MPPT (450/100) continues charging at 100%

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cotje asked Mar 6, '22

MPPT (450/100) continues charging at 100%

My new system consisting of 48V LifePO4 battery, Batrium BMS, GX, MP-II and MPPT 450/100 just has been working nicely for over a week, but now with more sun hours I notice the MPPT keeps charging at max Amp and does not do what the BMS is programmed for. The MP-II does exaclty what the BMS is programmes for.

Some details:

- BMS is connected to the GX by CAN

- MPPT is connected to the GX by VE-direct, configured as external control charging

- MP-II is connected to the GX by VE-Bus

I'm expecting the GX to tell the MPPT what it's charge limits are (over VE-direct). What am I missing here?

- do I need to control the MPPT with the 2-wire CAN option?

- do I need to configure DCVV?

- something else?

Kind of lost here. Any help would be much appreciated!

MPPT Controllers

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Answer 1 · 2022-03-06T15:09:07Z

cotje answered · Mar 06, 2022 at 03:09 PM

The manual states the following:

"Managed batteries or an inverter/charger with an external control system system can control the solar charger via a GX device.
The battery dictates if charging is allowed, and when charging is allowed, what charge voltage and currents are used. If external control is active this will be displayed in the VictronConnect App and also on the GX device."

This is exactly what my MP-II does, but the MPPT not (although it's showing 'external control').

The Batrium provides this info currently (at 98%):

1646579338559.png (18.2 KiB)

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Answer 2 · 2022-03-06T15:28:00Z

kevgermany answered · Mar 06, 2022 at 03:28 PM

You need DVCC.

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Answer 3 · 2022-03-07T13:24:22Z

cotje answered · Mar 07, 2022 at 01:24 PM

Hello, I just enabled DVCC but the Solar charger is still pumping all it can into the batteries while the BMS is communicating (over CAN) it should be much lower.

Any hint's for me to take a look at?

TIA!

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Answer 4 · 2022-03-07T14:34:03Z

cotje answered · Mar 07, 2022 at 02:34 PM

MPPT settings (11A is set by me on the MPPT to limit the current):

1646663584042.png (25.3 KiB)

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Answer 5 · 2022-03-07T16:00:35Z

nickdb answered · Mar 07, 2022 at 04:00 PM

BMS could be reporting an inaccurate SOC, some manufacturers have this issue - it will report 100% but be well under.

What is the battery voltage reported and how does that compare to it’s spec?

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cotje commented · Mar 07, 2022 at 05:28 PM

Hi Nick, the BMS will report how much current the charger should use at which SOC based on below picture. The Multiplus is doing this (on 'Keep batteries charged') just as it's told. The MPPT however is completely ignoring this and keeps charging full power, despite the externa control setting (and showing the bat-temp).

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Answer 6 · 2022-03-07T21:22:11Z

cotje answered · Mar 07, 2022 at 09:22 PM

Just found this in the ESS-guide:

Charger tab: the ESS Assistant will have already selected the proper battery type, as well as disabled the Storage mode.
Verify and where necessary change the rest of the settings: charge voltages & maximum charge current. Note that, for systems with the ESS Assistant installed, the MPPT Solar Chargers will follow the charge curve as set in VEConfigure. The charge parameters configured in the MPPT Solar Chargers are ignored in an ESS setup.

Strangely enough the MPPT behaves totally different from Multi in regards to charging...

Who has the missing link for me?

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Answer 7 · 2022-03-08T10:35:24Z

cotje answered · Mar 08, 2022 at 10:35 AM

An actual update of the charge behavior. I'm expecting the solar charger to follow the CCL value as the MP-II would do.

1646735717461.png (178.8 KiB)

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Answer 8 · 2022-03-20T13:53:14Z

cotje answered · Mar 20, 2022 at 01:53 PM

Hi all, I got it running and can conclude the following:

- The MPPT is charging based on settings defined on the MPII

- DVCC is optional

- While playing with the absorbtion voltage I could finally see the MPII going into Absorption. @nickdb was righta about this detail. I've lowered it from 56.8 to 55V and will go up in small steps to see what my batteries actually can do.

Thanks all for your feedback!

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nickdb ♦♦ commented · Mar 20, 2022 at 02:23 PM

@cotje DVCC is mandatory for this at it is responsible for actively controlling the different devices so that charging is properly coordinated. It is automatically forced on when a supported BMS is detected, for unsupported ones it must be manually enabled.

For reference from the docs:

Example 1 - Managed CAN-bus batteries For example, in systems with an Managed CAN-bus BMS battery connected, the GX receives a Charge Voltage Limit (CVL), Charge Current Limit (CCL), Discharge Current Limit (DCL) from that battery and relays that to the connected inverter/chargers and solar chargers. These then disable their internal charge algorithms and simply do what they're told by the battery. There is no need to set-up charge voltages or choose the charge algorithm type.

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Answer 9 · 2022-11-14T07:07:04Z

alpin28 answered · Nov 14, 2022 at 07:07 AM

Hallo, ja ich habe das gleiche Problem.

Wo muss ich das genau einstellen - unter Ladegerät?

Bitte um Info.

MfG

Joschi

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