Need ideas for a hand-made battery holder for a CR435 battery

[Lemosteam]

I have searched in vain for an off-the-shelf battery holder for the battery in question:


I am looking for ideas to fabricate something reliable, possibly incorporating some form of switch. 
Ideas?

[eric220]

What is this going to be used for?

For a physical clip, how about a fuse holder? For the electrical connection, it looks like there are LED tips made to secure over the end of these things. You might be able to hack one apart, remove the LED, and connect off of the leads.

[peteski]

That is a very usually shaped battery!  Rechargable?

What is its "real-world" application?

The shape of the holder can depend on where it will be installed.  Permanent or replaceable?

The most compact holder I can envision would be cylindrical. The battery would be slid into it pin-end first (like a headphone plug into a headphone jack).

What is the diameter of the end terminal pin?  I might have some nice gold-plated socket to accept that pin.

[C855B]

... For a physical clip, how about a fuse holder? ...

DING DING DING DING DING!

That size is designed to be use with 5mm fuse clips. According to the graphic on the barrel, then the (+) wire from your circuit goes to the clip, as the barrel of the battery is apparently the anode.

There are push-on connectors that can be used with the other terminal.

[peteski]

Fuse clip works for the positive end only.  I will later try to draw what I envision as a compact clip.

[C855B]

The way these batteries are used is a fuse clip for the body and a pigtail with a single-pin female for the (-) terminal. The pin pigtail would be a wire-wrap jumper cut in half.

[Lemosteam]

The end is in fact 5mm 4mm and the tip is 1 mm, but I want to use the pin end as a switched end, using a lever thru the bottom of a passenger car.  I want to stay away from a reed switch or track power to light the inside of my special observation car, which I'm working. Obviously I need the battery to be replaceable, but I also want the entire lighting and battery system to be contained up inside the roof casting so I only need to remove the roof occasionally

I came across these plentiful (but fairly expensive) lithium batteries at an auto parts store of all places.  It is used inside a pen light.

Peteski, I am not sure if it is rechargeable, but I can experiment.  The battery cylinder is coated with a printed tape except for a small portion at the positive end.

The three volts delivers a comfortable brightness without resistors using some magnet wire Christmas light sets I found at Walmart.

[peteski]

If there is a clear heat-shrink sleeve over the body then my idea for the holder would not work (unless the sleeve was removed).

However, before you start seriously considering using this battery, you might want to look at its specs first.

It has very small capacity (50mAH) and maximum recommended discharge current is only 5mA.  You should measure how much current your LEDs consume when hooked up to that battery.

At the 5mA current consumption the battery will last for 10 hours (it is not rechargeable).  Of course the voltage will drop below 3V even before full discharge.

Check the specs I found at http://www.powerstream.com/cr435.htm

I don't recall if you use DC or DCC. If you use DCC you would be much better off using track power and a simple de-flicker circuit for your lights. Maintenance free.  Well, the wheels would have to be cleaned from time to time. But that does not require the car to be disassembled.

[Lemosteam]

Thanks Peteski, just as I came up with a perfectly good solution, you throw a grenade! 

[peteski]

Thanks Peteski, just as I came up with a perfectly good solution, you throw a grenade! 

Sorry John - just presenting the facts... 

[Lemosteam]

Peteski, credits to the website you provided...  and you know I was kidding about the grenade right?

"This tiny non-rechargeable pin battery was originally developed for lures for large fishing fleets. It has a capacity of 50 mAH and a discharge rate of 5 mA. It can be used wherever a tiny non-rechargeable battery is needed. It is only 4 mm in diameter (0.16 inches, 5/32").

Advantages:
Can be used in the place of BR-435E, BR435, P139, P139-ND, BR-425E, BR425
Excellent voltage hold-up during discharge
Limited lifetime, the polymer seal lets the battery deteriorate, please use within 6 months of purchase
Fishing lure, float and pole lights, LED flashers, microphones. PDA pens"

I think I may have picked up some old batteries- these discharged within minutes as the bolded text above suggests.

I may just continue with this design, because I don't want to sink a bunch of money into a wheeled pickup on very old Lima trucks and all of the hassle with getting that to work. with this all i have to do is throw a lever.  I think I will try to buy some brand new batteries online to avoid the shelf life issue.  10 hours might be fine for its purpose.  If it doesn't work, I can always go to a more conventional approach.

Not sure I understand your this: "You should measure how much current your LEDs consume when hooked up to that battery." How do I do this with a multi-meter?

3v lights them well, but i am also concerned that the voltage drop will not even light them.  last night I measured the voltage on the battery at 1.8v and the LED's would not light.  do you think this will be an ongoing issue if the battery drops below 3V?

Again, please forgive my lack of ability to understand basic electroincs, it goes over my head ant part my hair.

[peteski]

I know you were kidding John. 

You measure the current that your LEDs consume just like you were to measure the current consumed by a locomotive: insert an ammeter (multimeter set to DC Amps, and 200mA range if that is a manual setting) in series with the circuit.  So it can go in either between positive or negative battery lead and the corresponding lead from the LEDs.  Use a fresh battery as the current will drop when the battery voltage gets lower.  If the LEDs consume 10mA at 3V then you are straining the battery (which is designed for only 5mA of current draw).  So it will not last very long,

UNlike other color LEDs (which have forward voltage around 2V), white and blue LEDs will need close to 3V to light up.  That is normal and as you observed, if the 3V battery voltage drops below that value, the LED will go dark.

UNfortunately there is no magic. A tiny battery will only produce small amounts of current. That is why EZ-Peasy lights use much larger button cells. They have 3 in series which gives you 4.5V and since they have larger capacity, they can supply more current for a longer time.

[Lemosteam]

ugh, yes I think it will be a problem, but I'll measure it anyway.  Back to the drawing board!

Any idea what makes it un-rechargeable?  Alkalines can recharge several times with special trickle chargers...

[C855B]

... Any idea what makes it un-rechargeable? ...

The fact that it will likely explode or at least catch on fire.    You don't wanna go there.

Lithium batteries have varying chemistries. Primary cells (single-use, non-rechargeable, like the one you have) use an electrolyte resistant to redepositing the ionic material back on the electrodes. Rechargeable lithium cells use a different electrolyte, and even that has to be handled with kid gloves - the charging current has to be regulated with a feedback charger monitoring the cell temperature. Exceed the surprisingly conservative minimum, and it's flambé time. There's been some press about battery fires in brand-name laptops due to chargers pushing the limits.

Anyway... alkalines... recharging those is more voodoo than science. You can kinda sorta top them off, but the resulting capacity is a tiny fraction of new, and there's the overheat/fire angle with those, too.

[peteski]

Like Mike said, various types of batteries have different chemistry and are specifically designed to be single-use or rechargeable.  Batteries are chemical devices and the internal chemical composition changes depending whether the battery is charged or discharged.  The chemical composition of single use batteries is not designed to be reversed once the battery is spent. Yes, applying electricity can partially reverse the chemical reaction and"charge" the battery, it is a risky proposition and the battery can only be partially "recharged".  I would also head the warnings  Mike mentioned about any type of Lithium based batteries. Single-use Alkaline and Zinc-Carbon batteries aren't as volatile (but can still get hot when someone tries to recharge them.  Like I said, they aren't designed to be rechargable in the first place.