My Inverter (Multiplus II 48/5000/70) calls for a 200 amp fuse between the battery and the inverter.
If I use a smaller fuse (perhaps 150 amp) or a 150 amp circuit breaker, is that OK, ie, safer?
The battery can output 101A~120A (for 3min) and 121A~180A (for 15sec).
Thank you!
If you have this situation at least ones then fuse will burn. The price difference is not so huge but you will avoid changing fuses from time to time.
I was thinking the lower amperage would protect the inverter “better” and if I keep it below 150 I can use 2/0 instead of 4/0 cables.
My battery system has 4, 51.2v, 100ah batteries – What could cause it to draw more than the 75a to 100a it is designed for? [I’m a newbie / novice, so please excuse my ignorance]
Thank you!
The fuse is there to protect the wire should a direct short occur on the way to the inverter or inside the inverter.
Protecting the inverter itself is secondary.
By using a 150A fuse, you are potentially limiting the surge capability of the Multiplus unnecessarily. Most fuses don’t blow instantly though, so short surges will be fine.
My philosophy is to give the battery to inverter cables the lowest resistance shortest path to provide the maximum benefit. Then you won’t have lights dimming or motors stalling, etc. If Victron recommends 4/0 AWG and 200A fuses, that’s what I recommend.
I don’t known which battery you have and how are they connected, but 4x100a batteries, if they are connected in parallel, from most of vendors, can be discharged around 200A as a bank. I have 6xPytes 48100, standard discharge current is 50A each. So be careful with installing 150A fuse
@NYSolar Have a quick read of especially the first para in the linked FAQ, the Victron recommendations for inverters have to take account of more factors. Larger CSA cable is always better, lower CSA is to be avoided. Putting in a smaller fuse will increase resistance and runs the risk of overheating the fuse because it is run at a higher fraction of its rated current.
Thanks - that’s a nugget of knowledge about smaller fuses creating more resistance as they are nearer their limit. I also found everyone’s info very helpful–many thanks! I ordered a 200A circuit breaker…I hope it works similarly to a fuse…
The inverter is rated for the fuse that the manufacturer recommends for regulatory testing. It is done this so I can assure you it’s not more protected.
The breakers work differently to the fuses. You can also have thermal tripping with a breaker.
The inverter has its own overload protections, they work well if the battery is sufficient.
A fuse blowing should never happen in normal operation, they are only there for if there is a problem.
This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.