Logical way to wire 4000 watts

hermit

Setting up a new system, this is what I have to work with 2) XW MPPT 60-150`s 1) XW4024 16) NAPA 6V 220Ah lead acid batteries 20) Canadian Solar CS6P-200`s and all fusing, shunts, gen start, wiring, trimetric etc. Some I purchased years ago and never used. Question is by looking at the chart I made for the set up I have does it make sense to wire my panels as ( 2 panels in series and 5 in parallel to each of the XWMPPT`s? ) and it gets -45c. Thanks.

Please see attachment...

Photowhit

Re: Logical way to wire 4000 watts

hermit wrote: »

Setting up a new system, this is what I have to work with 2) XW MPPT 60-150`s 1) XW4024 16) NAPA 6V 220Ah lead acid batteries 20) Canadian Solar CS6P-200`s and all fusing, shunts, gen start, wiring, trimetric etc. Some I purchased years ago and never used. Question is by looking at the chart I made for the set up I have does it make sense to wire my panels as ( 2 panels in series and 5 in parallel to each of the XWMPPT`s? ) and it gets -45c. Thanks.

MPPT charge controllers work most efficiently at about 2x the system voltage, so doing 5 strings of panels to each charge controller would be most efficient, that said, if you have a long run between the panels and charge controller higher voltages allow for lower line voltage losses over the same gauge wire.

You do have other issues you may not be aware of, 5 strings of 2 - 200 watt panels is 2000 watts, 2000 watts powering a 24 volt system could provide (2000/24=83) 80+ amps, you will be limited by your charge controller to 60 amps. Likely you might see 65-70 amps on typical days but you do have some loss there.

Are your batteries old? How many do you have? even 2 strings of 6 volt batteries in a 24 volt system will only be 440Ah, maximum charge rate of 13 - 15% is only 66 Amps. Typically you don't want more than 2 strings of batteries, half of your array would likely be fine for 2 strings.

zoneblue

Re: Logical way to wire 4000 watts

4kWp, you are into 48V territory. Can you exchange/sell/swap the inverter?

Photowhit wrote: »

MPPT charge controllers work most efficiently at about 2x the system voltage, so doing 5 strings of panels to each charge controller would be most efficient, that said, if you have a long run between the panels and charge controller higher voltages allow for lower line voltage losses over the same gauge wire.

You do have other issues you may not be aware of, 5 strings of 2 - 200 watt panels is 2000 watts, 2000 watts powering a 24 volt system could provide (2000/24=83) 80+ amps, you will be limited by your charge controller to 60 amps. Likely you might see 65-70 amps on typical days but you do have some loss there.

Are your batteries old? How many do you have? even 2 strings of 6 volt batteries in a 24 volt system will only be 440Ah, maximum charge rate of 13 - 15% is only 66 Amps. Typically you don't want more than 2 strings of batteries, half of your array would likely be fine for 2 strings.

hermit

Re: Logical way to wire 4000 watts

Quantity 16 batteries, I wasnt thinking about dc out amps, dropped the ball on that. Looks like another charge controller will be needed. Are there any issues with 3 charge controllers being hooked up in the XW system? Would I be better off with the XW 80-600 over the XW 60-150?

hermit

Re: Logical way to wire 4000 watts

No on the 24 volt to 48 volt step up. Bought all the equipment around 2008, was all new at the time. None of it has been in service as of yet. One of the charge controllers was just purchased last month and the panels last year. The batteries were purchased in 2009, regularly charged and equalized with 2 iota DLS 75`s. Who knows I might put the battery bank in service and find its on the way out. It was equalized 1X per month no trickle charging in between, never recorded voltages less than 6.26. At the time I thought I would be running a lot less panels but as pricing went down I purchased the 4000 watts.

Photowhit

Re: Logical way to wire 4000 watts

Batteries age regardless of use, they are near the end of their life cycle. As I said I wouldn't want to do 4 strings...

3 charge controllers should be fine, might just use the 2 asa said 5 strings of 2 each, you should be close to optimum 13 % charge rate and be a bit 'over paneled for those cloudy days.

Cariboocoot

Re: Logical way to wire 4000 watts

hermit wrote: »

Quantity 16 batteries, I wasnt thinking about dc out amps, dropped the ball on that. Looks like another charge controller will be needed. Are there any issues with 3 charge controllers being hooked up in the XW system? Would I be better off with the XW 80-600 over the XW 60-150?

Price the 600 Volt version and see what you think.
You could buy two Classics for what one of those things cost, and the Classics are better.

Dave Angelini

Re: Logical way to wire 4000 watts

You may be better off with both a -80 and the -60's. Do the math and calculations. If this is in a cooler climate and not subject to inspection you can over panel the controllers and they will current limit the inputs. Use your batteries up and stay away from parallel strings in the future. These controllers work very well together and the dozens of the ones I have used and specified have only one failure from a water heater pouring water on it. It still sort of worked after that. Good Luck!

hermit wrote: »

Quantity 16 batteries, I wasnt thinking about dc out amps, dropped the ball on that. Looks like another charge controller will be needed. Are there any issues with 3 charge controllers being hooked up in the XW system? Would I be better off with the XW 80-600 over the XW 60-150?