Battery current interrupt fuses

[MMarvin]

Originally Posted by tdf-texas

Class T fuses have an interrupt rating of 20000 Amps and should be used in lithium or paralleled lead acid battery installations. Both of these types of battery installs could produce current interrupt values that would exceed what an ANL / MRBF fuse could interrupt safely.

Maxi/Mega fuses have only an interrupt rating of 2000 Amps and should not be used as primary protection on lead acid or lithium battery banks.

Hi Tom,
Thanks for the info, but of course it leads to another question. My 1000 W inverter is fed by 2 AWG and a 200 A fuse, unknown type but appears to be ANL. From what I read here, my lithium application needs a class T fuse in a holder. Should I stick with the 200 A fuse or use a smaller one?
Marv

[tdf-texas]

Originally Posted by MMarvin

Hi Tom,
Thanks for the info, but of course it leads to another question. My 1000 W inverter is fed by 2 AWG and a 200 A fuse, unknown type but appears to be ANL. From what I read here, my lithium application needs a class T fuse in a holder. Should I stick with the 200 A fuse or use a smaller one?
Marv

I don't have a real good answer for this. Of course a class T fuse would be optimal but from what I have read, most of the lithium batteries have short circuit protection built into them. The rating for the short circuit protection is where I not sure what fuse is required - is the battery short circuit protection rated to handle the interrupt current. If it is then an ANL fuse would be fine - if it's not, then a class T fuse would be required.

No where in any of the lithium battery literatures can I find documentation of the short circuit interrupt current rating.

Keep in mind that the fuse is to cut off the current in case the battery cable / inverter was to short circuit. Without a high enough interrupt current rating, the fuse would continue to feed the short until the wire melted off, the short burned out, or the battery exploded with possible fire in the trailer. Also, this is a worst case scenario and the chances of it happening is very low. Risk management rules are that if the likelihood is low but the consequences high, then the risk must be mitigated.

The 200 amp fuse (ANL or class t) is to protect the inverter as well as the wiring so yes, you will need to stay with a 200 amp fuse. You bought your trailer right before mine and probably have a Mega fuse bolted directly to the battery post like my trailer did. You might want to read this thread - just don't use a Mega fuse!
https://www.escapeforum.org/forums/f...les-19164.html

[tdf-texas]

There are times when I wish I didn't have an engineering background in electrical safety.

I could go blissfully though life without worrying about "interrupt ratings". But I have seen some bad things happen in the past because the electrical wasn't correct. So I worry and try to let others know when things are not right. If they decide to not fix the problems, at least I would know they had the chance to avoid in case the bad things happened to them.

[oldwave]

My upcoming inverter install into a solar equipped trailer will include the go power class t fuse holder and 200 amp fuse.the price difference was nominal. I am also upgrading the feed wire from the wfco charger and the disconnect to 6 gauge.