This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
Hello,
Currently I'm using pylontech US3000C batteries with a Multiplus II GX 5000. The cells are 15s inside Pylontech. Nominal Voltage 48V.
I plan do make a DIY Batterie with at least 16s. But could also make the battery with 17s or 18s. I will never charge more than 3,55V per Cell.
Will the Multiplus be more efficient with the higher voltages or is there no effect?
Thanks so far.
Bye Dirk
Just checking if you went ahead with your project? Any complications:advice you may have?
I’m contemplating of going all in with 18s, checked the MPPT and it goes up to 65V, inverter the same, shunt it ok, no other components connected to the DC lines, Cerbo is on a separate 24V supply
there would be no measurable effect I would think.
you will definitly have more power available. As you have same Amps, but more Volts
not more power but more energy, yes
just keep in mind that
- choosing a 16S or 17S architecture will make it incompatible with any existing pylontech (15S)
- 17S means voltage can goes as high as 62V (3,65x17) all your hardware must be able to accept such a voltage
I will replace my Pylontech. So no issue at all. I will never charge up to 3.65 Volt. Max Voltage per Cell ist 3.45 Volt. I never use more. It is not necessary for Lifepo4.
First limitation is BMS. Not all can handle 18S.
Second limitation is mppt. Victron I think can charge to 64V, but I have never tried it.
Third limitation is inverter. MP2 has input voltage 38-66V, so it is ok, but better to check other inverters, just to be sure.
Forth is the law. Voltage above 60V is not considered as "safe" voltage.
Thanks, but first I will use a JK BMS which is flexible up to 24 cells.
Second, I will not use MPPTs.
Third point: I want to use Multiplus. No other inverters. In case in future is there an issue, I will remove one cell. It is DIY and very flexible.
Do you know something about efficiency increase?
All mppt delivering more power with higher voltage, limiting factor is the Ah from mppt.For example:
Pylontech @52V with 20A =1040W
Selfmade 17s @58.9V with 20A = 1178W
So around 13% more power delivery with one mppt is possible…
