Rejuvenating batteries

[msknight]

Hi Folks,

I'm a beginner with electronics and repair, but I'm attempting a project, one aspect of which is above my abilities.

The subject at hand is a portable cassette deck. Actually, at the beginning of December I didn't have any and now I've got four. It's a long story... they usually are with me.

But... they need gumstick batteries which are sealed lead acids. Presumably gel. I've read about restoration techniques for car batteries - https://www.elektormagazine.com/magazine/elektor-200109/17100 - de-sulphation they call the process ... something about feeding a 300hz pulse to reverse the chemical changes that have happened. Someone described the process as, "sketchy at best," but I've got to try.

However, like I said, I'm a beginner and I don't know how to construct a circuit that would do the job. And even then, I'll be doing it outside with some neutralisation agent to hand !!! Just in case, you know.

Can anyone lend a hand please?

[soubitos]

If THESE batteries are dead, have very low or no voltage and dont charge forget about them... anything you might try to "save"them is not only potentially VERY dangerous but to the best of my knowledge a waste of time.....


If you need to restore the decks and bring them to life in their original vintage state, ebay and the like might be your only chance (http://www.ebay.co.uk/itm/NOS-Aiwa-Sealed-Lead-Acid-Battery-PB-3-2V-470mAh-/371202098329 one of the first to pop out)


Otherwise, you can also replace them with lithium batteries (you will need a board like my TP4056FLEXADV)

[tautech]

Like soubitos says, the age of these batteries would most likely make them a waste of time to attempt to rejuvenate them. I've done a good amount of LA battery desulphation and you need to pick your battles to get much success.

Instead I'd be looking hard at alternative power sources for your cassette deck. How many batteries does it need to run ? How much physical space have we got to shoehorn another battery system into ?

[soubitos]

Quote from: tautech on Today at 11:17:50 AM

Like soubitos says, the age of these batteries would most likely make them a waste of time to attempt to rejuvenate them. I've done a good amount of LA battery desulphation and you need to pick your battles to get much success.

Instead I'd be looking hard at alternative power sources for your cassette deck. How many batteries does it need to run ? How much physical space have we got to shoehorn another battery system into ?

The size of the batteries, if i am correct is

66.04mm x 17.78mm x 5.08mm
Lithium batteries should work fine if they fit... 18650 are 65mmx18mmx18mm, they might snug in but they would protrude a lot... doing some searching, i found this one http://www.all-battery.com/polymerli-ionbattery37v300mah461540-1.aspx which is not expensive considering and i think would both fit perfectly and would offer a great lightweight alternative>All you need besides the battery is a proper charger and you are set..

[soubitos]

There are (??) also NiMH alternatives like this one https://picclick.com/New-Battery-Replacement-for-Aiwa-AM-HX50-AM-HX55-AM-HX70-160565746342.html

[msknight]

Thanks for the ideas folks.

These have all come from Ebay, but not NOS. I'll give Lighthouse USA a line, see if they do replacements for the 3, and I also need to rejuvenate some 4 as well. All 2v.

The other option is to remove the insides and use the cases to house other cells.

I'd at least like to try and get these running, though. If I can find one or two among the 8 that I've got, then they should be worth trying to resurrect, surely.

[tautech]

I'm guessing you need 3 for a nominal 6V supply, right ?

For desulphating 2 V cells you'd need to start from scratch and design a 2 V desulphator, no real hardship if you have the gear and time. Essentially they just zap the pates with several times the nominal voltage and a few amps.
Some make them as standalone and powered from another source but ones I made were powered from the battery itself and typically ran @ 1KHz.

But if you want this player to give any decent service I'd be changing the batteries to something readily available using one of the lithium technologies that will give better power density and lower weight.

[msknight]

Actually, it only needs one. I got extras from ebay because I knew the chances were  low of finding one that worked, but there was at least a chance.

I wouldn't know where to start in designing something of this nature, that's why I'm here.

I also found Lighthouse USA on Ebay and dropped them a note with what I need help with. I'm not sure they'll be able to help, but if you don't ask....

[PA4TIM]

I have build a desulfator (they are for lead accid batteries) and had it connected it about a year 24/7 to a battery in my lab. After a year it was still as dead as a Dodo.
It can work but only under certain conditions to increase the life of a battery. But once the battery is desulfated to much  it is over. my experiments: http://www.pa4tim.nl/?p=3538
Batteries are very complex because it is chemical and electrical and there are many types.

I had some "succes" on nimh and nicd by zapping it with a high current. see: http://www.pa4tim.nl/?p=5749
 Sometimes a few seconds with reversed polarirty to a lab supply works. But they are often just short time solutions and battery performance is not great.
It has to do with crystal grow/size.

http://batteryuniversity.com/  this is a very good site with very reliable information.

[msknight]

Thanks very much for this information. All good stuff.

My problem with this particular walkman unit, is that there is an external battery compartment for AAA batteries, but it is hard to source... and the external transformer connects through that external compartment... so without that compartment, I'm totally reliant on getting these cells to work.

So I've got nothing to loose except maybe a minor explosion....

[soubitos]

Quote from: msknight on Today at 01:33:50 PM

Thanks very much for this information. All good stuff.

My problem with this particular walkman unit, is that there is an external battery compartment for AAA batteries, but it is hard to source... and the external transformer connects through that external compartment... so without that compartment, I'm totally reliant on getting these cells to work.

So I've got nothing to loose except maybe a minor explosion....

Again... if you want to use these and not restoring them to their original state as vintage/collectible items, your best chance is to replace them with new technology... You mention an external AAA battery compartment though.. ok... where does it hook to the main unit? Can you post a photo of the connector?

If it is not something completely extraordinary you can use ANY type of power source as long as its correct voltage and can cover ampere drain.. you can make your own external power pack and please please forget anything explosive, Lead Acid explosion means horrible trauma.....

[coromonadalix]

well if you have a battery to spare,   dismantle it slowly and securely, remove the insides and try to solder 2 flexible wires and power up you unit that way to test it, i remember theses batteries ....

Bad souvenirs,  the secret was to always maintain them charged ...   pb1 pb3 pb5 proprietary cells,  but Aiwa made incredible Walkman at the time ...  always hated any companies who used special cells, i totally avoid them if possible ...

There's a few on Ebay  not sure if they are good, its an old technology ...

good luck

[msknight]

The PB-3 sits inside the unit. The AAA module is built to screw on the outside. I believe there is circuitry inside the AAA module to drop the current to 2V before it reaches the PCB, but I don't know as the walkman on the right is a P505 and the units don't cross over.

[jolshefsky]

Another option would be to 3D print a replacement enclosure then put a rechargeable lithium pack and a voltage-matching circuit inside. I'm assuming you should be able to charge it from the unit, but a microUSB at one end of the stick and an off-the-shelf charger would probably be easier.

[msknight]

I don't have a 3D printer, nor the knowledge on how to design/use them. Good suggestion though. If I can get a suitable lithium pack that would fit, that would be a start. Where can I source one from please?

[msknight]

Looks like once you get it out of the metal surround, that the battery itself has a nice case with a plastic film cover. Might just be the ideal holder for a new battery itself :-) - All I need to do is work out how to neutralise whatever's in there and dispose of properly.

Internal dimensions appear to be 58,, x 14mm x 6mm

[soubitos]

Quote from: msknight on Today at 04:34:35 PM

I don't have a 3D printer, nor the knowledge on how to design/use them. Good suggestion though. If I can get a suitable lithium pack that would fit, that would be a start. Where can I source one from please?

Check a few messages above.. suitable lithium polymer cell, i dont think you can find other sizes to suit you unless you order customs cells which cost ... a lot....

[msknight]

One of the other things I could do, in order to do bench testing, is install a USB input that would drop 5v to 2v. The question is, doing it safely in that kind of space. Nothing on Google comes up with 2v step down, however.

I'll keep searching.

[soubitos]

You can use anything from the clasic LM317 up to MC34063, there are literally hundreds of voltage regulators for the task....

[Armadillo]

Such old technology operate down to 2V??? Cannot be!   

Use a 2 cells lithium, the voltage will be just nice, don't need to step down or anything.

There is a external cradle for the battery, you can modify it to suit the 2 cells lithium.

[msknight]

"2 cells lithium" sounds like military terminology!  "These, Private, are not Drawers, cellular, pairs one!"

So where do I get these 2 cells lithium please? - Bear in mind that I'm still trying to find a course in basic electronics!

[Armadillo]

"2 cells lithium" sounds like military terminology!  "These, Private, are not Drawers, cellular, pairs one!"

So where do I get these 2 cells lithium please? - Bear in mind that I'm still trying to find a course in basic electronics!

Or use 2 nano tech wired in series to form 2S.
If you fly heli or drones, you will know all the batteries.
Size 50.8 x 13 x 8mm

[msknight]

Hmmm... 2 mill too high... so very nearly... but I'm going to contact Nano tech though. Thanks for the heads up!

[Armadillo]

Don't just simply trust anything you read on the web.
Normally teased the logical side of the mind and sounded "too" promising and waste human lifetime.

So here is the Lead Acid Battery Rejuvenator I built long time ago. Promise to break down sulfate that adhered to the electrodes.
There are Burst Rings of high voltage you can see on the oscilloscope. First ring burst as high as 70Vdc.
But after 1 day of rejuvenating, the battery is "SAME".   

So, if you put your "dead" battery onto adjustable lab voltage power supply, slowly increase from 2 volts up up up while observing any appreciable increase in charging current flow until you reach 50vdc stop. If no appreciable increase in current flow or no current flow at all, the battery is "DEAD" "DEAD" and don't waste your time as others have pointed up already. Otherwise "maybe" still can be saved.

Now the rejuvenator just sit there taking up my storage space.   


 

[kalel]

I'm not sure how I would go about the same thing (I have already learned some terms here - but I am still a complete beginner), but if you have a higher voltage source, and want to step it down to e.g. 2v, you don't necessarily need to build any circuit. You could buy a cheap circuit from eBay.

Just search for adjustable step down module (they are also known as buck - voltage step up would be known as boost). These types of modules should allow you to set any output voltage desired with a screwdriver (for the miniature ones).

Charging is another matter. If you have a battery pack with a plug, say those made for RC planes/copters as recommended above you could possibly solder a compatible plug (same as the charger would have) to the input of a step down (and the output would be connected to the device battery input). Then when the battery is empty, take the battery out, plug it into the charger to charge... and plug it back into the module once full (in case the buck output voltage depends on the input/battery voltage, I would also configure the output voltage on the step down module when the battery is completely full, so that it couldn't output too high voltage at any point).

I am not sure how to reuse the battery case. I would check some YouTube videos of the disassembly process first to see what to expect, but it's surely easier and safer (while maybe less aesthetically pleasing) to avoid using the original case if at all possible.