Chinese car fuses - warning - Page 1
Forum section: electronics / general

author: MF-jockey
author_rank: Regular Contributor
timestamp: July 07, 2025, 05:53:42 pm
content: I bought a box of car fuses from Aliexpress.I was quite surprised when I measured the internal resistance of some of the fuses. It was always about 3 mOhm from 2A to 15A, and the metal parts looked exactly the same.Then I tested the 2A fuses, and they lasted forever at 10A. It was now completely clear I'd been snagged a fake.The internal resistance of 10A fuses from other manufacturers is 6 to 7 mOhm. It should be much higher for 2A fuses.The question arises: in which other products do these fake fuses appear?Addendum: I later carried out more precise measurements, please see Reply #15

author: voltsandjolts
author_rank: Unknown
timestamp: July 07, 2025, 06:01:05 pm
content: Standard fitment on Chinese cars?

author: kloetpatra
author_rank: Regular Contributor
timestamp: July 07, 2025, 06:21:12 pm
content: According to pictures of other reviews to that same product, your fuse wire looks different. You may have received incorrectly produced fuses which are rejects.Also keep in mind that accuracy of the DE5000 is not suitable for 3 mΩ measurement. Accuracy is ±(1.0% + 3 digits).

author: Gyro
author_rank: Super Contributor
timestamp: July 07, 2025, 06:23:47 pm
content: Ironic that they should betooconductive!

author: kloetpatra
author_rank: Regular Contributor
timestamp: July 07, 2025, 06:27:54 pm
content: After taking a second look, your fuse looks like white transparent which indicates 25A. Transparent grey should be 2A!

author: wraper
author_rank: Unknown
timestamp: July 07, 2025, 06:40:46 pm
content: Bear in mind that you can easily buy the same garbage locally, it's not just Aliexpress problem. For example some years ago I've seen exactly the same issue with Bottari fuses that are sold at most of the gas stations and large grocery store chains here.

author: kloetpatra
author_rank: Regular Contributor
timestamp: July 07, 2025, 06:53:41 pm
content: Assuming you accidentally took the 25A and considering the inaccuracy of DE5000, your measurements are within common specs.https://m.littelfuse.com/~/media/automotive/datasheets/fuses/passenger-car-and-commercial-vehicle/blade-fuses/littelfuse_atof_datasheet.pdf

author: rteodor
author_rank: Frequent Contributor
timestamp: July 07, 2025, 07:13:16 pm
content: Out of curiosity I measured two of each in my set with YR1035+Code:+---------+-----------+-----------+|Crt.  | Z1  | Z2  |+---------+-----------+-----------+| 3A | 33.2 | 34.7 || 5A | 14.28 | 16.17 || 7.5A | 9.18 | 9.91 || 10A | 5.53 | 5.47 || 15A | 5.26 | 5.34 || 20A | 3.74 | 3.69 || 25A | 2.66 | 2.67 || 30A | 2.43 | 2.48 |+---------+-----------+-----------+

author: coppercone2
author_rank: Super Contributor
timestamp: July 07, 2025, 07:42:01 pm
content: Hmm I guess you can buy littlefuse fuses on digikey.I thought about it for a moment, its more expensive, but if you are actually doing something with a car, I got mega rage thinking about some wire burning up in a 'car conduit' that requires you to take the front seat and the engine to reach. So its probobly money well spenthttps://www.digikey.com/en/products/filter/fuses/139?s=N4IgjCBcpgbFoDGUBmBDANgZwKYBoQB7KAbRAGY5YAmCA86gBmoE4AWEepyxzi7sNT4AOAKzC2bAOx8GjShy7ywokAF0CABwAuUEAGVtAJwCWAOwDmIAL4E2LBCGSR02fEVIU4LQeq27IA2NzK1sQWAdoJ1RMXAJiSDJyFlEU8j8QHT1DU0sbAiZhYUdnVziPRJBqAAIAQQyswIBVMxNtAHkUAFkcNCwAVyMcfJAAWggo0tj3BLIwYoJRcjZ4NWt1oA

author: edpalmer42
author_rank: Super Contributor
timestamp: July 07, 2025, 08:25:09 pm
content: I just tested a batch of Littelfuse ATO fuses and had good agreement with the table posted by kloetpatra. Measurements were taken with a GW GOM-801G Milliohm meter which has a 20 mOhm scale. As a calibration check, I measured an Otto Wolff 0R5 standard resistor as 0R501.MF-jockey, are your fuses labelled on the edge with the rating? They should be, but with Aliexpress, strange things happen.....

author: Haenk
author_rank: Super Contributor
timestamp: July 07, 2025, 08:51:48 pm
content: Quote from: MF-jockey on July 07, 2025, 05:53:42 pmCheck Louis Rossmann - he purchased and investigated the same junk fuses. On Amazon.As a safety device which could stop serious damage to expensive components, I would only purchase these from reputable brands.

author: MF-jockey
author_rank: Regular Contributor
timestamp: July 07, 2025, 09:12:31 pm
content: Quote from: kloetpatra on July 07, 2025, 06:53:41 pmSorry, I'm not senile enough to confuse 2A with 25A. The camera brightened the colors.But thanks for the datasheet.Suggested by rteodor, I tested two of each the fuses with YR1035+. The results are somewhat inconsistent. Two of the 7.5A fuses with the highest resistance were able to withstand 10A again. After 6 minutes, no blows!I'm planning to run another test tomorrow up to 40A using the ET5410A+ electronic load and a battery.Actually, this junk isn't worth it.

author: MF-jockey
author_rank: Regular Contributor
timestamp: July 07, 2025, 09:22:34 pm
content: Quote from: edpalmer42 on July 07, 2025, 08:25:09 pmYes, all fuses have the value engraved on the top edge, even the microfuses.

author: kloetpatra
author_rank: Regular Contributor
timestamp: July 07, 2025, 09:24:00 pm
content: Sorry for initially questioning it, but 2A fuses weren't clearly visible in your first pictures and the DE5000 wasn't the right meter for the job.Obviously the fuses you got are really crap. Here is the video Haenk is referring to:

author: thm_w
author_rank: Super Contributor
timestamp: July 07, 2025, 09:40:49 pm
content: Quote from: voltsandjolts on July 07, 2025, 06:01:05 pmNo they'd be using reputable suppliers, not ordering random fuse kits from aliexpress.Xucheng fuse is ~2c:https://lcsc.com/product-detail/image/20A32V_C2905529.htmlLittelfuse ~4c:https://lcsc.com/product-detail/Automotive-Fuses_Littelfuse-0297010-WXNV_C151094.html

author: MF-jockey
author_rank: Regular Contributor
timestamp: July 09, 2025, 11:55:48 am
content: Now it's done: all fuse types were tested at up to 40A for at least 2 minutes. Some scrap, some smoke, and a fair amount of heat were generated. The results are as expected after the resistance measurement.Above 30A, the power limit of the electronic load kicked in. With the 12.8V LiFePO4 battery as a power source, the 400W are exceeded. I had to add a high-load resistor made of water-cooled iron wire.If you have fuses from an unreliable source, you should perform the resistance measurement and compare them with the values ​​from common manufacturers. An excerpt from the Littlefuse datasheet is attached below.

author: macboy
author_rank: Super Contributor
timestamp: July 27, 2025, 11:57:36 pm
content: Some things never change. I posted about this exact problem over a decade ago. The fuses I bought also survived 10s of Amps indefinitely. "Survived" means they didn't open/blow, but they did melt and smoke just as you experienced.https://www.eevblog.com/forum/chat/counterfeit-chinese-fuses/