has anyone used Littelfuse mini 58v fuses?

any one used these fuses https://www.digikey.com/products/en?mpart=0997005.WXN&v=18 they are 58v dc rated instead of the more common 32v dc rated. They are drop in replacements for older mini fuses.
These fuses are 42vdc nominal from what I have read and 58vdc rated.

Only ones of a small amperage I can find that are rated at more than 32 volts DC.

Was thinking 3 or 4 amp fuses between the 36v battery positive and negative

later floyd

Nice. That'd be a good drop in fuse as the holders for those have really tight slots to makes sure they have contact. They are a bit expensive, though.

Well connected a 8 36v batteries in parallel with 5 amp fuse on both positive and negative wires for each set of 2 batteries hooked it to my inverter input was 41.8v output was 122 vac on inverters display, with a dmm the output was 120-121vac .I plugged in my vacuum cleaner to inverter promptly blew 6 of the 8 fuses.
The vacuum cleaner is 9 amps @ 120vac I don't have an inrush amp meter. need to get higher amperage fuses, connect each battery individually with fuses, build a larger parallel bank.

9 amps x 3-7= 27 - 63 amps/4=6.75 amps-- 15.75 amps
in all cases the fuses may have blown. will check the Data sheet on the fuse.
Individually fused would be half the current / Larger Bank 1.5 (tested batteries) - 5 (total batteries) times Larger
building for max output 6000wsurge/36=167 amps. 167/20=8.35 167/40= 4.175
Looks like I should fuse each battery. please correct if I have made any mistakes in my calculations other than loses do to resistance, efficiency of inverter.

Later floyd

An inductive load can easily pull 5-10x the nominal when starting up. This is something many people tend to forget when designing and that's also one of the MAIN reasons I over and over say that you cannot do to small fuses (for instance cell fuses)

Also note that when you individually have several fuses in paralell they will NOT share the load equally. Especially not on 2nd hand batteries. On those you have uneven resistance causing it to be even more important to fuse correctly.

How much can your batteries take before they get damaged? I have no way following your calculation. No idea what you do with 27-63 and so forth

Its important that you always fuse to what the inverter specs should be the fuse. If the inverter says 100A max on battery and with slow blow fuse you cannot put in 5*20A fuses on 5 strings of batteries. You need to double them up atleast for it to work out in the end!


9*120 = 1100W. On battery side thats atleast 1300W. And on 41V thats 32A. Then we add upp the inductive scenario. Lets say 5x. Thats 150A on the battery. You had it fused with 40A total fusing capacity. They will take lets say 80A max for 1-2 seconds! Then they will blow up
(I might have missed something in my calculation and its just a guess work but its there to show you whats going on)

Also note that some inverters are better than other to handle spikes on inductive loads. Some rely more on battery others have built in big capacitor banks!

And for those who say "By doubling, or more, the fuse rating you are minimizing safety of possible shorts and shock hazards" I say, that's what a breaker is for on the AC side of things. The breaker is designed to handle surge currents without popping until the current draw is of sufficient length of time (usually around 5-10s) unless it's a dead short.
A 15A breaker can handle 30A surge without issue. It can even handle 15A load for quite some time before it pops (tho not recommended as each time this happens, the breaker is slightly weakened)

A 15A breaker should be able to handle it 100% of the time! It should be able to handle almost 120% of its load 100% of the time. Otherwise it would be a pain...
There have been many threads at it and can be googled for those interested. A fuse should be the weakest point but at same time not to week because then you just add extra work for your self instead of increase in safety

Here in the US, it is code to put 15A on a circuit that is designed to handle around 12A continuous. If you need 15A continuous, a 20A is used. That's why I worded it the way I did above

Yeah. You always design fuses 25% above its rated nominal current and then you pick the fuse above that. Same in Sweden.

If your load is 8A you go with 10A. If your load will be 10A you go with 13 and so forth. This is for AC loads and require that the wire will handle it. But its worth mentioning that you also need to consider what type of load...

If you got 10A resistive load a anormal 13A fuse will work but if its a 10A induction motor you need a 13A SLOWBLOW fuse or even 16A to even get it to work. Such a fuse can easily do 25-30A for shorter times

An inductive load can easily pull 5-10x the nominal when starting up. This is something many people tend to forget when designing and that's also one of the MAIN reasons I over and over say that you cannot do to small fuses (for instance cell fuses)

Originally I had planed on building the whole battery or what I had parts for. then test it. Glad i became impatient and found out I needed to go another direction on fusing.


Also note that when you individually have several fuses in paralell they will NOT share the load equally. Especially not on 2nd hand batteries. On those you have uneven resistance causing it to be even more important to fuse correctly.

The batteries are new. Sat in warehouse for 3 or 4 years. 10s2p 10C 2000ma per cell

How much can your batteries take before they get damaged? I have no way following your calculation. No idea what you do with 27-63 and so forth

I was under the impression that inductive loads pull from 3 to 7 times the nominal load The 27 -63 was for 3-7 * 9A = 27A- 63A

Its important that you always fuse to what the inverter specs should be the fuse. If the inverter says 100A max on battery and with slow blow fuse you cannot put in 5*20A fuses on 5 strings of batteries. You need to double them up atleast for it to work out in the end!

The inverter is rated at 3000 watts so 83.4 amps nominal 6000 watts surge 167amps.

9*120 = 1100W. On battery side thats atleast 1300W. And on 41V thats 32A. Then we add upp the inductive scenario. Lets say 5x. Thats 150A on the battery. You had it fused with 40A total fusing capacity. They will take lets say 80A max for 1-2 seconds! Then they will blow up ?
(I might have missed something in my calculation and its just a guess work but its there to show you whats going on)

I could make the Battery out of 4 individual banks made of 10 36v batteries with a single 65 amp(81.3A trip) 2 DC 2 pole circuit breaker on each bank and not use the fuses.

Also note that some inverters are better than other to handle spikes on inductive loads. Some rely more on battery others have built in big capacitor banks!

Supposablly The inverter has a large capacitor bank.

Later floyd

The good part is that you found out that those fuses arent big enough

I Will get higher amp fuses in a couple of weeks. In the mean time I salvaged the xt60 connectors I used with the 56v 5 amp fuses and crudely soldered them to a 10 mm copper tubing I had left over from the mini slit system install. Two piece each about 15 inches long separated with a 3/4 ch pcv pipe. I have 6 double xt60 connectors soldered to the copper tubing the ends were crimped over 10 awg then soldered. I installed a 30 amp airpax dc circuit breaker inline on two 10awg leads. Hooked up the inverter, hooked up the batteries turn on the circuit breaker turned on the inverter. hooked the same 9 amp vacuum that I had used before. turned it on. It works didn't blow the circuit breaker
Same setup as before 8 36v 10s2p batteries minus the fuses. How much higher do you think I need to go the fuses come in 10A, 20A, 30A might be other sizes but that is all I remember atm.
Abandoning the Busbars I had been using before too thick. Either will be 3/8"copper tubing or 1/2"copper pipe.
later floyd

It depends on how hard you plan on push those batteries. In theory those packs should not have to go above 2A = 2A main fuses but in real world you might have it designed for higher. Its important that the fuses will be able to break even if the battery bank is empty in term of a short! Some cell will easy do 10A meanwhile others only do 2-3A without getting issues and perhaps 8-10 burst!

Not an direct answer Im afraid But I feel i cannot give a straight answer since i know to little

The Battery had been tested on the 12th blowing 5 amp fuses,There were only three things different about this test I had removed the 5 amp fuses between the batteries and the bussbar, installed a 30 amp 2pole dc circuit breaker on the leads to the inverter and new bussbar material 10mm copper tubing.
maybe it needed the circuit breaker?
later floyd

Perhaps you were pushing it to hard from the start. Otherwise it wouldnt blow the fuses

Removing the fuses off the packs to put a combined breaker at the inverter isn't a good idea, imho. I'd have both the fuses and the breaker together. The fuses take care of the packs. The breaker takes care of the inverter.

Yeah all strings should have their own individual fuses just beware of if 1 break should rest go to? No they should not. So its important to design that too.

As I stated in a post above the fuses are on order they will be reinstalled after I get them. The batteries were only installed to test.

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When I get home from a trip, on Monday using my phone to post this

quick video of a short test on the 36v 48AH to 36v inverter powering the vacuum that previously had either blown the fuses or was without fuses.
The 36v hoverboard batteries are connected in parallel, 2 batteries per 20amp fuse on both positive and negative sides running to The main bus bars.
10mm copper tubing bus bar 10 awg tinned copper wire connects the bus bars to the 30 amp Circuit breaker 10 awg tinned copper wires connect to inverter.
Fuses used 20 amp @ 32v (not ideal i know)
Voltage 41.7 at circuit breaker
voltage 41.4 at inverter
I need to order some 15-20 amp 58v Fuses before building the battery banks. I want to have 4 36v 48AH banks might have to settle for 3.

Later floyd

I have used these fuses but it was probably overkill for my first go kart project. I was frustrated that the local auto stores only sold the 32V fuses since I needed something for my 52V pack of 18650 cells. I bought three of the 58 fuses off of eBay. The fuses were probably "used" but they worked fine for my application.