3 V 7500 mAh Lithium D cells

[lemlux]

I just received my EBAY order of 12 @ 10 D-cell packs of 5 serial 3 V 7500 mAh lithium D cells * 2 parallel configured as a 15 V battery pack. I understand that these were originally built to U.S. government spec as weather baloon power sources. My cost, including shipping, was $1.025 per cell -- about the cost of an alkaline 1.5 V D cell. They are cheap because they are almost 20 years old. The vendor assures me that most of the 7500 mAh capacity remains. I wonder what the U.S. government paid for these when they were new. (The only Lithium D cells I've previously seen are ultra low current designs and cost about $20 per cell.)

The cells are welded together with both positive button and negative case strip connectors at the top of each cell. The unconnected exposed recessed bottom surfaces with a central tab look like they are live negative contacts. I won't be able to tell until tonight.

I expect that it will just take a little solder to make the cells interchangeable with regular D cells in a flashlight.

Both negative battery lead wires go from battery through diode through fuse through diode to common cathode connector that apparently are designed as a safety factor to prevent both accidental shorting and overloading.
The vendor stated that maximum recommended current was 2.0 Amps. I assumed that meant 2.0 Amps per cell, but it may mean 1.0 amps per cell given the serial / parallel pack arrangement. I'll check voltage drop under load tonight.

Brightnorm's and Mr. Bulk's group buy packs will be sent shortly.

 

[Doug S]

You got a deal! These are LiSO2 cells. The consumer version of these configured as a regular "D" cell retail for $17-20 each. They have great high load capability. Short circuit current can reach 50A from a single cell! You will notice an interesting phenomenon with this type of cell after it has been stored for many years. The terminal voltage will actually rise under load in the first few minutes of use.

 

[highlandsun]

Can those things be recharged? This charger guide http://www.schulze-elektronik.com/guide/gisl6-e.pdf gives specs for recharging LiMnO (e.g. Tadiran primary) batteries.
(Looks like a pretty cool charger they're selling too, as well as comprehensive care instructions for batteries in general...)

 

[lemlux]

Doug S

The cells are indeed LiSO2 cells. I hope you're right about the great high-load capability. Maybe the fuses were designed to avoid frying weather balloon radio and instrument circuits.

I think more are available friom the same vendor at the same price. (In my case $99 plus $24 UPS Ground for 12 @ 10-packs.) They price in this quantity because the cardboard shipping case is the original packaging from SAFT America. Each battery pack comes in sealed heavy plastic bag that covers it's individual cardboard box. The shipping case has individual cardboard separators reminiscent of a wine box.

I bought them from:

S&G Electronics
618 S. 62nd Street
Philadelphia, Pa. 19143

email: [email protected]

highlandsun

I understand these to be primary one-time use cells.

 

[Doug S]

Originally posted by lemlux:
Doug S

The cells are indeed LiSO2 cells. I hope you're right about the great high-load capability. Maybe the fuses were designed to avoid frying weather balloon radio and instrument circuits.

I think more are available friom the same vendor at the same price. (In my case $99 plus $24 UPS Ground for 12 @ 10-packs.) They price in this quantity because the cardboard shipping case is the original packaging from SAFT America. Each battery pack comes in sealed heavy plastic bag that covers it's individual cardboard box. The shipping case has individual cardboard separators reminiscent of a wine box.

I bought them from:

S&G Electronics
618 S. 62nd Street
Philadelphia, Pa. 19143

email: [email protected]

highlandsun

I understand these to be primary one-time use cells.

<font size="2" face="Verdana, Arial">Lem: from your description, I believe that the battery packs you bought are BA5590/U Military batteries. Their principal use is in backpack radios, though likely they have been used for weather balloons and other purposes. The fuses are to protect the batteries and anyone nearby, not the powered device. Because they can provide so much short circuit current, if shorted they will heat up and become overpressurized. If you look at the bottom of these cells you will see two spots where the metal casing is scored. This is the rupture vent and is designed to let go between 450 and 500 psig [if I remember correctly]. If these happens, a large amount of SO2 gas is released. Very irritating, not unlike discharging a teargas canister if indoors. Don't let this worry you, the cells are actually very rugged. Just be sure that you don't short them. The "consumer" version of these has a 1A fuse built in. Yours don't. If you want to wow your flashoholic buddies, try 5 or 6 of these in series powering a 20W MR16 type 12V halogen.

 

[Doug S]

Originally posted by highlandsun:
Can those things be recharged

<font size="2" face="Verdana, Arial">No.

 

[lemlux]

Doug S

You asked for it. Here's what's printed on each battery box:

6135-01-189-7986
FSCM 31586 MFR/PN BA-5513/U (close to BA5590/U)
Battery, Lithium
1 EA
DAAB07-85-C-H326
A 05-86
EXPIRES 06/92
mfd 0586B

Thus, they are 16 years old and "expired" 6 years after manufacture.

The bottom actually has a 1/4" central circular depression with a short 1/16" wide tabsticking out about 1/8". The end of the tab looks like a small flathead screwdriver. I anticipated blobing solder onto this to extend the negative contact below the casing, but I probably shouldn't if it's a vent.

About 3/16" from the outside edge the bottom plate is recessed before it spreads out again. AT 180 degree opposed sides the plate has two raised sections that extend to the outside edge. The outside edge is scored at these points -- perhaps these are the rupture vents.

Can I blob solder on the central extension?

 

[Doug S]

Originally posted by lemlux:
The bottom actually has a 1/4" central circular depression with a short 1/16" wide tabsticking out about 1/8". The end of the tab looks like a small flathead screwdriver. I anticipated blobing solder onto this to extend the negative contact below the casing, but I probably shouldn't if it's a vent.

<font size="2" face="Verdana, Arial">What you are describing above is the tube through with the electrolyte/gas mixture was added to the cell during manufacture. It is then flattened and welded closed. I believe that the case and this tube are steel and hence I don't think you would have much success soldering to it. It would be best to use the existing welded-on tabs if at all possible. BTW, when unused, these cells have an internal pressure of around 60 psig. I believe that the pressure drops as the cell is used.

Originally posted by lemlux:
About 3/16" from the outside edge the bottom plate is recessed before it spreads out again. AT 180 degree opposed sides the plate has two raised sections that extend to the outside edge. The outside edge is scored at these points -- perhaps these are the rupture vents.

<font size="2" face="Verdana, Arial">Yes, those scored areas are the rupture vents.

I believe that the BA 5513/U and BA 5590/U are interchangeable. I think that I have seen them with dual markings.

 

[lemlux]

Doug S.

Perhaps I should fold and refold the anode tabs and build solder far enough out on the tops to reach into the 3/16" or so bottom cathode plate recess above the outside casing. As the anode button is also recessed it will be an effort to use individual batteries as opposed to 5-cell wired 15 V packs.

Well -- one of my anticipated uses was the 20W MR16 with 7 degree head mounted in a Mag Head attached to a modded Big-Beam light battery pack.

 

[Doug S]

Originally posted by lemlux:
Doug S.

Well -- one of my anticipated uses was the 20W MR16 with 7 degree head mounted in a Mag Head attached to a modded Big-Beam light battery pack.

<font size="2" face="Verdana, Arial">Well perhaps you could just use the complete battery pack for that application. The hardest part would be finding the plug for the existing battery connector.

 

[lemlux]

I tested two of the batteries in serial last night.

Unloaded voltage was 5.62 V which is consistent with what I've read about this chemistry actually delivering 2.8 V per cell.

Doug S was right about the voltage rise under load of these previously long-dormant cells. A 6.0 V 3.35 A bulb gradually increased from 4.85 V to 5.12 V over about 4 minutes. It was still rising when I turned it off.

Immediately thereafter, I tried a 6.0 V 1.35 A bulb and it pulled 5.33 V. (2 123's would deliver something like 4.7x V under this load.)

At the end of this cumulative 6 minute exercise the no-load voltage rose slightly to 5.64 V.

I interpolate that a 12 V 1.67 A 20W MR16 would receive about 13.1 V or so from one 5 cell string of the pack. This voltage is ideal for the 2000 hour MR16.

I can also put my 500 Lumen 12 V 3.0 A 36Par36 15 degree spot 4000 hour Halogen lamp in a Big Beam #166 (its a form-fit for the OEM 4.5 V sealed beam) I interpolate that it would draw about 12.8X V which is somewhat less than ideal voltage.

 

[Doug S]

Originally posted by lemlux:
I tested two of the batteries in serial last night.

Unloaded voltage was 5.62 V which is consistent with what I've read about this chemistry actually delivering 2.8 V per cell.

<font size="2" face="Verdana, Arial">Hmmm..., this 5.62 for two or 2.81V for one may be a problem. Never used cells, even if old, should show an open circuit voltage of between 3.01 and 3.03V depending on temperature [with the higher voltage at the lower temperatures <0C.] Is there any chance that your meter is off? As a spot check, a new from the package alkaline cell should read 1.56 to 1.60V.

 

[lemlux]

Brock reports that the SF N62 LA draws 7.65 V at 3.7 A on 4 @ fresh 123's. 3 of these D cells at 3.7 A extrapolate to 7.5x V.

I am modding a 3P body with a dummy battery to have a Tamaya connector that can be plugged into a power source. If I have Carley pot a PR base with a Tamaya connector coming out of it I can put 3 of these cells in a 3D Mag or Nordic flashlight and strap my 3P body to the front of the 3D body. This should give me something approaching 2 hours of run time with my 3" SF turbohead and an N62 LA.

Alternatively, I could put one of my W/A 01274 7.2 V 2.77 A LA in one of my Mag Chargers. This should draw about 7.6x V. At 7.632 V The 01274 bulb is rated at 678 Lumen and 20 hours life. 3 of these batteries should give well over 2 hours run time.

I could do the same in a Mag 3D with the same bulb if I epoxy a spend SF Pxx reflector reamed out to accomodate the 01274 bulb to the front of the threaded bulb retainer.

 

[Doug S]

Lem: you are talking about some serious light! BTW, once you get past that initial voltage rise, the discharge curve for these is flat as a table all the way to the very end. If you are interested, I can email you a pdf file of discharge curves for the individual SAFT cells used in these batteries.

 

[lemlux]

Doug S

I'd appreciate the PDF.

Another application in a Mag 2D:

Currently I run WA #01183 4.70 V 3.85 A bulbs in My UKE 4D light.

If I asked Carley to pot one or more of my spare 01183's into PR bases, a Mag 2D would probably draw around 5.0x V.

The 01183 bulb puts out 503 lumen with a 37 hour life at 4.982 V and 538 Lumens with 30 hour life at 5.076 V.

This combination should also run for 1.5 to 2 hours.

 

[Doug S]

Originally posted by lemlux:
Doug S

I'd appreciate the PDF.

<font size="2" face="Verdana, Arial">It's on its way. Also, here is a link for some discharge curves for a complete BA5590/U. Note that these curves reflect the voltage losses in the fuses and diodes. On further reflection [its been a long time] there may have been a connector difference between the BA5590/U and the BA5513/U but the cells are the same.

http://catalogs.eacnet.com/specs/68.41.pdf/BA-5590.jpg

 

[lemlux]

Doug S.

The PDF's you sent me include mention that maximum continuous current is recommended not to exceed 0.5 C which would be 3.75 A.

The applications I mention all would seem OK with the exception that the W/A 01183 is marginally above the recommended max continuous level. I could also run my 9 degree beam 12 V 3.67 A 44 W MR16 in either a Big Beam or a Mag 5D with a Carley ceramic PR adapter.

The specs also rate self discharge at < 3% per annum. Thus, worst case, 0.97 to the 16 th power would suggest that capacity could have dropped to 61.4% of original capacity.

 

[Doug S]

Originally posted by lemlux:
Doug S.

The PDF's you sent me include mention that maximum continuous current is recommended not to exceed 0.5 C which would be 3.75 A.

The applications I mention all would seem OK with the exception that the W/A 01183 is marginally above the recommended max continuous level.

The specs also rate self discharge at < 3% per annum. Thus, worst case, 0.97 to the 16 th power would suggest that capacity could have dropped to 61.4% of original capacity.

<font size="2" face="Verdana, Arial">Lem, FWIW, I once did a controlled discharge with an accurate CC load of some 11 year old Saft LO25SX cells and found that they still met original factory capacity spec. I would think that storage temperature would have significant affect on self discharge rates. These cells did read in the expected 3.01-3.03 Voc range before discharge.
You must have a sharper eye than me, I don't recall seeing that C/2 max in either of the files I sent. I recall something in the vein of "consult Saft".

What's life without the excitement of a little danger?

 

[lemlux]

Doug S:

The Saftlithium.pdf file has a page headed:

"Saft's Lithium Cell Ranges"

The second bullet point on that page says:

"Maximum recommended continuous current: providing 50 % of the nominal capacity."

Looking closer, the Li-SO2 cells are rated as having nominal voltage of 2.9 V. A chart containing the 7.5 mAh cell specifically shows that the capacity is rated at a current of 240 mA and that the maximum recommended continuous current on that specific cell is 3.0 Amps.

 

[lemlux]

It was easier than I expected to get three of these cells into a 3D flashlight in serial. I didn't have do any soldering -- just solder tab folding.

the OD of the cells seems a tiny bit wider than most D cells. The fit was too snug in a SL 20-X body but slid slowly into and out of the Nordic 3D body I had handy. I'll try a Mag 3D, Mag Charger, and Brinkman 5-3-2 body tonight.