Zamp panel feeding Goal Zero 400 Lithium

[ATskier]

I have a 90 W panel from Zamp that has specs saying max Open Circuit Voltage 23.8, voltage at max power 18V. This is now tethered directly to a GZ Lithium 400 via the plug in input; I noticed right under the input an ominious warning sign that says "Danger, never exceed 22V"

I had goal zero on the phone talking about connectors, and the guy did not mention any voltage issues with Zamps.

Has anyone ever had a problem with this setup?

Also, FYI I too was skeptical of the GZ products, but picked this 40 ah unit from REI garage for $99 and it has worked flawlessly.

 

[Jman99]

A guess id say it would be fine if the solar controller is PWM, there must be some overhead with voltage, but not much. I would imagine the SC in these would be complete toyz, if it says mppt is gonna be a fake.

 

[ATskier]

I too thought these were toyz, till I got one. Its not for my big camper, but for a little spacekap camperette I'm building out during the stay-home. Things I like about. Excellent metering. Shows in's and out's in multiple units. Time to full charge, time to empty. Also appears to have working temperature monitoring, aka it shut down charging yesterday AM (ambient 22 degrees F), till things warmed up. Also GZ sells a nice little cig lighter charger with an isolater built in, for something like $30; and all this is in a tiny package that is very easy to wire. I would be interested in hearing about any gotchya's with these from people with more experience to avoid them, and hope the solar panel doesn't blow up my new toy.

PS. I run two big lifelines in my big camper with a solid solar controller, fat wiring, but that is for something that needs alot more AH.

 

[john61ct]

It is never a good idea to push the voltage spec limit, if it says 22V max I'd keep it to 21V or below for longevity.

But that means **actual measured** voltage, at say 95% SoC in optimal insolation conditions.

Open Circuit spec - means no load at all - is largely theoretical.

 

[ATskier]

Yikes.
I will measure voltage under load.

 

[ATskier]

Well at non optimal insolation, 90% SoC, I saw 21 volts when first connecting panel and then a progressive drop over a minute or two ending at 12.2 volts. during that time there is a bit of a scary "buzz" out of the unit. I test more under different conditions.

 

[john61ct]

It is normal for crappy SCs - as all "included" ones are - to terminate early

which with LI chemistries is actually A Good Thing

Plus I doubt the "included" SoC meter is more than 10% accurate either.

In short, sounds OK so far

 

[ATskier]

Well I ran the battery down to 50%, attached the panel in the dark, and watched the voltage during a charge cycle with medium solar insolation. During most of the charge cycle, while under load, the voltage at the input to the Goal Zero from the panel was at battery levels, aka 11-12.4 volts. I didn't see it go through the last few percent; the solar controller inside the gz evidently switched the panel off completely, because voltage appeared same as no load, aka 22.1 volts at moderate solar. So I don't know what to think. I guess I need to run the battery down to 95% while solar attached on a clear hot day and see what input voltage is.

 

[john61ct]

Just get a proper solar controller and be done.

Victron 75/15 is probably not much more than 75/10.

Be sure you get SmartSolar, with the "Blue line" you'd need an add-on dongle.

 

[ATskier]

This is for a tiny little setup; If I add controller I am afraid it will "fight" with the built in one.

 

[john61ct]

No it won't. Nice steady regulated input is always preferred over crazy jumping around panel output.

Just the same as plugging in to charge a mains charger, DC-DC or from a well regulated alternator input.

 

[ATskier]

Charge port is tied to built in controller on these units rather than battery. Goal Zero gave me assurances that my Zamp panel with its 23.8v max open voltage and roughly 22 volt measured voltage under load will work just fine direct to the charge port. I will post something if I find any issues. At the moment, I am only dreaming of camping and actually being able to field test it!