Batteries in series : Mobiles

[Stevie_nottm]

Hiya all...

This is my first post, so do go gentle with me


I have a need for extremely long life from a mobile/cell phone
and am looking at the biggest battery life I can find (currently a
3700mah nokia compabible battery) for a project that needs to
have weeks and weeks of standby time. Could I fashion together
a pair or three of these batteries together to create a monster
battery to last for an incredible time?

If anyone has a better phone & battery combo with more than three
weeks of standby, let me know, my current best research finds
the nokia 5100 series with a 3700mah battery at nearly a 20 days
of standby.....


With thanks!!!

 

[Nigel Goodwin]

To join batteries in parallel you should really use isolating rectifers to prevent current backfeeding into the batteries.

I'm presuming this isn't for a mobile device? (as three batteries would be a bit clumbersome), so have you considered a car battery?. You would probably need to drop the voltage down, but an in-car supply lead would probably do that.

A car battery would make three phone batteries look rather puny :lol:

 

[Stevie_nottm]

Thx for the reply...

As far as size goes, the best way to say it would be 'portable', as it
needs to be reasonably small, so a car battery is a no-go really, either
way, a package that could be strapped together in a not too pretty
fashioned way would suffice.

In my mind, i'd love a really tiny flip phone (an old motorola ??) with
a battery pack about the same size would be perfect. Anything else
small would be good, but battery longevity is my no.1 goal.

 

[McGuinn]

AFAK, all these Nokia batteries have a serial line return for passing battery manufacturer codes and such back to the handset during power-up. Some will not run without receiving the correct manuf codes.
Hence the third pin on the battery module...

 

[zevon8]

You also have to take into account the "self-discharge" factor for these batteries. Where I work we have uP based controllers running equipment in sleep and standby modes, where the batteries are self discharging more than the load of the electronics. In some cases we have had to add small solar panels to float charge the batteries to extend the service life.

While this example is probably beyond your case, I would imagine that you will find you reach a point in AH capacity that does not bring any returns due to self-discharge.

Perhaps one of the smaller camcorder batteries would work?

 

[andy257]

just a pointer,

make sure you are aware of the configuration of the batteries. In your title you wrote "BATTERIES IN SERIES" . As Nigel has pointed out they would need to be wired in PARALLEL if you want a longer life span.

You may already be aware of this but if not i hope it helps

andy