Hmmmmmmmmmmm... is this bad? (some minor[?] ACM heat damage)

[MaxLinux]

2 hours ago, Marty Backe said:

I've even contemplated adding a clear Plexiglas window on the side so that you can peer inside the wheel with a flashlight. Then I would publicize the crap out of my modded wheel.

In addition to making inspection easier, this could be a coolness mod, similar to windows on PCs.

A typical example:

 

[esaj]

7 hours ago, Paddylaz said:

So....should EVERYONE take a look at the insides of their euc every few weeks/months? Or is there an inherent 'fragility' to the Gotway electronics? 

The problem could come up with any wheel, but Gotways are likely more prone because the motor power is so high (something like 1500W rated/3-4+kW max?) and the motor will draw sustained large amperage during climbing, something like 50A or more constantly? That will heat things up over time. There are of course more factors at play (rider weight, speed, motor efficiency at different speeds, ambient temperature, connector quality, crimp/soldering quality, etc...). So far, I don't recall other wheels ever melting the cable sheathings or heating up the connectors enough to cause visible damage.

[US69]

23 minutes ago, esaj said:

So far, I don't recall other wheels ever melting the cable sheathings or heating up the connectors enough to cause visible damage.

Very, very old KS18A 1200 (first Version/batch) had that Problem, too. But it didn't work out as bad as on GW, "just" some heatshrink was melted. On all later 18" KS implemented thicker wires then...

[meepmeepmayer]

10 hours ago, Paddylaz said:

So....should EVERYONE take a look at the insides of their euc every few weeks/months? Or is there an inherent 'fragility' to the Gotway electronics? 

I mean, when you say a demanding ride, presumably if the Gotway 'let's' you do it in the first place without a cut-out, doesn't that mean it's within normal safety parameters? Or not?

(apologies..... I have the electrical knowledge of a grapefruit).

It can't hurt, but you don't have to unless you do mountains with a latest Gotway. @esaj said it very well.

All these high-power, big-batteried wheels simply can create very high currents on steep inclines. More than the Gotway motor cables can continuously take (older ones rated for ~22A 16AWG, newer GW motors have cables rated for ~32A 14AWG; thicker cables would not fit through the thin axles so there's no easy fix), so the cables will get hot after a few minutes and ultimately melt their insulation and short together.

Not much info available, but here's what I believe is the state of things:

• ACM and msuper V3 can be fried this way reliably. @zlymex has a mountain riding/testing group, and they seem to encounter this regularly.
• Monster: the one time the Monster rode along where an ACM fried and died, it did an overheat warning and showed no damage. So it may be the case, for some reason, the Monster overheats before the cables would start melting.
• Latest Kingsongs: they have fuses (40A I believe) so they would probably warn you or just the fuse fails but the wheel is ok (and maybe the KS won't even let you push them so much). @Christoph Zens has some good experiences with a 16B/C on mountains as well.
• Rockwheel GT16: no idea, but I guess it has fuses too. Nobody tested it on mountains to my knowledge.
• Other wheels don't seem have the power and batteries for this to happen.

[meepmeepmayer]

Plexiglass window: I've though about this yesterday as well But not sure if you'd ultimately see everything well enough... if one does this mod, it might as well be removable so you have tool-less, quick  access to the board compartment.

[Bob Eisenman]

On 8/10/2017 at 11:11 AM, meepmeepmayer said:

Overview. You can see a bit of damage at the one motor connector covered partially by that heat sleeve.

So...it's a 'to the motor' wiring issue

because....

it looks like the wiring (blue & yellow & green) and white tubular material coming from the board is doing fine but the wiring (blue & yellow) going to the motor (?)/is discolored along the length that is shown in the photo.

Red & black (yellow connector) are from the battery to the main board (?)

On the humorous side, if that is possible... Could the overheating involve regenerative power issues going down steep hills?

Good luck!

[Chriull]

9 minutes ago, Bob Eisenman said:

...

On the humorous side, if that is possible... Could the overheating involve regenerative power issues going down steep hills?

...

No - is (should) imho not possible. From the ks16 i have seen max regenerative current of about 15A - so quite nothing compared to the motor current for strong accelerations/going uphill especially at lower speeds...

regenerative currents should not be much higher, to give the liion cells a chance to survive... but who knows what they designed - i did not see too many regenerative current measurements till now and as far as i remember non from a gotway...

could be that in some cases regenerative braking is switched to "power" breaking which could again lead to quite high motor currents...

[Chriull]

On 11.8.2017 at 0:55 PM, meepmeepmayer said:

...

• Latest Kingsongs: they have fuses (40A I believe) so they would probably warn you or just the fuse fails but the wheel is ok (and maybe the KS won't even let you push them so much). @Christoph Zens has some good experiences with a 16B/C on mountains as well.
• Rockwheel GT16: no idea, but I guess it has fuses too. Nobody tested it on mountains to my knowledge.

The fuses are at the battery side where the currents are lower than on the motor side. So the fuse rating has nothing to do with the current the motor cables have to deal with...