Question UPS nJoy Cadu vs Kraft&Dele, which is better?
Question UPS nJoy Cadu vs Kraft&Dele, which is better?
I wish to purchase a 2000vA uninterruptible UPS power supply. My available budget is up to 120$. I am unfamiliar with this type of product and have several queries about it. Those who own such equipment like this:
1. Are Kraft&Dele and nJOY reliable in this category? I’m interested because my budget matches theirs.
2. Do some UPS models claim an automatic restart feature, while others don’t mention it? I want to know if all of them offer this, even if not stated clearly?
3. Between nJOY Cadu and Kraft&Dele, which is the best choice?
4. Lastly, for future reference, what distinguishes UPS models with pure sinusoidal output from those with simulated sinusoidal versions? Why does a pure sinusoidal model cost twice as much? What makes it more expensive?
Thank you,
https://i.postimg.cc/vZXZkLh0/ups.jpg
These are lesser-known brands, but they might simply be unfamiliar in English-speaking regions.
However, depending on your needs, you may prefer not to use them.
It really comes down to what you intend to safeguard with these devices.
The power supplies you see today often carry 80plus ratings, indicating high efficiency.
Their performance relies heavily on the quality of the input signal waveform; poor quality can lead to irregular spikes and flat areas in the graph.
This inconsistency may prevent the supply from delivering its full capacity and could even risk damaging the unit.
Such supplies are commonly found in desktop computers, but some laptops and advanced monitors or TVs might also be affected.
It’s unclear if many users opt for non-sine wave UPS systems for their computers, as they’re not fully aware of the alternatives.
Typically, people don’t rely on UPS for extended periods—often just a few hours a year—making it difficult to assess long-term effects.
Power supplies are unlikely to fail catastrophically, but their lifespan may be shortened.
In any scenario, running a modern computer with a simulated sine wave UPS is not advised, especially not with a generator.
I haven't used these brands before... But after studying and working extensively in Power Electronics... And reviewing their specifications, I can say that... nJoy stands out more...
+ it responds quickly during AC interruptions...
+ it uses a Pure Sinewave Inverter design, likely employing an H-Bridge circuit.
+ it offers more advanced features compared to Kraft and dele...
+ it has a narrower voltage range, which I find particularly suitable for PCs.
+ it includes additional safety mechanisms...
Moving on to the second point...
What is the automatic Restart function?
When the UPS is fully charged... and during a power outage... it powers your PC, but after some time the battery depletes and the UPS shuts down...
If your UPS lacks an automatic Reset/restart capability... once the mains are restored, it won't turn on automatically unless you manually press the power button...
If your UPS has an Automatic Reset/restart mode...
Once the mains are back on, the UPS output will activate (if it's still operational).
Lastly...
Modified Sinewave inverters actually utilize an H-Bridge inverter. This allows current to flow in one direction for 12 milliseconds, then open circuit for 4 milliseconds, and again reverse direction for 12 milliseconds with an open circuit. This generates periodic Square wave signals with a dead time of 4 milliseconds... In theory, the RMS value matches that of AC Sinewave, but...
+ Generally, Modified Sinewave inverters are slower in detecting AC faults, so they may take around 20-30 milliseconds to respond after an outage. They are easier to construct and can offer more features... But...
+ Under no load on the output, they produce very high voltage spikes—similar to about 400 voltage peaks—which is extremely hazardous...
+ They emit a loud humming noise.
+ They are more susceptible to failure due to larger current spikes in MosFETs...
Sinewave inverters, on the other hand... perform the same with rapid on-off cycles of MosFETs and variable dead time...
Their operating frequency can reach up to 200KHz for quicker response times and reduced long-term changes...
They are safer, more efficient, and more reliable than Modified Sinewave inverters.
They do not produce buzzing sounds or high voltage spikes during operation... So it's best to opt for pure sinewave inverters. ✌🏼
It's unclear what you were checking. nJoy offers various UPS units, including some with pure sine waves; the Cadu line seems to be their entry-level models, which claim to use simulated sine waves.
...S... cadu 2000 is really a Modified Sinewave inverter based UPS... Still decent considering the cost... But as I mentioned before, I've never used Njoy ups before. I can't say anything about it, but the spec sheets seem promising and the internal photos are interesting too.
Can't comment specifically on nJoy
regarding UPS, but based on their past issues with power supply problems, I would absolutely avoid purchasing anything from them, particularly safety equipment. They used to print fake 80 Plus labels on their PSUs and once caught doing so, they began creating their own labels that closely resemble theirs. Their PSUs were inexpensive and full of faulty components, targeting mainly Romanian customers. I wouldn't rely on their UPS unless a credible source thoroughly inspected the parts.