Placing a new battery
 

Right now my MP4 has only about, say a 4 hour life span while music is playing. If that. But I have a second gen ipod wannabe. And you cant open it from the sides, and it seems I can only push the inside up and out. Im not sure if Im presenting what im saying correctly, if you dont understand I can draw a diagram. But I was wondering would it be safe to push the inside out to replace the battery and maybe the flash drive?

Here is an ebay pic of the item I have

http://i1.ebayimg.com/05/i/000/8a/a8/37d3_1_b.JPG

Relikk , to open the 2nd gen clones, you'll need to pry up the cover on the top/bottom. There should be a screw that secures the front and back casing hidden below the cover. After unscrewing, the casing should open easily either by sliding or lifting apart.

Re: Placing a new battery
 

Lattesurf , thanks for that. I was observing the mp4 later on and thought that could be it.

Would it be hard to put the tabs back onto the mp4?

Relikk , the cover that are pryed up usually are just stuck on using double sided tape. So removing and replacing back won't be difficult.

Re: Placing a new battery
 

Lattesurf , ok thanks that helps. Would you also happen to know what kind of batterys they use? or does it vary depending on the player. And would this be a safe task? Ive read many people shorted out their players and yatta so my mom is also worried about the player dying on us.

Relikk , with every hardware mod done on a player, there is definitely risks involved.

However, if you're not comfortable with soldering, get a friend good in it to do it for you.

Any typical lithium battery should do the trick. Those ipod replacement batteries on ebay would work fine. Provided you don't overcharge it for too long. As some others damaged their players when it was overcharged.

Re: Placing a new battery
 

Lattesurf , Well good thing I know people comfortable with soldering, I dont have steady hands.

Would you be able to link me to one of those batterys, ive seen many kinds on ebay but im not sure exactly which one it is. And for overcharging, are you talking 7+ hours?

Relikk , actually those on ebay are all about the same. You'll need to open your player and measure the max allowable space for the battery (length x width x thickness). Then find a battery with the same or lesser dimensions, which some sellers lists them in the ad. Typically the ipod shuffle and nano battery would fit.

A higher mAh rating would be better, gives longer playtime.

Regarding the charging issue, it depends on what you use to charge your player. The typical AC adaptor charges at 1A or 1C, whilst USB charges it at 100mA or 0.1C.
So if your battery rating is 250mAh, which means it can deliver full 250mA in 1 hour. The player would be fully charged (from a "flat" battery) in 2.5hours using USB, or 15mins using AC adaptor.
So when over-charging is concerned, it just means not exceeding the 2.5hrs or 15mins by too much.

Re: Placing a new battery
 

So leaving the player charging for 24 hours is a no no? I would of thought that it would go into a trickle charge after it's fully charged? that's not true? What about leaving the charger itself pluged in all the time? no good also? Burn out? toast? all of the above?

gbakakos , for trickle charge, the charge rate should be at 0.1C or 100mA. The USB port should be alright, but not on the AC adaptor. Since the AC adaptor supplies 1A which is 1C, the trickle charge current is too high.

Besides, there are no safety cut off sensors in the AC adaptor. So the adaptor would continue supplying 1A even when the battery has charged fully. This 1A is what causes battery damage when it is over-charged.

These players are cheap goods, so you can't expect sophisticated features like cut-off/temperature sensors in the chargers, as what all brand-name players or rechargeable batteries/chargers have.

So basically, when it's charged full, unplug your player. Trickle charging for extended periods isin't good for the battery either.

Yes, but arent there overcharging IC sensors in the batteries themselves? At least the good ones. I posted a link here (in the OTHER thread on this issue) to an EBay seller that is selling a quality product with overcharging IC's. And if there's still a risk with overcharging ICs, I'm wondering if you can get a brand name charger that will work in charging these players? (It woiuld have to accept a standard usb cable at least)

(Relikk: Check out that eBay link in my other post. Not all lithium batteries are created equal! The battery he is selling uses Japanese cells (but assembled in China no doubt), and not the cheap CHinese cells that have a greater reputation for swelling).

michiganjfrog , in general the cheap replacement batteries don't have much IC protection within it. Even those that do, i guess it would pretty much be at the very minimal.

The Japanese cells you mentioned might be of the higher quality, and probably contains better IC protection to cut the charging current off when full.

It is possible to use brand-name lithium chargers, but not very practical in these players. They don't come cheap, around the range of $70-$150. And you will need to remove the battery to slot into the charger itself, just like charging AA/AAA in wall socket chargers. As these chargers uses temperature sensors in addition to voltage sensors to sense the capacity state of the battery.

But normal charge via AC or USB with the cheap batteries would be fine. Just keep the overcharge time as minimum as possible, and you'll avoid the battery swelling.

Re: Placing a new battery
 

That's not always possible, though. You might start charging, then you have to go out in a rush, youi forget youre charging your player. Next thing you know, you come back, your house has burned down! That may be a bit extreme, but Ive seen the youtube video of what could happen when you overcharge a lithium battery... pretty scary. Its not just chemicals melting keyboards but fire that could catch and spread. So it people are going to use these cheap AC chargers to charge their battery, it is good advice in any case to have a good quality battery and not overcharge it.