Is 30ft extension cable too long for a portable kit

I just ordered a renogy 200w suitcase style solar panel kit to help keep my RV batteries charged when I camp off grid.my question is about the length of extension cable I can us before experiencing significant power loss. I'd like to use a 30 ft 10g cable. Thoughts? Experiences?

That is going to depend a lot on the voltage of the panels. Those 200 watt Renogy panels are probably low voltage therefore you will experience greater voltage drop over longer distances.

10AWG is good in most cases, but more information is needed. Look at the specs on the back of the panels and figure out it they are in parallel or in series. This site is helpful if you want to find out more about voltage drop in wire runs.

Renogy is known for hanging the controllers off the panel, keeping the controller close to the battery is more effective. I would think #10 is fine for your intended use.

You will do better if the controller is at the battery.

time2roll said:

You will do better if the controller is at the battery.

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Simply because you want to keep the highest voltage for the longest travel distance.

Try inputting different voltages into the calculator linked in post #2 to see the difference.

You can series your panels and use an MPPT that can handle higher voltage to 12v nominal. 100v is not uncommon.

Plug that into the calculator and it will show 10 AWG quite sufficient.

I like making my own cables. I’ve found if you are not dealing with a lot of wire, The price difference between 10 AWG and 6 AWG is not huge. I have two sets of cables I built. One is 10 AWG and about 10 feet. The other is 40’ and 6 AWG.

With the panels, going greater than 10 AWG becomes challenging because MC4 cables do not come greater than 10 AWG. That caused me to use a short length of 10 AWG in each MC4 cable, and then folded that over to and inserted into a butt splice with a lenght of 6 AWG between them. Someone posted a 6 AWG wire to a 10 AWG pin crimp that would be better, but I did not save the link. Still can’t exceed the 30 amp limit on the MC4 cable even with bigger wire.

when it comes to dc voltages, cable losses are really just a simple matter of wire resistance (make sure you loss calculator includes BOTH legs of wire) times the current squared. Because the current is squared this is why raising the voltage and keeping the current lower is a big factor in reducing the wasted energy in heating up your wires. Your current is the bigger factor and with your 200w panel at "probably" 12v thats at most 16amps...so you may have around a 0.5v drop

if I use a wire size calculator (http://circuitwizard.bluesea.com/#) and enter in 16amps, 12v, 60ft of wire length I definitely do not get 10awg unless I change to allowable voltge drop to something much more than the "usual" 3% (or in my case I always use 1% allowable) hehe

Whinny said:

Renogy is known for hanging the controllers off the panel, keeping the controller close to the battery is more effective. I would think #10 is fine for your intended use.

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I didn't even think about the Renogy "suitcase" product being an all-in-one product with the solar charge controller attached to the panels. I was just assuming that the panels were a standalone branded fold up type no other electronics included. I'm not familiar with Renogy's product lines.

Well, what I said still applies if the voltage running from the Renogy kit is DC. And if the kit includes the MPPT charger at the panels that's unfortunate. It is preferable to run higher voltages long distances instead of stepping the panel voltage down to whatever the charging voltage of the batteries are and then traversing that distance.

Thanks for all the information, it's been very helpful

I use the Renogy 200w solar suitcase with the controller mounted on the panel and connect directly to the AGM battery on the tongue of my Aliner camper. I am in the process of designing a 12V 100ah LifePO4 heated Battleborn system for our camper. I will be installing the battery inside the camper and bringing the wires that were at the tongue inside to the battery. Our camper has a Zamp solar port that I have already reversed the wires as the Zamp connector is opposite the Renogy SAE connector. I too would like atleast 30'-40' of extension from the solar port to the Renogy suitcase (plus the 4' inside to the battery). It sounds like I will be much better off removing the Renogy Voyager 20A PWM controller from the panel and mounting inside even though Renogy says that voids the warranty :-(. Then going 10AWG from the panels to the Zamp solar port to the controller inside next to the battery. Is that the consensus here? or will I get away with 10AWG from the panel with controller to the ZAMP port and battery?

Thanks to everyone on this thread

Teton_Pug said:

removing the Renogy Voyager 20A PWM controller from the panel and mounting inside even though Renogy says that voids the warranty

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If I was already in the process of doing that and voiding the warranty, I'd have to look at replacing the pwm controller with something better after it is removed. Are there specifications printed somewhere on the panels? That may be cost prohibitive considering what was already paid for the kit, etc... Although the new SCC could be used in the future for a larger upgraded array if that's something possible in your future.

corporate.joe said:

If I was already in the process of doing that and voiding the warranty, I'd have to look at replacing the pwm controller with something better after it is removed. Are there specifications printed somewhere on the panels? That may be cost prohibitive considering what was already paid for the kit, etc... Although the new SCC could be used in the future for a larger upgraded array if that's something possible in your future.

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Much appreciated. I called Renogy and after the Tech put me on hold, they came back and told me removing the controller from the panels would NOT void the warranty. I moved the Renogy PWM 20A controller into the camper next to the battery and went with 30' of 10AWG extension cables outside to the panels. I did read on Renogy's web site that they recommend mounting the controller on a vertical surface. Unfortunately the only spot I could really mount it and make it easily visible was on the front side of the storage compartment which is at a 21 degree angle. Does that really effect the PWM Solar controller? I will eventually go to a MPPT.