ALLOSUN Battery Internal Resistance Meter/Battery Voltage Tester/Digital Battery Analyzer CECOMINOD062345

This is an excellent 4 wire Kelvin battery impedance meter for the money. Nice LCD display. Works as advertised. I use a Lacrosse BC-700 for charge and capacity tests and this meter for battery internal impedance tests. This allows sorting and matching of AA flash batteries for minimum photography flash recycle time. For more stable readings, put the battery in a good metal battery holder and measure the impedance across the battery holder terminals.The meter does indicate a 1 when it is out of range, which is typical for all meters of this type.An instruction manual in English would be an improvement. Amazon provided the manual in English when requested.

I agree with three other reviewers. This meter is junk. Quality control was non-existent. The meter never worked, straight out of the box. Once a (verified good) battery is installed, the meter cycles through random numbers for about 5 seconds and then locks up displaying either 1 or-1. This happens on all switch positions, both volts and ohms. Turning the meter off does not reset the electronics. The meter will read 1 or -1 immediately after turning back on. I can reset the meter by disconnecting the battery and re-connecting it, but it again displays random numbers for about 5 seconds before permanently locking up again. This product is trash, and I will be returning it to Amazon for a refund.

My first specimen lasted two and one half years, until it went kaput overnight. I was using it as usual one day, and at very next day, it was no longer a resistance meter. As failed, in all three resistance/impedance ranges: it would display a two digit number when open circuit (should be 'I' for infinity); and a three digit number on a conducting resistor. Even on shorted test leads, it displayed a bogus three digit number, higher than open circuit's two digits.Its circuit board has four turnable adjustable things (trimpots maybe). Having nothing to lose, I played with all four miniature dials: three didn't seem to do anything, and one of them tweaked least significant digit up and down by one count. (I don't remember which function was affected, volt or ohm.)I looked at it this way: thirty dollars spent for a tool which served two and one half years, is like twelve USD per year for rent/functionality. And it didn't become completely useless, just disabled: it is still a handy battery potential tester, a 50 V D.C. voltmeter. Every home should have a basic multimeter at this twenty-first century, but as most still don't: there is vacancy for battery potential meters, to be filled by these failed battery impedance testers. Pattern failure in this model of appliance is not an urgent escalating e-waste problem.While I am upset because it failed and doesn't seem easily fixable, I was satisfied enough with it, to order another. I did consider other options, and decided to just buy another one of these. My second specimen was dead on arrival: in a different way from how my first failed, this new-DOA was also only a DC-voltmeter. This DOA specimen displayed every resistance/impedance as zero. 0 Ω, in all three ranges. Ships from Amazon.com Sold by Amazon.com Customer Service Amazon.com, it was replaced five days later. This replacement (my third specimen) worked on arrival, but it lasted only two days. Two days after first use, it failed just like second specimen: measures anything as bogus 0Ω.I was completely satisfied with this measurement instrument, when it lasted two and one half years. Receiving two bad units in a row (one dead on arrival, one dead after two days) is not bad luck. There is a real problem here: either a major design oversight, or practically inexistent quality assurance.If I were Amazon.com: I would stop sale immediately and test each and every unit in inventory. If I were all-sun (Eastern Intelligent Meter Co.): I would retire the model EM3610, "go back to the drawing board" and re-engineer it. I want to see a new, hardness improved, model EM3611 Battery Internal Resistance Meter, with three year warranty.

This is probably the cheapest internal battery resistance tester on the market - but precision is surprising, better than I anticipated. My top of the line iCharger DUO measures perfectly internal resistance of all the cells of multi-cell LiPo battery packs but as for Li-Ion result is 10 times higher than norm... Even soldering of gauge #8 leads to the battery holder tabs did not help. This small pocket device does the trick - 4-wire leads + 1kHz measuring pulses is the best solution. Samsung Li-Ion 18650 25R shows under 20mOhm as it should be. But to get stable result holding the leads tight is not easy- surface of the contact introduces significant additional resistance. I suggest pressing tips of the leads perpendicular to the Li-Ion battery tabs.The only way to improve accuracy as I see it would be replacing the hand-held leads with stationary leads-in-battery-holder to improve contact. I am considering doing this for 18650 batteries tests. (Although leads are permanently connected inside the tester to minimize contact resistance).Beware: it came with only Chinese manual . Upon my request all-sun emailed me English manual - it is quite well written.

Initial disappointment was the accompanying instruction manual is in Chinese and I don't speak Chinese let alone read it. I'm one of the impulsive people who generally don't worry about manuals except when all else fails. So I rip the plastic wrap off the 9V battery supplied and switch it on to see " -1". And that's when I went to the useless manual. So I found the English version on line and that didn't tell me what -1 was. So I remove the battery and it's reading 5.3V .... not bad for a 9v battery that has 9001 certification stamped on it an a supposed production date of 07-2020. Otherwise, the meter meets my purpose. Just glad I read the review highlighting EMF interference so as I'm aware.

The Internal Resistance Meter showed that every 12v battery I tested had zero internal resistance. Good batteries, new batteries, old batteries, and bad batteries. I ordered a replacement and it also has the same problem. It never gives usable readings for any 12 volt battery tested. Now I have 2 to return. I bought a 3rd Internal Resistance Meter from another seller and it works great, but at a somewhat higher price. The Allosun Battery Internal Resistance Meter is useless.