Sea Change
Well-Known Member
Yep that looks like the right thing.
It makes class T look cheap though!
Will Prowse Testing main battery fuses
- Thread starter simonfraser
- Start date
It makes class T look cheap though!
Trident
Well-Known Member
There is a lot of debate about this - while we all know the IRC can be huge on LiFePO4 cells , by the time you add in busbars between cells, the terminal clamp, the wire, the fuse holder and the fuse, most agree that the IRC is much reduced. I would always use classT but several very reputable battery manufacturers say that ANL with a 5000A IRC rating are suitable and sell them with their products . (Note ANL have the higher rating than Mega fuses at 2000A)
In testing with reasonable sized battery packs - 400-600 AH, the ANL fuses failed safe (ie blew and did not conduct current afterwards) every time .
As I said, I would not fit other than a class T (NH work but I prefer Class T and the prices have dropped a lot) but even a professional could be forgiven for using an ANL fuse on a smaller system when the manufacturers of the batteries may well have recommended them.
As I tend to tear in to those who do bad work I try also to be fair to those who may conscientiously follow manufacturers advice and frankly probably did no harm.
Trident
Well-Known Member
Your bete noir, Renogy sell them with their LiFePo4 batteries under their own brand (not of course that the fuses will be made by them)
Even large well known companies (that I use myself for solar) tell customers and "professionals" alike that these are ok
Trident
Well-Known Member
I spoke to a pair of domestic sparks yesterday who are off to install a full off grid system in a remote house and wanted a pair of "cheap inverters, 3000w" if I had any. A discussion ensued , no idea about LF inverters and the advantage for continuous use, no idea about the benefits of using a 24v or better still 48v system (especially as its all for conversion to 220v via the inverters) and no concept that one type of LifePo battery might be better than another ... never got as far as fuses. I know they work with domestic systems not DC etc but they didn't seem to have the basic concepts and are fully certified professional NICEIC electricians wiring a full off grid system to a house which the owner has left them to plan as well as install . Gulp
jakew009
Well-Known Member
I agree I don't think it's necessarily fair to say that lithium without a class T fuse is always bad. It's much more nuanced than that.
My biggest bugbear with 'ANL' fuses is the amount of junk versions on the market. I think that's what Will Prowse was trying to get at in his video.
For instance, this Renogy ANL fuse spec sheet tells you nothing useful at all: https://images.thdstatic.com/catalog/pdfImages/b1/b1dea9bd-1833-4382-8d7c-affcbfdbb164.pdf
I'll ignore the nonsensical 'Interrupt Capacity' column in the table. In my opinion this sort of shit has no place on a boat ever.
This Eaton ANL fuse datasheet has an AIC of 2700A @ 80VDC, still very low. Sure it's probably higher at 12V but Eaton weren't prepared to put that on the datasheet.
https://www.eaton.com/content/dam/e...ion/fuses/data-sheets/bus-ele-ds-2024-anl.pdf
In the machines that we manufacture that have big lfp batteries in them, we use a lot of Eaton AMX fuses: https://www.eaton.com/gb/en-gb/catalog/electronic-components/amx-and-amh-fuses.html
They are identical in size to a MIDI fuse, dirt cheap and rated for 8 kA @ 63 Vdc all the way up to 300A.
I thought about using these on my boat but decided I couldn't be bothered with the inevitable questioning. It's also not easy to get big wires on them without factory made busbars.
Generally speaking fuses are one of the few things that I genuinely think are worth paying the premium to have a known brand on them with a proper datasheet. You won't find any no name Chinese megafuses under the bonnet of your car...
jakew009
Well-Known Member
I also always find it interesting that these Chint CB-125A's that you see on all the server rack batteries are rated for 20kA@60VDC.
Even these dirt cheap things have a 10kA rating @ 110VDC
https://www.screwfix.com/p/chint-nb1-63a-sp-c-curve-mcb/1471V
Even these dirt cheap things have a 10kA rating @ 110VDC
https://www.screwfix.com/p/chint-nb1-63a-sp-c-curve-mcb/1471V
PaulRainbow
Well-Known Member
No mention of being DC rated in the data sheet though.
Alex_Blackwood
Well-Known Member
Alex_Blackwood
Well-Known Member
May be more suitable? https://www.fruugo.co.uk/2p-mccb-so...jdLZGNzLPJIQmFLmSz0Wd2RGJooZbJQBoCAvwQAvD_BwE
jakew009
Well-Known Member
An entirely unbranded mccb from Frugo that’s way more expensive than a proper Class T… rather you than me.
Alex_Blackwood
Well-Known Member
It is an example! loads around to choose from
Note that it is a Moulded Case Circuit Breaker (MCCB) not Miniature Circuit Breaker (MCB).
PaulRainbow
Well-Known Member
There are indeed loads around, many look identical to the one you linked to, with various oddball names on them and some have slightly different spec's.It is an example! loads around to choose from
This one is a particular bargain https://www.alibaba.com/product-det...1601432093533.html?mark=google_shopping&seo=1
2 year warranty, CE approved
A quality one will be more expensive that a class T fuse, so i think i'll stick with the fuses.
Daverw
Well-Known Member
Sea Change
Well-Known Member
By the way, I recently bought a couple of Renogy Class T fuses which were a decent price, only to discover that they are only 10kA AIC. Not very impressed, I thought the AIC rating was part of the class T spec but clearly not.
st599
Well-Known Member
Nope, the spec just says:
Electrical equipment intended to interrupt current at fault levels must have an adequate interrupting rating to handle the maximum current it may need to interrupt.
