Which voltage tester?

[Rarebird]

I read a thread on another forum that said that when the voltage of a battery, fully charged, has dropped %10 it is time to replace the batteries. (It also said all batteries should be at 4.2v fully charged when new? That didn't sound right.) It seemed to me it is time to get a voltage tester.

My batteries, I imagine, have gone through about half their expected life, but hard to say. I'd like a voltage tester that is reasonably accurate, but I'm on a budget, so it shouldn't break the bank. Any recommendations?

Also, if you use them past the point of the %10 voltage loss number mentioned above, will it be dangerous or harm my device?

BTW, I'm using a Nebox and a Cupti with Samsung 25r INR batteries.

Thanks in advance for any help!

 

[DaveP]

Lithium batteries are usually at a 40% storage charge when you buy them, unless the vendor stuck them on a charger before shipping. Pop them in the charger as soon as you get them. If you want to store them for a long time, run them down about half before doing that and they will stay healthier during storage.

The 25R's are a good choice. You should get a couple of years or more out of them, especially if you rotate two sets in and out of the charger. That does depend on how you vape. If you are a high wattage vaper, you put more stress on the batteries than you do tootle puffing at 10 watts.

When batteries lose voltage in a short period it's time to replace them. internal resistance is part of that and it increases over time. When your vape time begins to drop noticeably, they are on their way to end of life. The best judgment factor for battery replacement is performance. Right off the charger an 18650 should read 4.1v to 4.2v. Some chargers cut off at 4.15v and others cut off at 4.2v. The real test is performance. You know about how many hours you can vape on a pair of 18650s. When that begins to drop noticeably, replace them. $12 for a pair of batteries that last a couple of years in rotation is pretty reasonable.

You can spend a lot of money on a really good volt-ohm meter, but you can also get a good meter for less than $30 that will do the job well and last for years. Fluke 87 is the gold standard for technicians at about $180. Harbor Freight makes a couple of meters that work fine for vapers at prices from $3 to $30, less on sale.

This one is my first choice for vaping and around the house testing. It's a similar design that mimics the Fluke 87 and some reviewers point out that its internal chip is similar (cloned) to the Fluke meter. It goes on sale for about $24 and comes with a Fluke style rubber cover that protects it from drops.
11 Function Digital Multimeter with Audible Continuity

This one will do every thing you need to do for vaping and general voltage/resistance checks. You can sometimes get the one below free with a coupon purchase or pay $3.99 for it when it's not on sale.
7 Function Digital Multimeter

 

[Barkuti]

Hard to beat sets for the price:

• DT 830B LCD Digital Multimeter AC/DC 750/1000V Voltmeter Ammeter Ohm Tester Meter Digital Multimeter-in Multimeters from Home Improvement on Aliexpress.com | Alibaba Group Black.
• Yellow DT 830B LCD Digital Multimeter AC/DC 750/1000V Amp Volt Ohm Tester Meter Digital Multimeter-in Multimeters from Home Improvement on Aliexpress.com | Alibaba Group Yellow.

To get the special sale price, add the item(s) to your wishlist. Then open the app and purchase 'em there.

Cheers