My general experience of customs duties is VERY HIT AND MISS. It depends on where the goods came FROM, who they were carried BY, and what the sender might have DECLARED on the CN22 customs form. And that's just the UK! Other countries no doubt differ. Your mileage WILL vary.
I thought I'd "got away" without alerting the customs' interest, KMEL, but a couple of days after my Maynuo load landed with me, and invoice for GBP£25 followed - that's £15 VAT , and £10 to the carrier for the charge to levy the VAT charge! Charges on charges - great. That's the key, of course, make a deal whereby there is something in it for the carrier, and for sure they will collect your country's taxes from you!
OK - a few words on my Maynuo 300W 500V electronic load so far.It came well packed and double boxed, with soft, "giving" packaging which will decelerate any delicate electronics to rest over a few mm of travel, so subjecting the items to lower "G" forces. Some firmer packaging (such as expanded polystyrene) I've seen in other instruments does not do this. GOOD
It came with the WRONG manual - FAIL
It came with the WRONG (wong?) Mains lead - FAIL! OK, I've got spares, but surely that is easy enough to get right?
It came with a propriety to USB interface which you
need to hook the load up to anything else (GOOD -
MAKE SURE you ask your supplier if that's included - it may not be as standard)
It DID NOT come with any PC software on CD - EVEN THOUGH that appeared in the eBay photo! FAIL But at least you can download it.
The PC software is pretty comprehensive, but the screen is probably designed by a 12-year old who hasn't got a degree in man-machine interfaces - number display is CR@P - mimics 7-segment displays -
WWHHAATT??? Should have stuck with a more readable Arial font, instead. NEAR FAIL
There are a number of mistakes in the printed specs - FAIL, but overall the accuracy is good within spec (which is pretty tight). Certainly, specs are 10X tighter than cheaper electronic loads. GOOD
The instrument did include a calibration sheet - Good
There are too many digits on the display! It's like measuring something with a ruler and declaring it to be 251.348mm long. It
might be, or it might be 251.5mm long. You cannot tell with the measurement device in question, so the last digits are irrelevant.
The load's accuracy and performance are pretty good, but accuracy goes off at very low currents - below a few mA. You can manually compensate for this, though.
You can
apparently adjust the electronic load's current setting, for example, in increments of 10uA, but the smallest incremental change that the load will actually resolve is 50uA. Another example of somewhat pointless resolution.
There are temperature sensitive fans, which vary continuously and smoothly according to the temperature demand - GOOD (not just on/off)
The display features four simultaneous measurements of Voltage, current, power and parameter under load control (voltage, current, power or resistance). Good
The displayed character size is a little smaller than the ITECH/BK equivalents, as a result. You can get around this with the software app, if necessary.
The instrument is quite DEEP, but when you open it up, you'll see why - big, long heat sinks.
The case is of good quality overall. Standard tilt bail. Nice. Rubber bumper thingy at the front. I can take it or leave it (so can you - it comes off easy enough).
Most annoyingly, they have mounted the number pad buttons the wrong way up! Telephone style 1>9, rather than calculator style. You have to stop and think before keying a value in. Try rearranging your keyboard keys A>Z, and see what that does for your typing - FAIL
PROPER ON/OFF Switch - when it's off, it's off. GOOD
DO NOT RECALIBRATE THIS DEVICE (done through the front panel). I have £$%^&'d up the high current range as a result, and so far cannot get it back. FAIL (on the part of the user???) Waiting to hear from Maynuo...
Internal construction looks OK. It's no Agilent, but it will do. I don't get goosebumps plugging it into the mains... GOOD (enough)
There are no fewer that EIGHT paralleled MOSFETS sharing the load in my Maynuo. They don't look like they'll have a hard time doing their job.
Because the regulating elements are MOSFETS, the resistance of the load cannot go down to Zero. Mine goes down to about 0.25 Ohms
It is CEII marked (whatever that actually means), but the instrument does not carry any specs regarding isolation performance. The input is floating (not connected to earth), but how far away can I take it? 500V? Dunno
The computer interface NEEDS to use an external Propriety USB, 232 or 485 lead. (I've got the USB lead). These leads DO offer electronic isolation from the load - IMPORTANT
There is a rear-mounted BNC socket which carries a voltage proportional to the current flowing. Cheaper electronic loads skip this. This is useful for displaying current transients on a scope - GOOD. But again, Caution - this circuit is not isolated from the device under test.
Also rear-mounted wiring for separate load voltage sensing (to get around voltage drops of long cable at heavy currents) GOOD
Also Trigger inputs/outputs. Again, I've not seen these features on cheaper loads. GOOD
There are some great built-in battery test modes (cheaper electronic loads may skip these)
And the ability to program different currents or whatever at different times/durations, so that you can observe how your supply handles transient load changes. You can also set start up ramps (how quickly the load "comes on") - GOOD. Again, you may find these missing on cheaper loads.
YES, it's the same as the ATTEN, and YES, it is bl00dy similar to the ITECH/BK, but not the same. Probably a direct copy, from the country where the word "Copyright" means: "if you are going to copy something, copy it right"
Yeah - over all, quite happy with my purchase. But with just a
little extra polish here and there, and more attention to detail and western standards, they could turn a good product into a GREAT product. C'mon, Maynuo...
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