Voltage bouncing with Multiplus 12/3000

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dkyork asked Apr 3, '20

Voltage bouncing with Multiplus 12/3000

Hi everyone,

I installed a brand new Multiplus 12/3000 yesterday with 4 Lion energy 1300 lithium batteries. I used all 4/0 cabling and the ones between the batteries are exactly the same length. I'm currently hooked into a stable 50 AMP plug on my house and have a BMV-712 installed. I also have the Smart Dongle. My absorption and float rates are configured at 13.9. When monitoring voltage from the BMV or the Smart dongle, my voltage is bouncing hard between 13.5 and 14.3. If I change the absorption rate to 14.4 or 14.6 per Lion Energy, my voltage will bounce between 14 and 15 volts. I was told my voltage should be stable and not bounce like this.

Below are the steps of troubleshooting I've been able to do thus far and looking for assistance, as I'm not an expert by any means.

- Updated software to v469

- Turned off 150/100 MPPT charge controller(I don't have panels yet anyway, but just in case)

- Voltage is bouncing at all the batteries with multiplus charging in absorption

- With inverter off, Voltage is stable at 13.6ish volts at all batteries individually and off parallel leads

- Turning inverter back on, voltage bounces again at each battery and main leads from battery to inverter

- Changed absorption charge rate in multiplus settings, 14.4,14.6, etc.. still bounces, but higher

I'm not sure what else to do now and looking for troubleshooting guidance. Should I open up the Multiplus and measure the voltage coming out of the terminals where the battery leads come out of? Should that voltage be stable?

Thank you,

Dale

battery charging voltage

screen-shot-2020-04-02-at-115428-pm.png (359.6 KiB)

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klim8skeptic ♦ commented · Apr 03, 2020 at 07:46 AM

Showing the BMV amps would be helpful.

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dkyork answered · Apr 03, 2020 at 10:29 PM

Gents, problem solved. The smart dongle was wired into the Battery terminals on the Multiplus and was the cause of all the issues. As soon as I moved the smart dongle wires to the battery, the Voltage remained stable with cat5 plugged in. Alan Santos Buch helped me resolve this, so many thanks to him.

Btw, I read all the manuals except the Smart dongle one. SHEEESH!!! There is a video on AMSolar where they show it hooked up to the Multiplus and I assumed it was supposed to go there. BAd on me for not verifying!

Take care all and thanks for reading.

Dale

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Modifications Space

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Answer 1 · 2020-04-03T07:05:33Z

Guy Stewart (Victron Community Manager) answered · Apr 03, 2020 at 07:05 AM

While the voltage issue is occurring, can you put a multimeter onto the individual batteries terminals to see if any, one, or all are behaving?

Did you charge each of the batteries individually before connecting them together?

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Answer 2 · 2020-04-03T14:48:23Z

dkyork answered · Apr 03, 2020 at 02:48 PM

Hi Guy,

I did that yesterday as part of my troubleshooting steps, but will try again when I get back outside in a few minutes. The voltage bouncing is all the time during absorption. I need to check bulk again. Should I measure right off the Multiplus as well to see if it's bouncing right off the battery terminal hookups on it?

I was not able to charge the batteries individually before hooking them up. You think it's just equalizing?

Take care,

Dale

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Answer 3 · 2020-04-03T15:25:11Z

dkyork answered · Apr 03, 2020 at 03:25 PM

Hi Guy,

Here's what I just did. Multiplus is currently in Float mode now. Voltage is still bouncing like crazy. I measured the voltage on each battery in the parallel bank. I also measure off the bank main leads back to inverter. I measured directly off the inverter battery terminals. Voltage is bouncing on all of them. I've attached the latest screenshot fluctuating over 1V every second.

thank you,

Dale

screen-shot-2020-04-03-at-112409-am.png (354.3 KiB)

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Daniël Boekel (Victron Energy Staff) ♦♦ commented · Apr 03, 2020 at 09:38 PM

Hi @DkYork

as already asked by someone else: please also show Current in the graph (click on 'none' and select Current)

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