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]

Are you selling back?

oh, no, no, no

first, I don't want to go through those hoops - Selfish Solar, as Jack Rickard stated - lots of inspection hurdles
second, my inverter can't do that
third, the local grid's circuit currently is NOT accepting more Netmetering - there is a hydro dam on that circuit and they have enough generation

Hence my projects on using and storing what I generate - 'need more batteries' is the current motto

 

[Jennifer]

oh, no, no, no

third, the local grid's circuit currently is NOT accepting more Netmetering - there is a hydro dam on that circuit and they have enough generation

Heck, at the rate you're building that system out, the local utility probably doesn't have the infrastructure to handle you dumping power onto the grid... LOL

 

[dougbert]

Got the 2nd water heater working and it took a full load until the sun went down.
Don't know if the entire tank heated up, but the top half got to 90F

 

[dougbert]

Full sun today and the 2 water heaters (100 gallons total) reached full temperature of 100+F today. Some heat left over from yesterday.

below is the day's Solar generating load chart

The top green (current) peak just after noon, is the transition from BULK to ABSORPTION
The little blue (voltage) peak just before noon, is the water heater diversion load kicking in

Then around 1PM, the battery reaches complete FULL (nice flat blue line), while the green current line continues its downward slope, as expected during ABSORPTION phase. This continues until just after 3:30PM when the current green line drops a whole lot. That is when the water heater internal thermostats turn totally OFF as the water has reach selected temperature in both tanks.

I noticed this a bit later, and seeing still great SUN, decided to turn up the thermostats to 125F in order to pack more heat into the tanks. I do have a temperature mixing valve so no extremely HOT water goes to faucets.

Notice the slight blue voltage drop just before 4PM, that is when FLOAT phase is entered at a slightly lower voltage than BULK and ABSORPTION phases.

If all the power were utilized, that green curve would form a nice bell shaped curve. That area below such a bell curve (after that initial highest peak) and the actual green line is UN-USED PV power.

I am looking for possible loads I can add to utilize/tap some of that PV power. Ideas anyone?





Current ideas on my list are:

Summer AC
Attic and room FANs
Future Electric car charging
BITCOIN Mining?


In the winter, with less sun and cloudy/snow, I will need that reduced excess power to just run the house.
It is the summer time that poses a wonderful problem.

Side note: My wife still walks behind me on a sunny day turning lights, fans and other things OFF when I leave the room
LMAO

 

[Jennifer]

Current ideas on my list are:
Summer AC
Attic and room FANs
Future Electric car charging
BITCOIN Mining?

Rent your basement out to the local hells angels chapter for a marijuana grow op, those HID lights they use will take all the power you can give them, and you’ll make some new friends at the same time... lol

 

[Hedges]

I am looking for possible loads I can add to utilize/tap some of that PV power. Ideas anyone?

Nightcrawler harvesting?

(No need for worm farming, and you can sell what you catch to the local McDonalds)

 

[Hedges]

Rent your basement out to the local hells angels chapter for a marijuana grow op, those HID lights they use will take all the power you can give them, and you’ll make some new friends at the same time... lol

Also, no fear of panels being stolen. Not an approved crime in their neighborhood.

 

[Hedges]

Make hydrogen.
Flare it off at night.

 

[dougbert]

LOL, you two

 

[dougbert]

Status lights indicating: RED diversion system on, each green light indicates the respective heater reached HI TEMP, and no longer heating, but is enabling a downstream output circuit

 

[dougbert]

Ordered battery #8. Once it arrives, I will balance the 2 modules so I can place them in series, then manage them and the rest of the pack to a common voltage, then finally install the 2 new modules

Total storage will be 40kwh! (more in the future)

Thought to share my current cost outlay up to this point. I have not included the wiring and conduit of Phase 1 (2000 time frame), nor the mounting brackets of Array 1. This cost is what I have now spent for Phase 2. That includes all new panels, new inverter, new charge controllers, new batteries and wiring of Array 3 and Array 4. (Wiring for Array 1 put in 2000, Array 2 put in 2016 not counted here)

Total: $27,200

For:

40wkh of storage
EVTV battery controller on Tesla batteries to ensure safe charging and operation within environmental limits
7260 watts on 4 arrays.

• Max wattage possible is 4 controllers able to support 3400 watts each, 13,200 watts.
• Realistic max will in the 10,500 to 11,000 watts due to space to put panels

5500 watt inverter on 48v batteries
4 charge controllers and ingress and egress breakers for the same
4 disconnects for the arrays,
4 Midnite solar surge suppressors
4 Contactors controlled by the EVTV battery controller to disconnect arrays for error conditions

Result: 97% off-grid for the nearly past 2 months, after battery modules #7 and #8 are installed that should up that percentage
Monthly production in the 700-800 kwh range (I have computers on all the time)
daily production average is 28kwh, with peaks of 42kwh during high load consumption (ie wash day once a week)
AND water heating as a diversion load, 2 50 gallon tanks, after battery is full

Still un-tapped energy loss due to under utilized PV generation and system loads not being on - no where to use it = yet
Summer room AC and house cooling fans will be on as the temps reach above 90F in the summer

 

[dougbert]

March 8th to April 7th billing cycle:

33 kwh bought
$19.23 bill

nice

 

[dougbert]

Ok I got burned in the process of buying module #8

It arrived quickly and safely and well packed BUT

it is missing the Tesla BMS board along with it's connector that I must have

This is the SINGLE picture in the ebay ad:



This is what I got with an aftermarket BMS - which I cannot interface with nor trust:



This is what I expected



So I have sent an email to seller requesting a return, we shall see if he honors the request, or will I have to escalate to EBAY

The Price and shipper were fair

From this I take away:

Ads must have more pictures of module than just one
A Picture must including the BMS board and connector

These types of events are possible. Only mad at the delay. Darn

First reply from seller:

Doesnt need digital equalizer​

Second reply

Thats what ad stated battery with bms for solar​

 

[dougbert]

ad is below:

Item specifics​

Condition:	Used	Chemistry:	Lithium
Other Part Number:	cell tesla 85	Modified Item:	No
Brand:	panasonic	Custom Bundle:	No
Non-Domestic Product:	No	Manufacturer Part Number:	tesla
Warranty:	No Warranty

The modules are comprised of 3400mAh cells arranged in a 74p6s configuration. They are rated at 500 amps, 750 amps peak. They have an integrated liquid cooling/heating system, but they can also be air cooled in light duty cycle applications. They also have an integrated connector with cell level connectivity for BMS systems and two integrated thermistors. The packs contain 444 cells, and each cell is independently safety fused on both terminals.

Voltage nominal: 3.8V/Cell, 22.8V/Module
Charge voltage cut-off: 4.2V/Cell, 25.2V/Module
Discharging cut-off: 3.3V/Cell, 19.8/Module
Maximum Discharging Current (10 sec.):750 Amps


He copy/pasted the above from standard ad script

 

[Hedges]

"

Modified Item:

No

"

Seems modified if an aftermarket BMS has been added?

But it says "integrated connector ... for BMS" that you highlighted. Did it say BMS included?

I have had sellers accept returns for a "no return" item when there were problems with it. Sometimes I offer to cover shipping.

Any chance you can pick up a Tesla BMS from someone who hacked their pack for other voltage use?

 

[dougbert]

My request for return

Here's what happened
Apr 23, 2021
You created a return
Order number


Reason for return
Missing parts or pieces

Comments
I believe the seller intentionally mis-represented the item being sold. It is a Tesla battery module which normally includes the standard Tesla BMS (Battery Management System adapter). Other sellers do this. This is my 8th module I have purchased, but I assumed the missing part of the module was present The single picture in the ad does NOT present the after market BMS. This required removal of Tesla BMS and insertion of the after market one. But this is NOT described in the ad. I have contacted seller and he lastly replied with: Thats what ad stated battery with bms for solar . Picture one below is of the item as received with after market BMS Picture 2 is from another current seller of Tesla modules with the green Tesla BMS board present along with the board s connector (it has the black plug with cut wires on top). Other sellers do this same disclosure Picture 3 is my target application that utilizes that connector on the green Tesla BMS board. Without that board I cannot utilize this module with the original Tesla BMS operations. My expectation is that a seller will represent such an item as complete as other sellers do, and in a one-off case, document the alterations and replacements. This did not occur in this transaction. This module is missing the very critical Tesla BMS board which is used in managing these modules. Again, I believe the ad is misleading and mis-represents the condition of the module


He has business 3 days, till April 29th to respond officially.
Then I ask ebay to get involved

Its a risk I understand on ebay, but sad that somebody didn't properly document his modification with his own BMS

 

[Hedges]

You might want to delete that PII and order number.

 

[dougbert]

"

Modified Item:

No

"

Seems modified if an aftermarket BMS has been added?

But it says "integrated connector ... for BMS" that you highlighted. Did it say BMS included?

I have had sellers accept returns for a "no return" item when there were problems with it. Sometimes I offer to cover shipping.

Any chance you can pick up a Tesla BMS from someone who hacked their pack for other voltage use?

good catch, I sent that info on Modified: No to the seller as well

I probably could get a BMS, but not too happy about hacking it back into the module, and I don't know if different years have different operational characteristics that could impact things.

there is an ad for one at https://www.ebay.com/itm/114245664148?hash=item1a99927d94:g:Z0MAAOSwVope1fCX
for $115

 

[dougbert]

the seller finally reached out to me by phone # and we talked. He realized I am a bit more advanced than he is (his words) when I explained that one can use the original Tesla BMS. So he is going to look for the Tesla BMS he removed if it is still in his bone pile. He does these modifications for solar installations in CA, but had not heard of the pack controller.

He has offered to pay me back for a BMS if I can find and buy one off of ebay if he can't find it.


I have found there are 3 revisions of the board.

2 on Module S,

• V1 PCBA 1020796 (c) 2012
• V2 PCBA 1028578 (c) 2013

I have 4 of V2 now and 3 of V1

along with new modules with a 3rd board type, without connectors


V1 used individual wires to connectors that plug into the card





V2 uses a very delicate ribbon cable top and bottom of the card





and the one I just got does not have, but a 3rd connection mechanism, which is the one he modified and sent me - I am looking for PCBA number

Here is the video he followed to rewire this module

found a board with those connectors:

PCBA 1014183 Rev 1


So, there are possible options, even returning the module, he is willing to do that if need be.

Summary: I found bought the same BMS that he removed for $70 and he is refunding that $70
Saves on shipping the module.
Learned some stuff about the Tesla BMS
Will be just some simple soldering

here is the replacement card I ordered that matches the one he took off:





downside: have to wait a few days for the board to show up

 

[Jennifer]

All my boards are rev 1 and I believe those are soldered to the boards, I don't recall seeing any plugs... that sucks... just goes to show, just cus you've been happy with previous items from the same seller, trust NO ONE!!!!

As you're a customer of the ESP32 BMS, I bet you the guys at EVTV have one kicking around they'd send you cheap.

Jen