They never do. One of the many disappointment with ISDT.
Again, new firmware 2.0.0.5 dated 27.1.2026. I returned my ISDT C4 EVO charger, so I cannot verify that the new firmware solved this problem.
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I have just puchased the ISDT C4 Evo - just arrived and updated to firmware 2.0.0.5.
On a 1.5v Li-ion AA on charge I am seeing 5.2v across the battery with the periodic drop to 1.5v (assume stop charging to check voltage). So, if that is a change from what others had on earlier firmware, it looks good.
I was though expecting to do an Discharge/Analyse on these batteries to get the capacity (just based on current x time until voltage cuts out) but menu only shows charge or destroy. I haven’t read what destroy would do to this type of battery as the internal battery circuit would cut the discharge so cannot be destroyed?
Any advice?
Discussion with Copilot on the destroy mode for 1.5v liion batteries, i finally got it to give me this.
Final, precise summary
For the type of 1.5 V Li‑ion AA/AAA cells you described:
- The C4 EVO cannot damage them in Destroy Mode
- Destroy Mode acts as a normal discharge test
- The capacity reading is accurate and useful for real‑world runtime
- The internal Li‑ion cell is never exposed to the charger
- The converter protects the cell from over‑discharge
Everything you reasoned through is correct.
They probably gave it that name specifically because the charger’s purpose is to discharge the cell to zero. The fact that the cell has a circuit that only simulates this is a different matter. Additionally, the ISDT is protected in case the circuit fails or you insert a discharged Li-ion battery without the circuit.
Tried two times Auto with latest 2.0.0.5/ First time with old AAA Eneloops. Detected first as NiMH, then switched to LiIon, had to override. Second time with 1yo Panasonic 18650 - detected as LiIon, then switched to LiFePo, had to override too.
Why don’t they make FW opensource? It would have been fixed in a matter of weeks.
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I bought it again to test the updates, and it seems to be even worse. I was charging three LADDA 2450 AA batteries. One ended at about 2700 mAh, but the other two were still charging. At 3400 mAh, I pulled them out, they were incredibly hot, and I couldn’t hold them. I chose NiMh mode 1A.
Back to the drawer I guess or maybe we should stick with the Kyosho firmware and just avoid charging at low voltage to prevent early termination issue.
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Mine just had a “runaway”. First AAA inserted, selected NiMh chemistry, charge, 0.3A current. It started. Inserted next one, same program was automatically applied. In several minutes I noticed 2nd AAA is being charged with 1A. Holy molly 
Thanks for sharing this. I went with Kyosho firmware and so far everything works as it should, albeit the ability to charge at lower current, I have several AA batteries to power up my Tamiya Mini4WD (Panasonic Eneloop, Sanyo Eneloop White 1900mAh, Fujitsu White 1900mAh, Fujitsu Pink 950mAh, Eneloop Lite latest gen 1050mAh). For the lightweight batteries such as the Pinks and Lites, I have to charge them @ 0.4A and the regular 1900mAh ones @ 0.5A. For Discharging a static 0.5A values for both batteries.
At those currents, it doesn’t trigger early termination but I cannot breakin batteries with those values - but fortunately the cycle modes works as an alternative.
NC3000 Octa is the best though, but using Kyosho firmware made my two ISDT C4 Evo, from bums in the drawer into workhorses on racing day.
I’m not sure Kyosho FW performs correct capacity calculations either, if I find time I’ll do some testing, but from the first look I suspect it has similar issue of capacity miscalculation.
Thanks for the heads-up, if that’s the case then I’ll stick with my Octa as that capacity miscalculation is a sure way to destroy my batteries in the long run.
So far though, I’m seeing correct charge and discharge values when using cycle mode on them, i.e. Fujitsu Pink 950mAh, charges up to 900-1000mAh, and discharges at 900-980mAh each cycle.
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No, incorrect calculation of capacity will not damage your cells. Cut off happens because of delta V, not because of capacity reached.
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Since I’m a bit lost, which is the most usable firmware? For instance, what are the issues with the Kyosho FW? Does it support 1.5V Lipos? Thanks!
Kyosho FW does not support 1.5V LiIon.