From what I understand, you also want to include cell-balancing for LiPos into this BMS. Don't you think this makes the whole project overly complex? There are so many dedicated devices for this task and only very few people are using LiPos on a boat or in an off-grid location anyways...BTW, I'm observing your projects for quite a while now. You are really doing a fantastic job, thank you! I'm in an off-grid situation with solar, batteries, an inverter and a 24v generator. A combination of your alternator regulator, bms and possibly also the mppt solar controller would be perfect for me!
All the best from Germany,
Good question, and as I started to type the reply it become obvious I could not keep my thoughts to a few lines. So - the topic of Scope Creep.
All projects have it. There is an old, but perhaps not PC, saying in the Tech industry that at some point in time Marketing needs to come into the lab - gas all the Engineers and take what is setting on the bench; else nothing will every get to market. My original DC generator started out as a simple regulator, expanded to include engine start/stop, then throttle control. And hey, how about a remote panel as well! So, what about this Cell balancing I poke at..
I think one will find we are rather close to a cross-over between traditional FLA batteries and LiFeP04. Much depends on import duties and taxes, as well as if the LiFeP04 cells live up to their projected life expectancy, but given their wider usable range - as well as better charge efficiency, once might find they are very close to a Return On Investment cross over point with FLA.. This is a long way to say; I think we will see more LiFeP04 deployments over the coming years.
But I also think there will continue to be lots of traditional lead-based storage out there as well. Hence my general goal for all these projects: Multi-chemestry, and 12..48v deployments.
But what about the Cell Balancing: There seems to be a bit of dynamics in the LiFeP04 world to simply monitor, or have active balancing. Will take time for that to settle. My idea is to have as an option the ability to either monitor for imbalance, and/or provide for some type of active balancing capability. This could range from simple monitoring using an existing modules such as the: http://www.cleanpowerauto.com/ modules. ( I have shared a few Emails with him.) to doing an full monitor/balance.
My work plan is to settle on a concept for the cell monitoring /balancing, as that will drive what hardware interface is needed in the main module. Then develop the main module (Battery MONITORING module) to work in conjunction with the MPPT controller and a future DC Generator / alternator regulator. Once all that is completed, can go back and add what every approach for the balancing / monitoring. But in any case, it will be an add on option, and it is a 2nd tier work effort. Just need to get a vision of direction today!
(And again Thank you Kia for your questions: Is nice to know some folks are out there)