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***jradomski*** · 6th October 2006, 15:29

Quote: (Originally Posted by Skipbreather)

Hi Joe-

Thanks for the info re 1.5 V Lithums. I’ve always viewed them as sort of neither fish nor fowl and so have no actual experience w/ them. I’m genuinely curious about where you have used them & found them to be either cost efficient and/ or superior electrically to a quality AA alkaline. The packages make all sorts of claims, but I value your real world experience.

I looked closely at Li-Ion rechargeables when searching for a solution to 18 cell alkaline AA packs. The energy density & discharge characteristics are indeed the best of the commonly available technologies, but without exception all the sources I consulted referenced how fussy they are when charged- essentially do it right w/ a Li-Ion specific circuitry charger or risk a fire. The clincher for me turning to NiMH was how ugly a flood to the battery compartment would have been w/ Li-Ion. All rechargeables are nasty when shorted, but LI-Ion are particularly so.

Best,
Ken

Li-ion charging technology has come along way... There are many ICs that do all the work for you... I have built a few chargers.. I recommend using ICs from linear technology... they are easy to work with and are readily available.. You can even get one of their "development" kits and easily turn it into a charger..

see this link
http://www.linear.com/pc/downloadDoc...1,C1003,D11357

or

http://www.linear.com/pc/downloadDoc...2,C1185,D10777

Asto flooding, its not as bad as you think.. most current Li-Ion packs have built in short circuit and over/undervoltage protection.. so shorting the pack externally wount be a big deal... Many packs are also sealed, but some extra protective sealing might be a prudent idea...

the 1.5v lithium cells are good for devices that can't deal with a declining voltage well.. (like somethingwith a motor ex. cassette player).. these will work perfectly until they just die.. They also work well in flashes where the constant volatges keeps the cycle time fast..

For devices that depend on a lower voltage as a warning the cells are getting low, you must avoid them.. I recommend against them in my HH manual for this reason.. I did some testing... It works perfectly, then all of a sudden the handset is totally dead...

6th October 2006, 15:29	#6 (permalink)
*jradomski* Moderator Current Rebreather/s: Inspiration Classic Sport Kiss Optima rEvo Other CCR Other Rebreather/s: Inspiration Vision Evolution Megalodon Classic Kiss rEvo Other CCR Join Date: Mar 2005 Location: "Da" Bronx Posts: 3,126	Re: Rechargeable battery packs for the Meg Quote: (Originally Posted by Skipbreather) Hi Joe- Thanks for the info re 1.5 V Lithums. I’ve always viewed them as sort of neither fish nor fowl and so have no actual experience w/ them. I’m genuinely curious about where you have used them & found them to be either cost efficient and/ or superior electrically to a quality AA alkaline. The packages make all sorts of claims, but I value your real world experience. I looked closely at Li-Ion rechargeables when searching for a solution to 18 cell alkaline AA packs. The energy density & discharge characteristics are indeed the best of the commonly available technologies, but without exception all the sources I consulted referenced how fussy they are when charged- essentially do it right w/ a Li-Ion specific circuitry charger or risk a fire. The clincher for me turning to NiMH was how ugly a flood to the battery compartment would have been w/ Li-Ion. All rechargeables are nasty when shorted, but LI-Ion are particularly so. Best, Ken Li-ion charging technology has come along way... There are many ICs that do all the work for you... I have built a few chargers.. I recommend using ICs from linear technology... they are easy to work with and are readily available.. You can even get one of their "development" kits and easily turn it into a charger.. see this link http://www.linear.com/pc/downloadDoc...1,C1003,D11357 or http://www.linear.com/pc/downloadDoc...2,C1185,D10777 Asto flooding, its not as bad as you think.. most current Li-Ion packs have built in short circuit and over/undervoltage protection.. so shorting the pack externally wount be a big deal... Many packs are also sealed, but some extra protective sealing might be a prudent idea... the 1.5v lithium cells are good for devices that can't deal with a declining voltage well.. (like somethingwith a motor ex. cassette player).. these will work perfectly until they just die.. They also work well in flashes where the constant volatges keeps the cycle time fast.. For devices that depend on a lower voltage as a warning the cells are getting low, you must avoid them.. I recommend against them in my HH manual for this reason.. I did some testing... It works perfectly, then all of a sudden the handset is totally dead... __________________ Joe Radomski CCR Trimix Instructor Trainer ANDI Instructor Trainer Director #10 All posts are personal opinions and DO NOT reflect any affiliated agency unless specifically stated. Last edited by jradomski : 6th October 2006 at 15:36.
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