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James Minnie avatar image

Multiplus-II 48/5000/70-50 BMZ ESS 7.0 Not Charging

We are installing the following system:


Multiplus II (48V)

MPPT 250/60 tr (DC Coupled)

BMZ ESS 7.0 Battery

CCGX

Using ESS Assistant


The inverter keeps on failing on low battery although battery is 58V. Battery SOC is 51%. At times it goes to Charger in Absortion mode but is not charging. How to get it in Bulk mode or to charge via the grid?


ESS Settings:


TAB: General

System frequency 50Hz

Shore current 50.0 A

Overruled by remote unchecked

Dynamic current limiter unchecked

External current sensor connected (see manual) unchecked

State of charge when Bulk finished 95.0 %

Battery capacity 157 Ah

Charge efficiency 0.95


TAB: Grid

Country / grid code standard Other: not compliant to any grid code standard

LOM detection AC input 1 Type B (safe)

Accept wide input frequency range (45-65 Hz) checked

AC low switch mains off 180 V

AC low switch mains on 187 V

AC high switch mains on 265 V

AC high switch mains off 270 V

UPS function checked


TAB: Inverter

PowerAssist unchecked

Inverter output voltage 230 V

Inverter DC shut-down voltage 37.20 V

Inverter DC restart voltage 43.60 V

Low DC alarm level 43.60 V

Do not restart after short-circuit (VDE 4105-2 safety) unchecked

enable AES unchecked


TAB: Charger

Enable charger checked

Weak AC input unchecked

Stop after excessive bulk unchecked

Lithium batteries checked

Use equalization (tubular plate traction battery curve) unchecked

Charge curve Fixed

Absorption voltage 60.75 V

Float voltage 60.00 V

Charge current 50 A

Repeated absorption time 1.00 Hr

Repeated absorption interval 7.00 Days

Absorption time 1 Hr


TAB: Virtual switch

Virtual switch usage Do not use VS


TAB: Assistants

TAB: Assistant Configuration

ESS (Energy Storage System)

*) System uses LiFePo4 with other type BMS

(This can be either a BMS connected via CAN bus or a BMS system in which the

batteries are protected from high/low cell voltages by external equipment.)

*) The battery capacity of the system is 157 Ah.

*) Sustain voltage 50.00 V.

*) Cut off voltage for a discharge current of:

0.005 C= 52.00 V

0.25 C= 50.00 V

0.7 C= 49.20 V

2 C= 48.00 V

*) Inverting is allowed again when voltage rises 1.20 V above cut-off(0).

*) Relevant VEConfigure settings:

- Battery capacity 157 Ah.

- PowerAssist unchecked

- Lithium batteries checked

- Dynamic current limiter unchecked

- Storage mode unchecked


Any advice for charger setup?

Multiplus-II
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5 Answers
James Minnie avatar image
James Minnie answered ·

BMZ Laptop Communication.pdf

By connecting to the BMZ battery and checking the Pyrofuse voltage the state of the fuse can be determined. It should be less than 500mV.

I attach the BMZ Service Tool software for and info about communication.BMZ Service Tool.zip

@rossmuller1


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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

95% sure:

Battery is not connected to inverter or not turned on somehow.

revert to battery manual if everything is connected properly.

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@James Minnie

If it is this the Helderberg Solar site, there is something wrong with the battery, or the connection to it.
Either a fuse is blown, or the battery is not connection internally.


Thanks Daniël,


Yes, it is the Helderberg Solar site. Battery = BMZ ESS 7.0


Strange, battery LED indicates normal when switching BMZ on (solid green). When switching off DC (58V) falls away from Lynx bus (on MPPT and Inverter as well). Switching BMZ on DC is back. Cannot find anything related in manual. Will revert to supplier and BMZ support.


Feedback: Problem solved by replacing faulty Pyro-Fuse. All indications for fuse was that is healthy but eventually went into a faulty state. Initially fuse voltage reading was 630mV (should be below 600mV). Eventually it went up to 3000mV and battery into fault condition (flashing red). With new fuse voltage at 560mV and all OK.

rossmuller1 avatar image
rossmuller1 answered ·

Hi there all I think I am having the same issue here, have 2 x 150/70 VE Direct MPPTS with a 5kVA Multiplus and a BMZ 7.0 ESS. Keeps saying low battery when there is loss of mains and battery voltage is at 58V and 71% but not supplying power.

I have noticed now that the voltage starts fluctuating from 43.15V and 61.2V. Almost instantaneously when under load with no grid. But as soon as the system starts up the voltage is back to 58V.
i did check continuity on the fuses in the battery but i did not check the mV.

No more than 60W going into battery at the moment.
Please help as battery supplier is not assisting urgently enough.

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James Minnie avatar image James Minnie Daniël Boekel (Victron Energy Staff) ♦♦ ·

The problem was the Pyrofuse inside the BMZ battery that was partially blown. Although no error indication the battery could not take load or charge. Once replaced the problem was solved.


Apparently these fuses can be damaged by shocks i.e. bumpy roads or drops.

Hi James, I think I have the same issue. How do I get to the pyro fuse? thanks

Hans Schive avatar image
Hans Schive answered ·

Hi James, can I ask what specifications you have on the solar system in this installation?

Also, in the Victron BMZ ESS intstallation guide (victron_bmz_ess_7.0_ess_9.0_ess_x.pdf) it says in the notes: BMZ batteries and MPPT Solar Chargers with a VE.Can communication port cannot be both connected to the CCGX, because of different canbus speeds. Use Solar Chargers with a VE.Direct comm. port instead.

Did you use the SmartSolar MPPT 250/60 (SCC125060310)?


Kind regards

Alex

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Hi Hans, not sure what specs you are looking for. Victrons VE.Can to CAN-bus BMS patch cable is used. Just make sure to connect the correct ends to the BMZ and Venice device (marked on cable).

Used MPPT 250/60 tr



hpro123 avatar image
hpro123 answered ·

Greetings fellow Victrons.

I stumbled onto this thread while looking fo strange behavior of ESS 7.0s.

So @Daniël Boekel (Victron Energy Staff)

this was due to a failure of a €1 fuse inside the ESS?

TIA, Chris

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You'll have to ask @James Minnie but those fuses are not €1 I can tell you.

James Minnie avatar image James Minnie Daniël Boekel (Victron Energy Staff) ♦♦ ·

Apparently these fuses (Pyrofuse) can be damaged by shocks i.e. bumpy roads or drops.