Li-Ion 3.7V pack

[Darth Cruor]

I was considering using a rechargeable li-ion 3.7 battery pack to power my green K2 (by my reckoning, no resistor would be needed (correct?)), but I can only find 7.2 in the shop. No that it would be a huge problem, I would just use a 2.7 resistor. But to save time soldering an extra part (I'm very lazy), I would prefer to use a 3.7 pack. What I was wondering is, as I'm unfamiliar with this field of power sources, is whether or not the li-ion smart charger will charge a 7.2 pack at 3.7V? I have a feeling that my hope will fall short, but I can only ask right?

[Clockwork]

Sorry, but the voltage of a Li-ion pack depends on 3 things, how many cells, how they are wired and what control IC you have. These things all have to agree, so you couldn't just get a 7.2 pack and hack out the second cell, because the control IC would freak out. If you want a 3.7 pack, there are plenty of placed to buy them, but you will need a 3.7 pack and a 3.7 charger. no way around it

[xwingband]

Getting a 3.7V pack to avoid soldering is silly... you'd be avoiding ONE solder of a resistor. Although a 7.2V pack is not a good choice with a resistor anyway.

[Novastar]

Single, protected Li-Ion cells can be found other places online as well. Besides you could always ASK Tim... some time ago, when he didn't "carry" single Li-Ions in the online store, I spoke with him, and he said he had a few, so I bought them.

But either way, what is being said thus far is right: you can't "mix and match" the PCB/IC controllers and cells. The PCB has to match what you're doing voltage-wise.

Additionally, different PCBs for Li-Ions work in different ways. For example, you can find ones that limit amp draw to "X" while some other PCB limits to "Y".