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Steve Mullins avatar image
Steve Mullins asked

What would cause Regular High Voltage Alarms with Multiplus?

What could be causing my Multiplus to generate a regular High Voltage alarm on my BMV. I have disconnected my solar charge controller to isolate the Multiplus as the only item charging the Lithium battery bank.

Multiplus-II
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5 Answers
Steve Mullins avatar image
Steve Mullins answered ·

Here’s an example from in the past, where I was not drawing any high amps from ththe batteries, yet the inverter seemed to issue high voltage for a short time.


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boekel avatar image boekel ♦ commented ·

could it be you have batteries that disconnect (in- or externally) from the system? that, or loose connections could explan this.

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Paul B avatar image
Paul B answered ·

what have you got the high voltage allarm on the bmv set to and what have you got the multiplus charger setting set to.


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robbo avatar image
robbo answered ·

14.6v is quite high for Lithium's, I would change your Multiplus charger settings, Ideally should be 14.2v

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Steve Mullins avatar image
Steve Mullins answered ·

I am using Battleborn batteries so I have asked them their recommendations. They recommended setting the high voltage alarm to 14.7 on the BMV. I also notice the high voltage occurs when the Multiplus state goes into absorption mode which I thought we didn’t want for Lithium batteries. Any thoughts on what settings can prevent the Multiplus from going into absorption mode. I’ve also asked Battleborn batteries for their thoughts as they originally sent recommendations on the Multiplus charge settings.


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boekel avatar image boekel ♦ commented ·

you can just use the same voltage for absorption and bulk


what I wrote before: what kind of battery, might have internal disconnect.
https://battlebornbatteries.com/wp-content/uploads/2017/09/Battle-Born-Manual.pdf

I think a cell reaches the upper voltage limit and the battery disconnects itself.
Contact the battery supplier with this data, sounds like it's got too much imbalance and needs to be balanced / replaced.

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Steve Mullins avatar image
Steve Mullins answered ·

Heres an historical log showing ve bus state and voltage.




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boekel avatar image boekel ♦ commented ·

that looks like a normal curve.

however, when the batteries are balanced, I'd not charge higher than 14,2v (minimum voltage for balancing according to manual), and not stay there for more than 30 minutes.

the batteries are really fully charged when floating at 13,6 for a while, higher voltage means shorter life, but you seem to need it to balance the battery internally.

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