Bright idea or not...2X 14500 in parallel

[bob4apple]

I'm thinking that a flashlight using two 14500 batteries in parallel would have a lot of virtues. It would be fairly small, very bright, and have a nice long runtime as well. I'm not aware of any existing light that is built like this.

So, I throw it out to you- bright idea or not?

 

[rmteo]

A single 18500 will give near the same capacity, same voltage for about half the price of 2x 14500. The only difference is the diameter is 4mm larger (18mm vs. 14mm).

 

[Gunnerboy]

2x14500 parallel would have the same voltage and roughly the same capacity as a single 18500. It would be no brighter, and the 18500 is already compact. Plus, most folks are comfortable with tubular-shaped hosts.

 

[bob4apple]

OK guys, thanks. That makes a lot of sense to me.

 

[MaxIcon]

Also, when running batteries in parallel, you have to be concerned about relative output, as any difference between the two batteries will result in current flowing from one to the other.

You'd probably need to charge them in parallel to make sure they were matched up.

 

[FreeMagenta]

The problem of charging one battery by another - can't it be avoided by placing a diode on each battery, so the current can't flow in reverse direction (i.e. battery can only discharge)?...
Edit: My apologies for unintentional thread necromancy :/

 

[monkeyboy]

Running them in parallel is not a problem. Just make sure that they are in the same state of charge. No need to charge them in parallel, just use 2 fully charged cells. You're more likely to have a bigger difference between cells with parallel charging.

 

[TyJo]

Old thread by the way (which is fine). I thought the concern with matching cells was when the cells are in series (potential reverse chargeing, vent/flame), wouldn't they be fine if they were voltage mismatched in parrellel?