Or if you have multiple parallel strings of cells being protected by the same set of fuses, then you could change the design to fuse each string separately.
![battery fuse battery fuse](https://m.media-amazon.com/images/I/41BuB3ODImS._SL500_.jpg)
If you can't achieve a fast enough fault clearing time, then the easiest and cheapest option is probably to go for a faster acting fuse like a class T fuse. I would recommend a max clearing time of 0.5 -1s. Then look at the graph for your fuse and find how quickly it is going to clear the fault current calculated above and make sure you are comfortable with the clearing time. Note: If you have multiple strings of cells being protected by the one pair of fuses, then this fault current should be based on one string of cells, because you might have the other strings out for maintenance. Then calculate the fault current of your batteries (unfortunately not easy for LiFePO4 cells as per this thread), divide it by 2 to include a decent safety factor and account for impedance of cables/busbars, aging of cells etc.
![battery fuse battery fuse](https://i5.walmartimages.com/asr/de639c56-b9a8-41ac-9e42-44b1ee6942a6.7fa2bdd4964c86c88c87c103bec41b4e.jpeg)
I think the way you should be selecting your fuse is by first determining the maximum sustained current they need to carry (I.e the max charge or discharge current of all your inverters/chargers combined) and selecting a fuse rating that is a bit above this value.įor me this is 180A, and I obviously went for a 200A fuse. I based my fault clearing time calculations off the maximum bolted fault current, which I downgraded from 2758A per bank to 1500A per bank to account for aging of the cells, so if one bank was feeding into the fault at 1500A the fault would clear in 0.4s. and a fast fusion would be a uR.Ĭlick to expand.Yes, from what I understand the curves for gL and gG should be the same, hence why I said gG which is the more modern standard. The knife fuse on the picture is a gL, the new standard is gG. they do different things than a class T and for different reasons. To say better is a very wide brush to paint with. Just look around, it’s mind boggling how the bar for acceptable level of failure/ risk has fell so low in the last 20 years… Today,low price is king, not quality, skill, sensibility or common sence.
Battery fuse how to#
In the world of ventures that can kill/ harm you if the gear failed ,“ Head room “ and safety margin in anything you depend on is your friend, “redundancy” is your friend, “back up systems “is your friend…the highest quality you can afford is your friend.Īnd yes the conversation seems to be much of the time ,about how to get somthing for nothing far too often anymore ,by too many people.
![battery fuse battery fuse](http://www.aidunelectric.com/uploads/1m/2006/hrc-nh0-fuse-link-500v-up-to-160a.jpg)
that is a “minimum point “ of acceptability for people who have read about danger, but not experienced it up close and personal, or maybe can’t afford anything better. Secondly, a wise man whose life or health depends on his equipment has no room for the term “sufficient”. Are your cables able to sustain that ?Ĭlick to expand.To say better is a very wide brush to paint with. You can see that a 200A fuse will not blow under 700A before 10s or even something like 500A for 1000s.
Battery fuse pdf#
I see that you used a 200A knife fuse, if i follow Legrand PDF (i dunno if their devices follow the same standard as your) There is also an information of the power draw of the fuse at it nominal current, example : 160A fuse draw 12.3Watts. M i reading it correctly ? Or m i totally wrong here ? not after 1000s or more, but only after let's say. i need my fuse to blow at 150A, and the proper one seems to be a 63A one.
Battery fuse full#
Just as an example, with this baby (I'm in France and Legrand is a French brand)Ī full documentation on how, when those fuses blow.Īnd for what i see. Click to expand.The knife fuse on the picture is a gL, the new standard is gG.