Solar power help please

[Irish Rover]

I posted a thread last year about installing a generator and the consensus seemed to be to upgrade my solar instead. I currently have 2 x Shell solar panels rated 85W each which I reckon are over 15 years old. Each panel is connected to a separate Steca Solarix Gamma 12V 12 Amp charge controller. There is a separate Centaur 12V 30 Amp charger for the shore power. I also have a separate Victron phoenix inverter 12V 750va.
I'm planning to buy 2 x Sunpower Maxeon 400W panels which appear to be the best available here in Turkey. My question - is will the existing Steca charge controllers be suitable for use with the new panels and, if not, what do I need? Although I'm pretty much a tech numpty I know there are very modern integrated shore/ solar panel charge controllers/inverters on the market but I'd like to keep the cost as low as possible without unduly compromising the end result. By the way I'm not planning to attempt the installation myself.

 

[V1701]

Lots of options but I think in your position I'd have the two new panels wired together in parallel, routed through a single new controller (you'll need a new controller anyway, the old ones are not going to be sufficient to cope with the output of even one of the new panels). Whether you have separate engine starting and domestic battery banks may influence how you configure the system but you can keep it simple and have the solar output just going to the domestic bank. So you can get away with as little as a new controller that will cope with the output of 800w of solar...

I would keep the shore power separate...

Edit - 800w is a good amount of solar (and 5x what you had before), assume you'll be increasing battery bank accordingly?

 

[Norman_E]

Your charge controllers will be far too small. 400 watts at 12 volts equals over 33 amps, so you will need much bigger controllers. If keeping the panels separate then two 40 amp controllers IMHO.

EDIT: You also need to consider the voltage output of the panels. You need to make sure that the panels you are considering are designed for use with a battery charge controller as domestic type 400 watt panels tend to be rated at quite high voltages, like 70 volts in some cases, which is too high for most charge controllers though fine for a grid tied inverter, which is what they are designed for.

 

[PaulRainbow]

Panel specs are:

Nominal Power (Pnom) 400 W
Rated Voltage (Vmpp) 65.8 V
Rated Current (Impp) 6.08
Open-Circuit Voltage (Voc)(+/–3%) 75.6 V
Short-Circuit Current (Isc) (+/–3%) 6.58 A

Current controllers are unsuitable. Victron 100/30 controllers would be a good choice, one per panel.

https://www.victronenergy.com/uploa...charge-controller-MPPT-100-30-&-100-50-EN.pdf

Victron Energy SmartSolar MPPT 100V 30A - SCC110030210

 

[vas]

I'm planning to buy 2 x Sunpower Maxeon 400W panels which appear to be the best available here in Turkey. My question - is will the existing Steca charge controllers be suitable for use with the new panels and, if not, what do I need?

blimey, they are expensive!
for the cost of one of them you could have 2 360W panels (at least next door here in Greece)
rest I agree with PR of course
If your batteries are decent (in size/condition) you wont need the shore power anymore. I have 600W and I don't during the summer with two 80lt fridges and all the rest (gas cooking!)

V.

 

[Irish Rover]

Thanks for all the advice so far. These are the same brand as the existing controllers and reasonably priced compared to the Victron. Would they be OK Steca Solarix 4040 Solar Charge Controller 12/24 V DC 40 A LCD Display IP32 5 V USB 1.5 A https://www.amazon.de/dp/B01306WBAW/ref=cm_sw_r_apan_glt_i_KBAJPMAHMMF9XE4MMZHG

 

[vas]

Thanks for all the advice so far. These are the same brand as the existing controllers and reasonably priced compared to the Victron. Would they be OK Steca Solarix 4040 Solar Charge Controller 12/24 V DC 40 A LCD Display IP32 5 V USB 1.5 A Steca Solarladeregler Solarix 4040 12/24VDC 40A LCD Display IP32 5V USB 1,5A : Amazon.de: Gewerbe, Industrie & Wissenschaft

I'd never even consider a PWM for that much solar (imho)
go for Victron bit more, but much safer/better.
and remind us what batteries you have now on service plz, you are 12V iirc?

 

[PaulRainbow]

Thanks for all the advice so far. These are the same brand as the existing controllers and reasonably priced compared to the Victron. Would they be OK Steca Solarix 4040 Solar Charge Controller 12/24 V DC 40 A LCD Display IP32 5 V USB 1.5 A https://www.amazon.de/dp/B01306WBAW/ref=cm_sw_r_apan_glt_i_KBAJPMAHMMF9XE4MMZHG

They will work out pretty expensive when you connect them to your panels and they burn out. The panel voltage far exceeds the maximum that the controllers can handle. I'd still go for the Victrons.

 

[William_H]

I am getting my education here as I had no idea 400w panels were available for domestic roof top PV systems. I thought the limit was around 250w per panel. Perhaps the technology has improved vastly. The physical size limit being that which a man can handle on a roof. Possibly the 65v output is a clue to higher power. In any case as said for a 12v battery you must have an MPPT controller capable of delivering the max current about 20 amps per panel. (and of course capable of handling the 65 volts. )
As said the Victron is recommended. The link does not work for me but from what I can see Steca do PWM regulators. This means it can only reduce the power to the batteries. Yes they can switch 12v to 24v mode but best if you have a 20v panel for 12v or 40v panel for 24v. 65v at 6 amps either connected directly to the battery or via a PWM regulator would still only give 6amps at 14v. the remaining 50v would be dissipated in the panel itself (wasted) and as said more likely teach your regulator how to smoke!
Victron are not the only makers of MPPT regulators but there are so many claiming to be MPPT which are not. The max voltage in spec can be indicative of true MPPT. MPPT is like a transformer which converts what comes in to exactly the voltage required for battery charging. This transformation enables an output in current increased by the proportion of voltage drop. So 60 v in converting to 15v at battery gives 4 times the current out to that which goes in. (less losses say 95% efficiency) It can actually track (change by adjusting load) the voltage input to most efficiency for the panel as well.)
ol'will

 

[vas]

W,
300-320W was tops (at reasonable price of say 200euro a piece) back in 2017 when I fitted two on my boat.
Now indeed you get 400W + but getting over 48-50V open circuit is a bit of an issue and definitely limits the options you have on controllers.
all of them are in the 1X2m so 2sqm size bracket and 20kg so theoretically easy to handle, in practice not so due to size.

 

[Irish Rover]

Thanks again for all the help especially @vas and @PaulRainbow . Much appreciated. Victron it is then. I did admit I was somewhat of a tech numpty ?.

 

[Irish Rover]

W,
300-320W was tops (at reasonable price of say 200euro a piece) back in 2017 when I fitted two on my boat.
Now indeed you get 400W + but getting over 48-50V open circuit is a bit of an issue and definitely limits the options you have on controllers.
all of them are in the 1X2m so 2sqm size bracket and 20kg so theoretically easy to handle, in practice not so due to size.

The panels I'm planning to order are Maxeon 3 and they're 1069mm x 1046mm and weigh 19Kg each. Last price I got here in Turkey was $635 including VAT. Expensive but I want a good recognized brand.

 

[vas]

I do remember you are not an expert electronics diyer. Doesn't mean you have to waste your hard earned cash, does it?

1X1m and 400W? are you sure the sizes quoted are right? very much doubt it! 1X2 more like it.
not quite sure why you need a good recognised brand for something relatively simple and build in PRC anyway. Especially for hard rigid panels and NOT semi flex ones where brand indeed makes a difference.

I recon it's more important to spend money on the MPPT which is going to convert what the panel "collects" into usable energy.
still haven't remind us your batteries though or to put it another way:
#1 batteries
#2 MPPT
#3 panels
(that's of course imho)
where we both are there's plenty of sun, making sure you can harvest and store it is most important.
if panels are next to each other, you could only get ONE MPPT Victron charger for your panels, dunno 30/100 or something

 

[Irish Rover]

I do remember you are not an expert electronics diyer. Doesn't mean you have to waste your hard earned cash, does it?

1X1m and 400W? are you sure the sizes quoted are right? very much doubt it! 1X2 more like it.
not quite sure why you need a good recognised brand for something relatively simple and build in PRC anyway. Especially for hard rigid panels and NOT semi flex ones where brand indeed makes a difference.

I recon it's more important to spend money on the MPPT which is going to convert what the panel "collects" into usable energy.
still haven't remind us your batteries though or to put it another way:
#1 batteries
#2 MPPT
#3 panels
(that's of course imho)
where we both are there's plenty of sun, making sure you can harvest and store it is most important.
if panels are next to each other, you could only get ONE MPPT Victron charger for your panels, dunno 30/100 or something

That was a typo on my behalf. The panels are 1690 x 1046.
The reason I'm going for a recognised brand is because there are so many chancers here selling shit and when the wrong thing arrives or the bloody thing doesn't work you're on your own. I think the first thing they learn in business school is how to shrug their shoulders. I got in touch with Sunpower directly and they referred me to their distributor in Turkey and I'm buying direct from them. I know they're expensive but I'd rather pay over the odds now than end up with some rubbish that doesn't work or gives trouble.
I have 2 battery banks with 3 house batteries in each total 540AH and a 95 AH starter battery in each. The two banks are connected in parallel. I could be wrong, but as far as I recall what I was told one of the existing panels charges one bank and the second charges the other bank plus the 2 starters. I guess I'll stick with that arrangement for the new panels unless the installer advises otherwise.
Thanks for your patience.