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jkirkebo avatar image
jkirkebo asked

Smartsolar maximum battery voltage

I am looking for a MPPT charge controller to charge a 11S lithium pack. However I cannot find any info on the maximum battery voltage of the different SmartSolar units (just a generic 12V24V or 48V statement).

It seems the absorbtion/float voltage can be set freely on these units but which unit can do the necessary 46,0V? Do I need to go to the expensive 150/35 or will the 100/20 do that? Input is only 440W@72V so no more that 10A output. Thus the 150/35 would be massive overkill.

It's not exactly easy to find small low-power 46V capable charge controllers...


MPPT Controllers
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3 Answers
stevo07 avatar image
stevo07 answered ·

Have a look at the datasheet below. The voltage absorption and float voltage limit is stated:


https://www.victronenergy.com/upload/documents/Datasheet-SmartSolar-charge-controller-MPPT-75-10,-75-15,-100-15,-100-20,-100-20_48V-EN.pdf

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jkirkebo avatar image
jkirkebo answered ·

Maybe I'm blind ;)

I can only find the following line:

Charge voltage 'absorption' 14,4V / 28,8V (adjustable) 57,6V (adj.)

It says "adjustable" but not what the limits for adjustment are. I was not aware there was a 100/20-48 model, that one will be perfect if the absorbtion and float voltage can be adjusted as low as 46,0V. But I need to know in advance, to expensive just to buy one to test :(

Same goes for float. I need it to charge up til 46,0V and hold voltage there until there is not enough sunlight anymore to do that. This is for a 11S lithium pack, thus needing the same value for bulk/absorption/float.

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adev avatar image adev commented ·

In the VictronConnect app there is a demo section where you can create virtual instances of all these products. I just did so for the 100/20_48.


With the battery set to 48v, there is still no way to adjust the bulk voltage. Abs, float and equalization can all be adjusted between 36.00v and 69.56v - to 2 decimal places.


I hope that’s helpful.

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Mark avatar image
Mark answered ·

I recommend to download the free VictronConnect software, then use the DEMO feature to select any potential MPPT unit and have a play yourself to see what the charge voltage can be adjusted to (as well as how it all works).

As long as the unit is capable to charge a regular 48v battery I think it should be fine.

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jkirkebo avatar image jkirkebo commented ·

Thanks, that did it :)

Using the demo mode I was able to set all voltages to 46V no problem, the maximum voltage is actually 69,56V for the 100/20-48V so it'll work fine also with 16S lithium. Great news, finally an affordable 48V MPPT :)

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Mark avatar image Mark ♦♦ jkirkebo commented ·

Glad to hear - sometimes its easiest/quickest to just try for yourself! :-)

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adev avatar image adev jkirkebo commented ·

where you able to also change the bulk charge voltage?

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Mark avatar image Mark ♦♦ adev commented ·

The absorption voltage IS the target voltage during the bulk phase. They are not 2 different voltages.

During the bulk phase the battery is charged with as much current as possible until the absorption voltage is acheived.

Once the absorption voltage is achieved then the phase description changes from bulk to absorption and the charger reduces charge current as required to maintain the absorption voltage setpoint.

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adev avatar image adev Mark ♦♦ commented ·

OK that’s something I obviuosly didn’t understand from looking through the settings, thanks.

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