LithFire-X, LLC (dba LithSafe) has developed our patented methodology; 'SCIC': suppression through cooling, isolation and containment. We have developed methods for the safe testing transport and storage of lithium ion technologies.
I've designed a few boards that use LiPoly batteries with the Microchip MCP73833 charger chip. It seems to work well in singles, but I haven't been brave enough to run a few in series for some 12V motors.
My first thought was to have an MCP73833 for each LiPoly cell. The Vin sides would be in parallel and the Vout sides would be in series. However, as soon as I drew that out in my head, it became clear that it would end up all explody due to the common ground on one side and non-common round on the other.
I need to switch the whole system between parallel and series, grounds included. I could certainly do it with some relays or multi-pole switches, but automatic would be cool.
It's been on the back burner for a while, but I've got some pretty good small 12V motors that I want to use. The search for a non-explosive solution is back on.
I will be designing a charger for a series stack of LiFeO4, to reach a high voltage. I plan to make individual, Isolated chargers for each sub-pack. This is for my regular day job. However, I will share my general approach, so you all can have some fun.
Duane -- the LiFePo4 Batteries are used in Power Tools for Motor Drive (Will take more abuse than Li-Poly Battery) -- Something to think about for a mobile robotics device -- also they will take about 350C heat rather than 100-150C heat(failure point for LI-Poly)
Check out the ams AS8506C autonomous balancer: passive or active mode up to 7 cells. Integrated w/ temp sensor +2 temp sensor inputs, all necessary analog functions & switches built in. No error prone code or micro needed. Only 3 resistors needed: one for discharge 2 for high and low thresholds. Balancing & Monitoring now simplified in the real analog world.
What are the engineering and design challenges in creating successful IoT devices? These devices are usually small, resource-constrained electronics designed to sense, collect, send, and/or interpret data. Some of the devices need to be smart enough to act upon data in real time, 24/7. Specifically the guests will discuss sensors, security, and lessons from IoT deployments.