Tesla S Battery Bank for Solar

[Maddog55]

I was wondering about the differences between Tesla 24V modules, Battle Born 12V LFP, Victron LFP and how a BMS would work for the Tesla monitoring its cells.

Sounds like the BMS monitors each cell within the battery.
Victron LiFePO4 batteries says 4 cells for 12.8V battery, 8 cells for 25.6V battery, & the BMS protects each individual cell

Battle Born LiFePO4 12V 100Ah - didn't see how many cells per battery on their site.
The BMS protects the cells against excessively high or low voltages, high currents, short circuits, and excessive heat or cold
https://battlebornbatteries.com/are-...-bms-built-in/m

Tesla Model S Lithium Ion Battery 18650 EV Module - 22.8 Volt, 5.3 kWh - http://www.evwest.com/catalog/produc...roducts_id=463
The packs contain 444 cells.
Tesla cells - nickel cobalt manganese aluminum oxide cathode and a graphite silicon anode.
http://media3.ev-tv.me/TeslaModuleController.pdf

Is there a BMS like the EVTV Tesla Battery Module Controller or https://hackaday.io/project/10098-model-s-bms-hacking that works with the module's cells.
96 cells or 444 cells per module?
The 85KWh pack contains 16 modules, each of which is a 6s 74p array of 18650 cells, 96 series cells total. Each 6s module communicates with a master BMS via an isolation barrier, the master BMS talks to the ECU and charger and controls the main contactors. https://hackaday.io/project/10098-model-s-bms-hacking

Gene, you bring up a good point. I’m not sure how effective a Victron BMS would interface with Tesla batteries. My simple mind assumed the BMS would monitor the state of charge on the unit per bank as a whole and make appropriate adjustments. But as you pointed out, the Tesla battery configuration is different then the typical LiFePo4. My focus was on capacity.

I’m looking at 4 panels of 24v 350 watt solar capacity. Assuming on ave 35 amps per 100 watts of solar;
350 watts * 4 panels / 100 watts * 35 amps/day = 490 amp hrs * 24v = 11,760 watts generated per day on average.

3 Tesla battery banks in parallel is about 5.3kWh * 3 banks = about 15.9kWh.

Assuming drain and top off parameters are 20% and 97%, the usable draw down range would be about .77 of 15.9kWh or about 12.2kWh of usable power from 3 Tesla battery banks. This is a good fit with the solar panels generating about 11,760 watts per dat on average. There’s a lot of power to play with and ample storage capacity.

$1,200 * 3 Tesla batteries with 12.2kWh of usable energy at & $3,600 is a bargain. But I do see your concern about BMS and it is valid. I thought the Victron would monitor the terminals of the 3 Tesla battery banks hooked up in parrellel. I’d have to defer to a EE. I have no clue.

[Maddog55]

Two inverters.

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I find it interesting that we can got two different answers from two different sales persons working for the same company. Are you sure he’s not trying to up sell you an extra inverter? (Tongue in cheek)
It’s actually 3 different answers as another sales rep recommended the Quattro with a Smart ATS to power both Legs. And yes, he’s from Victron also.

Tom from Mortons on the Move bridged the neutral wire via a manual switch, very clever, simple, and functional. Oh and cost effective I might add.

I need to figure out how stock 30 amp power powers both legs.

[MidwestCamper]

I'm thinking about using a used Tesla S battery module 24V, 250Ah, 5.2kWh for the TT solar battery bank. It would be a used one from a wrecked Tesla.

Has anyone tried this?
Any pros / cons?

I've also been intrigued with the Tesla battery solution since no drop in battery can match the energy density or quality of the Panasonic cells that are used by Tesla or LG Chem or the Sanyo cells that are used by other makers. Also been looking into the possibility in buying these high quality cells and making a high quality battery.

https://vruzend.com/

[CWSWine]

This might be of interest but I learned a lot from watching the installation and the capabilities that he had on batteries including AC. This is the last in the series as he walks through the installation of a 24-volt battery and solar system.

https://www.youtube.com/watch?v=2z9xAKtu7rw&t=0s

[alanhenson]

I find it interesting that we can got two different answers from two different sales persons working for the same company. Are you sure he’s not trying to up sell you an extra inverter? (Tongue in cheek)
It’s actually 3 different answers as another sales rep recommended the Quattro with a Smart ATS to power both Legs. And yes, he’s from Victron also.

Tom from Mortons on the Move bridged the neutral wire via a manual switch, very clever, simple, and functional. Oh and cost effective I might add.

I need to figure out how stock 30 amp power powers both legs.

Yeah I'm confused now.

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[DaveMatthewsBand]

...Also been looking into the possibility in buying these high quality cells and making a high quality battery.

Hey let us know if you end up building a custom battery, I'd like seeing the specs and resulting performance you get with it.

Thanks

[MidwestCamper]

Hey let us know if you end up building a custom battery, I'd like seeing the specs and resulting performance you get with it.

Thanks

The specifications are on the cells. The battery bank is just the culmination of those cells. You can buy very high quality LG Chem cells for example that come with a spec sheet and where they are sourced....Korea.

[Gyro Gearloose]

Are you sure he’s not trying to up sell you an extra inverter?

Brigded the neutral wire via a manual switch, very clever, simple, and functional. Oh and cost effective I might add.

I need to figure out how stock 30 amp power powers both legs.

Actually I like the idea of 2 - 25 or 30 amp inverters. Redundancy is how we did datacenter and networks between sites in the computer world.

So if you had 2 - 30 amp inverters, if one of the phases went down you could still operate on that phase at 30A, or Bridge the the still working phase to both phases and limit youself to 30A like you were on 30A shore power. This keeps you functional till you can get the bad side fixed.

You last question does not make sense "I need to figure out how stock 30 amp power powers both legs."

[DaveMatthewsBand]

...
So if you had 2 - 30 amp inverters, if one of the phases went down you could still operate on that phase at 30A, or Bridge the the still working phase to both phases and limit youself to 30A like you were on 30A shore power. This keeps you functional till you can get the bad side fixed...

That’s a good idea, maybe I should have done that. Our inverter is 60 amp and our entire trailer is wired to it. But we do have gobs of power on each circuit this way.



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[Dynamowhum]

I want this for the future. Thanks