Greetings. I have a 120amp breaker/cutout between 9 200 watt panels to the MPPT. This is installed just before the MPPT, protecting the ‘PV’ input side. In the system diagrams, I show that there is another breaker/cutout installed between the ‘BATTERY’ side of the MPPT, which then feeds into the LYNX 1000 distribution/shunt.
Should I even worry about installing a second breaker/cutout between the MPPT & the LYNX, as the LYNX has the MAXFUSE bridge, where I’m able to install a 120amp max fuse? Thank you…
120A sounds rather high for the PV input side to the MPPT. If you have several strings (sounds like 3s x 3p) - then the strings should be individually fused at approximately 16A.
The MPPT has an internal fuse on the battery side, and you can also protect the wiring / MPPT with a fuse in the LYNX - max rating should be about 90A (1.25X I). So the nearest rating to this is 100A. A breaker is not needed, except for easy disconnection - not normally required.
Thank you. I appreciate the insight. I paid for a system, which was void of any real instructions. I have 3 sets of 3 200w Panels in ‘series’, then grouped ‘parallel’ on the +/-Buss in the roof combiner box. I’m getting my breaker size by the Short Circuit Current (ISC): Each 200W solar panel has a short circuit current of approximately 10.2A. For 9 panels, the total short circuit current would be 9 x 10.2A = 91.8A, then adding 22.5amps & rounding up to 120amp breaker/cutout.
The attachment shows two breaker/cutouts in a baby box, one 50amp between the panels & the mppt going into the PV side, one 100amp between the mppt & the lynx 1000. In place of the 100amp breaker/cutout, I have a 60amp, as this is just what was sent. The 120amp was to be installed in place of the 50amp, which is still in place. I figured the 50 had to be a mistake?? So as it sets with my array, thats a 50amp between Panels, & MPPT PV(in), & a 60amp between MPPT battery out to the LYNX. Massive Victron woes… Much appreciated…
In series the voltage is x number in series, amps stays the same as 1 panel.
In parallel the voltage remains the same as 1 panel and amps is x number in parallel.
Thank you again
For 3 strings (panels in series) Each string should be fused at 1.25 the Isc of the modules.
Also the fuse from the MPPT to the bus should also be rated at 1.25 - 1.5 times the expected current. As this appears to be a 24V system, 1800W of modules should give ~75A, so depending on the mppt (60A or 70A?) the fuse should be 80 - 100A.