What battery charger will test and reveal capacity mAh?

I want to know if these batteries I’m buying are true to the advertised specs I paid for. Namely Samsung 30Q bought from Banggood recently. I’ve got a few chargers that say they give mAh readings but don’t. Instructions don’t tell how to get this reading.
Nitecore D4
Nitecore SC4
XTar VC4

Someone said the Opus BC3100 does this. Anyone have a recommendation, I would appreciate it. Thanks for your input.

Those really won’t work. You want:
Zanflare C4
Lii-500 Engineer
Opus BT C3100 (couple different similar models to this one)

My current favorite is the C4. Inexpensive, easy to use, seems pretty accurate. Internal resistance measurement works, unlike the Lii-500.

They may give mAh readings, but only during charge cycle, which is not going to be accurate.

The more accurate method of measuring capacity is during discharge cycle, so you need to find a charger that has discharge capabilities, such as the ones that flydiver mentioned.

Here is a list of all analyzing chargers that HKJ reviewed/tested:
http://lygte-info.dk/info/roundCellChargerIndex%20Analyzer%20UK.html

Just be aware that not all of them work with Li-Ion cells - you have to look at the “Chemistry” column.

These are some I’ve been looking at. Thanks for your reply and suggestions. I appreciate them. :+1:

Exactly! During the charge cycle. The way they advertise the charger is a little short on info like this. Thanks for your input. I appreciate it.

I know nothing about chargers….with this charger, can i put an older 18650 in it, having the charger discharge it and then charge it up to full, and i see how many Mah its accepting?

If a reputable 18650 is labeled 2500mah, and its only accepting 1600mah (by doing the discharge first), does that mean the battery has about ran its course?

How does a battery “get old”? by accepting less mah than its supposed to?

Sorry for the noob Q’s

No……you charge it completely > then you discharge it to a known low/safe level which measures the capacity. Charge capacity is not accurate, especially with NiXX chemistry.

Simplified, as batteries get old their internal resistance increases, which lowers their performance = their ability to sustain voltage under the required load. It may work OK in a low performance application, but do poorly or fail when more current is required.

They also start to lose capacity. Don’t equate claimed capacity with measured capacity. Almost all batteries don’t quite live up to their claimed capacity, but good ones get very close. Crappy batteries often are seriously under their claimed capacity. For some batteries these fake claims are ridiculous.

If the mAh out is off the mAh in for an unprotected Li-ion cell (not sure whether or not protection circuitry consumes much/any current on its own while charging), then there is either something seriously wrong with the cell or the charger.

I’m sort of a newbie too, but I have been doing some charge/discharge testing as of the past couple of months or so, sharing a little ‘first-hand’ experience:

Based from what I read (a number of HKJ’s reviews for various chargers and also some message threads in this forum):

Chargers that have charging capacity reading (ie. how much charge was placed into the battery):
to get a correct reading, the battery must of course be drained to nearly empty (otherwise, you can’t charge more capacity into a battery that’s near full).

The XTAR VC4 (which is my first Li-Ion battery charger) will be able to give a nearly correct reading provided the Li-Ion battery is nearly empty.
(VC4 only charges, so it shows charging capacity; it does not have a discharging function, so it can’t show discharged capacity)

But, according to some posts I read (I think HKJ mentioned), is that Li-Ion’s charging capacity is almost equal to the discharge capacity (charged to 4.20v; then discharged up to the cut-off voltage).

However, for NiMh batteries, the amount charged is generally not equal to the discharging capacity (I’m not very sure of the reason why, and also whether it’s higher, or it’s lower).

These are for “good” batteries.

~

Now, for “bad” batteries, the charged and discharge capacity could be greatly different.
I’ve had some 18650s I salvaged from laptop battery.
Since I was a newbie, I hadn’t known much (plus the fact that I didn’t have new “genuine-branded” 18650s at that time), so I just charged those salvaged 18650s. They were rated 2200mAh, and the charged capacity was around 1000-1200mAh. They seem to be charging fine, other than the reduced capacity. Doing a discharge test, the discharged capacity seems slightly lower, but not too different, something like 900-1100mAh discharge capacity. So it’s still Ok.

But then I had another set of salvaged laptop battery (they were also labeled 2200mAh).
Now these batteries are “bad” (well, I didn’t know yet at that time).
I charged them using the XTAR VC4, and they don’t seem to stop charging. About 4-5 hours later, I notice the batteries were getting quite hot — the capacity charged reading were already around 2500-3500mAh! I removed the batteries and did a discharge test (after they’ve cooled down a bit), and they seem to have around 900-1200mAh (almost similar to the first set I got). So the discharge capacity is the more precise reading. The charge capacity is wrong because the charging was not terminating (due to them being “bad” batteries).

(Side note: for charger/analyzers (it seems chargers are also called “analyzers” if they can also do discharge test to measure the battery discharging capacity), discharging rate might be configurable. Having a slower discharge rate (eg. 300mA) could show a wee bit more capacity than discharging at a higher rate (eg. 1000mA), depending on the type of battery. I think for a beginner, this probably may not be noticeable and negligible.)

That experience with ‘bad’ cells is a compelling argument for having an analyzing charger vs something like the Xtar that only measures charge capacity. That, and the ability to program it, let it run until it’s done, and get the results. Manually discharging to a ‘known’ low cut-off in a reliable fashion is certainly possible but is going to be far more of a pain and not very precise unless you are quite diligent.

I had an Xtar. Fine charger, but I sold it when I got the Lii-500. Costs about the same, about as easy to use, does more. I got the C4 to check it out and like it even better and it’s also in the same price range. I don’t see a compelling reason to have a Nitecore, Xtar, or similar instead of a decent analyzing charger unless it has some very specific charge qualities that you want/require.

Zanflare C4 works very nicely for this.

The only thing I don’t like is that compared to the Xtar VC4, the bays are narrower and it’s also much easier to knock a battery out which is a bad combination. You have to be pretty careful when loading the C4 if you’re doing all 4 bays.

The Miboxer C2-4000 analysing charger is also good, 2 slot 1.5A per slot

Thanks for all of your input guys. I’ve bought the Liitkola Lii 500 charger.
:+1: :beer:

is there a way to calculate to get the mah of a battery if you don’t have this chargers that can read mah?

Sure, but you’d need even more equipment that would be more fiddly and likely more expensive than a decent analyzing charger. You can get the Lii-500 or Zanflare C4 for under $30. Why bother with other methods?

Well, prior to getting an analyzing charger (chargers that can do discharge capacity test), I had been using a USB load meter (EBD-USB+), connected to an 18650 battery holder and with a USB to alligator clip to do discharged capacity testing.

What I did was to charge the capacity to full (my only lithium-ion battery charger that time was the Xtar VC4), then place the 18650 in the 18650 battery holder, and then connect the alligator clip to both ends of the battery holder (the other side is a USB that plugs to the EBD-USB+ load meter/tester). Then I set the EBD-USB+ software to discharge the battery at 1A, with an automatic cut-off of 2.0v. Then read out the capacity reading.

(I wasn’t familiar with 18650s or lithium-ion batteries that time, and checking the data sheet for LG HG2, it said cut-off 2.0v, so I selected cut-off of 2.0v when I did the test. The LG HG2 doesn’t seem to be a genuine LG HG2 though — it was my first 18650 battery and I didn’t know where to get genuine 18650s, actually I didn’t know where to get any 18650s yet at that time, so when I saw a local store with 18650, I grabbed it)

It was somewhat cumbersome to use though. Though the advantage of the EBD-USB+ is that it graphs the discharge curve, which can be informative when comparing different batteries.

The reading says 2463mAh capacity (which is much lower than the rate 3000mAh for a genuine LG HG2.

(You could also use a “hobby” charger to do something similar)