Chaining solar panels for goal zero yeti

[jbennettnew]

Hello all,

I am buying the new Goal Zero Yeti 1000 lithium battery pack. I just ordered two 100W Renogy solar panels. I currently have also a Powerfilm 60W foldable panel. I like the connectors that Powerfilm uses which are Delphi Weatherpack connectors. The Renogy panels come with A4 connectors, I'm not sure which company makes these but I plan on changing those connectors to Delphi. No issue there.

Powerfilm makes a daisy chain accessory to link two Powerfilm panels together.

https://www.amazon.com/gp/product/B003VOAZBG/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A1VOUFSIGRIGBC

My question is how are these constructed. I can only imagine they are combining the two positives in male terminal and the two negatives in the female connector.

https://www.waytekwire.com/item/31034/Delphi-12124582-Weather-Pack-Loose-Male-Terminal-/

Waytek Wire has a minimum quantity that you must order so I will have extra delphi terminals and bodies. I would like to make my own daisy chain accessory to combine the three panels together. I dont think you would be able to combine three positives into one terminal so I will have to build two daisy chains I'm thinking and link them all together that way.

Just curious if anyone has any input on how this should be done. I plan on use 2 conductor 18 awg wire, will this be sufficient or should i use 16 awg? Thanks guys.

 

[jbennettnew]

I just re-read this. I realize the positives dont just go in the male bodies and the negative dont just go into the female bodies.

 

[dwh]

260w? I'd use #12 (at least).

Can the Yeti handle that many watts (I know nothing about the unit).

What is the Vmp rating of the different types of solar panels?

 

[jbennettnew]

Powerfilm is 15.4v, Renogy is 18.9v. It will take 240w according to Goal Zero. I dont expect to actually see 260w from the panels at peak output but we will see. I just looked at the specs for the Renogy panels the leads are 12awg. Powerfilm uses 18awg. Here are some links if youre interested.

https://www.renogy.com/renogy-100-watt-12-volt-monocrystalline-solar-panel/#tab_prd-specs

http://www.powerfilmsolar.com/produ...productID=271511&productCategoryIDs=6578,6579

https://www.costco.com/Goal-Zero-Yeti-1000-Lithium-Portable-Power-Station.product.100338966.html

 

[dwh]

I dont expect to actually see 260w from the panels at peak output but we will see.

If you parallel them you certainly won't, since neither will ever operate at their respective Vmp (even if the Yeti has an MPPT charge controller).

 

[jbennettnew]

Ok good to know. The Yeti actually has two different charging ports. One is an 8mm which i already have all the connections needed to attach my Powerfilm panel. The other charging port is anderson plugs. I will plug the new Renogy panels in there.

Oh, and the Yeti has a PWM charge controller.

I am not very knowledgeable when it comes to electrical. Is there a way to chain two panels with different Vmp efficiently? What would happen if you wired them in series? Thanks.

 

[dwh]

Ok good to know. The Yeti actually has two different charging ports. One is an 8mm which i already have all the connections needed to attach my Powerfilm panel. The other charging port is anderson plugs. I will plug the new Renogy panels in there.

Just make sure that the anderson feeds to the charge controller input and not somewhere else - like straight to the battery.

Oh, and the Yeti has a PWM charge controller.

I am not very knowledgeable when it comes to electrical. Is there a way to chain two panels with different Vmp efficiently?

What would happen if you wired them in series? Thanks.

With PWM, the solar operates at battery voltage, so there is always some loss in solar output due to the mismatch between Vmp (optimum solar panel operating voltage) and battery voltage (actual solar panel operating voltage). Rigged in series, the voltage adds, so the Vmp would be something like (15v + 18v + 18v = 51v), so the loss from the mismatch would be even greater.

With PWM and rigged in parallel, each panel will be (independently) operating at battery voltage until the charge controller takes over limiting the voltage to prevent battery overcharging. So none of the panels' voltage will ever be allowed to rise high enough to reach Vmp, though the 15v panel will be operating somewhat closer to its own Vmp and will have a bit less percentage loss than the higher Vmp panels.


In other words, with PWM, rigged in parallel and using all "12v nominal" solar panels; the different Vmps don't matter - none of the panels will ever operate at Vmp anyway.

 

[dwh]

And no, there's no other way to rig different Vmp panels without getting some loss.

Parallel into PWM, the different Vmp doesn't matter, but you still get the normal PWM loss.

Series into PWM will make the array voltage higher and the loss will be greater.


MPPT hunts to find the solar operating voltage that produces the most current (amps). So by mixing Vmps into MPPT (series or parallel) you will cause the hunting to eventually settle on a solar operating voltage that is a sort of average of the different Vmps. But the "averaging" will be heavily biased toward the lower Vmp because as it hunts and raises the operating voltage above the lower panel's Vmp, that lower panel's currrent output drops, so the MPPT will see the dropoff in current and choose a lower operating voltage to get a higher amperage out of the solar. And thus, your higher Vmp panels end up operating at a voltage below thier own Vmp.


IF you had MPPT, I'd probably say dump the 60 and just run the 100s. The 100s operating at their proper Vmp would likely produce more total watts over time than the lashup with the 15v panel tossed in.

But if you had two 15v 60w and one 18v 100w, I'd say run 'em all and just live with the loss from the one panel operating below Vmp - your total watts over time would still be higher than just the two 60s.

 

[jbennettnew]

Understood. Thanks very much for the help!

 

[jbennettnew]

Why do you reckon powerfilm uses 18 awg for all their wiring and connectors? Is it sufficient? Renogy uses #10. What's with the variance?

 

[e60ral]

Just make sure that the anderson feeds to the charge controller input and not somewhere else - like straight to the battery.

It doesn't, anderson plug goes straight to the battery and is made for chaining batteries

 

[jbennettnew]

On the lithium yeti 1000 there is Anderson input for solar.