Zim's Powerwall

ZimInSeattle

Member
Joined
Aug 26, 2019
Messages
38
Hi DIY Powerwallers,

I had posted this in the wrong section. :dodgy: Re-posting here. :)

I have been lurking around here for a number of years. I'm very much into renewable energy and sustainability. My current home setup includes:

Rooftop Solar: 32 Solar World 275 watt panels with Enphase M250 microinverters facing south. 4 Solar World 290 watt panels with IQ7 microinverters facing west, and 3 290 watt panels with IQ7 facing east. System is grid tied and through production credits I haven't had an electric bill in over 5 years. In fact, I have made a minimum of $500 per year with the production credit. This includes paying for the 'fuel' of my electric car...

EV: 2016 Nissan Leaf with 30Kwh battery. I have been driving a Leaf since early 2011. Very early adopter.

Since the production credit program is ending at the end of this month, I decided I needed a battery to take more advantage of the net metering which is in place here in Washington until at least 2030.I originally was starting to collect 18650 cells, but ultimately decided to make my battery from Leaf modules.


As you can see in above image, I have very limited space so I had to build my own power distribution panel as the Schneider Electric mini PDP and Conduit Box would not fit in the space available. The inverter is a 6848 XW+ with System Control Panel in place of original control panel and a Conext ComBox temp installed above it. The raceway is WireMold 3000 series. The battery box below I built from a heavy duty shelving kit cutting down the side rails from 18 inches to 16 inches and welding steel panels in place of the particle board shelves included with kit. Box is approximately 36" wide by 30" high x 16" deep. Welded all the outside panels and wheels on the bottom. There's currently 49 Leaf modules in there, 28 lower ones I got from GreenTech Auto on Ebay and the 21 top shelf ones from TechDirect. I had originally tried to bid on salvage Leafs to get my modules, but kept getting outbid so I just decided to buy them from these dealers. I haven't tested any of them, but they are supposed to be at about 70% capacity. My purpose is for energy arbitrage rather than backup power as the power has never gone out here for more than a few seconds in the 7 years we've lived here. I do however have a 4000 watt natural gas powered generator tied into AC2 input on the inverter should I ever need backup power. My thinking is that I should get about 15 to 18 kwh out of the battery which will easily run the 10 circuits I have in critical load sub panel in the evening hours. Once the production credit program has ended, I plan to have the 7 panels with IQ7 microinverters AC coupled into critical load panel.

For my BMS I have the Batrium Leafmon starter kit. Not sure how I'm going to integrate it with the XW+ as it appears the Conext Bridge is no longer available since Schneider integrated Lithium Ion battery compatibility directly into their inverters. I have emailed Batrium about writing firmware that uses Modbus in place of CAN bus over the RS485 port of the ComBox to control the inverter but haven't received a response. I do not understand why this couldn't be done as Modbus is a royalty free protocol and is widely used. I have the Modbus Conext mapping address document and am perfectly willing to let Batrium use my inverter as a test mule. I know some here have more or less the same setup that I have and any suggestions on how to integrate the Batrium and XW+ would be appreciated. I really don't want to dust off my computer science degree and write the code myself or spend more money on the Schneider BMS when the Batrium with Leafmon is such an elegant setup for monitoring Leaf modules.

As of now I'm waiting for battery cable and more bus bar to arrive. Hopefully within the next few weeks I'll be up and running. Thanks.
 
ZimInSeattle said:
I had posted this in the wrong section. :dodgy: Re-posting here. :)

We could of just moved it for ya ;)
 
Back
Top