Adding solar panel

[DipstickDash]

Hey all,

I'm pretty new to the solar scene.

I live in England. I'm repairing & converting what was a rusty old big van into a camper. In the meantime I'm learning as much as I can about solar power and systems. I'm using my shed until the van is ready.

I built a 12v 280AH battery pack using EVE cells from Shenzhen Basen on Alibaba. I'm satisfied with the cells and supplier. I installed a 120A BMS that goes by many names, I ordered from QUCC on AliExpress.

The MPPT I am using is EPEVER Tracer 4210AN, I purchased on Amazon.

I purchased a solar panel from Ebay (340W JA Solar). I checked the panels voltage, then I installed it to the MPPT, then the battery, using 4mm cable (which I think in US is 10 AWG)

It worked okay... I think.

I mean it's winter, the weather here has been abysmal. Wet and overcast for as long as I can remember. When the sun pokes and peaks through the clouds and makes an appearance the current goes up to around 3-4A. Which I think is fairly low for the panel size & Imp of 9.79A. Could it be down to poor positioning / location of the panel? Please advise and let me know if there's anything else that could be lowering current and how I can improve it.

I haven't added any fuses yet, I only had one panel and the Isc was almost half of the maximum fuse rating of 20A however...

I've purchased another solar panel from EBay. I plan to connect the panels in parallel. They're similar specs to each other, not quite the same. I think they're close enough so as not to cause a big issue but I could be wrong. Please correct and advise me if I am.

The new panel is a 335W. The deviation / difference between the panels is: 5W, 0.12Isc, 1.1Voc, 0.72Vmp, 0.06Imp.

My first fear is that by adding the extra panel I'll exceed the rated charge power of my MPPT (which is 520W on a 12v setup) And I could potentially damage my MPPT. After a bit of reading I think maybe it's okay, as long as I don't exceed the max PV Array power which is: 780W.

I'd hugely appreciate any advice in regards to the deviation and difference between panels. Whether my plan to wire them together in parallel would be problematic.

Perhaps more importantly. Whether my MPPT would handle the two panels?

Like I said earlier; I'm yet to add fuses. I think this now has to change. The combined Isc would be slightly above the max fuse rating.

What kind of fuse is best to add? I've seen and read people simply using inline blade fuses, I thought these were used mainly in vehicles. Forgive me if it is nonsense or silly, but would these very small wires increase resistance and decrease the current? And finally where would be the best places to add fuses and a circuit breaker?

I appreciate there is a lot to digest here & I have asked a lot of questions. I'd appreciate insight, and ay advice and suggestions are hugely helpful. If nothing else I have recapped and summarised my progress so far & I have compiled the points I need to research next haha.

Thanks for your time, and sorry for being such a noob (I'm working on it)

Daryl

 

[chrisski]

In my signature block there’s some math about mismatched panels to get accurate results, but looks fine.

I’m guessing your panel output is fine compared to what I see on a rare cloudy day.

I recommend looking in the Epever manual to see if the panel wattage are OK. To some degree they can be overpaneled. The SCC will only pull power it needs.

 

[WYtreasure]

Hey all,

The MPPT I am using is EPEVER Tracer 4210AN, I purchased on Amazon.

I purchased a solar panel from Ebay (340W JA Solar). I checked the panels voltage, then I installed it to the MPPT, then the battery, using 4mm cable (which I think in US is 10 AWG)

It worked okay... I think.

Hey Daryl,
Check your manual, it says hook up the battery first. Is your controller still working?

I mean it's winter, the weather here has been abysmal. Wet and overcast for as long as I can remember. When the sun pokes and peaks through the clouds and makes an appearance the current goes up to around 3-4A. Which I think is fairly low for the panel size & Imp of 9.79A. Could it be down to poor positioning / location of the panel? Please advise and let me know if there's anything else that could be lowering current and how I can improve it.

Point your panel at where the sun should be and check it then. It's March now, maybe you will get direct sun.

I haven't added any fuses yet, I only had one panel and the Isc was almost half of the maximum fuse rating of 20A however...

I've purchased another solar panel from EBay. I plan to connect the panels in parallel. They're similar specs to each other, not quite the same. I think they're close enough so as not to cause a big issue but I could be wrong. Please correct and advise me if I am.

The new panel is a 335W. The deviation / difference between the panels is: 5W, 0.12Isc, 1.1Voc, 0.72Vmp, 0.06Imp.

That deviation may not seem like much to you but may be to the controller. I really do not know.

My first fear is that by adding the extra panel I'll exceed the rated charge power of my MPPT (which is 520W on a 12v setup) And I could potentially damage my MPPT. After a bit of reading I think maybe it's okay, as long as I don't exceed the max PV Array power which is: 780W.

Some overpaneling is usually permissible but NEVER EVER go over on the volts. Volts go up when temps go down.

Hit me up with an update on your progress.

 

[12VoltInstalls]

maybe it's okay, as long as I don't exceed the max PV Array power which is: 780W.

The max voltage is most important

signature block there’s some math about mismatched panels to get accurate results, but looks fine.

I would try the panels in series if max volts from panels is less than 80 by adding the two max volts VOC on the labels. The 40AN can’t exceed 100V and cold temps raise voltage

 

[WYtreasure]

Here's a condensed excerpt from Page 9 of the Manual where "I think" they are saying the controller can be overpaneled by 50%. That's alot.

 

[45North]

I wouldn't get your hopes up. Between your northern location and typical crappy weather you're always gonna be wishing and hoping for more sun.
I wouldn't bet the ranch on solar but realistically it might be more of a fun hobby.
Is your climate improving? I hear more people are growing wine grapes there now. At least you don't have to deal with much snow

 

[WYtreasure]

I wouldn't get your hopes up. Between your northern location and typical crappy weather you're always gonna be wishing and hoping for more sun.
I wouldn't bet the ranch on solar but realistically it might be more of a fun hobby.
Is your climate improving? I hear more people are growing wine grapes there now. At least you don't have to deal with much snow

The OP has been offline for a while now. I think I've hijacked the thread while still discussing the OP's Charge Controller. ?