should I buy a hobby charger?

I guess you are right.
But since the OP mentions large lead acid batteries and parallel charging 6 cells at 1A each the ISDT may save a lot of time.

Plus it is much cooler.

I have a B6 Mini and the SC608. I like them both, but the SC608 is very nice design I just have not used it enough to give a strong recommendation on it yet. I like it enough that I’m buying their new model the Q6 Plus. If I was buying today, I’d wait until you can get a Q6 Plus and start with that, learn something about it and then you can make your own informed choice on your second charger if you need one.

As hobby chargers those 15-40$ ones are good for common RC battery packs, small solar batteries, modded power tool packs or selfbuild e-bike battery

For analysing cylindrical cells there are good 2 and 4 slot chargers, using a RC charger is a lot more time consuming
To fast charge 18650 or 26650 there are some 2A chargers, I would not use a hobby charger

But if you want to get a good calibration or a high power discharge to refresh big lead batteries there are other professional chargers

Wouldn’t hurt them to charge to 4.35 either. Maybe lose a few life cycles out of 400, but whatever

I think for now i’ll keep using my friends charger for the lead acid batterie, as I only need it once a year. If i can find an all in 1 solution great but I don’t think that will be possible.
I read the whole tread about isdt 608 and I might go for it (already asked for a code maybe I should ask one for the 620 also). Only thing bout 608is that it cant read Ri of single cells just from packs. Am i correct?

Sorry i don t reply to everyone but i m on a phone and it s a pita. But i do apriciate the replies

I’m not on the latest firmware but yes seems like you must use the balance tab to get IR estimates.

What is a good charger or other device to test LiIon cells for capacity, internal resistance, and max current under load?

You test the resistance with a multimeter, and the capacity with a hobby charger that has a discharge function which almost every good one does.
There is no max current under load, unless it’s protected. This is why they sometimes explode.

Before buying a 608 make sure you look at the new Q6 Plus.

I did but I can t seem to find much info on it, not like 608 on the rc forum.

From the op:

“My budget is around $50 but I wouldn’t mind paying more (even double that) if it’s really worth it.”

I suggest you get a hobby charger (for charging six or more cells as you mentioned, individual cell analyzing, 4.30v and some lead-acid batteries, etc.)
however, this thing can only charge/discharge, in parallel or series more than one cell but of the same capacity always and Mode, which is not optimum for salvaged cells. (major disadvantage of a hobby charger: you can only analyze one cell at any given time)

AND

an Opus BT-C3100 v2.2 (for analyzing salvaged cells 4 at a time without the hassle of cables and holders, charge up 4.35v, do almost everything the hobby charger can do but can do this in any combination of modes(charge/discharge/refresh) and/or cell chemistries at the same time, etc. with individual read-out for each bay.

These two can be had for less than $100…

I have both and couldn’t be more happy. I used to scour around for laptop batts all over town too.

That’s what I was planning to do cheers.

How important is Ri measurement for determening a cells’ quality?

It’s a nice feature for salvaged cells, of which a majority of them has undergone a long, hard life and would surely have high ir values already. This can be very helpful to salvaged cells for though some of them might charge near 4.2v volts, it cannot tell you the real health of the cell until you try it in high-drain lights (it cannot sustain prolonged turbo mode, sometimes jumping down in mode in less than a minute to the next lower mode , this happens from cells with high Ir)

Edit: After re-reading your op and your succeeding posts, and perhaps the joy of analyzing salvaged cells are your more important concern, a hobby charger has indeed very little appeal because it can only analyze cells singly thereby very time-consuming. (I have gone through this route before)

Perhaps getting two analyzing chargers like the Opus has the better suitability to your needs (plus the added feature of no more wires to connect, no battery cases to buy or fabricate, analyze up to 8 cells at once, etc., etc., though it was a great experience having gone through it all)

Thanks for the tip but after reading the test on the opus I m not convinced. Tbh i don’t understand it all to wel but i don’t like the current spikes it takes from the ps. And at $40 i would expect something better. If i would cash out €80 for 2 i think I would be better off going for the mc3000 instead and take my time for testing. But now I m thinking a hobby charger for charging and an opus or liitokala for discharge testing multiple cells at a time. But as I understand it the lii doesn’t do discharge test, it gives capacity after recharge or did I mis something.
Edit: keep in mind that I ll hook em up to a 12v batt most of the time and I don’t know how they will handle the current spikes. These are NOT car batteries which can handle a high initial current draw.

That current spikes was only present in the earliest version of the v2.0.

The 2.0 version had initially inflated ‘Charge’ figures (not in the more important Discharge figures), and was initially ‘cured’ by a higher amperage ps, but a resistor was added to the succeeding versions (middle production run of the 2.0, then the 2.1, that even with the same 12v, 3A since the beginning, good accuracy was attained, up to now with the 2.2 version.

And by the way, I also have the MC3000.

” But as I understand it the lii doesn’t do discharge test, it gives capacity after recharge or did I mis something.”
The Liitokala Lii_500 engineer has 2 capacity tests “Fast” & “NOR” (normal).
In “NOR” mode it fully charges the cell, fully discharges it measuring capacity then fully recharges the cell.
In “FAST” mode it discharges the cell then charges it measuring the ma required to fully charge the cell as the capacity.
The “NOR” test is more accurate than the “FAST” test as the “NOR” test is measuring the ma the cell can discharge from fully charged where as the “FAST” test is measuring the ma the cell takes to become fully charged which will be more than the actual ma the cell can discharge.
I have several analysing chargers for cylindrical Li-ions including the Lii-500 & Opus & the Lii-500 is my preferred charger.

I have found a far more useful “Internal resistance” test for me to be very simple.

I have a load (in my case an old dust buster that pulls a hefty amount of current). I then put the cells in my cell holders with built in volt meter and connect them to the load.

I watch the voltage and then sort them according to how much voltage they are able to maintain under load. This applies very well to flashlight use.

For example a 30Q might hold 3.5V and HE2 3.6v and a GA something like 3.3v.

Most salvaged cells end up in the 2.6-2.8V range with a few getting close to 3V and a lot under 2.6V (where the volt meter doesn’t work anymore.

Anything over 2.6V I keep around, over 2.8V I put into regular use as long as they do not get warm when charging or self-discharge.

Under 2.6V goes into my “wait and see box”. They all go in fully charged (already tossed the one that got hot during charging). After say 6 months any that are still holding a good charge with minimal self discharge get saved for low drain projects, all the ones that self discharged significantly get recycled.

I have ended up with something like a 10-15% success rate for usable cells, 20% low drain reserve cells and the rest are bad in my experience. Overall if you have to pay much at all for used battery packs, it is best to pass. Now new old stock is great on the other hand.

Now I have been waiting to get a constant load source so I can test the cells a bit more precisely but have not had the funds to get one.

Yes, I do this too, but instead of the cell holders with a volt meter, I use my Zebralight SC600, put in Turbo mode. This light, with a ‘healthy’ cell will go on Turbo for exactly 5 minutes then steps down to High.

Tired cells (meaning high ir) steps down the Zebralight a lot less than 5 minutes, really tired cells just for seconds.

That works too, I am just too impatient to wait 5 minutes for each cell test, I prefer 5 second per cell lol.

Course things are a bit different when you have ~100+ cells to sort through at a time vs 10.