Thanks for the review!
v3.0… third time lucky, perhaps? :zipper_mouth_face:
Yes, switching is efficient, linear is less efficient. Linear is sometimes used to generate exceptionally “clean” power.
You are correct - the difference is not relevant to fixing the problem with this charger. As HKJ mentioned, all that’s needed is a PSU that can withstand 10A pulses w/out much sag. If I followed what HJK said correctly, the PSU needs to be able to supply 10A on a 20% duty cycle.
What I wonder is whether the problem couldn’t be addressed with a battery reservoir. A 12v SLA battery is often used to smooth out larger setups. Maybe a 4s1p LiFe pack could be used to smooth out this setup. I guess that’s more expensive than just using a bigger PSU 
How do you go about finding one that can do this 10A 20% duty cycle ? Are we talking about a standard power brick with the right specs or is this special equipment ?
Sorry, I did not mean to over-complicate things. You may use a >10A power brick (or whatever) and be done. There may be smaller, cheaper power supplies which can withstand 10A for 0.01s (the length of the pulse) with the 10A draw being “on” for 20% of the time overall. In that case you could save money/space. For example, some small power supplies can generate the current but would get too hot if used 100% of the time at 10A.
EDIT: HKJ already mentioned that he does not like to do it, but the cheapest and most readily available high-current 12v DC power supply for most folks is a PC power supply. Most lower end PC power supplies cannot handle a high cross-loading (loading only 12v and not 5v), but 12v @ 10A is easy, even with no loading at all on 5v. You can scavenge a PC power supply out of any old used PC for free, cut all the unused wires off, and hookup the 12v wires to a plug, banana receptacles, or whatever. I find that Dell power supplies are exceedingly solid and live long lives. Other brands vary, and I keep away from the off-brands.
I haven’t seen any other chargers at this price point with the same feature set that does a better job. The charging current may not quite reach 2x2 or 4x1, but it’s still faster than my I4 with the same number of cells. The biggest concern I have is the longevity of the power supply and fan. Luckily, both are easily replaceable.
KuoH
I have charged and discharged ( my Panasonic NCR-PFs at 4 x 1A each, using the stock power supply (used 220VAC in my place) and they all had been charged fully without a hitch. (the charge figures are the subject of this discussion, but the Discharge numbers are correct) You might have seen photos of it in the gb thread.
OK, that makes a lot more sense now. Thanks for the clarification. Finding one that is 10a might be a little more difficult and the only donor computers around only have generic PSU. I previously cancelled my order on this to investigate the issues and it seems it’s not that big of a deal if we change out the supply. There definitely isn’t any other charger that can do everything this does (4x1a, 2xa, nimh, lion, analyze, charge specs). Still, it wouldn’t be unreasonable to expect the charger to be shipped with the appropriate pack, or whatever technical changes necessary to be made.
Oh lastly wight, you said the right supply would be >10a correct ? Will 10 do, or is it recommended to exceed 10?
I'm doing multiple tests to confirm this, but I am currently using a repurposed computer PSU, the same one I use for my hobby charger that is capable of 40A on it's main 12V rail and I'm getting differences between charging and discharge of less than 3% for all four bays. Sure my PSU is about three times the volume of the charger itself, but, heck I already have one.
10A is enough, the charger only uses an average current of 3A. The problem is that it is distributing this between drawing 10A in 0.01sec pulses and about 0.1A for the rest of the time.
Usual a power supply can deliver much more than rated, but only for a short time. The problem is that this capability is not specified, i.e. how much overload and for how long is unknown.
A 10A supply will definitely deliver 10A, but a smaller supply may also work.
I got the V2 from the gearbest groupbuy.
I tried to lube the fan as it was too noisy and I only had WD-40 available. I think i put too much WD-40 as it’s hard to control for samll quantity. At first the fan couldn’t start by itself. I had to spin it so it can start. Then it can stop and then it could restart itself. I was a bit scared but when it’s too hot, the charger pause himself.
Then I used a vaccum cleaner to try to remove the WD-40 excess, now it can start itself and the result is a much much quiter fan, before I can hear it clearly from any distance, now I have to be close by it to ear it. I think a replacement can be good but the 25x25x7mm size make it hard to find, the papst 252N which is 25x25x8 would fit maybe with adjustment but it’s nearly the price of the charger… So the lubed stock fan is good for me now.
Then I opened the charger and tried the 4.35V switch. Nothing difficult to open it and to toggle the switch.
It charge normaly up to 4.20V but from 4.20 to 4.35V it reduce intensity between 200 and 300mA and under 100mA at the end. The result is that it take forever to charge a 4.35V 18650, even a used one with lower capacity. With one battery mesured by the charger itself at 1600mA (yes it’s really used), it took 17 hours at 700mA charging intensity. Exploiting the hidden capacity of those 4.35V 18650 seemed good but I may return the switch to 4.20V, it’s safer and faster.
HKJ, your explaination on PSU is very interresting. I always thought that devices drawn only the ampere it needed from more powerfull PSU, I mean that a 5V 2A PSU give only 1A to a phone for example that only require 1A as the PSU is colder than when it charge a 5V 2A device. Now I know it works with impulsion. We tend to use more powerful PSU as fake and cheap PSU don’t deliver the advertised power.
That is still correct, but as can be seen with this charger, the needed current can vary, in this case very fast (20 times each second) and over a very wide range (0.1A to 10A).
Power supply specifications are also simplified, a more correct specification could be:
12V 3A continuous.
12V 5A for 0.01sec
12V 7A for 0.001sec
The last two could also be made with a curve.
Look at this data sheet for a more professional power supply, it has a 3 second and a continuous rating: http://www.mouser.com/ds/2/260/SDR-75-spec-258628.pdf
Opus V1 и V2
I checked. This is not so.
So it is better to use lower current like 500 or 700ma for both liion and nimh?
I can only show what my equipment records.
If your charger does show V2.0 and chargers with the same profile as my V1 charger, then there must exist two different V2 chargers.
One of those meanwell sdr 75-12 costs 48€, thats more than the charger. How much better would it be with it?
That power supply does not really fit the charger. The maximum current might be slightly to low and it switches completely off if overloaded, you don't want that.
What you pay for with this type of power supply is reliable 24/7 operation for many years.
OBSERVATIONS: (Cells used are Panasonic NCR18650PF 2900mAh)
DISCHARGE CAPACITY variance between using Stock Power Supply and 15A Regulated DC Power supply: .013%
DISCHARGE CAPACITY to CHARGE CAPACITY variance using same power supply (15A Regulated DC): 1.1%
DISCHARGE CAPACITY to CHARGE CAPACITY variance using stock power supply: 29.6%
CHARGE CAPACITY variance between using Stock power supply and 15A Regulated DC Power supply: 30.9%
In all sessions, 1A rate was selected in all bays.
Summary:
On Discharge Capacity readings, only .013% is the difference between using the stock power supply compared to 15A regulated DC.
On Charge Capacity readings, 29.6% is the difference between using the stock power supply compared to 15A regulated DC
My conclusion: For people who are satisfied with just knowing the DISCHARGE CAPACITY of their cells, the Stock Power Supply would suffice, as their is virtually no difference between the stock and 15A power supply. (only .013%)
(upcoming will be the comparative readings between Stock Power Supply versus a salvaged computer PSU)
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Thanks Tatasal, that shows you can solve my biggest gripe by changing the adapter. I still think it should’ve been supplied by manufacturer, even retrospectively. China shipping is cheap as chips and we’d all appreciate that they do it right.
Unless you really consider charge figures to be really that important, you really don’t have to change the stock power supply. The dicharge capacity is a far more important spec. l suggest you just try one first and see if it’s really necessary
Ok so we know the discharge capacity show good. The charge capacity show decent if you swap the power supply.
How about just putting the cells, is there an option to tell the capacity by just putting the cells in the charger? sorry i have low experience with chargers, i know my question my sound silly 