Mixing batteries with CAN comunication and not CAN in one busbar.

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marekp asked Aug 28, '22

Mixing batteries with CAN comunication and not CAN in one busbar.

Is it possible to have LFP battery with CAN communication and the second one (also LFP) with no communication connected to one bus-bar with a SmartShunt for SOC calculation?

Can I choose to use SmartShunt for SOC calculation instead SOC reported by CAN?

The existing system is using a Pylontech type battery (Turbo Energy) and we have a good deal on 400Ah Winston cells ($50 a piece).

Can battery build with those Winstons, equipped with its own BMS, be added to the common bus-bar with the CAN connected battery?

VE.Can

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johanndo commented · Aug 29, 2022 at 05:25 PM

If you know what you are doing, yes, you can use a BMV or SmartShunt instead for SOC and ditch the CAN BUS, program your system and use different batteries with their own BMS logic and disconnect gear in case of issues. And they can share bus bars.

They have to operate at the same voltages (same cell count, same chemistry)

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Answer 1 · 2022-08-29T16:14:27Z

snoobler answered · Aug 29, 2022 at 04:14 PM

Is it possible? Sure. I don't see why not. A decent BMS should calculate it's own SoC, but a smartshunt would be needed to integrate it into the ecosystem.

Personally, I would want separate fusing and cut-off switch.

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Answer 2 · 2022-08-29T16:24:46Z

nickdb answered · Aug 29, 2022 at 04:24 PM

If the packs have different charge requirements (pylons usually lower voltage due to fewer cells) it could get exciting.

Special batteries tend to have special problems.

Good luck!

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Answer 3 · 2022-08-29T18:37:22Z

marekp answered · Aug 29, 2022 at 06:37 PM

@nickdb

@snoobler

@JohannDo

Turbo Energy battery is similar to Pylontech, 15s LFP.

The Winstons are separate 3.3V LFP cells that will also have 15s configuration.

Main question is how to make them work together and be reconized by GX as one big battery?

1. One battery connected to GX with CAN (Turbo Energy) and the other (15s in Winstons) connected to the same bus-bar and having its own BMS with disconnecting relay?

Is it possible to have GX disregard SOC info from CAN and use total SOC from Smart Shunt?

2. Set up the Winston 15s pack with "2 signal BMS" assistant and Turbo Energy battery connect only to bus-bar without setting up CAN connection to GX.

SOC will be calculated by Smart Shunt.

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Answer 4 · 2022-08-30T00:16:54Z

snoobler answered · Aug 30, 2022 at 12:16 AM

If #1 will work, I don't know how.

#2 should work.

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Answer 5 · 2022-08-30T11:46:25Z

Alexandra answered · Aug 30, 2022 at 11:46 AM

@MarekP

It will adhere to the charge current limit of the managed battery if it is connected, so the charge will be slower for the two. But SOC remains about equal /correct when bus barred.

With the DCL as well and you can get a system shutdown on higher loads because DCL has been met (according to one battery).

If they are both able to run dumb and have same charge voltages charge amps and discharge ability (ie 60A discharge) etc. It does work. As long as the combo is properly sized.

It is not supported so if an unstable system is the result, it really is your responsibility

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