Re: [time-nuts] Li-ion Battreries

Hi Mark: I agree. The Vietnam era PRC-25 radio had a solid metal battery box that was water tight and used a BA-4386 battery with Magnesium chemistry. http://www.prc68.com/I/PRC25.shtml#DCP The problem was that as a normal part of its operation the battery releases hydrogen gas. I know

Re: [time-nuts] Li-ion Battreries

No way will an ammo box explode and send shrapnel flying. Even if filled with machine gun bullets and tossed in a fire. The rubber gasket fails and the pressure escapes. A slow burning object like a battery will never cause steel to fragment. If someone made a video it was faked The purpose

Re: [time-nuts] Li-ion Battreries

Whatever makes you feel safe, Mark. The internet has a plenitude of horror stories, some of which would make you think that the only prudent course was to store them in an underground bunker. Our study used several hundred batteries, all stored in surplus cal .50 ammunition cases in

Re: [time-nuts] Li-ion Battreries

Those hobby packs are typically LiPO, chosen for the energy density, and they often (usually?) run them with minimal protection circuits to reduce weight. Not recommended practice for building devices. BMS When I built a 12 cell series 10Ah pack, I went with LiFePO4 and a custom-configured

[time-nuts] Li-ion Battreries

They can be if you store them in something like an ammo box. If they "go off" in the sealed box the pressure builds, the reaction rate increases exponentially, and voila... shrapnel time. There's a video out there showing the results. Most people recommend storing them in nomex/kevlar

[time-nuts] Li-ion Battreries

In the days prior to my recent retirement, when I was directing research at a large VA Medical Center, one of our projects used inordinate quantities of 18650 Li-ion batteries. We found in short order that buying from Amazon or eBay was penny wise and pound foolish. Rather than flogging the

Re: [time-nuts] Li-ion Battreries

On Sun, Jan 22, 2017 at 9:36 AM, Mark Sims wrote: > I have a LOT of experience in testing and using 18650 cells. It is a > horrible place for the un-initiated to be. The market is so saturated with > dangerous fakes and inferior, over-speced cells that finding a genuine

Re: [time-nuts] Li-ion Battreries

The reason I made the post is after bad experiences I found a vendor with genuine product and willingness to send you data sheets and my tests confirm data within 3%. Can not ask for more. Can tell all the stories mentioned, been there done it, that is why I felt it will be useful for time

Re: [time-nuts] Li-ion Battreries

I'm using Lithium batteries too. Button for everything. For stationary lab bench use where AC mains is available and all I want is back up our the lead/acid gel cells work fine. They are cheap, large and heavy and will take abuse and don't normally catch fire. For the mobile devices that I

Re: [time-nuts] Li-ion Battreries

One of my hats is working with a recycler to help them best utilize their input stream of recycled electronics. To that end, I take a lot of things apart, looking for failure mechanisms. This allows me to discover common problems, and to suggest which items are economical to repair, and which

[time-nuts] Li-ion Battreries

I have a LOT of experience in testing and using 18650 cells. It is a horrible place for the un-initiated to be. The market is so saturated with dangerous fakes and inferior, over-speced cells that finding a genuine cell is a vanishingly small probability. Hopefully the seller mentioned

Re: [time-nuts] Li-ion Battreries

Recovered cells aren't only sold through ebay parts adverts - they're also used for production. I recently bought a few cell phone boosters which consist of an 18650, a charge circuit and a voltage booster to 5V. They were low cost and nicely made with an extruded aluminium case and they worked

Re: [time-nuts] Li-ion Battreries

Well worth mentioning that you have found a reputable vendor. I may give them a try. A while back, I bought a dozen 18650 inexpensive(<$5 each) cells from 3 vendors picked at semi-random on eBay (4 from each) for evaluation and I tested each one of them with a data logger. The best one had about

Re: [time-nuts] Li-ion Battreries

Just a quiet message that needs to be said: 18650 style LiIon cells are indeed one of the most common styles of LiIon cells, but with their popularity comes a great deal of fraudulent sales activity. The 18650 cells are used in all sorts of trendy gadgets, like the vape appliences for niccotine

Re: [time-nuts] Li-ion Battreries

I use 4 cell balancing and protection circuits, cost a couple of $ more but well worth it, I use holders because of limited availability of cells with straps, but rest assured they are held down (discarded PCB)'s, I on purpose did not get into technical details I was only trying to share

Re: [time-nuts] Li-ion Battreries

Hoi Bert, On Sat, 21 Jan 2017 08:08:22 -0500 Bert Kehren via time-nuts wrote: > purchased _2x Samsung 35E 3500mAh 10A 18650 High Drain Rechargeable Battery > > INR18650-35E_ > (http://www.ebay.com/itm/112173495496?_trksid=p2060353.m2749.l2649=STRK:MEBIDX:IT) > for

[time-nuts] Li-ion Battreries

In the seventies I used F size NiCad’s in applications like OCXO’s later Rb’s for power backups. Later switched to Ni-MH in all cases needed complex charge control and cutout to protect batteries. Today I have switched to Li-ion mainly because of the low cost reliable power management