Jump to content

Battery Protection from Short circuit?


leaves
 Share

Recommended Posts

Hi Guys

 

Need some help. I want to put a safety device in-between my battery and Solar Charger

The Battery In (+) and (-) are installed pretty close to each other on the controller.

What can I use on my battery for just encase the the two terminals connect either by failing out the charger or accidentally touching?

Thanks! L

Link to comment
Share on other sites

  • 2 weeks later...
  • 1 year later...

Tried the car fuses, they are 12v, so not good for solar systems.

 

For days I smelled plastic, it was the 20a car fuse plastic melting, using 2 x 200w panels on an 20amp Phocos controller.

 

Take the cable amp rating and install a fuse that will go before the cable melts.

 

Trust me on this one: Do not use car fuses.

Link to comment
Share on other sites

Tried the car fuses, they are 12v, so not good for solar systems.

 

For days I smelled plastic, it was the 20a car fuse plastic melting, using 2 x 200w panels on an 20amp Phocos controller.

 

Take the cable amp rating and install a fuse that will go before the cable melts.

 

Trust me on this one: Do not use car fuses.

 

The purpose of a fuse is to isolate a circuit at a specific voltage after it went open circuit because of a fault condition. A car fuse is typically designed (rated) for 32V (if I'm not mistaken) and that means that if you have 32V or less across the fuse when it opens up, it will isolate the 32V or less, but it might not "stop" a higher voltage from arcing over. You can use car fuses of the appropriate ampere rating for 12V and 24V inverter systems, but not for 48V systems and not for PV connections.

 

The reason why you smelled burnt plastic were maybe because of a bad connection somewhere in or close to the fuse or fuse holder which caused it to overheat. Keep in mind that in case those "car" fuses "blow" because of a fault condition, they might not be able to isolate the PV circuit if the PV voltage is much higher than what the fuses are rated at.

Link to comment
Share on other sites

Ask yourself the question: Why skimp on fuse costs?

It is all about protecting your wires, to not cause fires, to protect your expensive equipment and as with everything in life, would you trust a 20c fuse, or a +-R150 fuse?  

 

My car fuse was installed between the solar panels and controller, to protect the wires coming from the panels.

The panels can push a max of 7.15amps, well below the rated 20amps of the fuse I installed.

The volts may reach 42v at times which, I was told, is not to bad either, the amps are the issue.

 

What I missed at the time was 42v @ 7.15amps going for 4-7 hours each and every day ... are where car fuses become a very bad idea.

 

Car fuses are designed for cars and cars have manufacturers requirements. As such, in a car the biggest amount of amps drawn, is a car's starter motor, for few seconds, right? The rest of the car has fairly low amps at wot, 12-14.6volts?

 
So nowhere in a car is there a current running as what can run in solar systems / UPS'es / inverters, for extended periods of time right?
 
In my opinion car fuses are not designed for such an application and therefor nowhere near as save / bullet proof devices one needs for handling currents for extended periods of time, as is needed in solar systems.
 
I would avoid them. 
 
These are my opinions and experiences in and around car fuses and using them in applications that require DC power for extended periods of time.
Link to comment
Share on other sites

I found them lacking in the way they connect to the wire: a single screw.

 

Connections in solar systems must be proper, otherwise you could cause a problem.

 

With solar wiring, I like to ensure the connection is as best as it can be, i.e. crimped if I can.

 

These links are for pictures only:

These are ok for certain applications: http://www.aliexpress.com/item/10-units-of-PV-solar-fuse-15a-1000VDC-fusible-10x38-gPV-with-holder/32242575250.html

 

But, you do not want to do this with them. To disconnect them under load is not advisable.

 

 

 

This is what I am using, pain in the backside if you do not have a crimping tool, but it is in my opinion the best:

http://www.google.co.za/imgres?imgurl=https://dh778tpvmt77t.cloudfront.net/images/products/5001.jpg&imgrefurl=https://www.bluesea.com/products/category/Fuse_Blocks&h=1494&w=1629&tbnid=8XmwuPojHDqm2M:&docid=ZfcG32aH2aHdDM&ei=1fPdVdytJMPravLoivgG&tbm=isch&ved=0CC4QMygrMCs4yAFqFQoTCJzs986fx8cCFcO1GgodcrQCbw

 

Have a DC breaker to disconnect the cable, before you remove the fuse.

Link to comment
Share on other sites

  • 2 weeks later...

I use something similar. They're commonly used in car audio installations and can be brought from the bigger car audio installation places. Make sure it has M8 or  M10 bolts and you're fine ;)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...