Dangerous e-bike chargers found on Amazon and eBay

[sjpt]

I realize 2 amp isn't the mains current. The difference is that the 13 amp plug wasn't designed to have any active components in it, just the connections and the appropriately rated fuse, so nothing that should generate significant heat.

Putting the AC->DC and voltage conversion circuitry in the plug is another matter. As has been commented on elsewhere, even separate brick battery chargers often get significantly warm.

 

[Andy-Mat]

I realize 2 amp isn't the mains current. The difference is that the 13 amp plug wasn't designed to have any active components in it, just the connections and the appropriately rated fuse, so nothing that should generate significant heat.

Putting the AC->DC and voltage conversion circuitry in the plug is another matter. As has been commented on elsewhere, even separate brick battery chargers often get significantly warm.

Does that really happen? I had not seen that mentioned before......
No wonder they are considered dangerous......
regards
Andy

 

[guerney]

It's be wonderful if Chinese ebike battery manufacturers agreed a simple open comms protocol to enable battey BMSs to totally switch chargers off, once cells are charged and balanced.

 

[sjpt]

Does that really happen? I had not seen that mentioned before......
No wonder they are considered dangerous......
regards
Andy

When I first read the article (about the time of the first post on this thread when the article came out) I read it as that. I just looked again at the article and it seems quite confusing on that point.

The charity looked at the mains plugs in the charging devices and said that all were so visually substandard that no test purchasing was necessary.

Mains plug in the charging device sounds like an integrated plug/charger, but ...???
I hadn't thought that there wasn't much room for a fuse in such a device, but now I think of it that may be fairly standard practice; and even on a very low power device that could be an issue if there was an internal fault, or if the DC cable out got broken (run over by an office chair?)

 

[Andy-Mat]

It's be wonderful if Chinese ebike battery manufacturers agreed a simple open comms protocol to enable battey BMSs to totally switch chargers off, once cells are charged and balanced.

Well said.
As far as my (limited) experience tells me (probably only about a dozen chargers, all much the same!), none are made to operate like that, at least none that I myself have experience of.....
The way I do it, is to purchase a cheap 24 hour timer, the ones with the synchronous motor drive, not digital, and rewire the motor so that when the timer activates, it switches "itself" off. A 5 minute job with a soldering Iron. The biggest problem is possibly not having the correct special screwdriver that some need to undo the screws....make sure that you have the right tool before purchase.
I 100% believe that leaving batteries on long charges, destroys the battery within 12 to 24 months.
The 12 months disasters are from several people I know, who thought that ALWAYS having the battery connected to the charger, except when riding, was a good idea!!
Please do not ask me how that idea started, as I haven't a clude as to how people got this it.
Furthermore, this can also cause a bad fire, as some people have found out the hard way!
regards
Andy

 

[Laser Man]

It's clear from the wording the charity used that they just looked at pictures and condemned the chargers because of the mains plugs.

Seems to me that if the manufacturers concerned can't meet the British Standard for mains plugs (which have been in force for many many years), then what safety standards have they ignored *inside* the chargers that can't be seen.

 

[WheezyRider]

Dont know yet, but one thought occurs to me.

I was measuring at the charge port, to get at the actual battery terminals needs a dismantle of the pack.

Now if the charge appears to work with a diode in series with the output of the charger, then its possible Swytch already have a diode on the charge input as protection. That would then make sense of the circa 42.7v input.

And I admit I never checked, but I have just now, and the back of the charger is in fact labelled 42.6V.

Moral of story, do not assume a charger for a 36V battery will always measure 42V .............

Glad you got to the bottom of it. That's the trouble with proprietary stuff, can be difficult to know what it's doing.

 

[StuartsProjects]

Glad you got to the bottom of it. That's the trouble with proprietary stuff, can be difficult to know what it's doing.

And the obvious question;

What do other chargers do to guard against reverse polarity being applied to the battery\BMS ?

 

[WheezyRider]

Mains plug in the charging device sounds like an integrated plug/charger, but ...???
I hadn't thought that there wasn't much room for a fuse in such a device, but now I think of it that may be fairly standard practice; and even on a very low power device that could be an issue if there was an internal fault, or if the DC cable out got broken (run over by an office chair?)

It's not just a worry having the DC side fused, EU and US plugs have no built in fuse, so if an office chair cuts through a mains cable, you'd better hope there is an RCD and hope it trips!