I would like to test the health of individual 18650 battery. Basic metrics such as capacity, voltage. I don’t have any electronic equipment. Would the device below be suitable for the job? You would find this device on ebay searching for the keyword cellmeter.
Reading the description, it is not clear if this can be used to test individual 18650 cell, how to connect the cell to the device and how the device is powered.
No. It’s mostly a voltage checker and it’s primarily for RC packs. The balance tap plugs into the plug on the right side. For RC packs, it’s decent. It’s not designed for single can cells.
It won’t measure capacity. It will extrapolate what it thinks is the capacity from the voltage. This is (very) grossly accurate for lithium, useless for NiXX.
You want to get an analyzing charger. You’d pay $10 for that thing anyway. For $10-20 more you can get a decent 4-bay analyzing charger.
Start reading about analyzing chargers in this forum. For a list of chargers that have been given close scrutiny I’d start here: Table of tested chargers, comments?
You can re-arrange columns by clicking on them and go to individual chargers for a complete review.
Don’t settle for simple, cheap and lame, when you can have a decent tool.
My main concern is just to figure out if the pack of four Samsung INR-18650-35E ($22 USD) I have ordered on eBay are fake or not. Seller (kamping_official_store) seems to be a battery store and the product is clearly labelled as new Samsung.
I am not looking for any scientific analysis. Is there any empirical or common sense way to figure out? Maybe feeling by the weight, or just put in the flashlight at low light setting and figure out how long it takes to drain the battery?
I use either the ZHIYU or Kunkin. You’d need a battery socket or cradle. The Kunkin might be over kill for you. I use that mainly for testing power supplies and bigger batteries like 12v lead acid batteries. The ZHIYU requires a separate 12v power supply. The ZHIYU can be got at Banggood for $16.99 or possibly in the U.S. for more. Check also Ebay. Keep in mind that a constant current load is going to need a heatsink and fan (depending on the power its dissipating). If you don’t see any of that………it’s likely not what you want.
Most chargers don’t have built in analyzers. I find I hardly ever worry about it with flashlight batteries……….even though I have the equipment to do it.
Another way to get a ball park figure is to take one of your good current regulated flashlights. One that has constant brightness (meaning constant current to the LED) Put it on medium high level (say around 200 lumens) which would be about 350mA. See how long the light runs before it starts to drop down in brightness. Muiltiply the current by the time and you have approximated mAh. 200 lumen level should give you 3500mAh/350mA = 10 hours.
OK. Maybe not quite that easy to do. You kind of need some equipment. If you could measure the battery current for a given output with your digital multimeter, you’d get a little closer to your ball park figure.
You can do as @hiuintahs suggests and get a discharger + battery holder. I finally did that because the accuracy for internal resistance and the ability to reliably measure capacity is better than most inexpensive analyzers. I have at least 6 analyzing chargers already. But….you’ll pay as much for the discharger + power supply + battery holder as you would for a Lii-500 or similar. My suggestion, do that.
Without some kind of measuring tools, a digital voltmeter being one of them, you are mostly just thrashing around in the dark. You didn’t make a mistake, you created a learning opportunity. You will have a lot more in this field, a whole lot more. May as well get used to it.