| Products > Test Equipment |
| Measuring 100A DC current |
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| trobbins:
StrayElectron, the OP is proposing to use a 'standard' current shunt - that is a 4-point measurement. That is also quite an acceptable method for 1% uncertainty if appropriately managed, and the cheapest and most convenient, given the two meters available. Also you just provide a stereotyped response to anything made in China. A large number of top rated companies set up shop in China - their decision, and have sold worldwide. |
| Fungus:
--- Quote from: Stray Electron on June 07, 2024, 10:25:33 pm --- The OP is very naive is he thinks that a 200 Amp shunt from Alibaba is going to be anywhere near as accurate or the size or will dissipate as much heat as a good quality 100 Amp American shunt! Chinese products simply aren't made that way. --- End quote --- Complete rubbish. The Chinese are perfectly capable of making quality products if you're prepared to pay for them. The $10 shunts are probably not much use but a $75 solid copper one? What exactly could go wrong? A chunk of metal is a chunk of metal no matter where it's made. Shunt calibration isn't difficult - manufacture them to be a bit on the low side then use a file to increase the resistance to spec. The shunts inside every multimeter you own will have a few little nips in them if you look. I've bought a lot of really nice stuff on Aliexpress. The only things I definitely wouldn't buy are power MOSFETS, 16850 batteries, and multimeter fuses. They're almost guaranteed to be fake. Everything else? I'd give them a chance. Aliexpress returns are easy peasy, lemon squeezy - just drop the thing off at a collection point (usually the same places as take Amazon returns take Aliexpress returns too). |
| BillyO:
--- Quote from: Fungus on June 07, 2024, 10:57:00 pm --- --- Quote from: Stray Electron on June 07, 2024, 10:25:33 pm --- The OP is very naive is he thinks that a 200 Amp shunt from Alibaba is going to be anywhere near as accurate or the size or will dissipate as much heat as a good quality 100 Amp American shunt! Chinese products simply aren't made that way. --- End quote --- Complete rubbish. --- End quote --- I agree completely. I get sooo tired of all the China bashing that goes on. If your willing to pay $27,000 for a scope, the Chinese will make you a$27,000 scope that is probably better than any $27,000 US made scope. However, if you only have $40 to spend on a scope the Chinese can help you out and I guarantee it will be better than every $40 US made scope. There is no reason to believe those AliExpress shunts are garbage. None at all. |
| Martin72:
--- Quote ---The Chinese are perfectly capable of making quality products if you're prepared to pay for them. --- End quote --- Absolutely. But it's also true that you get what you were prepared to pay for. Because even the Chinese can't do magic. If you pay €10 for a shunt, you get a shunt for €10, but don't expect the properties of a €100 shunt (which may have a different material property so as not to drift too far away at higher temperatures). If you are aware of this, everything is fine. If you ignore the circumstances that make it so cheap in the first place, all the better. |
| Stray Electron:
--- Quote from: BillyO on June 07, 2024, 11:11:29 pm --- --- Quote from: Fungus on June 07, 2024, 10:57:00 pm --- --- Quote from: Stray Electron on June 07, 2024, 10:25:33 pm --- The OP is very naive is he thinks that a 200 Amp shunt from Alibaba is going to be anywhere near as accurate or the size or will dissipate as much heat as a good quality 100 Amp American shunt! Chinese products simply aren't made that way. --- End quote --- Complete rubbish. --- End quote --- I agree completely. I get sooo tired of all the China bashing that goes on. If your willing to pay $27,000 for a scope, the Chinese will make you a$27,000 scope that is probably better than any $27,000 US made scope. However, if you only have $40 to spend on a scope the Chinese can help you out and I guarantee it will be better than every $40 US made scope. There is no reason to believe those AliExpress shunts are garbage. None at all. --- End quote --- Everyone here seems to overlook the fact that the OP said that he wanted something cheap. He's not going to buy any top of the line product, Chinese or otherwise. It's not a question of whether the Chinese can build a good product but more a question of what kind of quality when you buy from an unknown seller on Alibaba at the cheapest price that you can find! FWIW I have no reason to bash the Chinese products, there are plenty of postings on this forum and many others, complaining about the quality of every Chinese electronic product that you can name! Fake transistors, counterfeit ICs, solder that won't stick to anything, "copper" wire that can't be soldered to; tiny capacitors inside of large cans with much higher ratings, batteries with physically impossible amp hour ratings, a water heater that uses the outer metal body as a current carrying conductor; the list goes on and on! I know from experience that even when Chinese products to work, most of them are rated right on the edge of destruction and there is no margin for error. And that's why with everyone here worried about the heat dissipation of the OP's shunt, I would not recommend buying one from China, regardless of the price. |
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