Newbie solar questions

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Re: Newbie solar questions

Postby Gordon-Loomberah » Mon Jun 15, 2015 10:01 pm

Welcome to the Energy Matters Forums Roundsole :)

Roundsole wrote:
Gordon-Loomberah wrote:...A single 150-200W panel would probably cover your camping needs, even in fairly cloudy weather.
A small 20 or 30A MPPT charge controller would be all you need. A Lithium battery would need to be about 120AH@ 13V (well under 20kg), or about 250AH @12V for a Lead-acid battery (very heavy!)


With your suggestions, what fuse would be needed between the battery and the charge controller and would it need to be fused between the charge controller and the 12v lights.? (Sorry hopefully not to much of a newby question)


In a camping set-up with one 200W panel and an MPPT charge controller for a 12V battery, a 20A or 25A fuse would do the job between battery and CC, but you need to make sure the wires are of sufficient current carrying capacity*.
If the CC had a pair of LVD terminals for loads, then you'd fuse it to suit whatever the max load rating was on that circuit. If running the load directly from the battery, it would depend entirely on the max load, so I cant really give a recommendation for that.

* If your cable is too small, then the resistance in the wire will mean that not enough current can flow to blow the fuse, even when there is a short circuit, and this could result in a fire, or at least melted plastic and toxic fumes.
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Re: Newbie solar questions

Postby Roundsole » Tue Jun 16, 2015 3:16 pm

Gordon-Loomberah wrote:Welcome to the Energy Matters Forums Roundsole :)

Roundsole wrote:
Gordon-Loomberah wrote:...A single 150-200W panel would probably cover your camping needs, even in fairly cloudy weather.
A small 20 or 30A MPPT charge controller would be all you need. A Lithium battery would need to be about 120AH@ 13V (well under 20kg), or about 250AH @12V for a Lead-acid battery (very heavy!)


With your suggestions, what fuse would be needed between the battery and the charge controller and would it need to be fused between the charge controller and the 12v lights.? (Sorry hopefully not to much of a newby question)


In a camping set-up with one 200W panel and an MPPT charge controller for a 12V battery, a 20A or 25A fuse would do the job between battery and CC, but you need to make sure the wires are of sufficient current carrying capacity*.
If the CC had a pair of LVD terminals for loads, then you'd fuse it to suit whatever the max load rating was on that circuit. If running the load directly from the battery, it would depend entirely on the max load, so I cant really give a recommendation for that.

* If your cable is too small, then the resistance in the wire will mean that not enough current can flow to blow the fuse, even when there is a short circuit, and this could result in a fire, or at least melted plastic and toxic fumes.


Thank you for the Info and the welcome.

I'm thinking of doing something similar to the OPs first question, running some outside lights around the house. (A) because we need some lights but (B) for me to dabble and learn about solar.
I currently have a 12v 130w panel and a 30amp charge controller inc timed light function, was planning on using about 30 to 40 watts of 12v lighting and getting a bigger battery than the small one I'm experimenting with at the moment. Will the 20/25amp fuse still be ok and what size fuse for after the charge controller to the dc lights?
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