michael d
off-grid solar pilgrim
I would like to read that discussion of paralleling fuses if you can provide the source...
right now I am not paralleling them,,,, but still researching that...
NH fuse in parallel?? aka NH knife blade fuse aka DIN NH blade fuse
- Thread starter michael d
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right now I am not paralleling them,,,, but still researching that...
michael d
off-grid solar pilgrim
Just as a sidenote, before buying anything else, please show me what you want to buy and what you want to do with it so that I can tell you if its the right thing or not
NV 2 C
NH 2 C
250A gL/ gG
this one seems to have a indicator of some sort (the fuse base is 8 inches long)
so if it has an indicator??? if it pops out that would mean the fuse is blown....
I have a 24-volt inverter running a 5000-watt load (sometimes) and use 4/0 cables between the LifePO4 battery and the inverter
5000 watts divide by 25.6 volts(nominal voltage) = 195.31 amps
fuse factor increase of 1.25 times
so 195.31 times 1.25 equals 244.14 amp fuse size
so I am thinking a 250 amp fuse is the correct size for a 5000-watt inverter load...
the catastrophe fuse is to protect the inverter..... hopefully
michael d
off-grid solar pilgrim
the 3200-watt 24-volt inverter: calculates out to needing 156.25 Amp fuse so a 160 Amp fuse should be about right.
3200 watts divided by 25.6 volts equals 125 amps
125 amps times 1.25 fuse size increase factor equals 156.25 Amps
the 15000-watt inverter is 48-volt.
so 15000 watts divided by 53.2 volts equals 281.95 Amps
281.95 Amps times 1.25 fuse size factor increase equals 352.44 Amps
I have 355 amp and 400 amp NH fuses... so either of those should work for the 15000-watt 48-volt inverter...
still trying to understand the fuse jargon better to get the right fuse for the different parts of the system...
DC-rated disconnects are still to be determined for better quality/ reliability.... still working on that part...separate from the fuse part.
the sun was out in good force yesterday (January 27th,2024)and production was good for PV with a little snow melting at 36 degrees Fahrenheit...
with improving outside temperatures >>> I was working on the support shelf for the larger LiFePO4 in the off-grid solar power shed....a heat wave compared to 20-30 degrees below zero Fahrenheit with wind chill a week before!!!
3200 watts divided by 25.6 volts equals 125 amps
125 amps times 1.25 fuse size increase factor equals 156.25 Amps
the 15000-watt inverter is 48-volt.
so 15000 watts divided by 53.2 volts equals 281.95 Amps
281.95 Amps times 1.25 fuse size factor increase equals 352.44 Amps
I have 355 amp and 400 amp NH fuses... so either of those should work for the 15000-watt 48-volt inverter...
still trying to understand the fuse jargon better to get the right fuse for the different parts of the system...
DC-rated disconnects are still to be determined for better quality/ reliability.... still working on that part...separate from the fuse part.
the sun was out in good force yesterday (January 27th,2024)and production was good for PV with a little snow melting at 36 degrees Fahrenheit...
with improving outside temperatures >>> I was working on the support shelf for the larger LiFePO4 in the off-grid solar power shed....a heat wave compared to 20-30 degrees below zero Fahrenheit with wind chill a week before!!!
michael d
off-grid solar pilgrim
I have Siemens 80 amp NH and 160 amp NH fuses as well..
I have triple fuse holders if I want to try paralleling any fuse for the smaller fuses. but have not tried that yet...
the smallest inverter is a 1500-watt 24-volt inverter.
so 1500 watts divided by 25.6 volts equals 58.59 Amps
53.59 amps time 1.25 fuse size increase factor equals 73.24 Amps >>>
so the 80 Amp NH Fuse would be right for the 1500-watt 24-volt inverter.
I have triple fuse holders if I want to try paralleling any fuse for the smaller fuses. but have not tried that yet...
the smallest inverter is a 1500-watt 24-volt inverter.
so 1500 watts divided by 25.6 volts equals 58.59 Amps
53.59 amps time 1.25 fuse size increase factor equals 73.24 Amps >>>
so the 80 Amp NH Fuse would be right for the 1500-watt 24-volt inverter.
michael d
off-grid solar pilgrim
more than one inverter can be connected to each LiFePO4 DIY battery....
each inverter will be fused separately....
usually no more than two inverters on any battery at the moment....
smaller inverter for smaller loads
bigger inverters for bigger loads on a bigger battery
NH fuse is the upgrade partially....
each inverter will be fused separately....
usually no more than two inverters on any battery at the moment....
smaller inverter for smaller loads
bigger inverters for bigger loads on a bigger battery
NH fuse is the upgrade partially....
Remote DC disconnect? Or just a manual disconnect?I plan to utilize the NH fuse-links between the high amp lifepo4 battery and the inverters...
I thought the PV fuses would be a step up in protection in case of catastrophe....
the price of class T fuses and fuse holders has increased significantly in the past year....
I was reading that the NH fuses are better (ie they do not explode ) at least the idea is to improve the system's safety...
I have 3200-watt inverters, 5000-watt inverters, and up to 15000-watt inverters hooked to 4 separate lifepo4 battery builds....
I also have some prebuilt lifepo4 batteries ...
at any rate, the primary purpose is to utilize the NH fuse between the inverters and the lifepo4 batteries...
The DC disconnect is another part I still need to improve in the system...
all is done off-grid with no connection to the grid....
more later,
Paralleling fuses is not the best idea as no 2 fuses have exactly the same resistance, so you always have a fuse carrying a higher current than the other one, meaning one will fail more likely. Then there will be an additional amount of time it takes for the second fuse to blow, which leads to a higher total energy in a possible short circuit and therefore probably more destruction/damages
Yes, the red tab on top is the indicator that the fuse has blown. On that ETI fuse you also have the red dot on the front, if its blown the rered dot will disappear
You dont calculate with the acutal voltages (25.6V) but instead with 24V or 48V to have some securitythe 3200-watt 24-volt inverter: calculates out to needing 156.25 Amp fuse so a 160 Amp fuse should be about right.
3200 watts divided by 25.6 volts equals 125 amps
125 amps times 1.25 fuse size increase factor equals 156.25 Amps
the 15000-watt inverter is 48-volt.
so 15000 watts divided by 53.2 volts equals 281.95 Amps
281.95 Amps times 1.25 fuse size factor increase equals 352.44 Amps
I have 355 amp and 400 amp NH fuses... so either of those should work for the 15000-watt 48-volt inverter...
still trying to understand the fuse jargon better to get the right fuse for the different parts of the system...
DC-rated disconnects are still to be determined for better quality/ reliability.... still working on that part...separate from the fuse part.
the sun was out in good force yesterday (January 27th,2024)and production was good for PV with a little snow melting at 36 degrees Fahrenheit...
with improving outside temperatures >>> I was working on the support shelf for the larger LiFePO4 in the off-grid solar power shed....a heat wave compared to 20-30 degrees below zero Fahrenheit with wind chill a week before!!!
If there is no need for remote switching then I would recommend using NH-Switches, here is one for a single NH2 fuse i.e.DC-rated disconnects are still to be determined for better quality/ reliability.... still working on that part...separate from the fuse part.
It takes one NH fuse (either NH1 or NH2) up to 400A. You can use it as fuse base and DC disconnect switch
Don't parallel them, it just makes things messy and problematic.I have Siemens 80 amp NH and 160 amp NH fuses as well..
I have triple fuse holders if I want to try paralleling any fuse for the smaller fuses. but have not tried that yet...
the smallest inverter is a 1500-watt 24-volt inverter.
so 1500 watts divided by 25.6 volts equals 58.59 Amps
53.59 amps time 1.25 fuse size increase factor equals 73.24 Amps >>>
so the 80 Amp NH Fuse would be right for the 1500-watt 24-volt inverter.
1500W / 24V = 62.5A (without your factor the best fuse would be 63A)
Times 1.25 would be 78.125A so the 80A fuse is your friend.
Each battery should have one fuse to the main busbar, every inverter should have one fuse to the busbar.
michael d
off-grid solar pilgrim
that is interesting the fuse base disconnect combo; it is somewhat expensive at 126 dollars plus tax on Amazon in the USA....
essentially a convenient fuse puller built in to the fuse holder...
michael d
off-grid solar pilgrim
thanks for all the replies, that is the plan...
michael d
off-grid solar pilgrim
manual DC disconnect
So you are based in the US? There are single pole NH disconnect switches from a lot of brands, not only ABB, maybe you can find a used, cheaper one.
I dont know your exact setup, but if you have multiple 24 or 48V batteries with inverters you could look for 3 pole NH2 disconnect switches, put a massive copper busbar on 3 of the poles of the NH disconnector and then have 3 connections, i.e. 2 fuses for 2 batteries and one for an inverter
michael d
off-grid solar pilgrim
found this fuse and fuse size table for NH fuses
michael d
off-grid solar pilgrim
yes, i have a hard search trying to find some things in the USA compatible with NH fuses....
I do have blue sea 350 amp DC switches I could put inline as manual DC disconnects....
Never seen the lower NHA fuses, cant find them on the internet either
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