Which wheels have fuse

[Wagtenor]

I'm wondering which wheels use fuse to protect control board.  From what I've read so far, King Song KS-16 and KS-18 has fuse.  I believe the fuse is rated at 40 Amps not sure if it is fast blow or slow blow type.  The use of the fuse gives me concern being since I'm a healthy 205lbs (94kg) man.

Mainly interested in: Gotway Msuper V3, Gotway ACM and InMotion V8.

Anyone with KS-16 that has had a fuse blow?  if so, was during riding? (I hope not!)

Thanks,

Sam

[Wagtenor]

Just viewed a V8 dissambly picture, it appeared to have a 30A fuse at the input to the control board.  Since it uses 800W motor like the ks-16, I guess the 40A used by King Song is OK at allowing the motor more amperage.

 

[Mono]

 

2 hours ago, Wagtenor said:

I'm wondering which wheels use fuse to protect control board.  From what I've read so far, King Song KS-16 and KS-18 has fuse.  I believe the fuse is rated at 40 Amps not sure if it is fast blow or slow blow type.  The use of the fuse gives me concern being since I'm a healthy 205lbs (94kg) man.

I have this concern too. One way how this could make sense is if the fuse can only burn, say to prevent a fire, after the control board has been failed for sure. That is, if the 25 or 35 amps will inevitably destroy the board anyway before the fuse can come into play.

 

Quote

I'm wondering which wheels use fuse to protect control board.  From what I've read so far, King Song KS-16 and KS-18 has fuse.  I believe the fuse is rated at 40 Amps not sure if it is fast blow or slow blow type.  The use of the fuse gives me concern being since I'm a healthy 205lbs (94kg) man.

Did you correct for voltage? According to my computations the difference between 40A on KingSong and 30A on InMotion is less than 7% in power.

IMHO, if this is a remotely decent design, a functional board should never draw enough current to burn the fuse. OK, up to speed of 2km/h would be debatable.

[dmethvin]

6 hours ago, Mono said:

I have this concern too. One way how this could make sense is if the fuse can only burn, say to prevent a fire, after the control board has been failed for sure. That is, if the 25 or 35 amps will inevitably destroy the board anyway before the fuse can come into play.

You can look up the curves for name-brand fuses to see how long it takes them to blow at which current levels. You can see one sample curve here for the Littelfuse MAXI series, which shows that even a 40A fuse can take a 100A load for about a second before blowing. If your EUC is drawing 100A for anything close to a second it is probably shorted.

http://www.littelfuse.com/~/media/automotive/catalogs/littelfuse_fuseology.pdf

However, I would not trust that a cheap no-name 40A Chinese fuse would follow the same curve as a Littelfuse data sheet, even if it was the same size and color.

[Wagtenor]

7 hours ago, Mono said:

 

I have this concern too. One way how this could make sense is if the fuse can only burn, say to prevent a fire, after the control board has been failed for sure. That is, if the 25 or 35 amps will inevitably destroy the board anyway before the fuse can come into play.

 

 

Did you correct for voltage? According to my computations the difference between 40A on KingSong and 30A on InMotion is less than 7% in power.

IMHO, if this is a remotely decent design, a functional board should never draw enough current to burn the fuse. OK, up to speed of 2km/h would be debatable.

@Mono The difference really boils down to how the two motors behave under load - i.e. peaks in current during demand periods, switching from forward to reverse, etc.  Not knowing the characteristics of the motors leaves the consumer in the dark really.  We can only hope the designers have done a solid design. But without having access to the test plans and test reports - we don't have way to know for sure, unless someone with access to all the different brands perform the testing.  But then we don't know variations that may occur during the products lifecycle - things such cost reductions, poor QC could definitely change things from batch to batch.

According to the law of conservation of energy though - you are right in that if both 800W motors used in KS-16 and V8 are identical - the Inmotion would draw less current because of the higher operating voltage.  I just don't have enough information to make a guestimate as to the adequacy of the 10A difference in the selected fuses though.  @dmethvin makes a good point about type/series of fuse in use also.  I'm not sure the volumes for these products but it would seem highly unlikely Littelfuse MAXI series are being used.  Maybe in one of them it maybe true - but again one would need to have access to verify and then as I mention above - the next batch could very well have a cheaper/ lesser known brand of fuse in them - because the design of the wheels are not actively certified/monitored by an independent lab such as UL (I do not believe).  

 

10 minutes ago, dmethvin said:

You can look up the curves for name-brand fuses to see how long it takes them to blow at which current levels. You can see one sample curve here for the Littelfuse MAXI series, which shows that even a 40A fuse can take a 100A load for about a second before blowing. If your EUC is drawing 100A for anything close to a second it is probably shorted.

http://www.littelfuse.com/~/media/automotive/catalogs/littelfuse_fuseology.pdf

However, I would not trust that a cheap no-name 40A Chinese fuse would follow the same curve as a Littelfuse data sheet, even if it was the same size and color.

Excellent observation @dmethvin.  So if I decide to get a KS-16 I should replace the existing 40A fuse with something like Littelfuse MAXI 40A.  Should still maintain warranty at least and give me just a little more confidence that short duration current spikes around 40A at least would not blow the fuse and put me in jeopardy.

 

Thanks guys - fortunately, I'm in no rush to purchase my next wheel.  So I can soak all this in.   

[Mono]

1 hour ago, Wagtenor said:

Not knowing the characteristics of the motors leaves the consumer in the dark really

We do know some things which derive from the underlying physics. For example, the highest currents occur at low speed, which is already a relevant insight.

[dmethvin]

19 hours ago, Wagtenor said:

 So if I decide to get a KS-16 I should replace the existing 40A fuse with something like Littelfuse MAXI 40A.  Should still maintain warranty at least and give me just a little more confidence that short duration current spikes around 40A at least would not blow the fuse and put me in jeopardy.

You could replace it if you just want to know it's a good fuse. Not sure what physical size the current fuses are but the MAXI should be close to the same size. Since all  these fuses are technically going over the max voltage rating (32V) I wouldn't go with a smaller form factor. 

[Jason McNeil]

What's the verdict from the forum about Fuses for GWs? Following the seared fingers of @Rehab1 & his ACMS+ project, the rare board blowout, perhaps it's time GW add an inline 80A fuse? The probability of pushing the Wheel beyond 6720W is pretty remote, ought to be plenty of safety margin & make the Wheels safer in the long run.  

I think this is going to be my next lobby project with GW...

[meepmeepmayer]

Fuses scare me because basically they sacrifice me instead of the wheel (and have possibly a lower emergency margin than the electronics itself). 40A fuse, I've seen 40A (for very short time) in Wheellog often enough, wouldn't want my ACM to cut out on me every time this happened - board was fine with it after all!

Higher A fuse, they only protect the mosfets/board in extreme sudden spikes (like a locked tire)? Not sure what they actually would do/when they would blow and instead of what.

Honestly, instead of a fuse I'd like the electronics monitoring themselves and simply warn me at critical numbers.

Very happy with your lobbying efforts. I guess a fuse here and there can't hurt (or can it?). But GW need to start with some general overall better theoretical design, not adding random parts that people request to reduce the risk from possible error source #129047782.

[Jason McNeil]

34 minutes ago, meepmeepmayer said:

Higher A fuse, they only protect the mosfets/board in extreme sudden spikes (like a locked tire)? Not sure what they actually would do/when they would blow and instead of what.

If/when there's a short in the power, it could lead to a spectacular battery fire: each 18650 cell has 1.77g equivalent of TNT x 120 cells = 212g TNT

It's been discussed elsewhere, but a fuse doesn't blow if it momentarily hits the rating, it has to be sustained for a couple seconds. Later mark KS have fuses, to no reported ill-effects.

https://www.researchgate.net/publication/257616077_Thermal_hazard_evaluations_of_18650_lithium-ion_batteries_by_an_adiabatic_calorimeter

[meepmeepmayer]

You don't have to disagree, that was a question As far as anything but rider safety concerns (like battery protection) I don't care about fuses at all, how many people had such problems?

Point is, the fuse A must be high enough that is does not crash you when the wheel electronics may have survived without the fuse. I'd rather have a x% chance of not crashing or a 100-x% chance of crashing and destroying a board instead of a 100% chance of crashing (without destroying the board) in a high A situation. Me before the wheel unless damage (and thus a crash) is 100% inevitable please!!!

[Jason McNeil]

25 minutes ago, meepmeepmayer said:

You don't have to disagree, that was a question

Sorry, my fault, I missed that...

25 minutes ago, meepmeepmayer said:

I don't care about fuses at all, how many people had such problems?

It's the sort of, even 1 case is too many. People on the forum know the facts that an Electric Unicycle generally uses higher quality components than the boards, but all it takes is for one battery fire where someone accidentally shorts their GW & the public perception about unit type safety (Wheels = good, Boards = dangerous, catch-on-fire) can change overnight. All the other vendors use fuses (even Rockwheel), they must consider it be an acceptable safety addition.

[steve454]

1 hour ago, Jason McNeil said:

What's the verdict from the forum about Fuses for GWs? Following the seared fingers of @Rehab1 & his ACMS+ project, the rare board blowout, perhaps it's time GW add an inline 80A fuse? The probability of pushing the Wheel beyond 6720W is pretty remote, ought to be plenty of safety margin & make the Wheels safer in the long run.  

I think this is going to be my next lobby project with GW...

Fuses are good, if they blow at slow speed, which hopefully means overlean trying for max acceleration and the rider does not get hurt.  I'd rather replace a fuse than a board.  But boards rarely blow out,   And high power draw is the main cause of failure.  Don't push it and it will last forever.

[meepmeepmayer]

Haha if even Rockwheel uses fuses, Gotway should have started yesterday. I understand your view from a battery and public relations perspective, and agree. Though as there have been no problems with this yet, it's not on my mind.

The one case is one too many is my view of a cut out that isn't 100% necessary (aka from a blowing fuse while without it the electronics would have survived). That's the only opinion I have about fuses.

[Rehab1]

 

4 hours ago, Jason McNeil said:

What's the verdict from the forum about Fuses for GWs? Following the seared fingers of @Rehab1 & his ACMS+ project, the rare board blowout, perhaps it's time GW add an inline 80A fuse? 

Unfortunately a fuse in my situation would have offered little value.

I would not be opposed to the fuse concept if data and specs were made available detailing examples of what wheel envelope parameters must be exceeded in order for a fuse to fail. 

[esaj]

Slow-blow fuses with high enough amperage should work. This image gives the general idea, the timing / amount of allowed over-current will be different for different fuses (usually the manufacturer will provide datasheets with charts or curves). Slow/medium fuses vs. fast vs very-fast ones, the slower ones allow currents above the rating for a longer while before blowing:

 

This one's from Littelfuse's ( http://www.littelfuse.com/ ) datasheets for certain blade-fuses, but these were rated just for 58V max (at higher voltages, the fuse may still arc allowing current to pass even after it blows):

 

But for the sparking issue, anti-spark / spark-protection / whatever-they're-called connectors would seem a better idea to me. If the fuse would be between the battery and the large bypass capacitors on the board, it might blow just because of the high capacitor current when connecting the packs (and if it wouldn't blow, it would still allow sparking). If it's after the caps, it won't help with the sparking during connecting either, but at least it won't blow due to capacitor charging.