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tochi avatar image
tochi asked

Charging not to 100%

Hello, we are using two MTTP 100/30 to charge our Bulltron 280 Ah Li Battery with our 600Wp solar panels, everything works fine so far, we are also pleased about graphical interface, very instructive. Nevertheless I'm wondering wether you intend to have direct communicatio between MTTP and battery via bluetooth to stop charging i.e. when filling grade of 80% is achieved. It is not always good to fill Li Battery to 100%. In case there is no communication possible, does it make sense to reduce the charging end voltage or reduce duration for adsortion charging to achieve not charging till 100%?

battery charging
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mvas avatar image mvas commented · 


. In case there is no communication possible, does it make sense to reduce the charging end voltage or reduce duration for absorbtion charging to achieve not charging till 100%?

You could do either one or both. Victron has a BMV that does provide a fairly accurate % SOC.

Periodically, you may need to balance the cells.



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Alexandra avatar image
Alexandra answered ·

@Tochi

It is an urban myth not to charge up a battery to 100%.

The battery manufacturer has already designed their bms to operate the cells within a certain range of the cells abiltity. That range already prevents them from being fully charged (to 100%) and fully discharged (to 0%). If you look up charged voltages for many lifepo4 cells they can be charge all the way up to 3.9v the manufacturer most likely already is not letting them go above 3.6v per cell.

So charge up and float according to the battery manufacturer recommendations.

When they say their battery is at 100% what they mean is 100% of what you are allowed to use.

As @mvas mentioned you will end up having cell balance issues.

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