Hi there N900 fans!

Today I found a battery originaly from nokia c6-00, to be more accurate the BL-4J.

Im using my nokia a lot lately out of home with no possibilty to charge so Im in need of spare batteries, so here comes the question:
Can I use the mentioned battery for n900? The size is the same, so the voltage as the original BL-5J (3.7V) but there are few specifications differences like below:

The original N900 battery:
1320mAh and 4.9Wh
But the battery I want to use as a spare one have:
1200mAh and 4.4Wh

I did a quick check, n900 boots up and working just fine, but will this not kill my nokia if I use it for loner usage?

In my opinion the BL-4J battery have just less capacity, but Im not a specialist so I rather ask, than fry my device.

Thanks in advance!

You should be fine.

i even got a BL-4ct handy that is chewed last in trips just need to put some folded paper at the bottom though

its specifation are
860 mah
3.7 volts
3.2 wh

my main batrey is belief premium 1500 mah

yeah, that i good to hear, I really need more power source

I will ask, are you sure that is really 1500mAh? I had an "ANDIDA" battery avaiable in poland that was meant to have 1600mAh but 3 years old original nokia battery was lasting longer

Apart from the shape of the battery, only Volt value must be identical ; Amper is equal to the capability of energy storage. More the amper value is high, longest the battery will keep without to be reloaded. Watts is function of Volt * Amper ; And Watts-Hour = https://en.wikipedia.org/wiki/Kilowatt_hour. N900 batteries must be genuine to be recognized by the BMS circuit of the phone.
https://wiki.maemo.org/Batteries

The (popular) Nokia Lumia 520 use a BL-5J too but with 1500mA.
And it's easy to get one.
I don't know much about he voltage though.

sure it is 1500 mah so better uptimes