help selecting ic for hot swappable battery pack

[kiyoshi]

Hi, I am trying to create a hot swappable 18650 battery pack for a project of mine that should not be turned off and will use two of these packs (one for redundancy). I have never done anything that involves charging and discharging batteries. As I was searching on newark I found two categories, battery charger and manager ic, but i'm not sure of the differences between the two. I am between a MAX1737http://www.farnell.com/datasheets/1917366.pdf or a ISL94202 http://www.farnell.com/datasheets/2256514.pdf. I prefer the ISL94202 because of its power up operation. I have already started drawing the circuit for the MAX1737, but I am unsure of the ICs I found . Are these ICs overkill for a simple project like mine? I plan on making a simple digital circuit to 'select' a pack to use so only one pack is used at a time.

thanks for you time

[m k]

Lithium cells are sort of unstable.
You need to monitor their use also.

[kiyoshi]

thanks, but wouldn't the ISL94203 already take care of that?

[m k]

Yes, but don't overlook the safety issues, even with small cells.
They can get very hot and then be initiators for bigger things.

[kiyoshi]

thanks, I looked more into the datasheet and it has two NTC thermistors. According to the datasheet at 55C it raises a fault bit and disables the battery so it seems to have some thermal protection. I basically got the circuit for the evaluation kit (pg 27, https://www.renesas.com/us/en/document/man/isl94202evkit1z-user-guide?language=en) and altered it slightly. I changed the current sense resistor so at around 8 amps it turns on the Overcurrent protection with the default configuration, lower than what was 'built-in', and I added two polyfuses and split the charge and discharge 'lines'. If something I've changed raises any flags please let me know, thanks.

I attached the kicad documents with the schematic and pcb layout if someone wants it. Though it still isn't tested, which I will with 3 batteries (minimum for the ic)