Mods with Voltmeters?

[ChrispyCritter]

From what I've read your ok at 4.25v with safety it's just you don't want to go much above that..but you're better off charging them to just below 4.2v for battery life (especially with high drains)..the charger I got with my "LT" kit charges at 4.19v and I tested a battery a few hours off the charger and it was at 4.17v.

 

[John D in CT]

Chris and knives, thanks for the excellent info.

My Trustfire TR-001 is charging at 4.27v, and the AW IMR 18350's [from Lighthound.com, who I trust] came off it about 3 hours ago at 4.26 each, and now read 4.23 each. Not going to lose any sleep over it right now, but you've both made me want to get a really good charger ASAP. I was all set to get an xtar, but I think I'll just get a Pila instead, unless another brand does this:

Pila IBC charger - the premier charger for Lithium Rechargeable batteries Charging process

Stage 1 – Automatic analyzing battery status
Stage 2 – Quick charge
Stage 3 – Slow charge
Stage 4 – Standby mode, trickle charge

Lithium Ion Battery Chargers

Nothing like a battery charger that's smarter than you are, I always say. And that's what my guys at my autoelectric place say for charging car batteries; start with higher amps to get the molecules moving, then nice and slow for the best charge. The Pila and XTAR both say they charge at 4.2. Sounds prudent to me to keep the unprotected batteries in a stacked battery mod as happy as they can be.

Pila IBC charger from Lighthound.com? $46.99. My face? Priceless.

Thanks again.

 

[adami]

Since this is apparently now a "why VMax is better than ProVari" thread, you should at least consider that 2x18350 vs 1x18650 is a more fair comparison due to their volume. I'm no math whiz but I think you'll find similar or better Wh for popular 18650s vs. 2x18350. AW to AW, the 1600 mAh IMR has a slight advantage of ~800mWh.

If the VMax uses a buck converter (I think it does?) then compared to a ProVari you'll probably get very similar usage times at the same output wattage. If you use larger 2000 or 2250 mAh high drain batteries the ProVari should emerge triumphant (but, of course, all due to the battery wizards). At higher amperages stacked batteries are the way to go, and barring battery advances, probably will remain so. IMR 18650s can handle the drain but most of them start getting pretty warm over 5A.

 

[John D in CT]

Since this is apparently now a "why VMax is better than ProVari" thread, you should at least consider that 2x18350 vs 1x18650 is a more fair comparison due to their volume. I'm no math whiz but I think you'll find similar or better Wh for popular 18650s vs. 2x18350. AW to AW, the 1600 mAh IMR has a slight advantage of ~800mWh.

If the VMax uses a buck converter (I think it does?) then compared to a ProVari you'll probably get very similar usage times at the same output wattage. If you use larger 2000 or 2250 mAh high drain batteries the ProVari should emerge triumphant (but, of course, all due to the battery wizards). At higher amperages stacked batteries are the way to go, and barring battery advances, probably will remain so. IMR 18650s can handle the drain but most of them start getting pretty warm over 5A.

I hope that this thread has not irretrievably become what you described, and again my apologies for the extent to which it has touched on being such.

I just wanted to recognize your point that is very well made, and duly taken.

Until such time that more capable 18350's are available, if ever, or an 18700 2500mah battery comes into existence, if ever, the edge in raw amp/hours does rest with the ProVari with or without an extension.

If my math/electrical theory was and is correct:

VMax: (2 x 18350) - 700 mah at 7.4 volts = 5,180 milliwatt/hours = 5.180 watts for one hour.

ProVari w/ extension: (1 x 18650) - 2000 mah at 3.7 volts = 7,400 milliwatt/hours = 7.4 watts for one hour.

ProVari w/o extension: (1 x 18490) - 1600 mah at 3.7 volts = 5,920 milliwatt/hours = 5.92 watts for one hour.

Total energy storage - advantage ProVari, all the way. VMax still has what I think is an inherent advantage of having higher electrical "pressure" to work with when putting out its 3-6 volts.

Now excuse me while I contact AW to see what the holdup is on packing more power into the 18350 size, and to see how that 18700 is coming along.

Thanks for the very civil, very well-presented post.