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tomskk avatar image

Setting up Old Multiplus with firmware 19xxxxx and Tesla Model S batteries

How to setup the old Multiplus with 19xxxxx firmware so that the Tesla is charged and discharged correctly ? I mean setting up minimal and max voltages.

Multiplus-II
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I'm having a very hard time configuring SimpBMS with 6S Tesla pack, combined with an older version of Multiplus firmware 1910209, MPPT 100/50 and Venus GX.

I'm posting some pictures of my settings from the real time situation, maybe some will find an answer why it is not working as it should.

1.) SimpBMS settings


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You'll need to set ESS mode (debug menu)
output 2 can then be used for a shunt-trip.

MPPT 100/50 settings


BMV 700 settings

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I'm sorry I missed the fact that the old firmware is not capable of using DVCC. I don't know from memory if the MPPT's listen to the BMS without DVCC enabled. did you try this?

The Multi you can use the two wire bms assistant I think.

I was affraid of that. But the Multi was not intended for Charging just for inverting. As far as i can see from the real time situation, the simpBms is controlling the MPPT charging current as the voltage goes up to the full SOC. The only problem is that simpBMS is not updating the SOC as it charges or discharges. And it also is not showing the Amps and the Wattage that goes in the battery. Dont know if that is also connected with DVCC ?

I think you'll need to read the manual of the bms...

SOC you can set voltage based
current the bms can only see if you connect a current sensor to it.

https://github.com/tomdebree/SimpBMS

2 Answers
Guy Stewart (Victron Community Manager) avatar image

Hello Tomskk,

While it might work, there are limitations using Tesla batteries with Victron equipment - there is a very in depth community post here that outlines what those are:

https://community.victronenergy.com/questions/5217/tesla-model-s-battery-multiplus-can-not-turn-on-in.html


Batteries that have been tested and are known to work reliably and as expected with Victron equipment are documented here - https://www.victronenergy.com/live/battery_compatibility:start


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tomskk avatar image

Thanks Guy, can you explain me the logic of Multiplus and charging from solar cells. I'm using Smart Solar 100/50 and am a little confused who is in charge of charging the bateries ? MPPT or Multiplus ? Multiplus won't be connected to grid.


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Hi @tomskk

Your BMS will be in charge of the charging voltage and current, maximum discharge voltage you'll have to set in the Multi

For safety set the charging voltage in the Multi and MPPT to a maximum of 4.1V per cell, so 24,6V

The BMS connects to your Venus, the Venus tells the Multi and MPPT what to do, if you configure like this document:
https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom
only you can leave 'SVS' on at the DVCC settings.

But....please make sure you have your wiring etc. properly and safely installed, maybe ask an electrician to help you with that.
Also make sure the battery has enough cooling, and your MPPT is mounted upright so the cooling fins can work.

Mounting equipment that produces heat onto a wooden surface I wouldn't recommend, the MPPT can get quite hot, and will dry out the wood until it gets easily combustible.

@Boekel thanks for the answer, will follow your recomedations. Yesterday the storm came to early and the sun was gone, and Tesla was only at 21.7V (bummer) so the Multi didnt want to start :-).


Disconected the NG125N and now must wait for the sun to fill up the Tesla over 21.8V so that the Multi will start inverting.


How much current can I allow MPPT to put through to Tesla cells ?


@Boekel the problem is when using DVCC on a Multiplus with firmware 1910209 the SimpBMS look like is loosing the connection. The Venus GX is going from Unknow BMS to Off, and all over again.



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