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Fra avatar image
Fra asked

Smartsolar equalisation and current from Smartshunt

Hello, I suggest to Victron to make a way that the equalization current of the smartsolar can be read by a smartshunt or a bmv via the VE smart network.



otherwise it is impossible to carry out a correct equalization phase if there are loads on the battery.


It is quite frustrating that the smartsolar can use the charging current of the smartshunt to terminate the tail current draw phase, and that it cannot do the same for the equalization phase.


for example if I set the equalization limit to 10% of the current of my smartsolar, it would be 3A (10% of 30A), but if I have 15A of loads on, the voltage will never increase because the charge controller cannot distinguish the current of the loads from that of the battery.


It would be very easy to do this since everything is already set up for the Ve Smart network.

MPPT ControllersBMV Battery MonitorSmartShuntVE.Smart Networkequalisation
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Alexandra avatar image
Alexandra answered ·

@Fra

Do you have enough power to equalize and run loads? is it able to raise the battery to the equalization voltage and keep it there for the duration necessary even under load? If not then you cannot equalize for that reason. nothing to do with the smart shunt or amps. It is everything to do with voltage.

I am assuming you have lead acid batteries and you are not confusing absorption and equalization here.

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Fra avatar image Fra commented ·
hello I understand perfectly what you mean.
yes .. I have enough power for loads and battery.

The problem is another.

EQUALIZATION works like this:

After the end of the Absorption the controller starts a phase with limited current and allows the voltage to rise up to the set equalization limit.

If the current limit is 10% it means that for my controller it is 3A.

now, if I have 8A of loads and 25A of maximum output possible, the controller will use 8a plus what it takes to get at least the absorption voltage ..
it means something around 10A (8A of loads and 2A needed to carry the battery charged to an absorption voltage).

but this means that the current limited to 3A will not be used correctly !!!
because according to the controller this current must already be exceeded to reach the starting voltage of the equalization. ie the absorption voltage.

Therefore the EQUALIZATION limit current works only without loads.

It should be possible for the controller to know the current going into the battery from the VE SMART network, just like it does for the tail current.

also the tail current function is unusable without VE SMART network with shunt, unless the battery is without loads.

the same happens with the equalization current limit.
If there are loads it loses meaning.

what you say I understand perfectly and it has nothing to do with what I am saying.
the question is more subtle.

I would like the voltage to be raised from absorption to target fi equalization WITH ONLY 3A FOR THE BATTERY.
THIS IS NOT POSSIBLE IF THERE ARE LOADS. BECAUSE THE BATTERY WILL LESS CURRENT THAN THE SET EQUALIZATION LIMIT. Regardless of whether I have 30A or 20A available.

But I probably can't explain well with Google translate.
thank you
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Alexandra avatar image Alexandra ♦ Fra commented ·

Because equalisation is such a delicate process, it is best to have a dedicated charger for it.

You cannot run loads off the battery during that period.

https://shop.pkys.com/Battery-Equalization_ep_44.html

The mppt even produces not a constant amp charge (that is a different part of charging stage) it like pulses the battery.

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Fra avatar image Fra Alexandra ♦ commented ·
Yes of course, I understand this.
But in my case the equalization is not harmful to the loads.

I do a very mild EQ.
Every 21 days.

My absorption is at 14.45v up to a tail current of 1.7% capacity.

once every 21 days I would like that after the end of the absorption, an equalization at 3A limited and with final target at 14.9v would start.
A very light equalization for my AGM batteries that allows me to use the lowest absorption and float voltage possible.


However this is only possible without loads.

with loads of more than 3A, the equalization becomes a simple continuation of the absorption, since the controller uses only the (free and NOT LIMITED) current necessary to maintain the absorption voltage (which is the starting point of the equalization).
But he never reaches the final equalization target, as he has already exceeded the equalization current limit to reach the starting voltage of the phase. Becouse never reach 3A in the battery, regardless from the total current avaiable.

Everything would be solved with an EXCELLENT function ALREADY PRESENT IN VICTRON PRODUCTS!
Ie the sending of the battery current in ve Smart by schunt.

in this way I would respect the equalization current limit of 3A regardless of the loads. And I would correctly see a slow increase in voltage from the start (absorption voltage) to the equalization voltage target.

It would not cost anything to have this possibility. because in fact it is already present in the software for other things (for example ending the absorption with tail current, INDEPENDENTLY FROM THE LOADS).
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