• Have you tried out dark mode?! Scroll to the bottom of any page to find a sun or moon icon to turn dark mode on or off!

diy solar

diy solar

Help fusing inverter to battery

EddyKa

New Member
Joined
Jan 24, 2025
Messages
1
Location
Uganda
I am doing a DIY solar system and am confused on what size of fuse i need to use between the inverter and the battery. Attached bellow is the inverter specification and under the inverter mode it shows DC input 24VDC and 158A, when i research online i find that i should use a 200A or 250A fuse. Please help with which fuse side to use. My battery bank is 24v 100ah
 

Attachments

  • 20241203_123729.jpg
    20241203_123729.jpg
    94.3 KB · Views: 19
Thread moved to the "Over Current Protection Devices".

Interesting label on the inverter. Is it VA or W for the rating. They're not the same thing! I took the higher of the two (Watts) and came up with a 225 amp fuse. 4000 watts / 24 volts / .94 inverter efficiency * 1.25 = 221 amps.
 
I would check your battery max discharge rate, as you state 24v 100ah battery bank and usual max discharge for most would be 1C = 100A.
 
That appears to be an oddball 4KW variation on a Voltronic Axpert VM II series inverter (normally 3KW or 5KW.) It appears to have an internal battery fuse as most Voltronic inverters do (150A in this case) referencing this service manual: https://domosimple.eu/forum/attachment.php?aid=2395. I know my Voltronic Axpert Max II came with a spare fuse in the box, did this one not come with a spare you can reference for the fuse rating? In any case, if it is using an internal 150A fuse putting anything larger than 150A outside of the inverter won't be useful, the 150A internal one will always blow first.
 
24v100ah - is that a single battery or several in parallel?

Assuming single that usually means 100amps max and you would fuse and wire to 125amps.

If it is several in series/parallel like a 2s2p setup then each battery set would contribute to the whole but the individual strings would need to be fused.
 

diy solar

diy solar
Back
Top