Solar Suitcase Lead Extension?

ScottG

I have a Renogy 100W Solar Suitcase with included controller. I would like to increase my cable length to allow more flexibility in positioning the panel at shady campsites.

To minimize voltage drop, I would like to relocate the controller nearer to the battery, then build a 25’ 10g extension cable to connect the panels to the controller. The simplest solution would be to attach the extension to the existing panel leads with MC4 connectors. However, the existing panel leads are only 14g. While I could upgrade the panel leads themselves, I’d rather not bother--since they are so short, I don’t foresee any problems with leaving them in place and attaching the larger extension cable directly to them.

To those of you with greater knowledge of solar configurations, does this sound reasonable, or am I overlooking something?

Thanks!

Nomad

Curious: What kind of voltage drop would you get and what is the affect - Takes a little longer to charge the batteries?

ericnliz

ScottG, I got my extender cables through Amazon. Description as follows: one pair black & red solar panel extension cable wire MC4 connector 10awg or 12awg. They offer them in various lengths. Let me know if this helps. They also sell the Renogy MC4 assembly tool.

ScottG

PXLated said:

Curious: What kind of voltage drop would you get and what is the affect - Takes a little longer to charge the batteries?

If I understand things correctly (and someone please set me straight if I don't)...

It depends on the length and thickness of the wire. Longer runs and smaller guages have more voltage. If you are trying to keep within the recommended 2-3%, heavier guage wire is called for if you are looking at distances of 20-25'.

Voltage drop is a bigger problem if your controller is not near your battery. the panels alone put out "excess" voltage (up to 18V), so losing a little en route to the controller is probably not a big deal. The controller, however, already limits what it sends to the battery, so you don't want to lose voltage on that leg. Charging a battery effectively is more about the difference in voltage than the time--if you don't have high enough voltage to "drive" the charge back in to the battery, you won't get a complete charge no matter how long you wait.

ScottG

ericnliz said:

ScottG, I got my extender cables through Amazon. Description as follows: one pair black & red solar panel extension cable wire MC4 connector 10awg or 12awg. They offer them in various lengths. Let me know if this helps. They also sell the Renogy MC4 assembly tool.

Thanks, ericnliz. I know you have the same suitcase I do. How long/heavy are your extensions, and are you running them between the controller and battery, or did you relocate your controller closer to the battery?

If you are running the extension between the controller and the battery, what has been your "real world" with charging effectiveness. It would certainly be simpler to leave the controller at the suitcase and just extend the leads to the battery, but I'm concerned about the voltage drop (as detailed in my response to PXL above).

ericnliz

ScottG, I ran mine between the controller and battery [sae 2 pin] connector. My controller is still inside the suitcase. Mine are 15', charges like a champ. The cool thing about the controller is that you can adjust it. If you don't have the user manual, you can download it from the Renogy site.

jkjenn

ScottG said:

I have a Renogy 100W Solar Suitcase with included controller. I would like to increase my cable length to allow more flexibility in positioning the panel at shady campsites.

To minimize voltage drop, I would like to relocate the controller nearer to the battery, then build a 25’ 10g extension cable to connect the panels to the controller. The simplest solution would be to attach the extension to the existing panel leads with MC4 connectors. However, the existing panel leads are only 14g. While I could upgrade the panel leads themselves, I’d rather not bother--since they are so short, I don’t foresee any problems with leaving them in place and attaching the larger extension cable directly to them.

To those of you with greater knowledge of solar configurations, does this sound reasonable, or am I overlooking something?

Thanks!

I think you are on the right track. I found a calculator that can help you determine voltage drop. Everything I have read indicates that it is better to have the controller near the battery, also.

I went with 8# wire. It is a bear to work with and almost wish I had gone with 10# just so it was easier to work with.

ericnliz

jkjenn, Yes, 8# wire is no fun to deal with. On ScottG's set-up, probably 10#, or 12# would be a lot more workable. ScottG, now that I re-read your post again about attaching to the existing cables, that's how I did mine also. I also used some automotive wire wrap to bind the two lengths of extension cable together. Even with the added length, I can still fit it all in the suitcase compartment fine.

Nomad

I have the Zamp with the controller at the panels and have a 25' 10 guage extension and haven't noticed any problems. Controller runs thru all the charge cycles same as it did before. Haven't noticed a difference between when I'm using the extension or not.

ScottG

Thanks for the calculator, Jenn. There's one on the Renogy site but yours is much more versatile. Playing around with it I realize that even with a 20-25' extension between the controller and the battery, the voltage drop is probably negligible under most conditions, supporting PXL and Eric's "real world" observations that their batteries charge just fine. I suspect what you gain by getting the panel into full sun more than compensates for what you lose in the longer run, even if it's downstream from the controller. It still makes sense to relocate the controller if you want to absolutely maximize your output, but there is a certain convenience to keeping the suitcase self contained.

I realize my primary question got a little lost in the wording of my OP. I was mostly concerned about adding a 10g extension while not upgrading the short 14g leads hard wired to the panels themselves. The calculator suggests that the upgrade would save a whopping 0.03V coming off the panels, so I guess I won't bother.  :-)