Using unapproved lithium battery with Quattro, pros and cons?

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Obo asked Oct 22, '20

Using unapproved lithium battery with Quattro, pros and cons?

I have read the page showing lithium battery compatibility at https://www.victronenergy.com/live/battery_compatibility:start, but still don't understand why you cannot use an unapproved lithium battery?

My understanding of lithium batteries is that most have an onboard BMS, that manages individual cell voltages and charging rates. If this is the case then what benefit do you get if the GX device can communicate with the onboard BMS? Is it just so that you can read the individual cell voltages through the VRM?

Any clarity would be much appreciated!

Cheers

Lithium Battery VE.Can

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Guy Stewart (Victron Community Manager) answered · Oct 22, 2020 at 11:05 AM

Hi @Obo,

The #1 reason is support.

The batteries on that list have been tested and are known to work. In most (all?) cases, there have been some adjustments made by Victron, the battery manufacturer, or both to improve product performance, reliability, or stability.

Given the cost and usual necessity of a power system, people don't usually want to take risks at trying some new experimental combination and figuring out all the edge cases where things don't work exactly as expected, how to fix them, etc.

So most people find products that are supported by all the other manufacturers in the system to be compatible with each other. This relationship is most critical between the battery and the power electronics.

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Modifications Space

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Answer 1 · 2020-10-22T14:11:15Z

duclos-laurent answered · Oct 22, 2020 at 02:11 PM

Hello @Obo and @Guy Stewart (Victron Community Manager),

I understand Obo questions as I'm on the same case.

I understand that there is a lot of lithium battery or cells manufacturers but a validation of 1 unbrand battery/cells manufacturer can help Victron customer with general wiring recommendation, Victron material to use and Victron product parameter.

I will try to use a 16 Lifepo4 cells + BMS + BMV-700 plugged on a Multiplus 2 48/3000 and if this global system does not work I will not know if the problem comes from BMS / BMV-700 or Multiplus 2.

I don't speak about a detailled wiring illustration or a detailled parameter setup for every possible configuration but general requirment from Victron for other unapproved battery can help.

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Answer 2 · 2020-10-25T11:14:35Z

tony-c answered · Oct 25, 2020 at 11:14 AM

The "real" LifeP04 batteries cost considerably more that the unbranded made in China. (Bear in mind the majority of cells are made in china). The main deficiency in the cheaper ones is their relatively dumb internal BMS. However having a Quattro make solving that deficiency quite simple.

What is missing is a trigger from the batteries BMS to tell the Quattro stop the charging. Quattro in its "Assistants" offers a couple of solutions. The two signal BMS support assistant can either "Force to Float" or "Disable charger". I used a programmable voltage sensitive relay to close contacts when the battery voltage was stable at 14.2. It cost the princely sum of $25. The purists will no doubt explain that I am not achieving the maximum charge, which is true. But charging to 96% at a fraction of the cost of the "Real" lithium was a perfect solution.

The wiring was simple and the config easy.

I have removed 6x140A AGM and now run 2x200A LifeP04 and all is good.

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