Has anyone ever tried reviving an AIWA PB-3/4/5 lead-acid walkman battery using the "just add distilled water"-technique described in some YouTube videos and elsewhere? I am not asking if it makes sense to do this – I am well aware that there are rechargeable replacements available –, but would simply like to know if the technique works and does lead to a working new battery or not. Many thanks!
I'll just say I was here and no I haven't tried that cuz I don't have any of these kind of batteries. I do have car batteries but I don't do anything but add water to them even if they are low maintenance course. I try to buy batteries that are have the ability to add water to them and then I use a desulfator attached to the battery to keep it fully just non-sulfated and the one I use cuts off the voltage at 12.5 volts so it doesn't run the battery down
Since nobody seems to be interested in doing this, I decided to try it myself. Turns out that you can indeed easily rejuvenate lead-acid gumstick batteries, possibly also from other brands than AIWA. I'm documenting the process here to help others. 1. Check the voltage floor of your battery using a multimeter. Mine stood at 0,7V. 2. Open the metal clamps on top of the battery (next to the contacts) with the blade of a strong cutting knife and bend them back slightly. 3. Remove the entire plastic insert of the battery. Remove the additional plastic cover piece and also remove the paper circle and rubber seal under it. 4. Place the battery in a small container with distilled water until submerged. Keep pressing on the battery until no air bubbles rise to the top anymore. Should take 5 minutes or so. 5. Dry the battery and replace all pieces removed above. 6. Construct yourself a jig to be able to charge the battery from an external bench power supply. I used two surplus multimeter probes and a "helping hand jig" you can buy in an electronics store to hold them in the shape I needed for the battery to fit under them. Put the battery in your jig and turn on the power supply. I used the following charging regime: 20x at 4V, 1A. After one or two cycles you should see the power draw stabilize at 3V, 1A and 3W accordingly. Repeat this about 15-20 times for 5 mins each and 2 minutes cooldown. The battery will get a little warm while doing this. You should see the voltage floor rise more and more until the battery will no longer discharge quickly at 2V after a charge. Voilà. You've rejuvenated an old Walkman battery on the cheap and didn't have to order one of those newfangled ones from China for 10$ or so.
