> Am 18.08.2019 um 16:23 schrieb Andreas Kemnade <andr...@kemnade.info>: > > On Sun, 18 Aug 2019 15:19:22 +0200 > "H. Nikolaus Schaller" <h...@goldelico.com> wrote: > >> Hi, >> >>> Am 17.08.2019 um 20:17 schrieb Andreas Kemnade <andr...@kemnade.info>: >>> >>> Hi, >>> >>> I have these kind of replacement "batteries" for the gta04. >>> >>> https://misc.andi.de1.cc/gta04-batteries-small.jpg >> >> Nice! >> >>> >>> The right one works, but dimensions are not perfect and feels >>> more fragile. The left one worked shortly but then I had no output at >>> the terminals. There seems to be some problem between the gta04-side >>> battery - terminal and the B- test point. >>> >>> A picture of the protection circuit is here. >>> https://misc.andi.de1.cc/prot-circuit-small.jpg >>> >>> As I do not have too much spare protection circuits, do you have >>> any advice what I should take better care of for the next one? >> >> The role is to protect the battery cell and not the device powered >> by it. >> > Well, it is just the best mechanical fitness I have. > >> Well, you can bridge it if you connect an external power supply >> and not a battery which does not survive a short-circuit. >> >>> >>> Furthermore with the right one looking at the display is easier >>> and I could check current consumption. >>> >>> The whole thing is interesting because it would allow me to run >>> git bisect run with a closed gta04a5. Currently I am using the letux3704 >>> for it. >> >> I remember there was a schematics of the HF08 battery (fuel gauge >> and protector) but I did not find it any more. >> >> Here is an application note by TI and I assume that the HF08 >> battery is not very different: >> >> http://www.ti.com/lit/an/slua456/slua456.pdf >> >> Most important is that the current sense shunt resistor and the >> battery protection FETs are in the - side of the battery. So >> if there is a GND connection between the power supply and the >> USB shield this effectively bypasses the protection and the >> shunt resistor. >> > Well, I guess the shunt resistor is low compared to that bypass. > >> Or did I misunderstand the problem and you are looking for better >> mechanical design? There you might use three small screws contacting >> the battery springs of the GTA04. >> > yes, it is about the mechanics. I just want to avoid trashing another > protector pcb. I do not know the reason why that one got > apparently damaged. > The microsd adapter is already better than my screw approach. I > have checked power consumption of wifi in 2.6.32 (which does not have > hdq) using such a screw-based adapter. > >> Yet another idea would be to design a new "protector PCB" which >> only has the three golden battery contacts on one side and some >> solder points on the other. Since they are quite small, they >> are not expensive to be produced by e.g. aisler.net. >> > hmm, the contacts are just thing chemical NiAu? Or is hard gold needed > here?
hard gold just improves mechanical robustness for more plug-in/out cycles. IMHO this is not relevant here - and if the gold ever disappears you can take the next PCB :) BR, Nikolaus _______________________________________________ Gta04-owner mailing list Gta04-owner@goldelico.com http://lists.goldelico.com/mailman/listinfo.cgi/gta04-owner
