Why 3.8V? If you're using a regular li-ion battery, charge voltage is 4.2V, and charging should be stopped when the current flowing into battery held at 4.2V has dropped to capacity/20 or so (so 50mA for 1000 mAh battery)

yeah you right, i missunderstand somethink sry


... waiting for the pcb´s. Think i will receive tomorow.... hope so

Just now I got the boards. At work, I've quickly solder the battery witht it to charge fully. Today it charge the batterie with 500mA. 100mA is possible, too. But i will take to much time. I think about to integrate a switcher to have a option to change the mA from 100mA to 500mA.

Tonight my Jolla should be half full. Then I load again on to test if the battery is still OK.

After that I do with thoughts like I'm modding my LE TOH for it. Unfortunately I do not have a 3D printer.

I think about to install 3 mini switch
1) change the charging from 100mA to 500mA
2) cut the wire from charger to Batterie
3) cut the wire from batterie to Step-Up Booster

The Step-Up Booster has 1 red LED, the Charger self has 2 (green, red).
maybe I drill three extinguishers to the LEDs can also see from the outside.

but first one after the other

my charge test is done.

Charging the 3200mAh batterie with 500mA take 8h 8min

i use my phone down to 5 or 6%. than i connect the externel batterie + stepup booster... on this moment the batterie has 4.11v

there charge the internel batterie up to 90%. than there stops to charge if the battterie has 2,6/2.7v.

so, a 3200mAh externel batterie charge the internal 2100mAh batterie with hin 85%.

the charging self is middle warm, but the last 5% the charger is lottle bit hot

edit: so you can calculat it

1800mAh = 48% Charging
2000mAh = 53% Charging
2100mAg = 56% Charging
2500mAh = 66% Chatging

Unfortunately, the efficiency is not really good. A 3200 mAh battery for a single and not even fully charge a 2100mAh battery is unfortunately a waste of.
I decide to use a different variant of the external battery.

It will not use the pins to charge the internal battery but rather a change between the two batteries. I'll get to start the week a gold cap capacitor and hope it will work smoothly. I give notice later

this can't be a surprise.

this is a diagram from the pololu website


where they also state that their stepup regulators will operate in 70-90% efficiency. this also goes through the charging regulator on the phone side, which will also not be 100% efficient.

yeah my hope was that he can charge 100% the batterie (2100mAh) but he dont do that. 1785mAh.

this is why i change my plan. 8h charge for 1 day more working. i think its better to work with a switcher to change fast the batterie.
Hope that a gold cap capacitor 5,5v 220mF will help with switching a batterie without to reboot/shutdown the phone. the switch will take only 0,25/0,5 second.

Than we have biiiig power

?

you are designing your own step up regulator?

a small update... no any time for it.... i know its shocking








EDIT:
at moment is it 16mm thin

nooooooooooooo

why did you cut up that 'first one' cover?!?! :O