Equalization charge with a MPPT 75/15 controller

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zatux asked Jul 9, '19

Equalization charge with a MPPT 75/15 controller

Hi, I am trying to activate an equalization charge for a lead acid battery using a MPPT 75/15 controller.

The setup is used on a tower that provides Internet access. The tower is located on a mountain that is difficult to access physically. I have used an Arduino with an Ethernet shield connected to the TTL serial port of the charge controller and then patched onto the Ethernet network of the tower. I monitor the battery and solar panels and change settings as needed remotely.

It looks like the controller does not support manual equalization activation therefore I have tried to set the controller to do an equalization charge once a day (which I will take off once the equalization charge is performed) by setting register 0xEDFD to 1.

The problem is that the controller seems to merely extend the duration of the absorption charge to it's maximum time (6 hours for initial voltage less that 11.9) even if the current falls below 1 Ampere. The voltage still stays at the absorption level (14.38V) and does not increase to the equalization voltage. After the absorption stage the controller activates float charging.

The firmware version on the controller is 1.16.

Any help would be appreciated very much.

MPPT Controllers VE.Direct equalisation

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Modifications Space

Node Red Space

Answer 1 · 2019-07-14T10:05:30Z

Daniël Boekel (Victron Energy Staff) answered · Jul 14, 2019 at 10:05 AM

Hi @zatux
I've moved your question to the 'modifications' space, where technical questions outside the normal use are better handled.

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Answer 2 · 2019-07-19T22:14:54Z

neoneddy answered · Jul 19, 2019 at 10:14 PM

I would say you want to update the firmware on that. There are some critical bugs that were fixed that could damage the charger permanently.

I wonder if by the time you want to do the equalization charge it's too late in the day to get the amps required? or the battery isn't full.

Lastly, daily equalization charges?... Are you sure you want to do that? If it's a lead acid of any kind you're gonna gas the batteries. I hope there is a watering system for them if flooded, if AGM, you'll cook em, and if Lithium.... well, I don't think you should equalize lithium, use a BMS I'm told.

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zatux commented · Jul 20, 2019 at 11:21 AM

Hi neoneddy,

there is plenty of sunshine left when the charger enters float mode so an equalization charge should not be a problem for the panel.

I only want to perform an equalization charge once. I'm using a lead acid battery. My problem is that I cannot get the charger to perform an equalization charge. It seems that the 75/15 does not support manual activation for this and therefore I have set the controller to perform a daily equalization charge but it only extends the absorption time and the voltage does not increase.

Are you saying that the controller would be damaged when performing an equaliztion charge on the current firmware (1.16)?

Thanks

Nico

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