should I buy a hobby 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.

Your way is a lot less time consuming, I should say…never got to think about it before…but after I got my iCharger, and, after Li-ion cells got a lot cheaper, I never bothered with the salvaged cells anymore.

Do u get the capacity measurement after the discharge or do u have to wait until the cells are fully charged again? Point beeing that I charge like say 6 or 8 cells with hobby charger do a norm test on the lii but cut it short when I get the read out and pop in the the other 4 cells to test capacity and rechargr the just tested cells again with the hobby charger.

Is the capacity which a cell can hold in direct correlation with the Ri or are the 2 independent of eachother. Point beeing if I know the Ri is still low enough I would have no need to know the exact capacity a cell can hold and I could go TAs way, then I would have no need for capacity test.

You get the capacity figure as soon as the discharge has finished so yes you could pull the cells then & charge them up in something else & IR is shown during the test anyway, both in the charge & discharge cycles.
Yes generally a cell with high IR will not have good capacity.
The Lii-500 also shows IR when you are just charging a cell (not in capacity test mode) so you know the IR of a cell from normal charging.
You can get the Lii-500 for around $20-$25 sometimes as low as $15 when a deal is on so you could buy 2 :+1:
I really like them (I have 2 plus 8 of their smaller non analysing chargers 6 x Lii-100 & 2 x Lii-202) & prefer them to my Opus & MiBOXER C4 analysing chargers & also prefer them to my pair of Nitecore D4”s.

To test IR cheap meters are rubbish. I use a Hioki 3554, takes a second a cell and the meter is calibrated UKAS standards.

Readings are auto recorded and you can trend cells which is at least as important as the single reading itself.

But that Hioki 3554, although obviously very accurate, is about £2,000 isn”t it ($2,500).
The OP said “My budget is around $50 but I wouldn’t mind paying more (even double that) if it’s really worth it”

Yeah right 900 + to test a few salvaged celss rofl. Then what s the point in salvaging cells. I hope for your sake u use it in a prof setting. Thx for the input though

It was an example of not using a cheap meter, they are not consistent. I don’t use it commercially but I know people who do so I aquired it cheap, they would use cheaper meters if any were avalible that were any good.

The discharge test TA uses is probably better than any cheap IR meters.

Hey man I m sorry, I see now that my post is a bit condesending if that s the right word

My Hobby Charger recommendations:

or

or
Only 50 Watt!!

http://www.skyrc.com/index.php?route=product/product&product_id=200
or
50 watt

80 watt

I use 1S4P Unprotected 18650 cell holders wired up so I can Balance charge my cells (Parallel Connected).
http://www.ebay.com/itm/2-PCS-4-x-18650-Li-ion-Battery-Clip-Holder-Case-Box-8-Pin-Contact-/121457151980?\_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20140813130114%26meid%3Db99cc93b5ae4429aa220eb2f73f042d0%26pid%3D100262%26rk%3D1%26rkt%3D4%26mehot%3Dpp%26sd%3D121457151980%26clkid%3D4942104528337088887&\_trksid=p2047675.l2557&\_qi=RTM2067267&nma=true&si=q3O03D51sYJG8Zr2ntSU%252BzYPqOA%253D&orig_cvip=true&rt=nc

Wiring Harnesses I use:
For Balance port: I use the 4S one so I can Balance charge.

It is also very important to store the cells at the recommended OEM Storage Voltage. For most it is 3.8vdc.
I use this to discharge mine. Simple and works great.

I rig up 18650 cell holders in order to accomplish it.

You will also need a good DC power supply for it capable of an Input voltage: 11~28V DC for the 300 watt Reaktor. I set my up at 13.8vdc. Don’t forget you need one that can supply the amperage required as well.
I use a Server Power Supply I converted for it.
Lot’s of info here:
https://www.rcgroups.com/forums/showthread….-Power-Supplies

http://www.tjinguytech.com/my-projects/server-ps
Some for sale already converted:

Some good reading here on Hobby Chargers and Server Power Supplies.

Bill

For most hobby chargers you can salvage old laptop PSUs

One has to look at what their current and future charging requirements are and choose a power supply accordingly. I would suggest choosing a power supply with more power capacity (wattage) than needed since most of us always underestimate what we really need. This would also ensure you were set for all future charging needs.

LapTop power supplies would be under powered for my needs since they are under 100 watt.

Good Information Here on choosing a charger and Power Supply:
http://www.tjinguytech.com/charging-how-tos/wattage-for-charging
http://www.tjinguytech.com/charging-how-tos/shopping
Converting PC Power Supply
http://www.tjinguytech.com/my-projects/convert-pc-ps

Bill

It is very hard to overpower a laptop power supply charging 18650’s since you will be charging them in 1S parallel and most chargers max out around ~10A of current that means the max wattage it would need is less then 50W.

My laptop power bricks vary between 65w and 90w which is more then enough.

Oh my old laptop PSUs are all 120W
Gaming laptops of course

For the 50 and 80W hobby chargers a not gaming laptop PSU is strong enough

For those 300W chargers a good 500W PC power supply should be fine, they should deliver 300W 12V

I Balance charge all my 18650 cells. This requires that they be charged in series. Works well for my needs.
Bill

You should really consider going with a parallel charging setup.

Basically balance charging allows you to balance (duh) a battery pack that is made up of multiple cells in series and can not be separated.

Since we have access to each cell individually with 18650’s it is far better, quicker, and easier to simply charge them in parallel. This also ensures they are 100% balanced along with being way faster.

Balance charging will charge the cells up pretty quick at first but if the cells are not pretty close to balanced to start out with it can take many many hours to balance them as I am sure you have noticed. This is because it has to charge them up until the highest voltage cell is at 4.2V (usually a bit over that which is not good). Once that happens it stops charging and starts discharging the high voltage cell until it drops down to ~4.15v or so.

It then charges the entire pack again until that high cell once again reaches 4.2V. It then repeats this process until the pack is “balanced. Needles to say this is VERY inefficiency, wasteful and far from ideal method to charge cells and very time consuming. The only reason it is done is because in RC battery packs for example you can not separate the cells for individual charging so this is the best they can do.

Parallel charging on the other hand charges all the cells evenly through the entire charge process and balances them perfectly the entire time. It also reaches peak charge and stops charging, reducing wear and tear on the cells. Every discharge/charge cycle eats a bit of the total battery life, even the small ones from balance charging.

In a nut shell, if you are using a hobby charger to charge 18650’s, charge them in parallel. You will save a ton of time and it is better for the batteries.

As you can see earlier in this thread, I have a bank of 14 cell holders for mass charging 14 cells in parallel. Now at 5A charge rate it is a bit slow but still a whole lot faster then charging them with a balance charger. Plus if I want to go faster I will hook it up to my 15A DPS5015 and charge them that way, I rarely need to do that though since I have a lot of spare cells.

I have thought about getting a second Imax B6 and either setting them up in parallel or with separate charging banks to allow them to charge things faster. It still works out a lot cheaper then a 10A charger and I could add a 3rd for way less then a 15A charger.

Yes, it’s brand new so not much info on it yet. A bit more risky than and SC-608, but this company seems to know what they are doing so if you want to be a bit adventurous go for the new model and if it works out you get nice benefits… if not well you have to buy something else. The SC-608 will be less expensive and remember you may want to buy a power supply for the charger unless you have something you plan to rig up. They can be a bit pricy for a nice one.

Go slow. Maybe don’t try to do everything at once. Definitely for your Battery Pack salvage usage this is not what you want, but it sounds like you understand that.

is it really that you cant adjust end voltage with SC-608, cant find information, if so its lost opportunity. i have b6 mini and with that you can adjust anything.

but why is it that there is no good banks or holders available, i want couple spring loaded 4 bay holders which way i could charge 26650 through 18350 or so with hobby charger.