Do I really need fuses for small solar panel

[Ogbassist]

Basically as the title asks. Do I really need fuses? If so, will someone what fuses, and where to put them? I have a 100 watt panel, a 75 ah marine battery, a 30 amp charge controller( I think). I just need a little assistance on wiring this baby up please! thank you.

[Shockah]

Basically as the title asks. Do I really need fuses? If so, will someone what fuses, and where to put them? I have a 100 watt panel, a 75 ah marine battery, a 30 amp charge controller( I think). I just need a little assistance on wiring this baby up please! thank you.

Yes and No.

No. You don't need them to make the system work if all the wires are connected properly, to the correct polarity and no frays or chances of shorting.

Yes. You need them because there is always a risk of the wires NOT connected properly, NOT to the correct polarity and frays and chances of shorting.

Absolutely Yes, because you're not even sure what CC you have... which indicates you're not very thorough... which is normally the cause of the problems listed above.

Last but not least, Yes. You need a fuse on the panel and battery of the CC.
Because even if you hook everything up properly,
there is a later chance of the inverter shorting and frying the CC,
or the panel shorting and frying the CC,
or the CC shorting and frying the battery.

Fuse = Cheap Insurance.

0212041425.jpg

^^^ Fuses on a panel, battery and CC...
which are all smaller than yours.

[Shockah]

Basically as the title asks. Do I really need fuses? If so, will someone what fuses, and where to put them? I have a 100 watt panel, a 75 ah marine battery, a 30 amp charge controller( I think). I just need a little assistance on wiring this baby up please! thank you.

10amp-15amp fuse >>> 100Watt panel positive wire to CC
10amp-15amp fuse >>> CC positive wire to battery.
35amp-40amp fuse >>> Battery positive wire to inverter, if you plan on pulling your inverters full 400watt capacity from the battery.
If your load is less than the 400watt, then use an amp rating according to your load.

[mapmaker]

Do I really need fuses?

The usual rule for fuses is to size them to protect the wiring. Wires have a property called 'ampacity'. That's the number of amps they can safely carry. The fuse must be sized smaller than the wire's ampacity.

Another reason for fuses is to protect the things that are connected to the wires. In your system you must protect the battery (I presume your charge controller has its own built in fuse to protect itself).

Battery protection is very important. If you draw too much current (like a short circuit) your battery can explode and spray you with very hot sulfuric acid.

EVERY wire connected to a battery must have a fuse. The battery must be in a box to protect it from conductive objects falling on it and shorting it out. The cables from the battery box must be protected by conduit. The conduit runs to an electrical panel with OCP (over current protection = fuses or circuit breakers). Then you can connect your controllers, inverters, lightbulbs, or whatever to the battery through the appropriate sized OCP.

--mapmaker

[Ogbassist]

Yes and No.

No. You don't need them to make the system work if all the wires are connected properly, to the correct polarity and no frays or chances of shorting.

Yes. You need them because there is always a risk of the wires NOT connected properly, NOT to the correct polarity and frays and chances of shorting.

Absolutely Yes, because you're not even sure what CC you have... which indicates you're not very thorough... which is normally the cause of the problems listed above.

Last but not least, Yes. You need a fuse on the panel and battery of the CC.
Because even if you hook everything up properly,
there is a later chance of the inverter shorting and frying the CC,
or the panel shorting and frying the CC,
or the CC shorting and frying the battery.

Fuse = Cheap Insurance.

Click image for larger version.

Name: 0212041425.jpg
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^^^ Fuses on a panel, battery and CC...
which are all smaller than yours.

Maybe what I am confuses by shokah.. I can't really tell which wire comes from where. Will you please expalin where each wire comes from. I can't really tell in your picture.

[Ogbassist]

I'll post pics tonight of everything I have. I have like 20 feet of that agm wire. the wire that connects to the panel. Do i need all of that?

[inetdog]

I'll post pics tonight of everything I have. I have like 20 feet of that agm wire. the wire that connects to the panel. Do i need all of that?

AGM is a type of battery. AWG is a wire size standard but without the size number means nothing. It also does not tell you what type insulation the wire has and therefore how much current it can carry. For example #14AWG of type THHN can carry 15A without any safety problem, but still may not be good enough for you if the distance is long.
Regardless, even if the panels produce very little power the battery can produce an enormous (relatively) current if there is a short circuit at the panels.
As stated earlier you need a fuse protecting every wire that connects to the battery. Since the current from the panel and the current to the inverter can be very different, that amounts to at least two fuses instead of just one fuse in the main battery wire.

[Ogbassist]

AGM is a type of battery. AWG is a wire size standard but without the size number means nothing. It also does not tell you what type insulation the wire has and therefore how much current it can carry. For example #14AWG of type THHN can carry 15A without any safety problem, but still may not be good enough for you if the distance is long.
Regardless, even if the panels produce very little power the battery can produce an enormous (relatively) current if there is a short circuit at the panels.
As stated earlier you need a fuse protecting every wire that connects to the battery. Since the current from the panel and the current to the inverter can be very different, that amounts to at least two fuses instead of just one fuse in the main battery wire.

My bad. I meant MC4

[Ogbassist]

Ok so the video of my stuff can be found here - http://youtu.be/LsPvUByG7EY

What I need now is a good schematic of how to wire this baby up using fuses. I'm all about some cheap insurance

I also need to know if I need any additional materials for this. I'm thinking I will need some more AWG wire. I wouldn't know what gauge to use. Maybe 10-14 since it will be fairly short? Also I am still totally oblivious to these fuse connectors or fuse holders or whatever they are called. I will need 3 of them right? That's what Shockah's picture had, 3 of them. Thank you guys. Maybe this video will help me help you help me

[Ogbassist]

Ok I think I know what I need to hook the fuses up to - https://www.google.com/search?q=blad...ml%3B450%3B306

My panel came with 2 25amp fuses. Do all fuses need to be the same amp rating? Can they all be the same? It would make it a little more simpler.

[Ogbassist]

It was amazing! All the bands were super awesome! I finally figured out how to correctly wire it up and now I feel dumb because it wasn't that hard lol. I ended up running an AC fan off the power inverter for 4 days. I have one of those things that tells you how many watts/amps/volts appliances use, and the fan on high used about 40 watts. I ran it A LOT throughout the 4 days. I had a power strip plugged in helping all my neighbors charge their phones which is about 5 watts per phone. We had 0 problems. Battery stayed in the green the whole time. Thank you guys so much. If we didn't have that fan I would have died. It was super hot!


Thank you!

Mod note - links removed

[Shockah]

It was amazing! All the bands were super awesome! I finally figured out how to correctly wire it up and now I feel dumb because it wasn't that hard lol. I ended up running an AC fan off the power inverter for 4 days. I have one of those things that tells you how many watts/amps/volts appliances use, and the fan on high used about 40 watts. I ran it A LOT throughout the 4 days. I had a power strip plugged in helping all my neighbors charge their phones which is about 5 watts per phone. We had 0 problems. Battery stayed in the green the whole time. Thank you guys so much. If we didn't have that fan I would have died. It was super hot!


Thank you!