General Mod Questions

[zztommis]

Hey guys and girls! I've been a lurker on the mod forums for a couple of months now, and have built a couple of Nicosticks and a passthrough. One thing I've found is that the search function is certainly your friend, but a few questions I have I can't seem to find clear cut answers for.

1. When wiring for the batteries, on 1 mod I'll be using 2 14500's (or 10440's, haven't decided yet) in series, and on another, 2 18650's in parallel. I've seen some information regarding using "matched sets" of batteries to ensure equal charge and discharge rates, but no mention of this for most mods on here. Is this a concern?

2. Unlike most, my "sweet spot" is around 4.5 volts instead of 5. I got a few of the samples from TI (regulators and boosters). My question here is whether a diode or resistor can be added after the reg/booster to drop the Vout to the desired level?

3. I've been using one of these

Battery holder: AA x 4 with USB interface connector and Belt clip ("Out" / "IN" / "OFF" power switch) - RoHS Compliant

with a PT for a few days, but there is between 1.5 and 2 volts dropped under load. It starts out with 5.3V with fully charged NiMH batteries at the atomizer connector, but when vaping with either a 901 atty or a cartomizer, the voltage drops to 3.9V. It steadily drops off to 4.8V at the connector/2.9V under load over about 10-12 hours. (I've checked the PT on the computer's USB, where it gets a clean 4.8-4.9 volts, so I know it's not a PT problem.) Any suggestions?


Thanks in advance for any input!!

 

[Jason365]

I think if the batteries are new, it wont matter. just dont mix a 3 month old battry with a new one. I think? as i dont really know either. maybe some one else knows for sure.

And im pretty sure you can lower the voltage even more. But yet again I cant answer definitively

 

[Marctwo]

@1: Yes. Esp. in a high current device like e-cig's.

@2: Yes. But you can also output <5V with the TI.

@3: 4 fresh NiMH's give me >5.6V so if you're only getting 5.3 I'd say your batteries may not be up to the job. What is their mah?

 

[zztommis]

@1: Yes. Esp. in a high current device like e-cig's.

Does this require specific batteries, or is the age of the battery the factor, like Jason365 suggests?

@2: Yes. But you can also output <5V with the TI.

I see that now in the PTR08060 regulator data sheet (should have read a little closer, huh?), but don't see anything in the PTN04050 booster data sheet about <5V. Am I just missing it?

@3: 4 fresh NiMH's give me >5.6V so if you're only getting 5.3 I'd say your batteries may not be up to the job. What is their mah?

They're rating is 2600 mAh, but they have been around awhile!

Thanks, guys!

 

[bigozone]

actually the MOST IMORTANT reason to match batteries is when using them in SERIES due CHARGING which WILL OFTEN cause batteries to overheat and become useless... and MAYBE even VENT WITH FLAMES.... aka EXPLODE.

parallel battery setups are not QUITE as sensitive to reverse charging since energy from the bottom battery doesn't have to flow thru the top battery to get to the atty.

BUT IT IS ALWAYS WISE TO USE MATCHED BATTERIES AND KEEP SETS TOGETHER... i label mine with a sharpie so i can keep them together.

and if you ever feel your device getting HOT it's time to move it outdoors and remove the batteries ASAP... leaving the batteries outside for atleast an hour so they can cool and if they were to explode or vent then atleast your house isn't in need of a visit from the EPA.