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Post by ricksctc on Feb 10, 2018 14:26:00 GMT -8
Hi folks, I have a 200w system connected to a 30A Wanderer and I'm looking for clarification on fusing. While the manual says to fuse the Wanderer at 30 amps, it also says to "NEVER connect solar panels to charge
controller until the battery is connected.".
My confusion is based on the theory that, if the fuse from the battery opens, you would then have solar panels connected to the CC without the battery connected.
I'm wondering if I'm reading too much into it and if the "until" in the warning is the operative word rather than me reading it as "unless".
Thanks,
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Post by tattoo on Feb 10, 2018 16:10:55 GMT -8
Yes sir you are reading to much into it... Your panels should also be fused...
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Post by rabird on Feb 10, 2018 17:53:12 GMT -8
I would suggest ya fuse base on panel specs, expected output and wire size. It is OK to short a single panel, in fact that is a method of determine if it is good (measures amp output). If ya got 2 panels and one shorts what current would try to flow throught the shorted panel, again no fuse needed. over 2 (strings) and ya need fuses. www.civicsolar.com/support/installer/articles/when-fuse-when-not-fuselet's consider portable panels with the controller already hooked to the panels and THEN ya hook the controller to the batt, goes against the warning! bet it doesn't matter for PWM controllers! |
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Post by fargozombie on Feb 19, 2018 7:03:09 GMT -8
Hi folks, I have a 200w system connected to a 30A Wanderer and I'm looking for clarification on fusing. While the manual says to fuse the Wanderer at 30 amps, it also says to "NEVER connect solar panels to charge controller until the battery is connected.". My confusion is based on the theory that, if the fuse from the battery opens, you would then have solar panels connected to the CC without the battery connected. I'm wondering if I'm reading too much into it and if the "until" in the warning is the operative word rather than me reading it as "unless". Thanks, Great question; I had the same thought when I installed my little 100W Monocrystalline panel and Wanderer charge-controller on my off-road teardrop camper trailer. I fused the output of the charge-controller at the rated 30-amps and used 10AWG wiring to the battery. I did not fuse the solar panel. According to the RNG-100D spec sheet; the short-circuit current (I SC) is 5.75-amps. The panel factory wiring is 12AWG and my extension cable to the charge-controller input is 12AWG. As you know, 12AWG wire is rated at 20-amps, not taking into account temperature/cable spacing. So, the wiring insulation would not fail under a line-line short-circuit. As rabird so eloquently stated; "...If ya got 2 panels and one shorts what current would try to flow through the shorted panel, again no fuse needed.
over 2 (strings) and ya need fuses." So, as you know, if you parallel solar panels the panel output voltage would remain the same and currents (from each) is additive. Then, you should consider the individual panel short-circuit current rating and the current carrying capability of your wiring to determine fuse requirements to protect the wiring (prevent fires) in the event of short-circuit between conductors. As to your original question, I don't know the details of the Renogy PWM charge-controller. But, logically speaking I would say the concern is that if you connect the battery to the charge-controller after you have already connected the solar panel. The charge-controller, not having a battery voltage reference, would (probably) be at maximum output for a few micro-seconds. So, If I every encountered an open charge-controller output fuse (to the battery). I would; (a) disconnect the solar panel (b) replace the charge-controller fuse to the battery to avoid any potential over-current situation on power-up (c) verify the battery indicator is on (d) re-connect the solar-panel input to the charge controller...IMHO |
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