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OffGridInTheCity Build

2nd AIMS, 5th Battery, 400a ABB shunt-trip, and Batrium tidy-up in place.  After 2 and 1/2 years its coming together!  This take the system up to
- 45 x 285w panes for a 12.8kw array.
- 5 x 260ah batteries (70 packs) for a 1300ah@48v Batrium monitored battery bank.
- 2 x AIMS 12K for a total of 24,000w (100a@240v) AC output. 

For orientation, here's a long view and a cross view of the solar control room...


The new heat pump is scheduled for next week.  Meanwhile, I just couldn't wait to try out the new AIMS.    Its just getting warm enough to run the 23yr old AC for a couple of hours in the afternoon - so I turned AIMS #2 on and wa-la, it seemed to work find for the last week until yesterday. 

Now remember, this 4 ton AC Compressor is 23yrs old and it blows motor capacitors every year - I learned how to replace them 7 yrs ago and have put in 5 new 'starter motor' capacitors in last 7 yrs.  So the AC Compressor is old / suspect!! - but I didn't expect this.

Today my new AIMS inverter powered-up and then WHAM, shut-off.   After much fear, I discovered that the 250a breaker between the battery bank and the inverter had tripped.   At 250a * 56v that means the Inverter was attempting more than 14,000watts!.   Look at what I found on my Omega power monitor log:

You can see the inverter turn on at 4:28:12 PM... and then 15sec later the automatic transfer switch changed over from grid to inverter power and WHAM -  95.4a @ 196.4v = 18,736 watts.     No wonder the 250a @ 48v circuit breaker tripped.    

Smile  Shows the value in having proper circuit breakers.

SO...  I'm going to leave it alone and wait for new Lennox XP24-048 heat pump install next week.   I was assured by the installer that this thing has variable speed 3-phase motor technology with has a couple of benefits.....   
- It is soft start.  So I shouldn't see anything like 100a @ 240v!!
- It takes in AC,  converts it to DC, then to 3-phase AC, which give the variable speed motor control.... which means the ATS (and the whole 60cycle syncing issue) will not cause any problems.

I'll report back next week with good news I hope Smile

P.S. GOVT OVERREACH: An intersting tid-bit on Lennox equipment according to the installer.  Lennox specifically made their modern heat-pumps to connect directly to solar panels...  BUT,  in Oregon USA,  they can't install the solar feature because Oregon requires a 'special'  solar certificate - which requires journeyman+test to get.  So Solar technician cannot do HVAC and HVAC cannot do solar - so the feature sits 'wasted' in Oregon.  Thank you government!!
cowpen and ajw22 like this post
Finally, after 1.5yrs of manual monitoring - the Batrium is actually hooked up thru 48v->24v step-down thru relay #1 to ABB 400a shunt-trip to disconnect the battery.    

Big shout-out to @LithiumSolar youtube:  "Connecting an ABB Shunt-Trip Breaker to the Batrium WatchMon 4 BMS" -
All I had to do was 'follow along'.    Thank you sir!
NEW HEAT PUMP: Brand new, whole house heat-pump install completed yesterday, first morning of heat, and look at this...

Only a 4,000watt draw heating a 2600 sq ft home up from night-time 19C/66F to day 23C/73F. This snapshot is mid-process (69F) at 5:30am, dark, and outdoor temp of 4C/39F.    Its an iComfort S30 'thermostat' using the 'IQ Schedule" to transition from night to day and the system is set for 100% heatpump when outdoor is >= -9C/15F - so heatpump may be limited due to outdoor temp and/or the "IQ Schedule" transition is programmed to raise the temp slowly over several hours - I don't know.

I live in "Zone 4 (moderate)" climate and the specific equipment is 
- Lennox "SLP98V" ...SLP98VUH090XV60C: 5 ton Furnace/Air-Handler dual fuel w/gas as 2nd fuel, indoor unit. -
- Lennox "XP25"  ... XP25-048:   4 ton HeatPump, outdoor unit -
- System is SEER 20, HSPF 9.5 according to the installer Smile

We'll see over time and of course AC is not yet in play..  but this very first 'solar powered',  'whole house heat' experience is *fantastic* (to me) and exceeds my expectations as I was estimating more like 6000watts from googling.    The heatpump 'soft start' is very nice -  you can see it ramp up slowly from 3amp @ 240v to 6a to 11a to 15a over a couple of minutes which is gentle on the inverter.
cowpen likes this post

The numbers show an average of 23kwh/day thru last 1/2 of March for a 2600sq ft home.  That's fantastic (to me) as my average solar production was 40kwh/day - which means there is enough power to heat my house.    Here's the National Weather info for March to help quantify what the 23kwh/day is doing - its a mild climate...    

More Detail:
We let it go down to 68F at night, so in the morning the system needs to raise the temp from 68F to 73F (5deg).    This takes about 1-3hrs depending on the outside temp.  At 30F the heat pump can barely raise the temp of the house (e.g. 3hrs).   At 35F or above, it's adequate (2hrs).   In the 40F(s) its much more responsive in raising the temp (<2hrs).  

One thing that jumps out at me - is that in a serious WTH...  it would be smarter to wait till late-morning for temps to raise before trying to warm the house.  Its only <30F during the day for 'a few days' a year on average here.  The rest of the time, its always >30F.
Thank you for the valuable information.iam very much impressed with this one.
Looking forward for the good posts.

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