Battery fuse question

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avoleoo   10 W

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Battery fuse question

Post by avoleoo » Dec 13 2014 8:18pm

Hi guys im having an issue with battery fuse heating up for my 48v 20ah custom build liion battery. I was wondering if someone could suggest me a solution. Currently im using 20a fuse but the holder is no good it heats up fairly quickly. I also searched on ebay and could not come up with good solution that would look reliable. Please suggest.

dnmun   100 GW

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Re: Battery fuse question

Post by dnmun » Dec 13 2014 9:01pm

depends on size of the controller but i would recommend buying the big spade leg 40A auto fuses and solder the leads to it. or solder two on each side of the wire. where do you live? i can send some through US mail.

avoleoo   10 W

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Re: Battery fuse question

Post by avoleoo » Dec 13 2014 10:14pm

Hi. Im in West Palm Beach, FL. Good tip about soldering, it will solve heating issue. I just took apart my rubber fuse holder and it was melted from the heat. The only thing that worries me is that I will not be able to replace it on the go. Maybe putting two holders in parallel, hmm...

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friendly1uk   10 MW

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Re: Battery fuse question

Post by friendly1uk » Dec 14 2014 7:48am

I have gone parallel many times. It works fine. If one takes more power, it warms, raising it's resistance, convincing the power the other way is easier. I have gone as far as 6 in parallel.

Many of the holders are only rated 20 amps. It is usually the fuse heating though, not the holder. You could swap for a 30 amp fuse for short circuit protection, but it wouldn't be good overload protection, as the heat needed to melt a 30A fuse would melt a 20A holder. Especially the rubber ones. They form a nice thick insulating cocoon around the fuse, boxing the heat in.

If you buy a fuse to solder to, in order to make a fused link. Be sure it's not aluminium.
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dnmun   100 GW

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Re: Battery fuse question

Post by dnmun » Dec 14 2014 10:30am

avoleoo wrote:Hi. Im in West Palm Beach, FL. Good tip about soldering, it will solve heating issue. I just took apart my rubber fuse holder and it was melted from the heat. The only thing that worries me is that I will not be able to replace it on the go. Maybe putting two holders in parallel, hmm...
you do not wanna be replacing it on the go. the fuse is there only as a last measure of protection when the battery is shorted. you wanna use the most fuse capacity you can and not use the little 20A fuses and you do not wanna use the fuse holders at all. just solder two of the 40A auto fuses to the two leads and it will be permanent until you do something really stupid. then you can just put a wire across the blown fuse until you can get home and solder new ones in place.

avoleoo   10 W

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Re: Battery fuse question

Post by avoleoo » Dec 14 2014 4:55pm

dnmun, thanks, it makes sense, I will go with your suggestion. You said two fuses, one for each wire? Would you mind explaining me why two instead of just one let's say on + wire?

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biohazardman   100 kW

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Re: Battery fuse question

Post by biohazardman » Dec 14 2014 5:19pm

Not dnman but the two would split the amperage load if in parallel with each other it's a good thing to do if you are unable to find a fuse holder with heavier wire. Had the same problem with my first bike and just went to the auto parts store and found a holder made for more amperage although I used a lower rated fuse. That stopped the heating issue and I have only blown the fuse twice in 10K of riding.
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dnmun   100 GW

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Re: Battery fuse question

Post by dnmun » Dec 15 2014 5:09am

yep, using two fuses, one soldered on each side spreads the heat and lowers the resistance of the fuse to the flow of current. hard to solder the wire in between the two fuses though. there is only a few mm space between the legs so it wants to short out so you would be soldering on the outer edges of the fuse legs.

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gwhy!   1 MW

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Re: Battery fuse question

Post by gwhy! » Dec 15 2014 7:18am

just get yourself one of these and have done with it.. they are cheap enough.
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avoleoo   10 W

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Re: Battery fuse question

Post by avoleoo » Dec 15 2014 7:32pm

Thanks guys for your replies.

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