Saturday, March 26, 2011

Philips SBC HC8545 headphones

I've been using a pair of wireless headphones for some years now and the batteries are pretty much near the end of their life span, so what's the problem?


The problem are the batteries. Philips wants you to use their recharcheable batteries. What happens if you use other batteries? You get a perfomance drop; shorter battery life and an extremely reduced charge rate when placed in the base.
What makes their batteries special? Nothing much really, the only difference is that the batteries have an area near the negative terminal that is not insulated like the rest of the battery.
This terminal simply bypasses the reversed diode (zener? I didn't check) reducing the voltage drop on one of the batteries and I'm pretty sure that on the PCB there is another diode/zener for the other battery (why not just hot glue it like the other one? I didn't bother checking).
Here you can see the "special" terminal that conects to the battery case (anode) to bypass the diode.


This is how the battery interfaces with the contact terminal. Oh, look! A warning label!


And here you can see the complicated solucion to this problem, a pair of wires to permanently bypass the extra circuitry. Of course, this could also be a protection measument if you decide to use non-rechargeable batteries, but as I never place the headphones in the base when I'm using normal batteries because... well they're not rechargeable!
Hope someone finds this usefull! Happy hacking!

13 comments:

Tachikawa said...

Just use Sony Headphone...
(Promoting Sony)
It's a Sony...
Do please visit my blog...
I love your blog...

Kris said...

I really dont see why they have their own batteries. I would assume that they are just 1.2v. A google search shows that no one knows anything about them. The shortened sleeve could be for recharging them. Kinda like the 3rd terminal on most batteries (whatever that terminal is for).

I would think that you could use normal batteries in them. slight voltage change shouldnt damage them. its only .6v more

Servicio tecnico philips en mallorca said...

Really? it is true? i could never understand why companies like that uses the 'apple technique', it is to create own stardards and just annoy the buyers...

Anonymous said...

I have a Sony Earphones with exactly same system. You only need no peel a few of plastic cover on normal recargeable battery.

Juan Perro said...

I dont think that.

Anonymous said...

This has been a fairly common trick for years -- Sony used it in most of their Discmans, numerous FRS radio manufacturers have used it. They do it to keep their devices from trying to charge discharged Alkaline batteries if they're placed into the unit and the unit is plugged into its charger.

The simplest solution is to take a utility knife and simply slice the lower part of the label off of a generic NiCD/NiMH battery, pop it in there and you're good to go!

Anonymous said...

First I want to apologize for my english.

You don't have to do all that tedious work to replace the old batteries.

If you look carefully you should spot the difference between the original philips batteries and an ordinary batteries, this is, part of the lower plastic covering of the phillips batteries is missing.

You just need to remove part of the lower plasctic covering from the new batteries.

I've got a philips headphones with this system for almost 5 years and I changed the batteries 2 o 3 times using the method described before.

brendy. said...

Interesting. I've got a few sets of Varta 15 minute charge batteries, and that uninsulated band is how the charger knows that the batteries are Varta fast charges, not normal batteries.

When you say that the charge time is significantly decreased with third party batteries, is is possible that it is a safety feature to prevent overloading standard batteries?

Anonymous said...

The diode could be a temperature sense used to terminate charge e.g. see wikipedia NiMH page, search for temperature charging method

pc 360 headphones said...

I love Philips headphone because it is durable and it really have a great quality. My headphone is almost five years now and still it rocks.

speakers said...

Cool promotion. I use to have a set of them.

Smith Mosan said...

Hey my friends I tell you some tips about Comfort is very important and your headphones should be noise cancelling so that you can enjoy your film or TV show without distraction.A cushioned ear piece is also very useful because you may appreciate this feature more than anything else after viewing a movie for a few hours.
wireless headphones

Rene de Belgica said...

Thanks a lot! I lost the original batteries and have been trying for a while before looking for a manual and reading about "shortened sleeve batteries" Almost threw it in the garbage bin. Thanks again.