had C4 Evo in 2021, because i love the UI, and the smart layout, it can do a lot - except charging. Found it unusable due to the symptoms above, and swiftly returned.
was there any change meanwhile? I don’t know. There is a very recent firmware (Oct 2024): https://isdt.co/down/firmwares/firmwareDownloadList.json
and even an alternative firmware (2022):
It usually takes many years to fix the issue, for example, only now I can buy an Xtar charger, as it became consistent. I’d love to have C4 if it was confirmed to work.
I’m also curious what was changed or updated. If one look at their other brand - Limeta R4 Evo, description on Amazon says following: “Q: Does the charger support charging 1.5V lithium batteries? A: Yes, it does, although some products may require a firmware update”. And Limeta branded charger are usually a bit behind on their version of FW.
I updated my ISDT C4 EVO to 1.0.0.46 from October 2024
Here are some changes that I noticed:
Support for 1.5V Li-ion has been added (Charge and Destroy modes).
The End voltage can be configured between 2.50V and 3.30V in 0.01V steps for Discharge mode (Li-ion). It previously only went down to 2.90V.
The discharging current can be configured between 0.1A and 1.0A in 0.1A steps, the charging current can be configured between 0.1A and 1.5A in 0.1A steps, and the End voltage can be configured between 2.50V and 3.30V in 0.01V steps for Analyse mode (Li-ion). The discharging and charging currents were previously automatically set to 1A and the End voltage was limited to 2.90V. This change allows you to have much more control when analysing the capacity of cells.
Another update:
3. The discharging current can be configured between 0.1A and 1.0A in 0.1A steps, the charging current can be configured between 0.1A and 1.5A in 0.1A steps, and the End voltage can be configured between 2.50V and 3.30V in 0.01V steps for Analyse mode (Li-ion). The discharging and charging currents were previously set to 1A and the End voltage was limited to 2.90V. This change allows you to have much more control when analysing the capacity of cells.
Could you please elaborate on how to verify it? Are you measuring cell V right after it is charged? Does this happen every time with NiMH?
I’m expecting C4 Evo and wanted to check if mine is affected.
Interesting. If it were a software logic flaw, it would have happened with every NiMH I assume and every time… If it’s random then maybe some reading are not precise enough and that might be design / hardware issue… Just thinking aloud.
-dV/dT end condition for charging a NiMH cell might not be working for the C4 EVO. The charger stops at around 1.40V when using -5mV and 1.43V when using -15mV.
I think it should go to 1.60V before -dV/dT is detected. Here is a graph from HKJ’s review of the older C4 that shows what the termination should look like:
Another theory is that some chargers are extremely picky with the power supplies, maybe a voltage drop from the power supply leads to detecting of false voltage drop with NiMH?
However, USB-C-devices seems to be sensible, the worst example is the Xtar VC4SL but also some other Xtar with USB-power-supply are bad with NiMH-charging.
My Nitecore UMS4 and Skyrc NC1500 have also USB-power-supply but both not have these problems
Got my charger yesterday. Updated FW to latest. One major issue is some programs restarts after finish. I did number of tests with very good Eneloops AA and some junk no-name AA NiMh, and some half-decent old Turnigy AAAs . Powered by 5V, 2A and I tried another brand 5V, 2A power supply with same results.
So program ends, I can briefly see the “flag” (“finished”) icon, then charger acts as if I have just inserted cell again - it beeps, suggests last used program, and after several seconds starts it.
Two modes I tested that keep restarting and never end:
Analyze mode for NiMh. I saw maybe 5 times when this mode restarted - for 10 cells in total. And one time I had three cells - slots 1, 3 and 4. Slot 1 restarted, slot 3 and 4 completed without restart.
Discharge mode for NiMh. Several time this mode restarted, one time completed and did not restart.
One mode that doesn’t restart:
Charge mode for NiMh.
Can someone with recent FW check this? I want to understand if it’s FW bug or my device is faulty. Maybe I need to flash previous version of firmware… Will try tomorrow.
P.S. There are also minor issues, screensaver won’t activate when programs are running and sometimes graphs won’t update and show voltage that doesn’t change (while it’s clearly changes), two times I removed a cell and it reset programs for all slots with inserted cells.
So I did more tests with other power supplies (two different 5V, two different 9V), USB cables and firmware.
It’s a firmware issue I think.
ISDT 1.0.0.46 - inconsistent end of programs. It could restart (as if new cell inserted), it could finish, or it could give an error “Unknown Error! 0x400”.
ISDT 1.0.0.44 - no issued with restarting programs.
Kyosho 1.0.0.10 - no issued with restarting programs.
Strange. What is your HW revision? I have just received second unit and it “restarts” (actually acts as if call was re-inserted) as well. Both units are HW 1.0.0.4.
I will check the charging if mine terminate too early.
So I can’t reproduce the issue of early termination for NiMH at all. I went down to FW 1.0.0.44 (because 46 won’t won’t work with “Analyze”) and charged/analyzed 6 different NiMH AA and AAA cells from different brands and on different stages on life. I kept looking at the process and it was always about 1.55V when charger was stopping. Inserting these cells into BT-C3100 would add another 12-100mAh, but same happens vice versa - full charged on BT-C3100 cell would add some mAh.
Also week ago I cycled and then analyzed 8 very old AA and AAA and test results of C4 EVO and BT-3100 were very similar. So, no issues with early termination.
I assume there is something different in our chargers. There are at least two ppl (including me) who reported “restarts” and and at least another two (including you) that are not affected by restarts but affected by early NiMH termination.
What is your HW revision?
