Dangerous e-bike chargers found on Amazon and eBay
The products have since been removed from sale after an investigation by a consumer safety charity.
www.bbc.co.uk
Dangerous e-bike chargers found on Amazon and eBay
- Thread starter StuartsProjects
- Start date
I read it but it seems to be aimed at the plugs not being up to UK standard. So its not really an ebike thing at all, it could apply to any imported electrical product. I was expecting something about dodgy unbranded lithium batteries going up in smoke.
Of course, but it seems that a number of eBike chargers were found with dangerous plugs. So take care is buying an eBike charger off eBay etc.
I would be careful about buying cheap e-bike chargers from eBay. Two cheap ones I bought gave 43V output and not 42V. I had to modify them to be suitable:
www.pedelecs.co.uk
You can see the size difference to a typical SANS 2A charger.
I have set them to 41V now. They do get quite warm in use and would benefit from being fitted with a fan.
With any mains purchase off of eBay, you need to check it thoroughly in terms of the plug etc. Is it fused? Is the right gauge of wire used for its current rating? Does it use the right 2 or 3 core cable colour code?E.g. once I bought a cell welder and it had a 13A UK plug, fitted with a 20A fuse and a cable only rated for 10A.
Tuning cheap 42V charger
A while back I bought a couple of cheap 42V chargers as spares, so I could have one at work, at home etc. I got two for just under £10 each. They are quite a lot smaller than the SANS charger and looked good: However, when I checked the output, I was disappointed to see that it was nearly...
www.pedelecs.co.uk
You can see the size difference to a typical SANS 2A charger.
I have set them to 41V now. They do get quite warm in use and would benefit from being fitted with a fan.
With any mains purchase off of eBay, you need to check it thoroughly in terms of the plug etc. Is it fused? Is the right gauge of wire used for its current rating? Does it use the right 2 or 3 core cable colour code?E.g. once I bought a cell welder and it had a 13A UK plug, fitted with a 20A fuse and a cable only rated for 10A.
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I have one that looks similar to the smaller one in the picture. It was supplied with a Swytch kit for my Bromtoon.
Its gets too hot really, not dangerous melty hot, but too hot for long term relaibility. It ought to have a fan.
Would be interested to know the voltage it gives out, if you have an accurate multimeter.
42.67v off load, measured with a Fluke 87V, 41.9V on an Avo8MkV
So one gives an ok result, one too high...Which one do you believe has the best calibration?
I find this quite typical of multimeters in the 200V range - a lot of variation from one to another.
The Fluke, but thats digital so effectivly open circuit, so the charger output might be a little high.So one gives an ok result, one too high...Which one do you believe has the best calibration?
The Avo8 is an old style moving coil job and circa 50 years old, but puts a small load on the charger.
My other two digital meters, HP-90EPC 42.7v, OWON B35T 42.6V
Sounds like the voltage is 42.6V and the AVO is a little out of calibration after all these years.
Would you expect a load under the rated output current to make any difference? It is designed to be a CC/CV switched mode PSU, so if there is a load and the output drops, the regulator should tell the high voltage side to increase frequency of the input pulses to bring the voltage output back up to the set OCV value.
I would not be comfortable with an output of 42.6V. Not likely to cause a fire, but quite likely to reduce the life of the battery pack.
Most chargers that get hot have little or no ventilation so heat build up can't escape, for this reason I modded my sans and now none get hot.
It could do.
What you really need to do, rather than measure the open circuit voltage of the charger, is to measure at the time full charge is attained;
The voltage of the battery.
The output voltage of the charger whilst its still attached to the battery.
> 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.Dangerous e-bike chargers found on Amazon and eBay
The products have since been removed from sale after an investigation by a consumer safety charity.www.bbc.co.uk
An image (in the original article) of the offending mains plug would have been helpful. Or did I miss it?
When I have used SANS chargers as delivered from Yose Power, they have been set to 41.7 V by default and charge the battery to 41.7V. There is a little voltage relaxation after removing the charger, but I normally find this is less than 0.1V and the battery will be at 41.65V or so. It's similar when I set the chargers to 41V. The battery reaches 41V and then drops very slightly when the charger is removed, but not by much.
What would be interesting is what voltage you measure with a 42.6V charger as the battery reaches full charge.
Hopefully the BMS tries to dump excess voltage through the balance resistors, but the capacity for this is is not large, usually only a few 10 mA of current can be burned off. The current must fall to a small value, otherwise the charging light would not go from red to green. Would be interested to see what you measure when charging is complete and then what the battery voltage drops to after removing the charger.
One of those tiny triangular plus arrived attached to a variable voltage power supply last year, the pins are very close to the vertices, easy to end up touching them while plugging into a live outlet. They're also on a set of studio photography lights I bought three years ago. They're on all kinds of electrical equipment sold on ebay etc, not just ebike battery chargers.
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It appears that my Swytch charger is charging the battery to circa 42.64.
However a silicon diode in series with the charge lead does seem to charge the battery OK and then the voltage on the battery side is 42V.
Should be out on it later today, when I recharge it I will check it full charges with the diode in place.
That's really good to know. A major brand like Swytch you would expect to get it right. If the system is still under warranty, I would be asking for a replacement battery and charger.
Does the diode drop work ok? I tried that trick with my cheap PSUs, but found it would send the voltage reading all over the place...but I did not measure under load, just OCV.
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 .............
In what way?
That is actually the 36 volt DC charging current, not the mains 230VAC plug/socket current.
The actual AC mains current drawn to supply 2 amps DC at 36 voltsDC would therefore be much smaller than 2 amps.
And even if it was the mains current, it is still well within the design limits of a modern 13 amp Plug and ring main wiring!
Assuming a correct installation of course.
Therefore I do not understand your worries areb in this case!
Please explain.
regards
Andy
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