Miboxer C4-Plus Released on Amazon, BLF members enjoy 30%

[d_t_a]

@Lux-Perpetua

The new C4+ seems to be having some odd behaviour. According to its manual the maximum charge rate is determined by the internal resistance. So far so good. But when you put in a 18350 high current battery (e.g. Vapecell / Aspire) the C4+ would charge it with insane 2.5 amps, i.e. 2.5-3C! Of course, you can set it to a lower value manually but I would rather prefer it the other way around in order to avoid cell damages due to improper charge rates.

I believe that is a “normal” behavior because of the low IR of the Vapcell/Aspire 18350s. Since it doesn’t “know” about what type of battery, other than it has low IR (indicating high-drain capable cells that can accept high charge rate), so maybe it’s assuming this is something like a 30Q or VTC6 18650, which can be charged at high charge rates… Although in your case, it’s a high-drain smaller cell, so the charge rate cannot be too high. Perhaps charger manufacturer can also mitigate this by testing if it is a short battery, then even though it is low IR, the charge rate shouldn’t be automatically set too high?

Another important fact is that LiFePO4-batteries that must not be charged with the standard profile (3.6V instead of 4.2V) may be at risk when you encounter a sudden power outage without any supervision. Once power is restored the C4+ would automatically start to charge the LiFePO4 battery up to 4.2V, i.e. there’s an immanent risk of explosion. I am aware that this is probably a design flaw on more or less any chargers that can handle both 3.6V and 4.2V. Anyway, it’s something that should not be disregarded when charging LiFePO4 batteries.

Thanks for pointing that out about LiFePO4 batteries and automatic charging. I don’t have any LiFePO4 batteries yet, but will need to keep this in mind for automatic chargers. Maybe charger manufacturers would think of something to mitigate this kind of thing happening?