x 2 (81.8v), and hence works for my MPPT and hence I should have my 2 x PV in series?
 
Considering it never gets below 0°C there, they should be just fine, in series.
In fact, they'll be just fine in parallel, you would have a bit more current on the panels-to-SCC leg, but it's not much anyway.
Me, I don't bother with series, actually, I dislike high voltages more than high currents - and I have a small system anyway.

About the "modified" wave inverter... some 20 years ago, it was all I had (1.5kW), and I ran pretty much everything - except the washing machine and serious power tools, for which I used the generator - on it. Nothing ever blew up, but... maybe I just got lucky ;·)
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Considering it never gets below 0°C there, they should be just fine, in series.
In fact, they'll be just fine in parallel, you would have a bit more current on the panels-to-SCC leg, but it's not much anyway.

Good to know either way.

Me, I don't bother with series, actually, I dislike high voltages more than high currents - and I have a small system anyway.
I think you're the first I've read that's pro high-currents, howcome?

About the "modified" wave inverter... some 20 years ago, it was all I had (1.5kW), and I ran pretty much everything - except the washing machine and serious power tools, for which I used the generator - on it. Nothing ever blew up, but... maybe I just got lucky ;·)-
Also a rare opinion :)
 
I think you're the first I've read that's pro high-currents, howcome?

Because they're not really high. I have less than 1kW of panels, 800W (nominal) on one SCC, about 150W on another. 24V battery.

Small systems, with enough power for small needs, one can afford to...not really care :·)
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We don't know the breaking capacity of the mystery fuse.
Just because it has a similar form factor to the MRBF fuse doesn't mean its breaking capacity is comparable.

This fuse for example is very similar to an MRBF but only has a breaking capacity of 2000 amp at 32 volts.

Belated reply, the "MRBF" I have is a Littelfuse CF Fuse (not ZCase) clone/OEM https://www.farnell.com/datasheets/2246040.pdf , it's from : https://www.alibaba.com/product-detail/Autoido-Andu-Supply-30A-300A-Marine_1600266194951.html - and looking at the details of company, and product, it actually looks legit. Most every chinese OEM product I've bought that Ive done due diligence on has actually worked fine. Emphasis on due-diligence.
Coz, well, everything comes from there anyway.

EDIT: We're looking at the: "Interrupting Rating: 2,000A @58 VDC" vs MRBF 10,000A right?
And if so - could someone kindly explain to iNoob why 10x the actual 200a load is not enough?

Oh and I went and bought a 2kw Pure Sine inverter which will be the only inverter in my system now. Seems solid, looks like a local Oz company rebrand of a belgian product (likely via China) - 4000w peak! 2 yr oz warranty! https://www.nobullaccessories.com.a...tt-12-Volt-Pure-Sine-Wave-With-Remote-Control - site looks dodgy as, the company has good reviews and is legit.

AND the renogy shunt: https://au.renogy.com/500a-battery-monitor/
I realised my cables are mismatched - I measured the negative - which is 3/0, but the positive is 2 AWG ?‍♂️. Elec enginner friend recommend doubling cables instead of getting new cable, as I have enough excess, so will do that to give me effectively >4/0 where needed.
 
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Hey all, while I've only been here for a short (but good) time, I've been cramming the forums and interwebs these last few weeks and gleaning the generous knowledge by yall, so hopefully I've graduated from iNoob to pretty-damn-inexperienced. I've gone and got the sum total of my learnings to date into a purty diagram with a bunch of details, power estimates and item specs links that I'd love to get yr feedback on!
Any gotchas, catastrophic oversights, suggestions?

It's a live whimsical board, anyone can comment: https://whimsical.com/elec-diagram-QzadYSZ1ub4d25eF7eymgr@2Ux7TurymNFgqMdV36oS , or see image or PDF (with links) attached.

Qs, and background:
  1. I bought an RV converted pantech truck, adorned with star trek interior metallic paint, from QLD border (peak-covid Australian state border lockdowns) and got it back to Sydney, to strip and renovate. It's got some 12v loads I'm keeping (water pump, hot water heather, fan, exhaust fan, fridge, lighting circuit [replace with led strips]) and a ~10yrs old Mod sine 3kw (3kwM) 230v inverter, which was running off (now dead) lead-acid truck batteries pretending to be house.
    I've been wondering if adding a 1kw Pure Sine Inverter (1kwPS)* is a good idea ($170ish), and dedicate it to: Laptops 2 x 45" 4k TV, Media Player, Xbox, Microwave (not at same time) - and whatever else it might manage. I'm thinking the rare power hungry stuff I might run would be fine on 3kwM (power tools mainly, tool/phone chargers) yet have read mixed reports re what does and does not work ok on mod sine - any experience re that here?
    (* I'd planned to buy a new 3kwPS, but I've run out of $ and need to get in truck asap!).
  2. I've got a 300a MRBF fuse for battery + inverter, my 2 x 200ah batteries in parallel are rated for 300a max-discharge-5-secs, 200a consistent. While I thought I'd never pull 300a this calc now tells me that single-phase AC, amps: 300, volts: 230, power factor: 0.02 [1800w "real" use] = 1380w. Now I'm confused - pulling 1380w would pull 300a and blow fuse!? Is that wrong?
  3. I found these Blue Sea circuit breakers - very cheap here in oz, all have interrupt Capacity: 3000A @ 14.7V - Links: 25a, 30a, 40a - are these suitable?
  4. I'm using a 50a AGU fuse down from the 40a MPPT before Busbar, manufacturer confirmed the MPPT has 2 fuses and we're on a busbar with 3/0 awg wire, thinking this is ok?
Thanks chums! ?

I am another noob, but I can just chip in that visually it looks great! :)
 
EDIT: We're looking at the: "Interrupting Rating: 2,000A @58 VDC" vs MRBF 10,000A right?
And if so - could someone kindly explain to iNoob why 10x the actual 200a load is not enough?
The breaking capacity of the fuse should be higher than the amps your battery can dump into a dead short.
The dead short ampacity of your battery is a factor of its internal resistance of each cell and the combined resistance of all the joinery.
For a 4s LFP battery that is well in excess of 2000 amps and likely in the ballpark of 6000 amps.
A fuse that can't quench the arc from a dead short is a nightmare.
I realised my cables are mismatched - I measured the negative - which is 3/0, but the positive is 2 AWG ?‍♂️. Elec enginner friend recommend doubling cables instead of getting new cable, as I have enough excess, so will do that to give me effectively >4/0 where needed.
Assuming pure copper with 105C insulation...
2 awg can be fused as high as 200 amps.
Each wire should be fused separately though.

4/0 awg can be fused as high as 400 amps.

I thought Australia measured wire gauge in mm2.
 
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