Need advice, upgrading current solar system...

[Bbasso]

Thanks for looking and assisting.

My current setup is:
Two 100w renogy 12v
Two 155ah agm.
And the ecoworthy 20amp SCC.

What I'd like to do in the future is:
One 325w panel, unsure which but the Panasonic VBHN325SA16 fits sizewise.
I'll be keeping the same batteries
But my question is which SCC to use?
I like the features of the Victron SmartSolar with BT but unclear which model fits the panel the best.
Please give me your best advice.
Thank you.

 

[Bbasso]

Almost forgot to mention!
I'll be keeping at least one of the current 100w panel to deploy if needed. So please factor in the definite possibility of up to 550 Watts.
I hope to not need that much... but I'd like to not blow up the new SCC lol

 

[dwh]

I use a Victron 100/30 for my 300w panel.

It can handle panel voltage up tp 100v - good enough for my panel at 40v max and also for that Panasonic at 70v max.

It can flow up to 30a to the battery - good enough for 360w@12v so it would handle the 325w Panasonic.

You won't be able to mix the 100w panel with the 325w on the same charge controller - too great a difference in the panel voltages. So use the Victron for the big panel, and use the Ecoworthy for the little one.

 

[Bbasso]

If you don't mind, could you explain to me how the differences in voltage causes an issue?
Simple terms because I'm simple and not to waste too much of your time.
Thanks!

 

[DaveInDenver]

I think what @dwh means is that if the panel specs vary too much the MPPT algorithm won't be able to find the best operating point, e.g. the Vmp of each panel isn't likely to be similar at all.

 

[dwh]

Yea.

The Panasonic has a Vmp of 58v, the Renogy probably around 18v.

If you parallel them into an MPPT controller, the MPPT circuit is going to "hunt" to find the optimum operating voltage to get the most watts out of the array. It will end up settling on a voltage somewhere between 18v and 58v.

No matter what voltage it settles on, it will be out of optimum Vmp range for one or the other panel...or both. That's if it settles at all - it might just end up swinging wildly back and and forth in a never ending hunt for a proper operating voltage.

A slight mismatch in panel Vmp - like one at 18v and one at 21v - is tolerable; splitting the difference only results in a slight efficiency loss. But a big mismatch in Vmp is a nogo.


That"s if you rig the panels in parallel. You could rig them in series. Both are probably rated to 600v max. In series you would end up with an array Vmp around 76v, which is well within the 100v max of the Victron, and it wouldn't make the MPPT circuit wig out.

But you could only do that if both were permanent mount. If one is portable you'd have to set up the wiring so you could add a panel in series when you want to deploy the portable. That'd be a pain in the butt.

Better to just let the Victron handle the big permanent mount panel and use the extra charge controller for the portable.

 

[Bbasso]

You guys are awesome, thanks!
So the victron 100/30 fits the 325w panel ok, very appreciated.

 

[luthj]

Panels in series must have similar output current. Panels in parallel must have similar output voltage. The controller needs to be rated for the panels max output approximately. Panels will rarely ever output their rated power, so having a controller a bit smaller than the rated output is not a problem. Most controllers are output limited, so a slightly larger panel doesn't pose a safety risk.

For the non-12v nominal panels (like the 300W unit you mention), a MPPT controller is basically required if you want to get anywhere near optimal output. Cheap MPPT controllers are generally not worth their weight. There are plenty of quality MFGs though. The victron controller mentioned is output limited to 30A, which is more than 350W at 12V nominal.

 

[Bbasso]

Thanks!

 

[pdavitt]

The Victron 100/30 should be ok for ONE of the Panasonic panels you noted in your original post. However, if you are thinking about possible future upgrades to your panel capacity, it may not. The two numbers in most charger controller names have the following meaning.
The first, in your case (100) is the maximum input voltage from the solar panels. The second (30) is the max amperage that can be output to a battery. The Victron charge controllers are about 98% efficient, so one panel (325W) at Vmpp output will send 26.54 Amps to the 12V battery (325/12*.98). If you add a second panel in parallel, you will need to have a charge controller that is rated at at least 53 Amps.

Pat

 

[Bbasso]

I've learned about those numbers recently victron uses, thanks for confirming.
With my current Battery bank, and my current power consumption I don't think I'll need to upgrade the storage and any 300w+ panel should be just the trick to keep the bank happiest. So no need to buy a larger SCC then the 100/30.
And as was mentioned if I do want to hook up the other panels, I'll just use the current SCC.

Everyone's advice has been very helpful.

 

[FlipperFla]

Thanks for looking and assisting.

My current setup is:
Two 100w renogy 12v
Two 155ah agm.
And the ecoworthy 20amp SCC.

What I'd like to do in the future is:
One 325w panel, unsure which but the Panasonic VBHN325SA16 fits sizewise.
I'll be keeping the same batteries
But my question is which SCC to use?
I like the features of the Victron SmartSolar with BT but unclear which model fits the panel the best.
Please give me your best advice.
Thank you.

Look on the back of the panels or spec sheet and see what the amp rating is add them together for total amp output your controller will have to be equal to or higher than the total

 

[Bbasso]

Received another 100wt renogy panel Monday, waiting to mount, connect and watch my house batteries smile again.
Currently two 100wts... third soon as the rain stops.
Just FYI.

 

[Bbasso]

Having the third 100 panel up and harvesting for the past few days makes a noticeable difference in my batteries, most notably in the morning. The battery bank doesn't drop as much as before. (Charging better during the day )
I'm happy and I'm sure my batteries are too.
Thanks for the advice and help.

 

[IdaSHO]

How many amps are you looking to harvest per day?

I have 400watts pumping through the 20A Ecoworthy MPPT without trouble.
That's 200watts on the roof, and 200 watts deployed.

Rarely are they all getting sun (as intended) but when they do it will peak at 20A @ ~14v, but it doesn't hurt the controller.
It simply doesn't provide anything beyond 20A