If I put the batteries in the lights go red and then turn green when the battery is charged. I have noticed some odd behaviour with it though:
1) Yesterday a battery was charging (light was red) and I knocked the charger so the battery broke contact. After putting it back in properly the light no longer went red, it stayed green.
2) After this occurred I discovered that if the charger is already on when I put the battery in the light goes green but if I unplug the charger before putting the battery in, and then connect the power cable it goes red and seems to charge.
Is this normal? Why is it doing that?
Tested the battery voltage with a multimeter and it read 4.12v so I decided not to charge it anymore. Have also ordered the XTAR VC2 as apparently that’s quite a good charger.
1. I'd say that's not quite a problem.
Most chargers will probably consider an inserted battery as full if its voltage is over 4.1V (but will charge up to ~4.2v if not).
2. The behavior might occur due to a fault on how the charger takes its measurements.
For example it might be reading slightly lower right after being powered on compared to when it's fully 'warmed' up.
Again, I wouldn't consider this to be a major problem.
I notice this behavior on a few single-slot chargers — eg. the single-slot Sofirn charger (which Sofirn bundles with the flashlight kit bundle) has this behavior.
If the battery is somewhere around 4.10v (more or less — I think it depends on the charger sample), while the charger is already plugged to the USB power, it will show up “green” indicator (“full”).
If the battery is somewhere around 4.10v (more or less - depends on the charger sample), unplug the charger and plug to USB power, then indicator will be red (will be charging)
If the battery is closer to somewhere like 4.15v or so, then placing the battery in the charger (already plugged to USB), indicator will be green (“full”)
If the battery is closer to somewhere like 4.15v or so, then placing the battery in the charger and then plug the charger to USB, indicator will be green (full)
If the battery is closer to around 4.00v, then placing the battery in the charger (with charger already plugged to USB), indicator is red (charging).
If the battery is closer to around 4.00v, then placing the battery in the charger, then plugging the charger to USB, indicator is red (charging).
Actual voltage when this happens seems to vary a bit between charger sample to charger (since I’ve got several of these Sofirn basic chargers).
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BUT, I’ve also noticed the above behavior on some other chargers — I think the Eizfan NC1 / Yonii C1 also has this kind of behavior, and I suspect a few other similar type of single-slot charger also behaves likewise.
I think the Xtar MC1, which has similar design, is a bit better in this regard though. The voltage has to be closer to 4.20v before it will not try to charge the battery (ie. whether charger is plugged before or after the battery has been inserted in the single-slot charger).