Burned the fuse in battery

E-driver_

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Hi

I think I blew the fuse (?) in my ebike battery riding quite hard uphill with a slightly too strong controller perhaps.

Looks like in the picture. Any idea on what and how to change this? It is kind of melted into the black and green there. Can I just cut it off with a knife and solder on something different? And if so, what should I use?

Thanks
 

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You will find the post linked below very helpful, especially towards the bottom.

https://endless-sphere.com/forums/viewtopic.php?f=49&t=116968&sid=98342bfd5c223299c46667852f8afbc5
 
So I tried to remove the fuse out of the black rail-thing. But it was kinda melted.

So I just cut it off. Now it looks like in the picture. Any idea on what replacement I could solder on here to replace fuse and the rest of the functions in this thing? (I am not even sure about what functions it performs. Probably protection of the battery cells or something right?)
 

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E-driver_ said:
. Any idea on what replacement I could solder on here to replace fuse and the rest of the functions in this thing?

See the linked thread above.
 
docw009 said:
Your pictures are a little surprising. Appears to show remnants of active circuitry when all that was expected is a fuse holder.

Confirm that the little circuit board only had the two red wires going to it? No other wires?

In a couple of the earlier pictures you can see the little circuit board is part of the fuse holder. The more recent picture is deceiving because there is a thin red wire in the background that looks like it goes to the circuit board but it doesn’t. The OP just needs to cut off the old fuse holder, which is nothing but a tiny circuit board at this point, solder in a new fuse holder and plug in a new fuse. He should look at my recent post where I had the same exact problem, and several experts on this forum posted valuable advice and gave several examples of reliable fuse holders you can purchase, and I even show how I made a home built one.
 
docw009 said:
Your pictures are a little surprising. Appears to show remnants of active circuitry when all that was expected is a fuse holder.

Confirm that the little circuit board only had the two red wires going to it? No other wires?

Yeah it only had two red ones. Looks like this picture
 

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rick_p said:
docw009 said:
Your pictures are a little surprising. Appears to show remnants of active circuitry when all that was expected is a fuse holder.

Confirm that the little circuit board only had the two red wires going to it? No other wires?

In a couple of the earlier pictures you can see the little circuit board is part of the fuse holder. The more recent picture is deceiving because there is a thin red wire in the background that looks like it goes to the circuit board but it doesn’t. The OP just needs to cut off the old fuse holder, which is nothing but a tiny circuit board at this point, solder in a new fuse holder and plug in a new fuse. He should look at my recent post where I had the same exact problem, and several experts on this forum posted valuable advice and gave several examples of reliable fuse holders you can purchase, and I even show how I made a home built one.

Aha so I just need to solder on a new fuse holder, and then plug in a new fuse in to that new fuse holder? Any idea on what these are called, on for example Aiexpress? Just "fuse holder" with fuse or something perhaps?

The post you are referring to is the post above perhaps? Thanks
 
By the way could any of you tell me what the difference in function is between a fuse and a bms? Do they both perform some kind of heat-protection of the battery cells or something like that? And if so, what is the difference between them?
 
E-driver_ said:
rick_p said:
docw009 said:
Your pictures are a little surprising. Appears to show remnants of active circuitry when all that was expected is a fuse holder.

Confirm that the little circuit board only had the two red wires going to it? No other wires?

In a couple of the earlier pictures you can see the little circuit board is part of the fuse holder. The more recent picture is deceiving because there is a thin red wire in the background that looks like it goes to the circuit board but it doesn’t. The OP just needs to cut off the old fuse holder, which is nothing but a tiny circuit board at this point, solder in a new fuse holder and plug in a new fuse. He should look at my recent post where I had the same exact problem, and several experts on this forum posted valuable advice and gave several examples of reliable fuse holders you can purchase, and I even show how I made a home built one.

Aha so I just need to solder on a new fuse holder, and then plug in a new fuse in to that new fuse holder? Any idea on what these are called, on for example Aiexpress? Just "fuse holder" with fuse or something perhaps?

The post you are referring to is the post above perhaps? Thanks

Do you think it would be enough to buy a fuse holder like this picture below? It is rated at a max current of 30Ah. My battery is 36v 13ah.

The actual fuse that I put into the fuse holder should also have 30ah then? Or lower?

I could basically cut off the two red wires and solder them onto the new fuse holder, right?
 

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E-driver_ said:
Aha so I just need to solder on a new fuse holder, and then plug in a new fuse in to that new fuse holder? Any idea on what these are called, on for example Aiexpress? Just "fuse holder" with fuse or something perhaps?
Correct, just "fuse holder" will work, "inline fuse holder" might get slightly better returns.
E-driver_ said:
The post you are referring to is the post above perhaps? Thanks
Correct... "You will find the post linked below very helpful, lots of great info about fuses and the this specific issue, especially towards the bottom of the page.
viewtopic.php?f=49&t=116968&sid=98342bf ... 852f8afbc5
E-driver_ said:
By the way could any of you tell me what the difference in function is between a fuse and a bms? Do they both perform some kind of heat-protection of the battery cells or something like that? And if so, what is the difference between them?
A fuse protects against going over the rated amperage, which can cause electrical fires. A BMS stands for Battery Management System, and it makes sure the cells are charged evenly and correctly, without it the battery might not get charged properly, which could reduce efficiency, battery life, and also cause the battery to explode or catch fire.
E-driver_ said:
Do you think it would be enough to buy a fuse holder like this picture below? It is rated at a max current of 30Ah. My battery is 36v 13ah.
The one in the picture will work, but is very similar to the one that melted on you already, so there is a chance you will run into the same problem the next time you're powering hard up a hill, because that is when the motor is going to draw high amperage.
E-driver_ said:
The actual fuse that I put into the fuse holder should also have 30ah then? Or lower?
The actual fuse that you put into the fuse holder should match (exactly) the amp rating of the fuse that was in there originally. Hopefully you can still read that on the top of the fuse. Mine is 30 amps, but not all batteries are the same. Side note, fuses are rated by amps, not amp hours, so you will not find a fuse labeled 30ah, it will be 30a. Do not assume your battery is rated at 30 amps because it is a 36 volt battery though, the two numbers have nothing to do with each other.
E-driver_ said:
I could basically cut off the two red wires and solder them onto the new fuse holder, right?
Correct, including the smaller red wire I previously though wasn't going to the fuse, but I see now that it is.
 
rick_p said:
E-driver_ said:
Aha so I just need to solder on a new fuse holder, and then plug in a new fuse in to that new fuse holder? Any idea on what these are called, on for example Aiexpress? Just "fuse holder" with fuse or something perhaps?
Correct, just "fuse holder" will work, "inline fuse holder" might get slightly better returns.
E-driver_ said:
The post you are referring to is the post above perhaps? Thanks
Correct... "You will find the post linked below very helpful, lots of great info about fuses and the this specific issue, especially towards the bottom of the page.
viewtopic.php?f=49&t=116968&sid=98342bf ... 852f8afbc5
E-driver_ said:
By the way could any of you tell me what the difference in function is between a fuse and a bms? Do they both perform some kind of heat-protection of the battery cells or something like that? And if so, what is the difference between them?
A fuse protects against going over the rated amperage, which can cause electrical fires. A BMS stands for Battery Management System, and it makes sure the cells are charged evenly and correctly, without it the battery might not get charged properly, which could reduce efficiency, battery life, and also cause the battery to explode or catch fire.
E-driver_ said:
Do you think it would be enough to buy a fuse holder like this picture below? It is rated at a max current of 30Ah. My battery is 36v 13ah.
The one in the picture will work, but is very similar to the one that melted on you already, so there is a chance you will run into the same problem the next time you're powering hard up a hill, because that is when the motor is going to draw high amperage.
E-driver_ said:
The actual fuse that I put into the fuse holder should also have 30ah then? Or lower?
The actual fuse that you put into the fuse holder should match (exactly) the amp rating of the fuse that was in there originally. Hopefully you can still read that on the top of the fuse.
Mine is 30 amps, but not all batteries are the same. Side note, fuses are rated by amps, not amp hours, so you will not find a fuse labeled 30ah, it will be 30a. Do not assume your battery is rated at 30 amps because it is a 36 volt battery though, the two numbers have nothing to do with each other.
E-driver_ said:
I could basically cut off the two red wires and solder them onto the new fuse holder, right?
Correct, including the smaller red wire I previously though wasn't going to the fuse, but I see now that it is.

Aa ok. Very helpful. So the fuse protects the battery cells or does it protect the controller? When I went buying a fuse holder the guy in the store thought the fuse protected the controller from the battery heat. But I thought it was the other way around(?) It protects the battery from the controller drawing enormous amounts of amps?

I cannot read the old one unfortunately. It melted.

Aha so perhaps best to go even higher on the fuse holder the next time? Up towards 40 or something? I believe the max current on the controller is "Current: 35-+1A"
 
E-driver_ said:
Aa ok. Very helpful. So the fuse protects the battery cells or does it protect the controller? When I went buying a fuse holder the guy in the store thought the fuse protected the controller from the battery heat. But I thought it was the other way around(?) It protects the battery from the controller drawing enormous amounts of amps?

I cannot read the old one unfortunately. It melted.

Aha so perhaps best to go even higher on the fuse holder the next time? Up towards 40 or something? I believe the max current on the controller is "Current: 35-+1A"

The fuse can be sized to protect any of those things, but ultimately the fuse is there to protect your bike against you. For the most part, a BMS protects the battery. It may have overcurrent or short circuit protection, but if the BMS fails, you could size your fuse to open if there more current than the battery cells can safely deliver; so a secondary level of protection. It could be sized to protect the controller, but not a typical application, by limiting the amount of current the controller can flow. Many controller allow you to set the max current, but ultimately it's your throttle hand that protects your controller (or a heat sensor if equipped). It can be sized, like in most applications, to protect the conductor in the circuit from melting due to high current or short circuit. But ultimately, the fuse will blow because of something you did, or if you crash the bike.

I care more about me than my bike, and I don't want any additional components or points of failure between my throttle hand and the back wheel, so no fuses. I can take my time and be careful and not short wires while doing maintenance or assembly, and add reasonable crash protection to protecting my bike, but I want close to zero possibility of a fuse, breaker or BMS opening when I peg the throttle trying to cross a busy 6 lane road or highway.
 
rick_p said:
The actual fuse that you put into the fuse holder should match (exactly) the amp rating of the fuse that was in there originally. Hopefully you can still read that on the top of the fuse.
Green-colored fuse of this (automotive) type is standardized to 30 amp.
https://www.onallcylinders.com/2017/11/08/automotive-fuse-id-color-chart-for-car-truck-fuses/

OP: You state that you are going to solder in a new fuse holder. Judging by your comments (I could be wrong so please excuse if I am presuming incorrectly) do you have soldering skills/equipment/materials to do this?

As others have mentioned, this would be a better solution:
file.php
 
Aha good to know if I am out of solder or something.

My "soldering skills" are ahum.. in their youth. I have soldered a few things before but not many.

By the way thanks, this actually worked. See the picture. There you can see my 2 enormous solder globs.

Now until next time. Is it possible to find fuses and fuse holders above 30a? Seems that among the small ones in the store it was basically 30a that was the highest.
 

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E-driver_ said:
Aha good to know if I am out of solder or something.

My "soldering skills" are ahum.. in their youth. I have soldered a few things before but not many.

By the way thanks, this actually worked. See the picture. There you can see my 2 enormous solder globs.

Now until next time. Is it possible to find fuses and fuse holders above 30a? Seems that among the small ones in the store it was basically 30a that was the highest.

You probably won't need one. Your original holder was a piece of crap that probably couldn't handle 20A, from looking at those pics. And comparing the conductor size of the new one compared to the thin battery conductors, I think it will work fine. Plus, I'd worry that 30A from a 13Ah pack, that appears to be generic cells, may be pushing it's limits anyway.

Solder looks OK, just tape them up good since it looks like you didn't use heat shrink tubing.
 
I agree with @E-HP that your replacement fuse holder shown should do the job as the original wires sure can't handle much more. Fuse holders for higher amps look like this.

https://ibit.ly/651i

61MBFgFiMPL._AC_SL1200_.jpg
 
I recommend against any form of fuse holder built like that for applications like this. It depends on pressure, typically created by the plastic itself (or metal pushing against the plastic), such as spring force contact against the fuse, or plastic of the fuse holder securing the caps onto the fuse. If for any reason the contact resistance is high enough to cause heating, the heating will begin to deform the plastic (too often a fairly low temperature type), and the contacts may have less pressure against the fuse, which means higher resistance, whcih means more heating.

This is why the blade fuse holders fail, too, but it can happen with most of these plastic inline-housing types (all the ones I've seen in use in continuous-current applications tend to do it...in non-continuous-current it doesn't usually get the chance to heat up and deform the plastic). It certainly doesn't happen all the time, but it is a possibility, and the cheaper the holder the worse the design and materials and workmanship and the more likely it is to happen. Since under the wrong conditions it can cause a fire, or at best loss of system power leaving an EV "stranded" (or stuck with pedal power if you have it available), It's safer to avoid the problem altogether.

A bolt-on fuse, with properly crimped ring terminals on the wiring leading to and from it, is "never" ;) going to have that problem, assuming correct hardware is used to secure the ring terminals to the fuse, and water ingress is prevented so corrosion won't occur.

https://www.amazon.com/Carviya-Waterproof-Holder-Amplifier-Compressors/dp/B07KYG4YQR/ref=sr_1_5?crid=GMN3A8I70QJO&keywords=100+amp+fuse+holder&qid=1659964679&s=industrial&sprefix=100+amp+fuse+holder%2Cindustrial%2C120&sr=1-5
61MBFgFiMPL._AC_SL1200_[1].jpg
Diggs said:
I agree with @E-HP that your replacement fuse holder shown should do the job as the original wires sure can't handle much more. Fuse holders for higher amps look like this.

https://ibit.ly/651i

61MBFgFiMPL._AC_SL1200_.jpg
 
Fuses are really only for protecting wiring/motors. Time-load is not so bad for relatively low power but even this type:
https://au.mouser.com/datasheet/2/240/Littelfuse_Micro2_Datasheet-321077.pdf

Load% Min/Max time (s)
110 360/infinity
135 0.75/120
160 0.3/50
200 0.15/5
350 0.04/0.5
600 0.02/0.1

Are not going to protect electronics and are questionable for lithium batteries
 
The problem is that type of cheaper fuse holder, not blade fuses themselves, or that the load was too high, which will actually pop the fuse.
Its the slow corrosion buildup, and the terminals losing flex that starts the melting down.
I switched to ones like these, on boats especially, where this kind of melted holder happens surprisingly often.
IMG_20220809_110041626_HDR.jpgIMG_20220809_110026579_HDR.jpg
IMG_20220809_110047181_HDR.jpg
 
Voltron said:
The problem is that type of cheaper fuse holder, not blade fuses themselves, or that the load was too high, which will actually pop the fuse.
Its the slow corrosion buildup, and the terminals losing flex that starts the melting down.
I switched to ones like these, on boats especially, where this kind of melted holder happens surprisingly often.
IMG_20220809_110041626_HDR.jpgIMG_20220809_110026579_HDR.jpg
IMG_20220809_110047181_HDR.jpg

I have ordered a new one now because the last fuse of 30A also burned.

What happens if I don't use any fuse at all? I guess the amperage is never very high for long periods. But perhaps this would cause a fire or something eventually? Or just waste the cells?
 
That's what happened when I tried skipping a fuse on my first battery.
The sustained load was too much for the metal strips between the groups, until one got so hot it melted thru the shrink wrap on one of the cells and shorted and killed it.
 
Voltron said:
That's what happened when I tried skipping a fuse on my first battery.
The sustained load was too much for the metal strips between the groups, until one got so hot it melted thru the shrink wrap on one of the cells and shorted and killed it.

Ah ok I see. I am waiting for a 40a fuse now.
 
It seems like most fuse holders are only 30amps and that the volts are mostly up to 32volts.

What do you guys use for 36-52volt batteries? Fuse holders I mean. I only find those glass fuses above 30 amps.
 
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