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Opus BT-C3100 v2.2 Issues?
#21
Interesting.... Very, very interesting....
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#22
I thought all chargers did pulse charging as you guys are talking about. You can't get an accurate voltage reading without stopping charging for a second. I mean, you can't charge with a higher voltage than the battery and read the battery at the same time. Process is something like charge, check, charge big, check, charge little, check.
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#23
Hrmm, again... Interesting.... Very, very interesting....

*begins to deep pondering*
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#24
(10-20-2017, 03:10 AM)Korishan Wrote: Hrmm, again... Interesting.... Very, very interesting....

*begins to deep pondering*

Hmm indeed. It would make you wonder just how accurate an Opus could be if that's how it works. It would indeed allow the battery voltage to recover, even if only a little. Realistically it would need to be a constant load to be accurate, as that's what the cells will be doing when in service.

I have a ZB2L3 coming soon (from China, might take a while) will be interesting to see how the numbers vary. Although apparently there is no truly satisfactory method. Source: Battery University.

However, I do plan to test my completed packs with a known load, over a known period of time. While this again, may be inaccurate, my analogy is that, my discharge load is like a ruler, so long as I use the same ruler, my results will be consistent, and therefore accurate (not a true measure of capacity - but a true measure of performance)

My reasoning is that my initial setup will have minimal balancing capability, and so packs will need to be extremely closely matched. If a pack comes out of balance, I will add or remove cells from it, until they remain in balance. This has one upside, in that once I acquire a decent BMS, my packs will waste no power.

There are so many factors that have an effect on battery testing, resistance of the connection between battery and discharge, and ambient temperature.
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#25
(10-20-2017, 02:07 AM)shonalex Wrote: I thought all chargers did pulse charging as you guys are talking about. You can't get an accurate voltage reading without stopping charging for a second. I mean, you can't charge with a higher voltage than the battery and read the battery at the same time. Process is something like charge, check, charge big, check, charge little, check.

But pulses don't help with that either, the cell voltage doesn't drop fast enough to make it accurate this way. Also, there is no point measuring the cells idle voltage while charging in the first place. Why would you want to know the idle voltage while charging?
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#26
(10-20-2017, 02:07 AM)shonalex Wrote: I thought all chargers did pulse charging as you guys are talking about. You can't get an accurate voltage reading without stopping charging for a second. I mean, you can't charge with a higher voltage than the battery and read the battery at the same time. Process is something like charge, check, charge big, check, charge little, check.

Since you must always charge a cell using a Constant Voltage / Constant Current supply, then if the supply is outputting say 4.2V, but the cell is only drawing a small current, say <50mA, then you can say that the cell is charged to 4.2V without stopping the charge to check. Sure, the cell voltage will drop a small amount when removed from the charger, but is accurate enough for saying it is charged.
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#27
The TP charging units dont seem (normally) to charge higher than 4.2v. So when the current drops below a certain value, it stops. You can put an MM on the terminals and it'll show the actual voltage near end of charge
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#28
OPUS BT-C3100 in charging mode 1A and 4x cells NEEDS at least 12V 11A supply.
"charger draws about 10A and the power supply voltage collapses to about 6 volt, reducing the current to about 6.5A (The power supply is rated for 3A)."

Check this out ;Winkt's from someones tests Test

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#29
EGOksy You need to look at what they look at. They only check the pulses and they are way bigger than 3A yes. The charger over time never consumes more than 2A from the PSU. The problem is that the caps are to small and cant deliver the high current pulse.

It does NOT need 11A PSU continues. It need a PSU with good enough caps to deliver that during those 10ms its running the peak Wink This is actually nothing special in more sense than they didnt have big enough caps inside and rely on high current peaks
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#30
Hi guys, I'm testing some red hot Sanyos from old laptops at 1A. I have around 500 of them. They test 1500-2500mah, as I understand it should take 1.5-2.5hrs to discharge from 4.2V to 3 (2.8 or 2.9 or whatever OPUS discharges to) at 1A. But it takes way longer, 4-5hrs only discharging stage. I noticed it starts discharging at 1A, then shows 0ma discharge on all 4 slots for a few minutes, then shows ~1000ma for like 5 minutes, then again 0ma, and keeps cycling back and forth. But in the end it displays cell capacity with no errors as everything went fine.
1. Maybe it's overheating or smth? It behaves like that ONLY on discharge.
2. How accurate my discharge results are, +5% as usual for OPUS btc3100? Or like totally wrong results and my unit is faulty?

ps: I have a few more opuses shipping to me, but right now only this one unit.
ps2: I found all the answers here:
Opus 3100 v2.2 weird discharge pattern
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