question

kevin-murphy avatar image
kevin-murphy asked

Significant voltage fluctuation during absorption phase - Victron Multiplus 12/3000/120-50 120V VE.Bus

Need some help troubleshooting an issue that occurs during the absorption phase when charging from shore power using the multiplus. Everything works during the bulk phase, but when the batteries get to about 14.4v things start go haywire. Voltage goes up to about >15.5v then drops to 13.2v at 0 current. Every once in a while a current this keeps on going on and on. In the capture below there was 0 load on the 12v system with the MPPT and the Orion not receiving any current. See this example :

img-8836.png


*** Note everything works perfectly when charging with the MPPT. Same charging parameters.


My setup is composed of the multiplus, lynx distributor, Ve.bus dongle, smart battery sense, interface mk3 usb, BMV-712, MPPT 100/50, orion tr 12/12 (charges the starter battery) and 4 SOK 206ah batteries.


The multiplus was setup with recommended settings using the mk3. I have also reset the multiplus to factory and reapplied the settings. Verified that there is very minimal voltage drop from batteries to multi. Here are some pictures of the setup.


img-8834-small.jpegimg-8839-small.jpeg

img-8833-small.jpeg


battery charging
img-8836.png (995.9 KiB)
img-8839-small.jpeg (29.0 KiB)
img-8834-small.jpeg (35.1 KiB)
img-8833-small.jpeg (32.2 KiB)
2 comments
2 |3000

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OP, I will ask where/if you have installed the V Sense wires form the multiplus.

Your photos are "ordinary".

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Sorry for the poor pictures! I was converting from the iPhone and used the wrong setting.


Your comment lead to further searching of the comment pages on this forum and I found a couple of threads that referenced connecting the ve.bus dongle directly to the batteries. I did that and it seemed to help with the magnitude of the wild swings in voltage but did not resolve it completely. Maybe this was referenced in one of the manuals somewhere but obviously, I missed it!


I also noticed other users of this forum have run into similar problems. One crossing the Indian ocean. I'm wondering if there is some sort of systematic misconfiguration issue for these cases?


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4 Answers
trevor-bird avatar image
trevor-bird answered ·

Hello @Kevin Murphy .....That voltage variation could be attributed to an active BMS switching in and out. I understand the voltage is within the specification of the Battery but perhaps if the absorption voltage setting is lowered, that lower voltage may allow the BMS to not be so active.

Regards,

Trevor


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kevin-murphy avatar image
kevin-murphy answered ·

Alright I will try stepping down the absorption voltage and see what happens.

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kevin-murphy avatar image
kevin-murphy answered ·

Ok tried reducing the absorption voltage but it did not work. Any more suggestions?

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trevor-bird avatar image
trevor-bird answered ·

No, if you have taken the absorption voltage down significantly and it still happens I have no other thoughts. Sorry about that.

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Hello @Kevin Murphy , in the absence of any further assistance, perhaps read this post to understand a problem I had which’s need similar.

Regards

Trevor

https://community.victronenergy.com/questions/129138/quattro-shutting-down-lithium-batteries.html

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