How to make this device think it have a battery? - Page 1
Forum section: electronics / projects

author: Logan
author_rank: Frequent Contributor
timestamp: September 22, 2021, 04:39:08 pm
content: Hi guys.I have a thermal camera that will display a huge warning icon if the battery is low or not original.I disassembled the device and battery, look at the 4 photos.The original cells are 2 in serial, hence the battery middle pin.Anyone have ideas how to cheat the host to think it have an original healthy battery?I tried connect the power source to the "cell+/-" pins, but the battery circuit do not work. Maybe because the absent of middle voltage.Thanks.

author: DC1MC
author_rank: Super Contributor
timestamp: September 22, 2021, 04:44:52 pm
content: - The simplest approach is to get a similar cell and replace the dead one, if it doesn't have a controller that commits sepukkuat a specific number of cycles or voltage, you're done.- Next will be to see if you could identify the battery controller, see what signaling protocol it use and program something like ATiny 8 or similar to pretend it's a charged and happy battery.- Finally the worst is to identify yourself the protocol used with a scope and/or a logic analyzer and do the same "battery emulator".Cheers,DC1MC

author: mariush
author_rank: Super Contributor
timestamp: September 22, 2021, 05:46:49 pm
content: I assume you're asking because you want to power from a DC adapter of some sort?Ideally you'd just replace the two batteries.You could try faking around 4v (a nearly charged full li-ion battery) in the middle with 2 cr2032 followed by 1-2 diodes. Ex 2 CR2032 gives you around 6v..6.5v , a 1n400x diode drops 0.7v so with 2 diodes you'd be down to around 4v and the device will think it's a fully charged cell.Considering it only senses the voltages, the cheap cr2032 batteries would last a long time.

author: DC1MC
author_rank: Super Contributor
timestamp: September 22, 2021, 06:23:48 pm
content: Quote from: mariush on September 22, 2021, 05:46:49 pmIF (big if) the controller is on a simpleton side it may work, newer battery controlers do more testing than checking the voltage (charge rate, charge current, etc.). but is also not too hard or expensive to try and see what is happening.

author: Renate
author_rank: Super Contributor
timestamp: September 23, 2021, 12:07:13 am
content: I've done this sort of thing a lot. Mostly to avoid overcharging, swelling, exploding batteries.A battery connector can have other connections for a thermistor (or more sophisticated temperature measurement), a resistor to indicate what capacity/model battery is connected and sometimes real communication with a BMS.Different device react differently. Some don't mind having no battery. Some notice that current only flows OUT of the battery, but never IN. In that case a stupid device will scratch its head and say, "Hmm, the battery is 4.2V but it never gets any electrons. It must be at 0%"

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 25, 2021, 09:27:53 pm
content: So, what does the original battery look like and what is in it?You have not mentioned that.

author: Logan
author_rank: Frequent Contributor
timestamp: September 30, 2021, 04:43:34 pm
content: Quote from: Doctorandus_P on September 25, 2021, 09:27:53 pmPicture a and b are the PCBs inside original battery, cells are 2s3p per pack.

author: tooki
author_rank: Super Contributor
timestamp: September 30, 2021, 09:26:36 pm
content: Quote from: mariush on September 22, 2021, 05:46:49 pmQuote from: DC1MC on September 22, 2021, 06:23:48 pmGuys, guys, guys… did you not read the original post? They clearly state that the battery icon appears when a non-original battery is used, so clearly it’s not a “simpleton” that only “senses the voltages”. And in the photo, the bq2050 fuel gauge IC is plainly visible.Without a doubt the host communicates with the bq2050, and it’s likely they program something into it at the factory that lets them detect aftermarket batteries, too.

author: Labrat101
author_rank: Unknown
timestamp: September 30, 2021, 09:55:47 pm
content: Without a photo of the original cell .The cell probably has a double casing and there is a chip between one of the poles.I have seen this . The case may have to be cut open or there is a false top were the chipis mounted just under the top behind the vent with a small serial plate that . tells thecontroller if original . Similar idea to printer ink cartridges has a coded implant .A photo of the original cells would help . also the battery will look a little bigger .

author: Logan
author_rank: Frequent Contributor
timestamp: October 01, 2021, 02:03:50 pm
content: Quote from: Labrat101 on September 30, 2021, 09:55:47 pm

author: Labrat101
author_rank: Unknown
timestamp: October 02, 2021, 01:13:12 pm
content: Quote from: Logan on October 01, 2021, 02:03:50 pmIt would Have been nice IF you had Mentioned the the Model of your Thermal camera !!.These are from aCairns Viperbattery pack . These cells are 1250MA paralleled banks & Serial bank would give this power hungry beast about an Hour run time .And they suffer from the bulging .