Matching different sized panels

tonyat59

Hi,
I want to upgrade my 48v system by replacing my old PMW Charge Controller with a Xantrex 60A 150V MPPT Charge Controller.
Currently my panels are wired in strings of 4 [48v] but my problem is that I’m not sure of the best way to include the 4 Helios Panels with the MPPT controller. The details off the back of my panels are shown below.
Any suggestions would be much appreciated.

12x Isofoton I165, 165w, 12v [Monocrystalline]
Max Power: 165W ± 10%
Short Circuit Current: 10.14A
Open Circuit Voltage: 21.6V
Max Power Current: 9.48A
Max Power Voltage: 17.4v
Max System Voltage: 760V

4x Helios H1540, 165W, 12V [Monocrystalline]
Peak Power: 150WP
Short Circuit Current: 9.9 A
Open Circuit Voltage: 23V
Max Power Current: 8.42A
Max Power Voltage: 17.8V
Typical current at battery operating voltage [12-13v]: 8.8A

westbranch

Re: Matching different sized panels

Do you plan on adding more in the future? otherwise just shift PWM to 4 panels and MPPT onto 12 panels.
Have you looked at the Classic CC's?

tonyat59

Re: Matching different sized panels

Yes, the intention in the near future is to add another MPPT controller and another 2kw or so of panels. Is it OK then to have MPPT's and a PWM controller working together?
One of the reasons for going for the xantrex is I can get a good deal on them.

Thank Tony

westbranch

Re: Matching different sized panels

Yes they will work in parallel, but you might want to lower the charge settings on the PWM relative to the MPPT , so that they don't fight each other in absorb or float. Let the MPPT be in charge so to speak.

Cariboocoot

Re: Matching different sized panels

tonyat59 wrote: »

12x Isofoton I165, 165w, 12v [Monocrystalline]
Max Power: 165W ± 10%
Short Circuit Current: 10.14A
Open Circuit Voltage: 21.6V
Max Power Current: 9.48A
Max Power Voltage: 17.4v
Max System Voltage: 760V

4x Helios H1540, 165W, 12V [Monocrystalline]
Peak Power: 150WP
Short Circuit Current: 9.9 A
Open Circuit Voltage: 23V
Max Power Current: 8.42A
Max Power Voltage: 17.8V
Typical current at battery operating voltage [12-13v]: 8.8A

The Vmp's of these two panel types are are close enough that they can be used together. You would have strings of four in series for Vmp 69.6 and 71.2 respectively. Three strings of the Isofoton would supply 1980 Watts and one string of the Helios 660 Watts for 2640 Watts all together. On the XW 60 that should supply about 42 Amps peak, well within limits. Voc of the highest Voltage string would be 92 and would be below the maximum input Voltage even in the coldest temperatures (possibly 120 Volts).

tonyat59

Re: Matching different sized panels

Thanks for the replies.
My PWM CC has no adjustable settings so I can't lower the charge settings on it. I like the suggestion to make 4 strings of 4 and its reassuring to know that will work OK. Also I prefer it going thro one CC so that all the data is logged.

Also suggested was the Classic CC is this better than the Xantrex XW60?
One thing I liked about the XW60 & the Auto Generator Start was is ability to control many different types of generator, especially the quiet time feature. Can the Classic do that?

Thanks again
Tony

Cariboocoot

Re: Matching different sized panels

The Classic is better than the XW controller in that it has more features and functions. As such it costs more.

Charge controllers do not have automatic gen start: inverter-chargers do. There is no point in putting such a function in a charge controller because it needs something for the generator to power; i.e. a battery charger. I think you have the XW controller confused with the XW inverter.

Although technically the Classic's programmable AUX port could be used to start a gen connected to a stand-alone battery charger. The XW controller does not have an AUX port as far as I know.

tonyat59

Re: Matching different sized panels

Thanks for the info.
Xantrex do a separate box which links to the XW60 called the "XW AUTO GENERATOR START" this controls the genny with data from the CC...as I understand it!

Tony

Cariboocoot

Re: Matching different sized panels

tonyat59 wrote: »

Thanks for the info.
Xantrex do a separate box which links to the XW60 called the "XW AUTO GENERATOR START" this controls the genny with data from the CC...as I understand it!

Tony

But again useless without a battery charger. When you're into that size system you would probably buy an inverter-charger with auto gen start ability.

And I'll state again I'm not a big fan of such automated technology. Just more things to go wrong. Sometimes, however, you have no choice.