I’d like some help with ‘max fuse’ selection for hot terminals in the lynx 1000 distributor? My set up… 9× ‘RICH’ RS-m200 panels from the roof box. The panels ‘DC hot leg’ pass through a 50A 150vdc breaker. From here the leg goes into a MPPT 150/70 smart solar charge controller. Then out of the MPPT, into an additional 60a 150vdc breaker. From here we pass to the ‘LYNX 1000’ distributor, where I arrive at my first max fuse question. What size max fuse is placed across this gap for the ‘Solar panel’ DC hot? The next question is what size ‘max fuse’ to connect my ‘MULTIPLUS’ ‘24V/3000/70AMP’ on the same LYNX ‘1000’, which ultimately powers 2 30amp AC lines from 10 BattleBorn 100ah LiFe po4 batteries (5&5 in series for 24v)?
Finally…, should I pre-configure the system for LiFePo4 after the system is powered up from the battery banks, but before I bring the panels on/in line to the charging system? Thanks to the community…
Howdy @jtdscrap,
As a general rule of thumb, any fuse should be rated at 125% for the load it is designed to handle under constant conditions. So for the 50A 150VDC leg you would at minimum use a 62.5A breaker. The link below will take you to Victron’s Wiring Unlimited PDF which has a section discussing this very topic.
But you are looking to get a breaker as close as you can to the max current the circuit will see. The reason you go over and in general the reason for the extra 25% is for unaccounted surges and loads that we can not fully predict ahead of time. Such as sun changing its brightness and your inverter suddenly loosing a load but still getting full current from the solar cells with no where to route the power but to another load in your system which most times is the batteries. The power always has to go somewhere even if its not where we intended. The controllers will try to throttle this as quickly as possible but there will be a short period of time where the controllers still think they need to produce at 100% as the signal gets processed before being commanded to throttle back.
But the article below should cover what your looking for!
Section 4.6 - DC Wiring - Fuses and Circuit Breakers
Section 6.5 - AC Wiring - Fuses and Circuit Breakers
Thank you.
Your welcome!