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paul-f avatar image
paul-f asked

MPPT 150|70 / Solar Panel Upgrade - Do I Need a New Charge Controller?

controller.jpgcharge-controller.jpgHi all, are you all well? Hope so. I have a well-established solar and battery storage system and am looking to install some additional panels. The ones I already have at peak in summer produce just under 4kW but more generally between 1.5 and 2.5kW.

The charge controller for the PV is as above a MPPT 150/70 (pic included) and the new panels are Sharp ND130UJF (Pmax 130) new-panels.jpgof which there are 10 of them. The existing panels are facing due south and the new ones will be facing more or less due west, which means they will get full exposure between around 1pm to 6pm most days between May and September, so I expect them to have full capacity.

That said, from about 3pm on most peak days, the sun will be moving away from the south-facing ones thus slightly less input.

My question is then; can I use the existing charge controller or will I need an upgrade for what may be an extra 1kW or so?


Are there any other factors I should be considering too please?

I inherited this system when I bought the place so I am on a very steep learning curve still so easy to understand answers appreciated! :-)

Amy help and advice greatly appreciated.

Thank you. Paul

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3 Answers
JohnC avatar image
JohnC answered ·

Hi @Paul F

If you can get ~4000W through a /70 mppt then you have 48V batteries and it's maxed out. Probably on the panel Amps side too, as you must have numerous series strings. Given the different panel orientation and likely different string Voc, I'd go for an additional one. (Not an upgrade).

Those 'new' panels look pretty old too, but that's fine. They're '12V' panels, and for 10x of them into 48V you'll need to string them 5S2P (2 series strings of 5). That takes your panel Voc into the 150/ range too, and the smallest one of those is a 150/35 model. That's good for like 2000W, so plenty up the sleeve. You could have a play with this.. https://mppt.victronenergy.com

I suspect you may also benefit from a firmware upgrade on all your Victron kit. Features keep getting added, and while you're experimenting on your learning curve, fw hindrances will only hold you back.



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paul-f avatar image
paul-f answered ·

Hi @JohnC

Thank you very much for taking the time to give me this info. As I say, on a steep learning curve here and I think you have just confirmed that! :-)

And yes, with the panels I should have said "additional" and not new. They are from an ex-military place and I got them for next to nothing in return for a good deed. I tested them all before I took them and all seemed to be producing good output.

As for the firmware updates - I have recently updated the firmware on the CCGX as it was way out of date because it had stopped doing auto-updates. Presumably then there are updates for things like the inverter and the MPPT and it is as simple as doing it through this page I have literally just found!
DO you know of any risks or known issues with updates?firmware-update-page.png

In terms of the MPPT then - so no qualms in having the 150|70 and a 150|30 running alongside each other? The batteries are set to run at 48v as you correctly stated.

Thanks for the advice on the wiring and configuration for the panels too. I am enlisting the help of a company who install them, but generally they do them as an entire package from scratch. When he came to scope out what needed to doing his reaction led me to think I should do some research of my own. I am not inept when it comes to tech so I feel it is a good thing to try and get a much better understanding of the setup myself. I have the opportunity to be able to install a small hydro source too sometime in the near future, so all this stuff is very useful.

Again, thank you very much for taking the time to point me in the right direction.

Paul


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astrayan avatar image astrayan commented ·

What JohnC says is pretty accurate. However, I would not bother with second hand panels. It's to do with the effort of mounting small old panels with low output. When you put them in strings of 5, it wont be long until one of them suffers a solder failure and the string starts getting wonky. 10 x 130W old panels produces about 1000w, which is the same as 3 new panels.

If you were on a desert island with no laws, you could mount the new-old panels on the west, and connect them into the others, and it would work, if you matched the voltage roughly. But the law generally requires fuses on each string, so the other panels can't short into a defective string.

Yes, a bunch of MPPTs will work together. Technically you have to use different wires, and not join the negatives all the way to the battery.

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JohnC avatar image
JohnC answered ·

@Paul F

There shouldn't be any issues updating fw via VRM. The CCGX and Quattro are current already. The 1342 message is because you have an old CCGX which can't do the Quattro via VRM, so you'll have to live with that.

The two mppts should be fine together, although that 150/70 is 'end of life', but still supported. You might find it useful to invoke DVCC to tidy up common readings (if it's not already), see the CCGX manual.

That's actually quite a serious system you have there, and fooling with it you might find addictive. Masses of info on the Victron website, but you're 'in the family' now and most welcome to ask here if you get stumped on something tricky. Enjoy the trip up the learning curve..


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MPPT 150/60 up to 250/70 Manual

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