So let me show my ignorance. We have tools with batteries that are charged by cheap wall chargers. What is different about these other than size and capacity? I read the articles with charge curves, etc., so I guess it's a lot more complicated, but it seems that all that can be handled by a cheap chip coupled with appropriate sensors for voltage and temperature. Is it just a lack of manufacturing demand at this point for some company to bring a developed solution to the marine and rv market?
Difference is that the charger on your power tools or phone is specifically designed to charge those batteries and only those batteries. These cells are also very small, and require minimal charge current, so the cost
appears to be low because volume high.
It's not difficult to build a matched battery & charger as paired units that communicate together. All the tool makers & phone makers have slightly different approaches as to how they do this. Some choose to push the cells closer to the limit (Samsung for example) in favor of run time, but in the end they give up longevity and others are much more conservative and get closer to the cycle life the cell maker intends but the ultimate minutes of run time are often less.
On a boat we are attempting to adapt preexisting lead acid charging sources to LFP, and we have multiple charge sources, wind, solar, hydro, fuel cell, alternator, charger, inverter/charger etc. to deal with. Much, much more difficult to do safely and with the ultimate cycle life.
Many of these sources can not simply be "open circuited" by a BMS when the bank is deemed full because you'll create a voltage transient that can destroy not only the charge source but if the system is not wired properly, as in a dual-bus, then you can also destroy on-board electronics too...
Huge difference between charging a 400Ah - 800Ah LFP bank with multiple sources and charging a 1Ah to 5Ah +/- tool battery that is only ever charged by one specific charger & that charger was designed specifically for that battery.
When you look at the
actual cell cost of the cells in these tool batteries you'll quickly realize that these batteries and chargers are anything but
inexpensive..... Last year I re-built one of my brothers Li power tool batteries. The Li battery sells for $129.00 and had it had less than $14.00 worth of Sanyo 18650 cells in it, and I am not buying these cells direct from Sanyo in container quantities.