Xantrex Sizing Tool

nigtomdaw

Ive never looked at Xantrex Sizing Tool b4 because I was off grid and not grid tied. However Im still looking at the crop of New MPPT units. I already have 10 x 162 watt Sharp Panels and on visiting the sizing tool what a breeze.

It listed my panels, brilliant it listed the new XW60 MPPT charge controller (Note almost same input output spec as MX60) so after selecting my panels selecting the XW60 enter max lowtemp and avg hi temp voilla the calculations are done giving STC and PTC figures. All options of strings and series panels are given

Give it a try I thought it was brillaint:cool:

http://www.xantrex.com/support/xwsizing/Default.aspx

nigtomdaw

Re: Xantrex Sizing Tool

Hasnt anyone given this a test drive tonight ?:-)

niel

Re: Xantrex Sizing Tool

give it time as people will see it and play with it some.

Windsun

Re: Xantrex Sizing Tool

Been linked from here for 2-3 weeks http://store.solar-electric.com/xaxwmp60amps.html

nigtomdaw

Re: Xantrex Sizing Tool

SoZ it was so cool..............Niel,,,,, as I said .... ..................NAWS,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,says,,,,,,,,,,,,,,,, its NEAT !!


Idiots guide for us Numptys...like most of us!

nigtomdaw

Re: Xantrex Sizing Tool

Soz for the none Numptys out there unlike like me

mike95490

Re: Xantrex Sizing Tool

nigtomdaw wrote: »

Hasnt anyone given this a test drive tonight ?:-)

I'm waiting till sunrise, the cheap panels I got only work daytimes, and only a few good hours then.

nigtomdaw

Re: Xantrex Sizing Tool

mike90045 wrote: »

I'm waiting till sunrise, the cheap panels I got only work daytimes, and only a few good hours then.

Got to think on a global scale Mike, remember NAWS is international and the sun is always shining somwhere:p

nigtomdaw

Re: Xantrex Sizing Tool

Humm ? not many X fans

niel

Re: Xantrex Sizing Tool

yes it's nice. since you're just about begging for input on this i think it to be an interesting way to compare pvs and see some of their specs as i see some could change their voltage by temperature more widely than others and i didn't realize the differences are that much. my us64 is -74mv/c while a sharp185 is nearly twice that at -144mv/c. there are some even lower than mine as sunpower's spr95 is at -61mv/c. i didn't explore for the extremes, but there are also some even higher than the sharp too as the sanyo hip190 is -170mv/c. i note that they aren't comparing controllers and it appears they have thought of doing that. if they had it would indicate when exceeding the input of the controller or show limitations some controllers have, but there are many just as there are pvs. also noting their note on the bottom of the page for the 48amp max input due to nec rules.

it should also help those using controllers with max input voltages that are lower than some of the larger and more popular controllers. for instance my sb50 has a max input of 57v and the calculated voltage open circuit for 2 us64s in series at my record low would be 56v and i have heard that some have blown at this low of a voltage. i run parallel for that reason.

BB.

Re: Xantrex Sizing Tool

One thing to remember is that the Vtemp-coeff is actually porportional to cell voltage--and when you stack the cells together, the Vtc is multiplied by the number of cells in series (just like Vmp and Voc)...

So, for two of the panels mentioned, that actual Vtc per volt is:

US-64
Max Power Voltage - Vmp 16.5 Vdc
Open Circuit Voltage - Voc 23.8 Vdc
Voltage Temp Coeff - Vtoc -0.07378 V/°C
STC Rating - Pmp 64 Wstcdc
Max Power Current - Imp 3.88 Adc
PTC Rating 60.6 Wptc
Vtc/Vmp=-0.00447

Sharp NT-185U
Max Power Voltage - Vmp 36.21 Vdc
Open Circuit Voltage - Voc 44.9 Vdc
Voltage Temp Coeff - Vtoc -0.144 V/°C
STC Rating - Pmp 185 Wstcdc
Max Power Current - Imp 5.11 Adc
PTC Rating 163.3 Wptc
Vtc/Vmp=-0.00398

And one would see that based on Vmp, that the US-64 actually has about 10% more voltage change per °C change than the Sharp 185U...

Or, the US-64 will perform better cold and worse hot wrt to the 185U (or if your are watching for Vnever-exceed-cold--the US-64 will actually have a higher rise that then Sharp 185).

In reality, this is 10% difference of an already pretty small number and probably does not make a whole bunch of difference in real life power production. And a couple volts difference on a very cold day on a "high voltage" PV string...

-Bill

niel

Re: Xantrex Sizing Tool

that's true about the cells bill, but as a module i hadn't really thought about it and i find it interesting and somewhat useful in checking what voltage characteristics would be encountered for many differing manufacturers and models of pvs not to mention they may do the calculations for temps with different arrangements of the pvs. not too sure of the sunpower cell characteristics as i'd have to look that one up if i remember to do so. xantrex should add to this little sizing tool to show what works or not for other controllers too as it certainly will not hurt the saleability of the xw imho. then again, i suppose xantrex may not care that much if somebody uses another brand and goofs.;)

crewzer

Re: Xantrex Sizing Tool

Nigel,

I've played around with this tool (and several like it for utility-interactive inverters) and have found it handy.

However, I believe that NEC compliant systems here in the US must use the 690-7 temp comp factors when sizing an array. I've also heard through that the 2008 NEC will allow use of either 690-7 or actual temperature coeffcients. The latter will make the tool really useful.

Don't shoot the messenger!

HTH,
Jim / crewzer

P.S. I found the note re the NEC to be interesting...