Fuse issue

[deardancer3]

Yesterday I had a blown fuse ...but not in the usual way.

It was a 5AG 30 amp big fuse on a 360w cyclone powered by a 24v 20ah Headway battery system with no BMS on the output, just the charging side. (A 3AG looks like a 5AG on steroids.)

the fuse blew not with the main conductor in the middle of the glass going open, but by the base of the main conductor disconnecting from the outside conductor, ie the solder that holds the fuse conductor to the fuse external connector.

Is this a designed fuse fail safe on thees fancy fuses, or is this one of those fuse failures that I was warned about with chinese fuses? this was a fuse labelled BUSS and gold contacts if that means anything. these 5AG/AGU fuses are used a lot in auto high power stereos and go from 30 amps top 60 amps. I have the special 5AG fuse holder.

when the fuse blew i was doing and had been doing nothing special. just cruising along with sporadic use, pedal assisting.
no meter. I had been using this motor without problems for at least a year or two, battery is on its maybe 30th trip.
I swapped the fuse (no DVM with me) and the system has worked fine since then.

am having some network problems so my interaction may be sporadic.

d

 

[TMaster]

1. You may be on the edge of pulling 30 amps or you are pulling more. My fuse didn't blow right at the amp rating. They usually blow if the amps are prolonged higher then the rating or a big spike. I remember watching the amps on one of my setups and I had a 35 amp fuse inside, I was pulling up to 40 amps peaking for a few seconds and the fuse didn't blow.
2. The fuse was getting old and it wore out and finally blew from being weak.

I would just keep an extra fuse in your compartment or bag just incase it blows again, and you won't be stranded. Othewise put a larger fuse in, 35 or 40. That shouldn't hurt anything to put a larger fuse in. Your setup is always going to pull the same amount of amps that it has been doing ever since, no matter what fuse is in there. Unless you modifiy or add more volts. I like the auto blade fuses, don't have to worry about glass or anything.

 

[biohazardman]

Yes what he said is probly how it is. I had a 30amp fuse holder melt on me but the fuse itself held out for many months of riding. I replaced the ATM mini fuse holder and fuse with the physically larger ATC holder and all was good.

 

[heathyoung]

Not unusual.

I remember back in the dim dark past when there was a whole rash of these dieing the same way on car audio installations. Its actually a metal fatigue issue, the vibration in the engine bay (where they are normally mounted) killed them. It used to be the ones with the gold plated inside (fuse) wire that failed, the plating was crap and let go from the base metal. The best fix was to use genuine non-gold AGU's.

Genuine BUSS fuses are not gold plated either We used them in our old link UPS's, they are marked with BUSS AGU 40 on one end, and 32V on the other.

 

[deardancer3]

I think i have my answer; there is no "BUSS" on the fuse, just the advertisement for the harness said it.

Will look for real BUSS fuses Tomorow.

d

 

[deardancer3]

I put the new 30A fuse in and have been really loading the motor. no problems. This one was a real Buss fuse.

To see if it was a motor drawing slightly too much current for longer periods, I climbed tough hills in too high a gear, maintained high speeds into head winds. etc. no new blown fuse. and no cyclone yellow light. (cyclone 360w 20ah of headway 24v pack) NO meter yet. I do pedal a fair amount.


However, I noticed a few other things:

going fast for long periods (19mph AVG vs. my previous battery rationing 13mph) saves time and is really fun.

With big AH capacity, you dont have to worry about recharging even without battery rationing.

going fast for long periods (19mph AVG vs. my previous battery rationing 13mph) saves time and is really fun.

Aggressive acceleration with a chain drive can cause noisy shifting if your shifting system has any issues.

going fast for long periods (19mph AVG vs. my previous battery rationing 13mph) saves time and is really fun.

I do wish the 24v 20ah pack was lighter and smaller, but having good battery capacity means you dont have to ration the energy, and,

going fast for long periods (19mph AVG vs. my previous battery rationing 13mph) saves time and is really fun.

D

 

[fechter]

I've seen quite a few fuses 'blow' because there was a poor connection between the end of the fuse and the fuse holder that caused the fuse to heat up and melt the solder in the end.

Make sure your fuse holder is clean and has a tight connection. Check for fuse holder heating after running at high current for a while.