Dubious stuff from china

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station240

Member
Joined
Oct 9, 2016
Messages
177
List of various electronics to be wary of, usually sourced from china directly.
This is for stuff that is of poor design or quality, some of which is what I term Class 0 electronics (explanation later).

Cheap or sometimes not quite so cheap DC to DC converters.
These can vary from works well, to poor efficiency, to cannot ever meet the claimed power output.
Be ware some don't have proper (or any!) overload protection. Some claim have short circuit protection, but unless it's a dead short it doesn't trigger.
Also check capacitor voltages, and that they are not lower than what the input/output they are connected to claims to have.
Finally voltage adjustments can exceed what the device can handle.

18650's
Some new cells are actually recycled ones, or tiny e-cig cells with 'packing' material.
Faked cells are filled with sand, which means no risk of fire lol

BMS modules
Useless, give you a false sense of safety.
Better off with a cell monitor, or hunting down a real BMS.

Nickel strip
Laptop packs are constructed by linking 18650 cells together with nickel strip for high conductivity.
There exists Nickel Strip which is actually nickel plated steel. Beware of cheap nickel strip, which often states it is nickel plated.

Cheap 18650 tab welder
Can be one of these Class 0 products, that is dead on arrival.
There is one in the $200 range which has a common fault of a short circuit in the transformer, not hard to fix however.

LED lamps
Some styles of LED lamps are of very poor quality, in both complete light and module form.
An example is the LED floodlight which has a square array of LEDs in a sort of yellow block.
Main issue with these is the 100W comes with a 50W driver, but if you upgrade to 100W, it doesn't last very well. Poorly matched LEDs, so not suitable for dimable lighting.

feel free to add you own
 

station240

Member
Joined
Oct 9, 2016
Messages
177
There are three classes of electronics products.

Class 1 General Electronic/Consumer products
Basically stuff where it to works, but it's a minor inconvenience if it breaks.

Class 2 Dedicated Service Electronics
Where long life and service is required. If it breaks it's going to be annoying, but not life threatening

Class 3 High performance Electronics
Needs to work no matter what, lives depend on it.

I've also cynically created Class 0 electronics.
Which is where the bloody thing never worked, or had no ability to do what it claims.
These can be anything from outright scam products, anything with major design flaws, or just plain garbage build quality.
 

hbpowerwall

Administrator
Joined
Oct 7, 2016
Messages
1,978
I think you have something here for a great thread. Would be good to maybe have different replys for each item - bms, charger, inverter etc then ass people add to this list I can move into the right category. Mabye changing the name to "dodgy crap to steer clear of" so we don't just point fingers at china..
 

station240

Member
Joined
Oct 9, 2016
Messages
177
I'm not going to make a list of particular products, some don't even have a brand name.
But often there is a common theme of things to watch out for, common design flaws.
Some ebay sold stuff is designed to be as small as possible to save on postage, so leave out things like fuses. :evil:

I've only found the worst stuff to be from China, only place that seems to make electronics that is both badly designed, and cheaply made.
Such 'fun' things like the Capacitor Plague that sent some computer shops broke with warranty returns on PSUs and motherboards
 

Shoopinguin

New member
Joined
Oct 26, 2016
Messages
4
El-cheapo battery chargers
These darn things either do not work at all or very poorly. If it's a higher priced one with capacity measurement the values are more or less randomor way off.

"MPPT" Solar charge controllers
Even though these are reasonably priced, the devices do not implement a poper MPTT technique. Some are even worse efficiency wise than cheaper shunt regulators. The units that do work, produce a lot of harmful EMI. It's a real bummer. You simply can't find a reasonably priced controller for Lithium batteries that is any good at all.

Cables and wiring
Cheap cables are either poorly made or made of some strange material. What you'll find is mostly CCA, or even worse: CCS. CCA(copper plated aluminium) isn't actually too bad, as it has better conductivity per weight than pure copper. CCS(copper plated steel) however is absolute crap. Conductivity is very poor compared to even CCA. If you suspect these things in a store, you may be able to use some simple checks to determine if it's real copper or not. With a lighter flame, Aluminium will melt, while pure copper does not. With a magnet, you can detect CCS. Poorly made cables often have bulges in the insulation. You may find both stranded and solid core wire. Insulation material is either very thin or made of flammable plastic. Make sure to buy quality wires from reputable makers.

Power supplies
... or as i like to call them: Bloody deathtraps. The level of clearance and creepage distance is often substandard and will not pass any regulation test in any country (except maybe China?). This may not be a problem at first, but insulation degrades with age of a device. also hot and humid environments may lead to premature breakdowns and potentially lethal voltage levels on the output. The culprit is not always easy to spot. Even if the PCB fulfills all mandated regulations, a poorly made transformer can still ruin your day. And even if your power supply is not a shock risk, cheaping out can cause all sorts of nasty interferences when using devices.
 
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