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Flexibility of battery voltage with 75/10

I am going to be using a MPPT 75/10 to charge my custom lithium ion 18650 battery pack. The nominal voltage of the 18650 cells are 3.6V. The 75/10 MPPT is rated for 12/24V batteries. My question is the flexibility of this output battery voltage. Is the 12/24V rating supposed to be the nominal voltage of the battery? Building up an 18650 pack, the nominal voltages could be 21.6V for a 6S pack or 25.2V for a 7S pack. Is the 75/10 MPPT flexible so it could handle this? How much flexibility does it have?

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wkirby answered ·

It's quite flexible. There is the option to set user defined battery settings.
For a 6S or 7S (7S would be better) you still set the charger for 24V operation (because it's not 12V) and then you can choose a user defined preset and customise you absorb and float settings.

Download the VictronConnect app today and choose Solar Chargers / MPPT 75/10 from the list of demo devices and have a play.

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debug avatar image debug commented ·

Thank you very much! What would you say is the upper limit? The amp rating isn't an issue as there isn't many PV panels but more interested in volts. A fully charged 7s would be 29.4V since each cell would be at 4.2V. I originally wanted to build a 10S pack but the 150/35 is a bit overkill.

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wkirby answered ·

According to the demo app 34.78V seems to be the upper limit, which is like 8S. 8S is a bit awkward though, 7s is more in the range for 24V nominal. Keeping close to 24V nominal avoids compatability issues with other products (like inverters) that you may consider in the future.

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debug avatar image debug commented ·

Yes I have downloaded victron connect and found that as well. Thanks for the help!

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