I am constructing a solar-charged placard carrying 20 LEDs which shine at night and want to power it from an 18650 3.7V 2.8Ah Li-ion cell in the simplest possible way, if possible without using a charging IC even if the charging action is a bit inefficient. I realise Li-ion cells can explode and are easily damaged during overcharge or overdischarge. However, I've examined a couple of solar-recharged garden lighting products powered by Li-ion cells which are charged via a simple diode and lack any obvious protection against over/undercharging.
Does anyone here know how the designers of these products satisfied themselves that the product posed no risk to consumers and that the cell would not be badly damaged by possible over/undercharging? I can only guess that careful choice of PV panel V and I and battery V, I and capacity can eliminate explosion hazard and that cell damage will be too small to be noticed by the consumer. This is very much the stuff of in-house manufacturing know-how but I'd be really glad to hear your ideas on it.
Does anyone here know how the designers of these products satisfied themselves that the product posed no risk to consumers and that the cell would not be badly damaged by possible over/undercharging? I can only guess that careful choice of PV panel V and I and battery V, I and capacity can eliminate explosion hazard and that cell damage will be too small to be noticed by the consumer. This is very much the stuff of in-house manufacturing know-how but I'd be really glad to hear your ideas on it.