Is this ok?

[John117]

Fusing is a good practice.

There is a ton of experience on this site.

I see you have ambitions for future projects. That is exciting.

There are quite a few members who have already built their own systems. Their assistance can be invaluable.

While there are many different vendors and configurations there are a number of very important safety considerations to consider. Wire size, proper fusing, temperatures are just a few areas.

For instance make sure your battery has cold temperature protection if your area gets close to freezing.

As you move up in voltage you drop your wire size requirements because you are trading off amps for volts. There are essential safety concerns in all cases.

The resources section also has a lot of valuable information.

I personally have enjoyed YouTube videos. However there is a ton to learn that goes past most of them. What I found out is that a video only contains a small percentage of the information needed for a proper build. There are many foundational videos that discuss volts and amps. They are also helpful.

Thank you for sharing your project. It is a giant step to get from planning to implementation.

Thank you for the advices! I did ask about fuses/breakers in a different thread, one member basically told me after seeing my build, that the Victron will protect the load and itself with an included fuse and that my cables were ok for the amps the system pulls. He also said that because the solar panel will at most give 5 amps, the panel was ok unless lighting strikes.

I have watched videos and read a book, but I still don't understand A LOT including how to size breakers/fuses. In the future I want to go big like 800w or so, but I understand that playing in the big leagues comes with risks, so I will keep learning and take my time. Even this tiny system cost me around 600.00 (including those path lights). Anyway, thanks for the help, solar is awesome!

 

[HRTKD]

A basic rule of thumb for sizing Over Current Protection (OCP), which is a fancy way of saying breakers and fuses, is that it needs to be 1.25 times the nominal current that passes through the wire being protected. The guidance that goes with this is we're protecting the wire, not the device. There are exceptions to the 1.25 rule. We do not fuse for surge because surge is supposed to a momentary current, not a sustained current.

A solar charge controller that can produce 100 amps needs OCP of 125 amps.

There are ampacity charts for sizing wires. I do not use those charts. I prefer a voltage drop calculator that takes into account my specific situation of amps, volts and distance.

 

[John117]

A basic rule of thumb for sizing Over Current Protection (OCP), which is a fancy way of saying breakers and fuses, is that it needs to be 1.25 times the nominal current that passes through the wire being protected. The guidance that goes with this is we're protecting the wire, not the device. There are exceptions to the 1.25 rule. We do not fuse for surge because surge is supposed to a momentary current, not a sustained current.

A solar charge controller that can produce 100 amps needs OCP of 125 amps.

There are ampacity charts for sizing wires. I do not use those charts. I prefer a voltage drop calculator that takes into account my specific situation of amps, volts and distance.

Interesting, protect the cable... I have seen those charts for cables. I have sooo many questions... for instance I bought my wire from ebay and it said 150v but it didnt gave me amps... so how will i know the amp limits?

Another thing that is not clear to me is the rating of the mppt controller, victron moldel shows 10 amps. Does it mean that the solar pannels cannot exceed 10 amps? Or the load? Or the battery? Is confusing. 10 amps is not much given that my 50w panel produce 5.

Also the cable i am using is 10, and it almost didnt fit the victron. I have seen videos of people recomending 6 and 4 to wire the battery, wich makes sense, but most charge contolers dont have holes to fit those, so how?

 

[HRTKD]

Interesting, protect the cable... I have seen those charts for cables. I have sooo many questions... for instance I bought my wire from ebay and it said 150v but it didnt gave me amps... so how will i know the amp limits?

Plug your numbers into the calculator linked below. The distance is the round trip distance, not the way distance. You'll need to know how many amps you expect to go through the cable. For the voltage I typically use 12.0.

Interactive Wire Size Calculator

Battery Chargers, Inverters, Solar Components, and Wiring Supplies for Boats, RVs, and Off-Grid Applications.

baymarinesupply.com

Another thing that is not clear to me is the rating of the mppt controller, victron moldel shows 10 amps. Does it mean that the solar pannels cannot exceed 10 amps? Or the load? Or the battery? Is confusing. 10 amps is not much given that my 50w panel produce 5.

Can you provide a link to the exact Victron model you have? There isn't a 100/10 MPPT that I can find. Anyhow, the second number is the amps that the solar charge controller can produce. The maximum number of amps that you'll ever get into your battery from PV can generally be determined by PV Watts / System Voltage. If you have a 100 watt panel attached to a 12 volt system then the maximum amps will be around 8.3 amps.

Also the cable i am using is 10, and it almost didnt fit the victron. I have seen videos of people recomending 6 and 4 to wire the battery, wich makes sense, but most charge contolers dont have holes to fit those, so how?

My Victron 100/50 easily fit 6 awg welding cable. The datasheet for each Victron solar charge controller lists the size of the terminals.

 

[John117]

Plug your numbers into the calculator linked below. The distance is the round trip distance, not the way distance. You'll need to know how many amps you expect to go through the cable. For the voltage I typically use 12.0.

Interactive Wire Size Calculator

Battery Chargers, Inverters, Solar Components, and Wiring Supplies for Boats, RVs, and Off-Grid Applications.

baymarinesupply.com

Can you provide a link to the exact Victron model you have? There isn't a 100/10 MPPT that I can find. Anyhow, the second number is the amps that the solar charge controller can produce. The maximum number of amps that you'll ever get into your battery from PV can generally be determined by PV Watts / System Voltage. If you have a 100 watt panel attached to a 12 volt system then the maximum amps will be around 8.3 amps.



My Victron 100/50 easily fit 6 awg welding cable. The datasheet for each Victron solar charge controller lists the size of the terminals.

Mine is small, victron smart solar 75v/10 it has bluethooth built in, the picture is above. I will check the calculator, thanks!!