[beelz]

I have an ancient Siemens C25 and recently spent weeks trying to find a battery for it. Today succeeded, but the battery (clearly not made by Siemens) is a lithium ion (the original was a NiMH). It's 3.6 volts like the original but 900 mah, the original was 600 mah. The battery says Siemens C2588 and I googled that and it seems to be a variant of the C25 phone. The two phones look identical.

Anyway, the battery fits and the phone works with it. Now I'm wondering, is it okay to charge this battery with the original C25 charger, which was intended to charge a NiMH battery? I tested the charger and it seemed to start charging it, indicator on the display. But I only did it for a few seconds.

I wonder, now, when I try to fully charge it, is this safe? Do you think it might explode or catch fire? I intend to watch it very carefully as it charges. I do notice there are some other Lithium Ion batteries for the C25 on the internet. I am surprised as I thought a battery had to be same type as the original, not just same size with connector in the right place.

[SandStorm]

Your C25 charger is weak to charge that battery.
Try instead to find a charger of a M50 for example. they are more powerful than the C25 original charger.

You can charge it with your charger, thats no problem at all, but it will take longer to charge it, and i'll recommend you to charge with the phone turned off.

Lithium ION batteries have one circuit inside them, to protect the overcharge. In 2-3h hours, your phone will be ready to use.

Also, i think the polarity (+ and -) are the same as the old one. C25 batteries work on several models, like c25, C28, A35, A36, A40

[beelz]

Hmm...I'm also wondering exactly how long to charge this battery initially. The instructions in the manual were for a NiMH battery.

This battery is apparently "new" in that nobody used it before...but seems to have been manufactured 4 years ago if I read the label correctly.

Any tips re charging time? I think the manual says something like charge a new battery 12 hours or something but that would mean I'd have to do it while I sleep...which would make me nervous as I wonder if it could explode/catch fire...

[SandStorm]

The first full 4 or 5 cicles can be from 8h, no need to be more by cicle, we mean full charge and discharge until the phone turn itself off.

[beelz]

Thanks sandstorm, i didn't notice your reply before i posted that addendum...well the point is to save money while I wait for the phone makers to finally come out with a low-end phone that I like, since I can't buy the nice Siemens A31 because of that battery unavailability issue I posted about previously.

I had this really old C25 and decided it might hold me over until that day when Nokia, Motorola, et al stop making stupid trendy fashion phones and make a nice, cheap, functional, low-SAR phone with a decent screen that will please me. So anyway, I don't want to invest money in this ancient phone, would prefer to just use the charger I have. I see from your post that I can do it. Thanks! So what's all this stuff I read in the manuals and on the internet about initially charging a new Li Ion battery for 12 hours?

[beelz]

Thanks again Sandstorm, you mean it's better to charge it 8 hours at first, not just 2 or 3? You think I can sleep okay, not worrying about it exploding or whatever?

What about just charging it until the charge indicator reads "full" ?

I see that MOST of the C25 batteries on the net are now lithium.

[SandStorm]

that 12h are just recommendations since the age of the ni-mh batteries, and that kept until mow.
Then, after that first cycle, to charge until the indicator show full and then, the display goes blank is the best for Li-ION batteries.

[DireWolf]

Also, never mind what the manual says about needing to fully discharge the battery before charging it: that's for Ni-MH batteries. Li-Ion batteries are exactly the opposite: they don't mind at all partial charges and discharges, and can completely die if they're fully drained.

[SandStorm]

So, if your battery meter show only 1 or 2 bars, you can charge it back

C25, one oldie

[beelz]

Thanks again. Charged today 4 hours. No explosion, no fire...battery indicator reads full!

[SandStorm]

But i am smelling something burning...


OMG! My cake still in the oven!

[DireWolf]

What a waste of good cake...