Multiplus 3000 and second DC output

I would like to know why, on this diagram (https://www.victronenergy.fr/upload/documents/MultiPlus-3KW-120VAC-12VDC-400Ah-Li-VEBus-BMS-generator-MPPT-BMV-Cerbo-Orion- Tr-Smarts.pdf), the dc outputs 2 are connected to the lithium battery bus and the starter battery is connected to a small charger. According to the specifications of the multiplus 3000, the dc output 2 is intended for a starter battery and only produces a current of 4a. So, why not use output 2 for the startup bank?

2 |3000

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Alexandra ♦ commented · Dec 30, 2022 at 06:14 PM

The second output follows the charge profile of the internal charge profile.

Lead and Lithium have different needs.

And it is just an example demonstrating product configuration and uses possibilities not necessarily the only way it can be done.

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denis-roy Alexandra ♦ commented · Dec 30, 2022 at 08:01 PM

I understand that it is therefore not possible to program 2 different charge profiles. As my configuration is similar (lead and lithium), is there an advantage to connect the second output to lithium bank other than providing an additional 4a?

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kevgermany ♦♦ denis-roy commented · Jan 01, 2023 at 07:49 AM

No point. The normal output connections will give full power to the lithium bank.

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Matthias Lange - DE ♦ denis-roy commented · Jan 01, 2023 at 10:16 AM

That 4A output is not a dedicated charging output, it is just connected to the normal DC bus through some electronics.

Additionally that output is always active. If the voltage at the main DC bus is higher than the voltage at the 4A output there will be a current flow.

With a lithium battery at the main DC bus and a lead battery at the 4A output there will always be a small current flow from the lithium battery to the lead battery because the lithium battery has a slightly higher resting voltage.

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