Solar house generator I started DIY back in 2000 - My path from Trace to Xantrex (on FLA battery) to XW Pro inverters on Tesla Model S batteries

[dougbert]

Alright. I am fidgeting waiting for the XW Pro to get here, so.....

some minor updates to the AC side schematic diagram


Forward reference to the schematic in Post #1

Something I built DIY back in 2000 - my path from Trace to Xantrex to XW Pro inverters

2023-09-21 Version Update When I started this thread back in 2019, I did not realize it would turn into a build thread of my system. It documents What and Why I did things as well has How they were accomplished. It also shows designs that didn't work out, and also designs that did work out...

diysolarforum.com

One major addition is a 2nd range/oven recepticle from the main CLP to the wall behind the oven in the kitchen (directly above this area). This is inflight at the moment while waiting for parts, This will provide 2 seperate 4 plug outlets - one from the grid and one from the CLP

When I started to add this 2nd outlet, I discovered the range has a 3 plug cord. In 1996 the NEC started requiring 4 plug cording for ranges in new construction. As this house was being remodeled back in 1995 time frame, the 3 plug recepticle was installedl. How a 3 plug works is, it provides the two legs, L1 and L2 and a Neutral - but a jumper between the Neutral and the chassis ground of the oven. EGADS! As this unit did NOT have that jumper installed

So I quickly ordered a new 4 plug cord, box and will adjust the existing grid recepticle. Got a 10 ft section of 6/3 romex for $55 off off ebay and adding that now

 

[dougbert]

Inverter arrived early and safely

 

[dougbert]

Got the inverter lifted and tied down



other side view



wired up, tested, buttoned up and now inverter - I am BACK OFF of the grid






I admit I got one thing wrong, I plugged the cat 5 cable for the XW Pro's Xanbus into the Sync port. After verifying the entire run, I found that error, moved the cable to its proper place and then was able to see all the devices on the bus with InsightHome (Gateway box)

Now trying to get the Pro Charger to NOT charge the battery every time I turn on the grid input to it. I want the Pro charger to be inert unless I manually tell it to go.

I only want the grid to run AC bypass when the battery reaches LBCO of 38.4 volts. Then run the loads until 44.4 volt, and switch back to battery invertering. The MPPT 60 CCs will charge the battery. The grid is a backup resource for my design

 

[dougbert]

The XW Pro was built in May 2021 with the firmware of 1.11.01bn49

it has been in a warehouse for 18 months


Battery Type: Custom
Bult Termination Voltage: 49.2
Bulk/Boost Voltage Set Point: 49.4
Absorption Voltage Set Point: 49.4
LBCO: 38.4
HBCO: 58 (lowest the unit will go - the JITB will disconnect long before this reached)
Battery Bank Capacity: 1405 amp-hr
Max Charge Rate: 25%
Charge Cycle: 2 Stage

at the moment I have the charger disabled

 

[jensenq]

Got the inverter lifted and tied down

View attachment 121581

other side view

View attachment 121582

wired up, tested, buttoned up and now inverter - I am BACK OFF of the grid


View attachment 121583



I admit I got one thing wrong, I plugged the cat 5 cable for the XW Pro's Xanbus into the Sync port. After verifying the entire run, I found that error, moved the cable to its proper place and then was able to see all the devices on the bus with InsightHome (Gateway box)

Now trying to get the Pro Charger to NOT charge the battery every time I turn on the grid input to it. I want the Pro charger to be inert unless I manually tell it to go.

I only want the grid to run AC bypass when the battery reaches LBCO of 38.4 volts. Then run the loads until 44.4 volt, and switch back to battery invertering. The MPPT 60 CCs will charge the battery. The grid is a backup resource for my design

Wow! look at the capacitor bank in that beast!

You always do quality work, dougbert! Congrats on the new system. That inverter is a beautiful thing - I love how your other Schneider gear fits so well. I'm jealous!

 

[dougbert]

thanks @jensenq

been gone for 2 days for thanksgiving holiday. Got back and am experimenting with the interverter and charger to learn its operational behaviours

house has been in a minimal power draw configuration while we were gone

due to cloudy day today and yesterday, battery was at 45.6 volts when we got home after dark, after generating 10.8kwh
past 2 days, the system generated 20-24kwh

SO I wanted to understand the charger behaviour. I turned on GRID AC IN to the inverter.

I have found that when the inverter Quantifies an AC in, does the following, everytime AC power is applied:

It switched to the GRID, and began running the loads in bypass and after a pause it started the charger for the battery.

I found the meaning of the "A display status LED" in that it displays the number of DC amps being pushed to the battery.

The XW Pro has a charger limit of 140 amps DC in 240v configuration.
Under InsightLocal for the Setup of the XC maximum charge rate for the XW Pro device, there is a tunable "Maximum Charge Rate" in percent of the 140 amp capacity.

I played with this until I got maximum displayed of 108 amps, while I configured it for 78%. Making the percentage more, upto 100% it would not push any more amps. 78% of 140 amps is 108 amps. I do not know why it won't go more.

108amp at 48.0 volts is pushing 5.1kw into the battery. Utility draw is at 7.3kwh with the house draing 1.5kw. 1.5kw + 5.1kw is 6.6kw. Interesting numbers.

WIth solar generation my battery has accepted 180 amps at peak times in charging it, with good sun. Normal solar production is 5 to 6kw of solar incoming

At 108 amps the bus bars are at 95F, the 2/0 cable is is 90F, while the 4/0 cable is 85F
Battery itself is at 23C and is sitting happy

Normal utility draw maximum is 48 amp @ 240v = 11520 watts, so at the moment the inverter is passing 7.5kwh well below 11.52kw

Waiting to watch the bulk and absorption terminate at 49.4v

NOTE the old Xantrex 5.5kw inverter @ 120v would max charge at 2.5kw. I am now getting double that with the 240v

 

[dougbert]

It has been a week since the XW Pro was installed and it is running great

I have finished the installed of a 6 awg romex between the wall behind the range/oven and the critical loads panel (CLP).

Before that I swapped out the old GRID 3 prong 240v outlet and the range cord. Installed a 4 prong outlet for the GRID wire, also was 6 awg. Then swapped the range cord.
Finally added the new outlet to the CLP

40 amp breaker for both grid 14-50r and solar 14-50r

Here is the range, doing well after some 15 years



here is the wall behind the range, grid on the right, CLP outlet on the left. Yes there is a gas line there, but my wife is deathly afraid of gas due to getting blown up a couple of times as a child with bad ovens.

And still have to fix up the dry wall and the left face plate is arriving tomorrow



here is the WATTAGE meter from the DC shunt

this indicates the house is drawing 1.53 kw right now, normal range of usage for this time of night



so I turned on the oven, and this is what power draw occurred



that is 5.45 kw draw, so the oven draws 4kw. the period flashes, the pic missed an instance

turned on the large range top burner



and here is the draw



8.13 kw

 

[dougbert]

turned on an additional back burner for 2 burners running, and hit 10.6 kw





finally turned on a 3rd range top burner, and hit 12.2 kw.



The XW Pro can support the 12kw for 1 min
not bad, as it a 6.8kw continuous

I did not turn on the 4th range top

seems a 2nd XW Pro might be in the future - lol

 

[jensenq]

turned on an additional back burner for 2 burners running, and hit 10.6 kw


View attachment 122496


finally turned on a 3rd range top burner, and hit 12.2 kw.

View attachment 122495

I did not turn on the 4th range top

seems a 2nd XW Pro might be in the future - lol

This sequence of increasing the load power - well beyond the 6.8kW rating of your XW Pro - felt like the opening scene of Top Gun Maverick! Did you eject in time?? ;-)

 

[dougbert]

Well, the XW Pro does not do what my old Xantrex SW+ did, which is "Battery Transfer Mode". Rather the XW Pro does UPS Mode. Turning on GRID IN causes the Grid to power loads AND recharge the battery if the Charger is enabled. Once battery is charged, inverter turns off and stays in Bypass mode.

And I view the Grid as my Backup generator, until I get more panels installed....someday

I cannot find a mode where inverting is the primary mode, with Grid set as a backup option.

So.....

Following @pvdude 's link in https://diysolarforum.com/threads/adding-schneider-xw-pro.19090/post-238346 got me researching these crydom SSRs. I found a pair on ebay for $127, NOS I believe, and have ordered a heatsink ($101) that will fit 2 SSRs.




I will place these on my GRID IN 6awg incoming pair and control them with the XW Pro's Aux relay. Trigger on low battery. This will cause GRID IN to energize and recharge the battery and power loads automatically. Then at a set voltage, it will CLEAR the relays and go back to "Battery Inverter".

Instructions say use 2 8awg for the AC side. I found some 6awg copper lugs with a #10 ring hole that I will use.
The stud stands need some buffing, and I will get some better #10 machine screws, washers and lock nuts. Probably stainless

Need to find a box to mount above the raceway to put them in and other misc parts for this option.
Looking to set the Low Battery trigger at 40.5 volts, with Low Battery Cut Out at 38.4v. 40.0v is the lowest Low Battery the InsightHome will allow me to set.

 

[400bird]

I don't think my XW does that. But my battery voltage is always above the recharge voltage.

 

[dougbert]

I don't think my XW does that. But my battery voltage is always above the recharge voltage.

I am going to have to determine if the recharge voltage should be the same as the Low Battery voltage trigger or not.

I am solely DC charging and in the past week or so I have had to manually turn on GRID IN to get the battery up from 41 volts - lots of clouds and snow the past week.

With the Xantrex, the battery would reach the Low Battery Cut Off, turn off the inverter and goto Bypass automatically. Then wait for the DC CCs to recharge the battery at the trigger CLEAR voltage of 45v before switching back to invertering. That would happen by noon on a sunny day.

 

[JoeHam]

My Conext SW4048 behaves in a similar manner. I have to turn off the grid AC in to get it to use battery power. I can leave grid AC off most of the time but it’s embarrassing when I don’t notice the battery getting low and the critical loads panel shuts down. My wife is NEVER amused by this. I then have to scurry down to the basement and flip the 240V AC in breaker back on so the 4048 can charge up the battery and supply the critical loads panel.

I’ll be following along with your solution @dougbert but I really wish the 4048 could handle this.

 

[dougbert]

My Conext SW4048 behaves in a similar manner. I have to turn off the grid AC in to get it to use battery power. I can leave grid AC off most of the time but it’s embarrassing when I don’t notice the battery getting low and the critical loads panel shuts down. My wife is NEVER amused by this. I then have to scurry down to the basement and flip the 240V AC in breaker back on so the 4048 can charge up the battery and supply the critical loads panel.

I’ll be following along with your solution @dougbert but I really wish the 4048 could handle this.

what charge controller are you using? The Conext MPPTs have an AUX relay as well

 

[JoeHam]

what charge controller are you using? The Conext MPPTs have an AUX relay as well

I have a couple of Victron MPPT’s.

I’ve been unable to set the SW4048 to prioritize battery power until it’s all used up and then fall back to the grid. I think it should be capable of this.

Schneider tech support was awful a couple of years ago, maybe I need to revisit.

At any rate, I don’t want to muddle up your thread and look forward to seeing your progress in this part also.

 

[400bird]

I am going to have to determine if the recharge voltage should be the same as the Low Battery voltage trigger or not.

I am solely DC charging and in the past week or so I have had to manually turn on GRID IN to get the battery up from 41 volts - lots of clouds and snow the past week.

With the Xantrex, the battery would reach the Low Battery Cut Off, turn off the inverter and goto Bypass automatically. Then wait for the DC CCs to recharge the battery at the trigger CLEAR voltage of 45v before switching back to invertering. That would happen by noon on a sunny day.

I'm not sure how the XW behaves at the low voltage disconnect. But if you aren't using the XW for charging, the simplest version would be to turn off the charger. I know you said you use it occasionally, you could just turn it on as needed.

 

[dougbert]

I'm not sure how the XW behaves at the low voltage disconnect. But if you aren't using the XW for charging, the simplest version would be to turn off the charger. I know you said you use it occasionally, you could just turn it on as needed.

yet, that requires constant polling of the voltage to see how low it is, then manually turning it on. Not an acceptable option. I need/want automatic recharge, similar to inverters Trace and Xantrex had. I guess I want to use the Grid as a Generator, which comes on automatically when battery is low

 

[dougbert]

Making progress on the SSRs located on the GRID IN feedline

Installing holding box directly on the raceway, utilizing the old inverter's grid IN/OUT holes already drlled there. Nice re-use
This box sits below the bottom level where a 2nd Inverter would be placed, thus fitting into unused space, again Nice

Box has an insert plate that is removable. I have installed the heat sink and place the 2 75 amp SSRs on to it.
Fan will be mounted on the top of the box, blowing upward, drawing air from raceway via the entrance conduits
control line enters top left of the box, behind the door hinge
L1 and L2 enter from the bottom
12vdc line enters lower right
have finger protector covers for the SSRs

waiting for copper lugs with a #10 ring hole - the one seen in pic is a 1/4" ring hole for 6 awg wire
waiting for the 12vdc relay as welll




Parts:

Box https://amazon.com/dp/B08S6MGHXP?psc=1&ref=ppx_yo2ov_dt_b_product_details
heat sink https://www.mouser.com/ProductDetail/558-HS103
SSRs off of ebay, Crydom D2475-10 2 for $128
finger protectors that fit on SSRs https://www.zoro.com/crydom-fingerproof-relay-cover-ks100/i/G0910147/?q=G0910147
12v relay https://amazon.com/gp/product/B07T35K8S2/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
6 awg Butt Splice connectors https://amazon.com/gp/product/B07T35K8S2/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1
fan cover https://amazon.com/dp/B00315RFTK?psc=1&ref=ppx_yo2ov_dt_b_product_details
6 ga #10 Stud copper lugs https://amazon.com/dp/B00O7S7HVQ?psc=1&ref=ppx_yo2ov_dt_b_product_details

conduit, bone pile
80mm computer case fan, bone pile

 

[dougbert]

Received the 6awg #10 ring lugs, awaiting the 6awg butt splicers (since I need to lengthen the lines)

This feature will provide me with the Battery Transfer mode of operation, wherein Grid IN is available but will be enabled by the SSRs only in one of two cases:

1) Battery reaches a settable low voltage/SoC level - this will be done automatically and continually - and will go into Grid ByPass and charge the battery to a settable voltage/SoC level. I don't charge the battery until full via the grid. I allow the solar CCs to do that. Rather, this charging brings the battery up sufficiently to last 12 hours or so. Long enough for the sun to come up and charge the battery that way. If things are still cloudy, then this process will repeat until we get enough sun. Grid is my BACKUP, like a generator.

2) Manual enable of the Aux relay through the InsightHome web interface

 

[400bird]

But why?
I don't see the goal/purpose.

When the battery runs low, why not just let the grid power your loads and let the battery sit low overnight?

I leave my system connected to the grid all the time. Solar supports loads and charges the battery most of the time. I have set the "grid support voltage" to about 60% SOC, meaning if the power goes out I'll always have at least 60% of my battery capacity to make it through even the hottest nights.
Once the battery discharges to 60% it just sits there. I might buy 2 or 20 kWh, but I'll only buy the power I actually used. PV can recharge tomorrow, or not if the weather doesn't cooperate.

Seems like with your plan, any time you run the battery down, you'll be buying XX kWh, even if you only needed 100Wh to make it through the night. You might even buy enough that you have excess solar the next day, past what the battery can hold.